
==== Front
Sports Med Open
Sports Med Open
Sports Medicine - Open
2199-1170
2198-9761
Springer International Publishing Cham

39227485
759
10.1186/s40798-024-00759-9
Current Opinion
The Discrepancy Between External and Internal Load/Intensity during Blood Flow Restriction Exercise: Understanding Blood Flow Restriction Pressure as Modulating Factor
http://orcid.org/0000-0002-0731-1640
Bielitzki Robert robert.bielitzki@ovgu.de

1
Behrens Martin 2
Behrendt Tom 1
Franz Alexander 3
Centner Christoph 4
Hughes Luke 5
Patterson Stephen D. 6
Owens Johnny 7
Behringer Michael 8
Schega Lutz 1
1 https://ror.org/00ggpsq73 grid.5807.a 0000 0001 1018 4307 Department of Sport Science, Institute III, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
2 grid.410722.2 0000 0001 0198 6180 University of Applied Sciences for Sport and Management Potsdam, Potsdam, Germany
3 https://ror.org/01xnwqx93 grid.15090.3d 0000 0000 8786 803X Department of Orthopedics and Trauma Surgery, University Hospital Bonn, Bonn, Germany
4 https://ror.org/0245cg223 grid.5963.9 0000 0004 0491 7203 Department of Sport and Science, University of Freiburg, Freiburg, Germany
5 https://ror.org/049e6bc10 grid.42629.3b 0000 0001 2196 5555 Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, UK
6 grid.417907.c 0000 0004 5903 394X Faculty of Sport, Technology and Health Science, St Mary’s University, Twickenham, London, UK
7 Clinical Education Owens Recovery Science, San Antonio, TX USA
8 https://ror.org/04cvxnb49 grid.7839.5 0000 0004 1936 9721 Department of Sports Sciences, Goethe University Frankfurt, Frankfurt a. M., Germany
4 9 2024
4 9 2024
12 2024
10 9519 3 2024
29 7 2024
© The Author(s) 2024
2024
https://creativecommons.org/licenses/by/4.0/ Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Physical exercise induces acute psychophysiological responses leading to chronic adaptations when the exercise stimulus is applied repeatedly, at sufficient time periods, and with appropriate magnitude. To maximize long-term training adaptations, it is crucial to control and manipulate the external load and the resulting psychophysiological strain. Therefore, scientists have developed a theoretical framework that distinguishes between the physical work performed during exercise (i.e., external load/intensity) and indicators of the body's psychophysiological response (i.e., internal load/intensity). However, the application of blood flow restriction (BFR) during exercise with low external loads/intensities (e.g., ≤ 30% of the one-repetition-maximum, ≤ 50% of maximum oxygen uptake) can induce physiological and perceptual responses, which are commonly associated with high external loads/intensities. This current opinion aimed to emphasize the mismatch between external and internal load/intensity when BFR is applied during exercise. In this regard, there is evidence that BFR can be used to manipulate both external load/intensity (by reducing total work when exercise is performed to exhaustion) and internal load/intensity (by leading to higher physiological and perceptual responses compared to exercise performed with the same external load/intensity without BFR). Furthermore, it is proposed to consider BFR as an additional exercise determinant, given that the amount of BFR pressure can determine not only the internal but also external load/intensity. Finally, terminological recommendations for the use of the proposed terms in the scientific context and for practitioners are given, which should be considered when designing, reporting, discussing, and presenting BFR studies, exercise, and/or training programs.

Key Points

The application of BFR during exercise with low external load/intensity can lead to internal responses that are commonly associated with high external load/intensity resulting in a discrepancy between the characteristics of exercise and the acute psychophysiological responses.

The BFR pressure can be adjusted to increase the internal load/intensity (i.e., elevating physiological and perceptual responses) to intensify the exercise stimulus or to decrease the external load/intensity (e.g., reducing the number of repetitions when exercise is performed to exhaustion), which is of particular importance during musculoskeletal rehabilitation when high or cumulative low mechanical stress might be contraindicated.

We encourage researchers to adapt their wording in the BFR literature accordingly, given that the extent of internal load/intensity during BFR exercise is determined by the interaction of several external exercise variables (e.g., external resistance, number of repetitions/cycles, cuff pressure) to specify the generated exercise stimulus (e.g., “low external load BFR walking”, “low external load BFR resistance exercise”).

Keywords

Vascular occlusion
Metabolic stress
Muscle pain
Effort perception
Stimulus
Terminology
Otto-von-Guericke-Universität Magdeburg (3121)Open Access funding enabled and organized by Projekt DEAL.

issue-copyright-statement© Springer Nature Switzerland AG 2024
==== Body
pmcIntroduction

Over the last two decades, blood flow restriction (BFR) training has increasingly been used to improve performance across different populations (e.g., elite athletes [1], healthy active elderly [2], and patients during musculoskeletal rehabilitation [3]). In this regard, BFR has been applied during several exercise modalities such as resistance [4], endurance [5], balance [6], or whole-body vibration exercise [7]. To achieve a target restriction pressure, usually a pneumatic tourniquet cuff is applied to the proximal part of the limb to partially restrict and completely occlude arterial inflow and venous return of the blood, respectively [8]. It is known that the degree of restriction of arterial and venous blood flow induced by the applied cuff depends on various moderator variables including individual characteristics (e.g., blood pressure, arm circumference [9]), and cuff properties (e.g., width [10], stiffness [11]). To account for these moderator variables, the target pressure is commonly determined as a percentage of the arterial occlusion pressure (AOP; also referred to as limb occlusion pressure), which is defined as the lowest pressure that is required to occlude arterial inflow to the limb [12]. The external pressure generated by the BFR cuff promotes blood pooling, which induces a local hypoxic environment distal to the restriction [13]. It is assumed that the hypoxia-induced shift towards a greater proportion of anaerobic metabolism and the reduced removal of metabolites from the muscle produced during exercise leads to an increased metabolic stress and performance decline (i.e., motor performance fatigue [14]) compared to the same exercise without BFR [15]. When applying BFR, it is recommended to use 20–40% of the one-repetition-maximum (1RM) and < 50% of peak oxygen uptake (V˙O2 peak) or heart rate reserve for resistance and aerobic exercise, respectively [16]. In this regard, the terms low-load BFR exercise [17–19] or low-intensity BFR exercise [20, 21] are frequently used in the literature. However, the external load/intensity is characterized by the exercise characteristics (e.g., external resistance, repetition scheme, volitional muscle failure), while the internal load/intensity (i.e., psychophysiological responses) is mirrored by multiple variables including heart rate or rate of perceived exertion (RPE) [22–24]. In this context, the application of BFR during low load/intensity exercise and its mode of action can lead to psychophysiological responses that are typically not associated with low but moderate or even high external load/intensity exercise. Therefore, the aim of this opinion article is (i) to elaborate on the interaction between external and internal load/intensity moderated by the level of BFR and its relevance for researchers and practitioners as well as (ii) to discuss the potential of BFR as an additional variable to manipulate external and internal load/intensity when designing exercise and training programs [25].

Defining External and Internal Load/Intensity

Physical activity and/or exercise (e.g., running, cycling, swimming) triggers acute psychophysiological responses and can lead to chronic adaptations when the exercise stimulus is applied repetitively, at sufficient time periods, and with appropriate magnitude [23, 26]. To maximize long-term training adaptations, it is crucial to control and manipulate the stress applied to the exercising individual and the resulting psychophysiological strain. Therefore, scientists have developed theoretical frameworks that distinguish between the physical work performed during exercise (i.e., external load/intensity) as well as indicators of the body’s psychophysiological reactions and the strain experienced by specific tissues (i.e., internal load/intensity) in response to the applied external training load/intensity [22–24, 27]. The terminology ‘external and internal training load’ was recently criticized from a biomechanical perspective pointing out that load is a mechanical variable, which describes forces [28–30]. However, it was subsequently argued that mechanics do not have the monopoly on the term ‘load’ or other common terms like ‘stress’ and ‘fatigue’. Consequently, ‘training load’ must be considered a label representing a higher order construct with subdimensions (i.e., referred to as external and internal load from this point) that provides a framework to support the research and practical field [31]. The distinction between external and internal load allows for a better understanding of the training process and the associated exercise-related adaptations (Table 1). The external load is determined by the characteristics of exercise (i.e., physical work performed during exercise) and the measures to quantify the external load depend on the exercise modality (e.g., endurance and resistance exercise) and/or sport (e.g., team sports). For instance, during endurance exercise, the external load is determined, e.g., by the velocity, power output or total work, exercise duration, distance covered, and rest intervals. Similar metrics are used to quantify the external load in team sports (e.g., velocity, distance covered, accelerations), while the external resistance, time under tension, number of repetitions per set, number of sets, and rest intervals are often used to describe the external load during resistance exercise [23, 29, 32, 33]. To cope with the external load, acute and individual psychophysiological responses are initiated that depend on the exercise modality (e.g., endurance or resistance exercise) and specific contextual factors (e.g. personal and environmental factors) [23, 34]. Therefore, exercise-specific variables are used to describe the internal load. For instance, heart rate (HR) is often used to characterize the internal load during endurance exercise, although this marker is often not a suitable internal load measure for resistance exercise [23]. Besides physiological markers, perceptual responses during exercise (e.g., RPE or effort perception, exercise-induced muscle pain perception) can be used to characterize the internal load during several exercise modalities [33–36]. Given that the psychophysiological responses are strongly determined by the characteristics of the performed exercise [14], the respective internal load markers scale with the applied external load measures. Nevertheless, due to modifiable and non-modifiable personal factors (e.g., nutrition, training status, health, psychological status, genetics) that affect the extent of the individual psychophysiological response to exercise, the same external load (e.g., same running velocity) generates interindividual differences in internal load markers (e.g., HR, RPE). Moreover, modifiable personal factors (e.g., nutrition, training status) and environmental conditions (e.g., heat [37], local and systemic hypoxia [38]) can change, leading to different psychophysiological responses to the identical exercise stimulus in the same individual. Given that the interplay of the characteristics of the exercise, the contextual factors, and the resulting acute response to the exercise determine chronic adaptations and, thus, the training outcome, it is recommended to use internal load markers in conjunction with external load measures to monitor and control the training process [23, 39–42]. In addition, specific contextual factors should also be considered, especially if the training method used implies a deliberate change in one or more of these factors (e.g., hypoxia [43] or heat conditioning [44]).

In contrast to the general observation that performing exercise with higher external loads (e.g. 70% 1RM) [45] or until exhaustion [46] results in an increased internal load, similar high psychophysiological responses are also present when exercising with low external loads (e.g., 30% 1RM) combined with BFR. For instance, studies have found a similar RPE [47, 48] and discomfort [49, 50] for resistance exercise at ≤ 30% 1RM with BFR (65–75 repetitions) and resistance exercise at ≥ 70% 1RM without BFR (30–40 repetitions). Moreover, when BFR is applied during specific exercise modalities (e.g., repeated cycling sprints or resistance exercise performed to exhaustion) not only the internal but also the external load can be manipulated due to an accelerated motor performance fatigue development and the subsequent reduction in external load measures (i.e., power output [25], number of repetitions [51]). Therefore, an adequate exercise and training prescription should primarily focus on the internal load, while also considering external load and relevant contextual factors (i.e., modifiable and non-modifiable personal factors and environmental conditions) [27, 34].

Table 1 Definition and exercise-dependent measures of external and internal load as well as contextual factors during blood flow restriction (BFR) exercise

	External load	Internal load	Contextual factors	
Definition	Physical work performed during exercise	Acute psychophysiological responses	Modifiable and non-modifiable determinants	
Characteristics and measures	Resistance

e.g., external resistance, time under tension, number of repetitions per set, number of sets, rest intervals

	Resistance

e.g., effort perception, exercise-induced muscle pain perception

	Personal factors

e.g., training status, age, sex

Environmental factors

e.g., climatic and geographic conditions

BFR-related factors

e.g., cuff pressure1, type of application2

	
Endurance

e.g., velocity, power output or total work, exercise duration, distance covered, rest intervals

	Endurance

e.g., heart rate, blood lactate concentration, effort perception, exercise-induced muscle pain perception

	
Team sports

e.g., velocity, distance covered, accelerations

	Team sports

e.g., heart rate, blood lactate concentration, effort perception, exercise-induced muscle pain perception

	
1percentage arterial occlusion pressure

2continuous or intermittent (i.e., no BFR during rest or exercise)

The Discrepancy Between Internal and External Load during Blood Flow Restriction Exercise

Internal load Measures in Response to Exercise with Low External Load Combined with and without Blood Flow Restriction

When combining BFR with exercise using low external loads, the psychophysiological responses representing the internal load can increase compared to exercise without BFR (Fig. 1A). Therefore, the relationship between exercise (e.g., slow to fast running or cycling) and the intensity categories (i.e., light, moderate, vigorous, high [52]) does not apply for BFR exercise resulting in a potential discrepancy between external and internal load measures. A recent meta-analysis [46] revealed that when performing resistance exercise with identical external load at ≤ 30% 1RM, participants’ perceptual responses (e.g., effort and exercise-induced muscle pain/discomfort perception) were higher with BFR than without BFR. For instance, Miller et al. [50] reported higher RPE and muscle discomfort during leg press and knee extension exercise at 30% 1RM with BFR (50% AOP) compared to the same exercise (i.e., identical external load) without BFR. Similar results were found by Mok et al. [53] revealing higher leg discomfort during 5 walking intervals of 2 min at 5 km·h−1 with BFR (200 mmHg) compared to walking alone.

The different perceptual responses can be explained by accompanying physiological changes associated with BFR exercise. For example, given that exercise-induced muscle pain or discomfort perception is triggered by the stimulation of nociceptive group III and IV muscle afferents, venous blood pooling (induced by the external cuff pressure during BFR) might lead to venous expansion, which has been shown to stimulate group IV afferents in an animal study [54]. Moreover, nociceptive muscle afferents seem to be sensitive to high amounts of metabolites [55], which are associated with BFR exercise due to an increased anaerobic metabolism and impaired metabolite removal. In this regard, invasive catheter examinations by Franz et al. [56] have revealed that BFR (50% AOP) induced elevated venous blood lactate concentration (BLC) and increased metabolites (i.e., K+, Ca2+, Na+) leading to metabolic acidosis (i.e., lower arterial and venous pH) during 4 sets (75 repetitions) of unilateral biceps curls at 30% 1RM compared to the same exercising without BFR. Moreover, studies have shown, for instance, higher deoxyhemoglobin concentration as a proxy of metabolic stress during 4 sets (75 repetitions) of isometric knee extensions at 20% MVC [57], as well as increased muscle thickness as a marker for hydration-mediated cell swelling during 4 sets (75 repetitions) of unilateral leg press at 30% 1RM [58] performed with BFR compared to the same exercise without BFR. In this context, Kilgas et al. [59] found higher changes in BLC and quadriceps muscle deoxyhemoglobin concentration accompanied by higher exercise-induced muscle pain ratings during 6 cycling intervals of 2 min at 40% V˙O2 peak when using BFR (60% and 80% AOP) compared to exercising at the same external load without BFR.

The higher RPE or effort perception during BFR resistance [50] and endurance exercise [60] might be related to the loss of contractile function induced by the greater metabolic disturbance [61, 62] due to impaired removal of accumulated metabolites leading to decrements in Ca2+-sensitivity and/or release from the sarcoplasmic reticulum [63]. Based on the corollary discharge model discussed by Pageaux [64], the central motor command increases as a compensatory mechanism to counteract the loss of contractile function due to greater metabolic stress. The higher descending neural drive to the muscle (i.e., increase in muscle activity) is required to maintain the muscle forces needed for exercise continuation [35, 65, 66] resulting in a higher effort perception. In this context, Husmann et al. [35] showed that the application of BFR (60% AOP) induced higher ratings of effort perception accompanied by greater muscle activity in the vastus medialis and lateralis muscles during knee extension exercise at 30% 1RM compared to without BFR. These results are supported by Cai et al. [67] who found higher rectus femoris and vastus lateralis muscle activity as well as higher RPE averaged over 10 sets of whole-body vibration exercise in a squat position with BFR (140 mmHg) compared to identical exercise alone.

External Load Measures in Response to Exercise with and without Blood Flow Restriction Performed to Exhaustion

Furthermore, studies have shown a lower external load (i.e., lower number of repetitions) and similar perceptual responses during BFR compared to without BFR when the exercise was performed to exhaustion [68, 69] (Fig. 1B). In this regard, Kolind et al. [70] found that participants who performed one set of unilateral knee extensions at 20% 1RM with BFR (100 mmHg) achieved 43% fewer repetitions with higher exercise-induced muscle pain perception. However, although the number of repetitions was lower in the BFR condition, similar changes in muscle oxygenation and muscle activity of vastus medialis and lateralis were found at the respective percentage of time to exhaustion [70]. Comparable to Kolind et al. [70], Behringer et al. [71] found that BFR (AO−20 mmHg) reduced the number of repetitions during four sets of unilateral eccentric knee extensions at 75% 1RM, while inducing similar internal responses (e.g., peak BLC, insulin-like growth factor 1, creatine-kinase, muscle pain). Furthermore, Buckner et al. [72] also observed a reduced number of repetitions to exhaustion during 4 sets of unilateral elbow flexions at 15% 1RM with BFR (80% AOP) compared to without BFR. Therefore, the additional application of BFR during exercise performed to exhaustion can reduce repetitions and time to exhaustion and thus the external load, while eliciting similar levels of internal responses (e.g., blood pooling, muscle oxygenation, and muscle activity at the same percentage of exercise time) [70]. Furthermore, BFR was also shown to reduce the external load during maximal motor tasks meaning that multiple studies have revealed a reduced number of total sprints during repeated-sprint exercise to exhaustion [73–75]. This phenomenon might be explained by the accelerated motor performance fatigue development [14] induced by BFR, which was shown by Husmann et al. [35] who found a larger decline in maximal voluntary torque in the BFR (60% AOP) compared to non-BFR condition after each set during 4 sets (75 repetitions) of knee extensions at 30% 1RM. In addition, Behrendt et al. [38] found that BFR (40% AOP) led to a greater decline in mean and peak power output during 6 × 10 s repeated cycling sprints compared to the same exercise without BFR. The lower external load during each training session consequently results in a reduced external training load during an intervention period, as shown by Pignanelli et al. [76]. The authors found a reduction in external load (i.e., training volume) of ~ 33% during a 6-week BFR training period (60–70% AOP) using single-leg squats at 30% 1RM to volitional failure. Interestingly, despite a lower training volume, similar increases in muscle strength and size were found. This is of particular importance for musculoskeletal rehabilitation during which gains in muscle strength and size are desired but a high or cumulative low mechanical stress might be contraindicated [77].

Fig. 1 Schematic illustration of the influence of blood flow restriction (BFR) on example parameters of internal and external load during several exercise modalities with (A) matched external load and (B) to exhaustion. The numbers on the individual parameters refer to the articles’ reference list

Understanding Blood Flow Restriction Pressure as a Determinant to Modulate Internal and External Load

The current BFR literature describes the cuff pressure for resistance and endurance exercise to be sufficient and beneficial between 40 and 80% AOP [16]. Accordingly, the level of cuff pressure is a critical variable to manipulate the psychophysiological responses to BFR exercise [78–80]. For instance, Ilett et al. [57] investigated the physiological responses during 4 sets of isometric knee extensions (32 repetitions) at 80% MVC (i.e., high external load) and 4 sets (75 repetitions) at 20% MVC (i.e., low external load) combined with BFR at 80%, 60%, and 40% AOP as well as without BFR. The authors found similar BLC levels for high external load exercise without BFR and low external load exercise combined with BFR at 80% AOP as well as for low external load exercise combined with BFR at 40% AOP and without BFR. In addition, Hughes et al. [81] found a similar RPE during 4 sets of unilateral leg press exercise (75 repetitions) at 30% 1RM combined with 40% AOP, but a higher RPE when combined with 80% AOP, compared with 3 sets (30 repetitions) at 70% 1RM. In another study by Hughes et al. [82], muscle discomfort was found to be higher during 20 min of aerobic cycling at 40% V˙O2 peak with BFR at 80% AOP compared to 40% AOP. Furthermore, Loenneke et al. [48] found higher ratings of discomfort at 60% AOP compared with 40% AOP during 4 sets (75 repetitions) of bilateral knee extensions at 20% 1RM combined with BFR. The perceptual differences might be related to the higher mechanical pressure on the blood vessels leading to a greater extent of metabolic disturbances (e.g., higher deoxyhemoglobin concentration, increased venous blood pooling and expansion, greater metabolite accumulation) finally causing, for instance, higher muscle pain ratings due to greater activation of group III and IV afferent fibers [55]. This assumption is supported by the results of Bielitzki et al. [6], who revealed that effort perception, exercise-induced leg muscle pain perception, and myoelectrical activity of the quadriceps muscle (recorded via surface electromyography) were higher, while muscle oxygen saturation in the vastus lateralis muscle was lower during the last set of a static BFR balance exercise with 80% AOP compared to 40% AOP. These findings are similar to those by Ilett et al. [57], who revealed that BLC, HR, and muscle activity were higher, while muscle oxygen saturation was lower, when applying BFR at 80% AOP compared to 40% AOP during 4 sets (75 repetitions) of rhythmic isometric knee extensions at 20% MVC. Therefore, it can be assumed that physiological and perceptual responses during exercise with low external load combined with BFR depend, among others, on the applied cuff pressure [6, 57, 59, 81, 82].

Regarding the manipulation of external load, a recent meta-analysis by Cerqueira et al. [83] revealed that high cuff pressures are required to reduce the time to exhaustion and, thus, the external load. Therefore, the cuff pressure seems not only to modulate the internal load during volume-matched exercise but also the external load, when exercises are performed to exhaustion. For example, Jessee et al. [84] revealed lower repetitions to volitional failure during 4 sets of unilateral knee extensions at 15% 1RM with BFR at 80% AOP (mean: 73 repetitions) compared to 40% AOP (mean: 114 repetitions), while rectus femoris and vastus lateralis muscle activity in each set were similar between pressures. Comparable findings were revealed by Buckner et al. [72] during 4 sets (performed to exhaustion) of elbow flexion at 15% 1RM with BFR at 80% AOP and 40% AOP.

Of note, a recent study by Jacobs et al. [85] found that pneumatic tourniquet systems with autoregulation (i.e., cuff pressure adapts automatically to changes in limb circumference during exercise) have led to lower RPE and discomfort during 4 sets (75 repetitions) as well as a lower number of repetitions per set during 4 sets (to exhaustion) of unilateral knee extension at 20% 1RM with 60% AOP compared a non-autoregulated system. Therefore, cuff type (e.g., single- vs. multi-chambered bladder) and type of tourniquet system (e.g., non-auto- vs. autoregulated) might additionally influence the internal and external load [86].

In summary, current evidence indicates that the amount of relative cuff pressure (i.e., %AOP) can be used to manipulate physiological and perceptual responses during resistance [48, 79, 81], endurance [82], and balance exercise [6] as well as neuromuscular electrical stimulation [87] when the external load is kept constant (Fig. 2). The amount of BFR pressure is of particular importance especially when only very low external loads with a fixed number of repetitions are applied (e.g., ≤ 20% 1RM [78, 80], static balance exercise [6]). This might be relevant for individuals that are only able to tolerate very low external loads (e.g., during musculoskeletal rehabilitation). Therefore, practitioners (e.g., physicians and therapists) should be aware of the BFR pressure as an additional variable to manipulate psychophysiological responses during exercise. On the one hand, by elevating the cuff pressure, the stimulus during exercise can potentially be intensified by increasing physiological responses (e.g., BLC, deoxygenation, muscle activity) as well as reducing the cumulative external load (e.g., number of repetitions) when exercising to exhaustion. On the other hand, if participants or patients are less tolerant to pain (i.e., exercise-induced muscle pain, cuff pressure-induced discomfort), the BFR pressure can be decreased to lower the local hypoxic stimulus and support metabolite removal in order to lower perception of effort and pain. Since it has been found that perceptual responses to exercise are significant predictors of future physical activity behavior [88], reducing the applied BFR pressure might ensure exercise adherence. However, as with other forms of exercise, chronic exposure to BFR may attenuate perceptions of effort and pain thus reducing internal load and creating a window to increase external load [89].Fig. 2 Illustration of a conceptual framework of exercise with blood flow restriction. The external load is determined by a variety of exercise parameters, which also dictate the psychophysiological responses, and therefore, the internal load. The internal load in response to a specific external load depends on a multitude of influencing factors (i.e., environmental and personal factors). The level of relative cuff pressure, along with other variables, represents a modifiable environmental factor to manipulate the internal load. Relative cuff pressures between 40 and 80% of the individuals’ arterial occlusion pressure are assumed to induce favorable long-term adaptations

Conclusion

The additional application of BFR during exercise can, on the one hand, increase the internal load (i.e., physiological and perceptual responses to exercise) when the external load (i.e., physical work performed during exercise) is similar. On the other hand, applying BFR during specific exercise modalities (e.g., resistance exercise to exhaustion or repeated sprint exercise) can reduce the external load (i.e., number of repetitions, power output) by accelerating motor performance fatigue development without substantially different psychophysiological responses (i.e., internal load). Of note, there are several other aspects that influence internal and external loads during BFR exercise (e.g., continuous vs. intermittent BFR [90, 91]). Furthermore, the amount of cuff pressure applied during exercise can be used to manipulate internal and external loads to maximize long-term training adaptations and adherence.

Recommendations for Scientists

This opinion aimed to encourage scientists in the field of BFR research to use the established terminology external and internal load [23, 25] to describe the characteristics of the applied exercise protocol and the associated psychophysiological changes. Adopting this terminology may allow a more precise classification of the measured outcomes and a better understanding of the interactions between external and internal loads during BFR exercise mediated by the level of cuff pressure. Given that the interaction of several external exercise parameters (e.g., external resistance, number of repetitions/cycles, cuff pressure) determine the extent of internal load during BFR exercise, researchers are encouraged to specify the wording in their articles accordingly to clarify whether the external or internal load was low or high in their BFR studies. For instance, resistance exercise at ≤ 30% 1RM combined with BFR can lead to high perceptual responses (i.e., high internal load) and might benefit from a specification in wording by using the description “low external load BFR resistance exercise” instead of “low load BFR resistance exercise”. The integration of the terms external and/or internal load in the wording can be a helpful addition for the readers to instantly get a clearer view on the exercise characteristics and/or the psychophysiological response.

Recommendations for Practitioners

Practitioners should be aware of the differentiation between external as well as internal load and should consider the BFR pressure as an additional exercise variable when designing exercise and training programs (also with regard to the used cuff type and tourniquet system). The exercise/training stimulus can potentially be increased by elevating the cuff pressure. Furthermore, reducing the cuff pressure lowers effort and exercise-induced muscle pain perception, which is of particular importance for participants or patients with pain intolerance to increase exercise adherence. In addition, the external load (e.g., number of repetitions during exercise) can be reduced by adding high BFR pressures [83], while inducing similar internal responses. This could be of particular importance during musculoskeletal rehabilitation, when high as well as cumulative low mechanical loads may be contraindicated.

Abbreviations

1RM One-repetition-maximum

AOP Arterial occlusion pressure

BLC Blood lactate concentration

BFR Blood flow restriction

HR Heart rate

MVC Maximal voluntary contraction

RPE Rate of perceived exertion

V˙O2 Oxygen uptake

Acknowledgements

Not applicable.

Author Contributions

R.B., M.B., and T.B. substantially contributed to the conception and design of the work and wrote the first draft. A.F., C.C., L.H., S.D.P., J.O., M.B., and L.S. revised it critically for important intellectual content. All authors have read and approved the final version of the manuscript and agreed to be accountable for all aspects of the work.

Funding

Open Access funding enabled and organized by Projekt DEAL.

Availability of Data and Materials

Not applicable.

Declarations

Ethics Approval and Consent to Participate

Not applicable.

Consent for Publication

Not applicable.

Competing interests

Robert Bielitzki, Martin Behrens, Tom Behrendt, Alexander Franz, Christoph Centner, Luke Hughes, Stephen D. Patterson, Johnny Owens, Michael Behringer, and Lutz Schega declare that they have no conflicts of interest relevant to the content of this opinion article.

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Robert Bielitzki and Martin Behrens shared first authorship.
==== Refs
References

1. Held S Behringer M Donath L Low intensity rowing with blood flow restriction over 5 weeks increases V̇O2max in elite rowers: a randomized controlled trial J Sci Med Sport 2020 23 304 308 10.1016/j.jsams.2019.10.002 31672481
Held S, Behringer M, Donath L. Low intensity rowing with blood flow restriction over 5 weeks increases V̇O2max in elite rowers: a randomized controlled trial. J Sci Med Sport. 2020;23:304–8. 10.1016/j.jsams.2019.10.002.31672481 10.1016/j.jsams.2019.10.002
2. Patterson SD Ferguson RA Enhancing strength and postocclusive calf blood flow in older people with training with blood-flow restriction J Aging Phys Act 2011 19 201 213 10.1123/japa.19.3.201 21727301
Patterson SD, Ferguson RA. Enhancing strength and postocclusive calf blood flow in older people with training with blood-flow restriction. J Aging Phys Act. 2011;19:201–13. 10.1123/japa.19.3.201.21727301 10.1123/japa.19.3.201
3. Hughes L Rosenblatt B Haddad F Gissane C McCarthy D Clarke T Comparing the effectiveness of blood flow restriction and traditional heavy load resistance training in the post-surgery rehabilitation of anterior cruciate ligament reconstruction patients: a UK National Health Service randomised controlled trial Sports Med 2019 49 1787 1805 10.1007/s40279-019-01137-2 31301034
Hughes L, Rosenblatt B, Haddad F, Gissane C, McCarthy D, Clarke T, et al. Comparing the effectiveness of blood flow restriction and traditional heavy load resistance training in the post-surgery rehabilitation of anterior cruciate ligament reconstruction patients: a UK National Health Service randomised controlled trial. Sports Med. 2019;49:1787–805. 10.1007/s40279-019-01137-2.31301034 10.1007/s40279-019-01137-2
4. Gray SM Cuomo AM Proppe CE Traylor MK Hill EC Keller JL Effects of sex and cuff pressure on physiological responses during blood flow restriction resistance exercise in young adults Med Sci Sports Exerc 2023 55 920 931 10.1249/MSS.0000000000003103 36729632
Gray SM, Cuomo AM, Proppe CE, Traylor MK, Hill EC, Keller JL. Effects of sex and cuff pressure on physiological responses during blood flow restriction resistance exercise in young adults. Med Sci Sports Exerc. 2023;55:920–31. 10.1249/MSS.0000000000003103.36729632 10.1249/MSS.0000000000003103
5. Thomas HJ Scott BR Peiffer JJ Acute physiological responses to low-intensity blood flow restriction cycling J Sci Med Sport 2018 21 969 974 10.1016/j.jsams.2018.01.013 29650336
Thomas HJ, Scott BR, Peiffer JJ. Acute physiological responses to low-intensity blood flow restriction cycling. J Sci Med Sport. 2018;21:969–74. 10.1016/j.jsams.2018.01.013.29650336 10.1016/j.jsams.2018.01.013
6. Bielitzki R Behrendt T Weinreich A Mittlmeier T Schega L Behrens M Acute effects of static balance exercise combined with different levels of blood flow restriction on motor performance fatigue as well as physiological and perceptual responses in young healthy males and females Eur J Appl Physiol 2023 10.1007/s00421-023-05258-5 37429967
Bielitzki R, Behrendt T, Weinreich A, Mittlmeier T, Schega L, Behrens M. Acute effects of static balance exercise combined with different levels of blood flow restriction on motor performance fatigue as well as physiological and perceptual responses in young healthy males and females. Eur J Appl Physiol. 2023. 10.1007/s00421-023-05258-5.37429967 10.1007/s00421-023-05258-5
7. Centner C Ritzmann R Schur S Gollhofer A König D Blood flow restriction increases myoelectric activity and metabolic accumulation during whole-body vibration Eur J Appl Physiol 2019 119 1439 1449 10.1007/s00421-019-04134-5 30949807
Centner C, Ritzmann R, Schur S, Gollhofer A, König D. Blood flow restriction increases myoelectric activity and metabolic accumulation during whole-body vibration. Eur J Appl Physiol. 2019;119:1439–49. 10.1007/s00421-019-04134-5.30949807 10.1007/s00421-019-04134-5
8. Mattocks KT Jessee MB Mouser JG Dankel SJ Buckner SL Bell ZW The application of blood flow restriction: lessons from the laboratory Curr Sports Med Rep 2018 17 129 134 10.1249/JSR.0000000000000473 29629973
Mattocks KT, Jessee MB, Mouser JG, Dankel SJ, Buckner SL, Bell ZW, et al. The application of blood flow restriction: lessons from the laboratory. Curr Sports Med Rep. 2018;17:129–34. 10.1249/JSR.0000000000000473.29629973 10.1249/JSR.0000000000000473
9. Loenneke JP Allen KM Mouser JG Thiebaud RS Kim D Abe T Bemben MG Blood flow restriction in the upper and lower limbs is predicted by limb circumference and systolic blood pressure Eur J Appl Physiol 2015 115 397 405 10.1007/s00421-014-3030-7 25338316
Loenneke JP, Allen KM, Mouser JG, Thiebaud RS, Kim D, Abe T, Bemben MG. Blood flow restriction in the upper and lower limbs is predicted by limb circumference and systolic blood pressure. Eur J Appl Physiol. 2015;115:397–405. 10.1007/s00421-014-3030-7.25338316 10.1007/s00421-014-3030-7
10. Mouser JG Dankel SJ Jessee MB Mattocks KT Buckner SL Counts BR Loenneke JP A tale of three cuffs: the hemodynamics of blood flow restriction Eur J Appl Physiol 2017 117 1493 1499 10.1007/s00421-017-3644-7 28501908
Mouser JG, Dankel SJ, Jessee MB, Mattocks KT, Buckner SL, Counts BR, Loenneke JP. A tale of three cuffs: the hemodynamics of blood flow restriction. Eur J Appl Physiol. 2017;117:1493–9. 10.1007/s00421-017-3644-7.28501908 10.1007/s00421-017-3644-7
11. Bielitzki R Behrendt T Nguyen T Behrens M Malczewski V Franz A Schega L Influence of cuff stiffness on hemodynamics and perceived cuff pressure in the upper extremities in males and females: implications for practical blood flow restriction training BMC Sports Sci Med Rehabil 2023 15 134 10.1186/s13102-023-00745-w 37858237
Bielitzki R, Behrendt T, Nguyen T, Behrens M, Malczewski V, Franz A, Schega L. Influence of cuff stiffness on hemodynamics and perceived cuff pressure in the upper extremities in males and females: implications for practical blood flow restriction training. BMC Sports Sci Med Rehabil. 2023;15:134. 10.1186/s13102-023-00745-w.37858237 10.1186/s13102-023-00745-w
12. Zeng Z Centner C Gollhofer A König D Blood-flow-restriction training: validity of pulse oximetry to assess arterial occlusion pressure Int J Sports Physiol Perform 2019 14 1408 1414 10.1123/ijspp.2019-0043 30958065
Zeng Z, Centner C, Gollhofer A, König D. Blood-flow-restriction training: validity of pulse oximetry to assess arterial occlusion pressure. Int J Sports Physiol Perform. 2019;14:1408–14. 10.1123/ijspp.2019-0043.30958065 10.1123/ijspp.2019-0043
13. Pearson SJ, Hussain SR. A review on the mechanisms of blood-flow restriction resistance training-induced muscle hypertrophy. Sports Med. 2015;45:187–200. 10.1007/s40279-014-0264-9.
14. Behrens M Gube M Chaabene H Prieske O Zenon A Broscheid K-C Fatigue and human performance: an updated framework Sports Med 2023 53 7 31 10.1007/s40279-022-01748-2 36258141
Behrens M, Gube M, Chaabene H, Prieske O, Zenon A, Broscheid K-C, et al. Fatigue and human performance: an updated framework. Sports Med. 2023;53:7–31. 10.1007/s40279-022-01748-2.36258141 10.1007/s40279-022-01748-2
15. Karabulut M Cramer JT Abe T Sato Y Bemben MG Neuromuscular fatigue following low-intensity dynamic exercise with externally applied vascular restriction J Electromyogr Kinesiol 2010 20 440 447 10.1016/j.jelekin.2009.06.005 19640732
Karabulut M, Cramer JT, Abe T, Sato Y, Bemben MG. Neuromuscular fatigue following low-intensity dynamic exercise with externally applied vascular restriction. J Electromyogr Kinesiol. 2010;20:440–7. 10.1016/j.jelekin.2009.06.005.19640732 10.1016/j.jelekin.2009.06.005
16. Patterson SD Hughes L Warmington S Burr J Scott BR Owens J Blood flow restriction exercise: considerations of methodology, application, and safety Front Physiol 2019 10 533 10.3389/fphys.2019.00533 31156448
Patterson SD, Hughes L, Warmington S, Burr J, Scott BR, Owens J, et al. Blood flow restriction exercise: considerations of methodology, application, and safety. Front Physiol. 2019;10:533. 10.3389/fphys.2019.00533.31156448 10.3389/fphys.2019.00533
17. Centner C Lauber B Seynnes OR Jerger S Sohnius T Gollhofer A König D Low-load blood flow restriction training induces similar morphological and mechanical Achilles tendon adaptations compared with high-load resistance training J Appl Physiol 1985 2019 127 1660 1667 10.1152/japplphysiol.00602.2019
Centner C, Lauber B, Seynnes OR, Jerger S, Sohnius T, Gollhofer A, König D. Low-load blood flow restriction training induces similar morphological and mechanical Achilles tendon adaptations compared with high-load resistance training. J Appl Physiol. 1985;2019(127):1660–7. 10.1152/japplphysiol.00602.2019.10.1152/japplphysiol.00602.2019
18. Cook SB Scott BR Hayes KL Murphy BG Neuromuscular adaptations to low-load blood flow restricted resistance training J Sports Sci Med 2018 17 66 73 29535579
Cook SB, Scott BR, Hayes KL, Murphy BG. Neuromuscular adaptations to low-load blood flow restricted resistance training. J Sports Sci Med. 2018;17:66–73.29535579
19. Mendonca GV Borges A Teodósio C Matos P Correia J Vila-Chã C Muscle fatigue in response to low-load blood flow-restricted elbow-flexion exercise: are there any sex differences? Eur J Appl Physiol 2018 118 2089 2096 10.1007/s00421-018-3940-x 30006670
Mendonca GV, Borges A, Teodósio C, Matos P, Correia J, Vila-Chã C, et al. Muscle fatigue in response to low-load blood flow-restricted elbow-flexion exercise: are there any sex differences? Eur J Appl Physiol. 2018;118:2089–96. 10.1007/s00421-018-3940-x.30006670 10.1007/s00421-018-3940-x
20. Hill EC Housh TJ Keller JL Smith CM Schmidt RJ Johnson GO Early phase adaptations in muscle strength and hypertrophy as a result of low-intensity blood flow restriction resistance training Eur J Appl Physiol 2018 118 1831 1843 10.1007/s00421-018-3918-8 29934764
Hill EC, Housh TJ, Keller JL, Smith CM, Schmidt RJ, Johnson GO. Early phase adaptations in muscle strength and hypertrophy as a result of low-intensity blood flow restriction resistance training. Eur J Appl Physiol. 2018;118:1831–43. 10.1007/s00421-018-3918-8.29934764 10.1007/s00421-018-3918-8
21. Yasuda T Ogasawara R Sakamaki M Ozaki H Sato Y Abe T Combined effects of low-intensity blood flow restriction training and high-intensity resistance training on muscle strength and size Eur J Appl Physiol 2011 111 2525 2533 10.1007/s00421-011-1873-8 21360203
Yasuda T, Ogasawara R, Sakamaki M, Ozaki H, Sato Y, Abe T. Combined effects of low-intensity blood flow restriction training and high-intensity resistance training on muscle strength and size. Eur J Appl Physiol. 2011;111:2525–33. 10.1007/s00421-011-1873-8.21360203 10.1007/s00421-011-1873-8
22. Oliveira R Brito JP Moreno-Villanueva A Nalha M Rico-González M Clemente FM Reference values for external and internal training intensity monitoring in young male soccer players: a systematic review Healthcare 2021 10.3390/healthcare9111567 34946434
Oliveira R, Brito JP, Moreno-Villanueva A, Nalha M, Rico-González M, Clemente FM. Reference values for external and internal training intensity monitoring in young male soccer players: a systematic review. Healthcare. 2021. 10.3390/healthcare9111567.34946434 10.3390/healthcare9111567
23. Impellizzeri FM Marcora SM Coutts AJ Internal and external training load: 15 years on Int J Sports Physiol Perform 2019 14 270 273 10.1123/ijspp.2018-0935 30614348
Impellizzeri FM, Marcora SM, Coutts AJ. Internal and external training load: 15 years on. Int J Sports Physiol Perform. 2019;14:270–3. 10.1123/ijspp.2018-0935.30614348 10.1123/ijspp.2018-0935
24. McLaren SJ Macpherson TW Coutts AJ Hurst C Spears IR Weston M The relationships between internal and external measures of training load and intensity in team sports: a meta-analysis Sports Med 2018 48 641 658 10.1007/s40279-017-0830-z 29288436
McLaren SJ, Macpherson TW, Coutts AJ, Hurst C, Spears IR, Weston M. The relationships between internal and external measures of training load and intensity in team sports: a meta-analysis. Sports Med. 2018;48:641–58. 10.1007/s40279-017-0830-z.29288436 10.1007/s40279-017-0830-z
25. Mckee JR Girard O Peiffer JJ Scott BR Manipulating internal and external loads during repeated cycling sprints: a comparison of continuous and intermittent blood flow restriction J Strength Cond Res 2024 38 47 54 10.1519/JSC.0000000000004594 37889856
Mckee JR, Girard O, Peiffer JJ, Scott BR. Manipulating internal and external loads during repeated cycling sprints: a comparison of continuous and intermittent blood flow restriction. J Strength Cond Res. 2024;38:47–54. 10.1519/JSC.0000000000004594.37889856 10.1519/JSC.0000000000004594
26. Booth FW Thomason DB Molecular and cellular adaptation of muscle in response to exercise: perspectives of various models Physiol Rev 1991 71 541 585 10.1152/physrev.1991.71.2.541 2006222
Booth FW, Thomason DB. Molecular and cellular adaptation of muscle in response to exercise: perspectives of various models. Physiol Rev. 1991;71:541–85. 10.1152/physrev.1991.71.2.541.2006222 10.1152/physrev.1991.71.2.541
27. Jeffries AC Marcora SM Coutts AJ Wallace L McCall A Impellizzeri FM Development of a revised conceptual framework of physical training for use in research and practice Sports Med 2022 52 709 724 10.1007/s40279-021-01551-5 34519982
Jeffries AC, Marcora SM, Coutts AJ, Wallace L, McCall A, Impellizzeri FM. Development of a revised conceptual framework of physical training for use in research and practice. Sports Med. 2022;52:709–24. 10.1007/s40279-021-01551-5.34519982 10.1007/s40279-021-01551-5
28. Staunton CA Abt G Weaving D Wundersitz DWT Misuse of the term 'load' in sport and exercise science J Sci Med Sport 2022 25 439 444 10.1016/j.jsams.2021.08.013 34489176
Staunton CA, Abt G, Weaving D, Wundersitz DWT. Misuse of the term “load” in sport and exercise science. J Sci Med Sport. 2022;25:439–44. 10.1016/j.jsams.2021.08.013.34489176 10.1016/j.jsams.2021.08.013
29. Ide B Silvatti A Staunton C Marocolo M Oranchuk D Mota G External and internal loads in sports science: time to rethink? Int J Strength Cond 2023 10.47206/ijsc.v3i1.234
Ide B, Silvatti A, Staunton C, Marocolo M, Oranchuk D, Mota G. External and internal loads in sports science: time to rethink? Int J Strength Cond. 2023. 10.47206/ijsc.v3i1.234.10.47206/ijsc.v3i1.234
30. Ide BN Silvatti AP Marocolo M Oranchuk DJ Mota GR The misuse of “workload” in sports science and possible solutions Strength Cond J 2023 45 364 366 10.1519/SSC.0000000000000750
Ide BN, Silvatti AP, Marocolo M, Oranchuk DJ, Mota GR. The misuse of “workload” in sports science and possible solutions. Strength Cond J. 2023;45:364–6. 10.1519/SSC.0000000000000750.10.1519/SSC.0000000000000750
31. Impellizzeri FM Jeffries AC Weisman A Coutts AJ McCall A McLaren SJ Kalkhoven J The 'training load' construct: why it is appropriate and scientific J Sci Med Sport 2022 25 445 448 10.1016/j.jsams.2021.10.013 35523475
Impellizzeri FM, Jeffries AC, Weisman A, Coutts AJ, McCall A, McLaren SJ, Kalkhoven J. The “training load” construct: why it is appropriate and scientific. J Sci Med Sport. 2022;25:445–8. 10.1016/j.jsams.2021.10.013.35523475 10.1016/j.jsams.2021.10.013
32. Osgnach C Poser S Bernardini R Rinaldo R Di Prampero PE Energy cost and metabolic power in elite soccer: a new match analysis approach Med Sci Sports Exerc 2010 42 170 178 10.1249/MSS.0b013e3181ae5cfd 20010116
Osgnach C, Poser S, Bernardini R, Rinaldo R, Di Prampero PE. Energy cost and metabolic power in elite soccer: a new match analysis approach. Med Sci Sports Exerc. 2010;42:170–8. 10.1249/MSS.0b013e3181ae5cfd.20010116 10.1249/MSS.0b013e3181ae5cfd
33. Scott BR Duthie GM Thornton HR Dascombe BJ Training monitoring for resistance exercise: theory and applications Sports Med 2016 46 687 698 10.1007/s40279-015-0454-0 26780346
Scott BR, Duthie GM, Thornton HR, Dascombe BJ. Training monitoring for resistance exercise: theory and applications. Sports Med. 2016;46:687–98. 10.1007/s40279-015-0454-0.26780346 10.1007/s40279-015-0454-0
34. Gronwald T Törpel A Herold F Budde H Perspective of dose and response for individualized physical exercise and training prescription J Funct Morphol Kinesiol 2020 10.3390/jfmk5030048 33467264
Gronwald T, Törpel A, Herold F, Budde H. Perspective of dose and response for individualized physical exercise and training prescription. J Funct Morphol Kinesiol. 2020. 10.3390/jfmk5030048.33467264 10.3390/jfmk5030048
35. Husmann F Mittlmeier T Bruhn S Zschorlich V Behrens M Impact of blood flow restriction exercise on muscle fatigue development and recovery Med Sci Sports Exerc 2018 50 436 446 10.1249/MSS.0000000000001475 29112627
Husmann F, Mittlmeier T, Bruhn S, Zschorlich V, Behrens M. Impact of blood flow restriction exercise on muscle fatigue development and recovery. Med Sci Sports Exerc. 2018;50:436–46. 10.1249/MSS.0000000000001475.29112627 10.1249/MSS.0000000000001475
36. Behrens M Mau-Moeller A Wassermann F Plewka A Bader R Bruhn S Repetitive jumping and sprinting until exhaustion alters hamstring reflex responses and tibial translation in males and females J Orthop Res 2015 33 1687 1692 10.1002/jor.22935 25941064
Behrens M, Mau-Moeller A, Wassermann F, Plewka A, Bader R, Bruhn S. Repetitive jumping and sprinting until exhaustion alters hamstring reflex responses and tibial translation in males and females. J Orthop Res. 2015;33:1687–92. 10.1002/jor.22935.25941064 10.1002/jor.22935
37. Racinais S Périard JD Karlsen A Nybo L Effect of heat and heat acclimatization on cycling time trial performance and pacing Med Sci Sports Exerc 2015 47 601 606 10.1249/MSS.0000000000000428 24977692
Racinais S, Périard JD, Karlsen A, Nybo L. Effect of heat and heat acclimatization on cycling time trial performance and pacing. Med Sci Sports Exerc. 2015;47:601–6. 10.1249/MSS.0000000000000428.24977692 10.1249/MSS.0000000000000428
38. Behrendt T Bielitzki R Behrens M Schega L Acute performance, physiological, and perceptual changes in response to repeated cycling sprint exercise combined with systemic and local hypoxia in young males Physiol Behav 2023 267 114217 10.1016/j.physbeh.2023.114217 37127074
Behrendt T, Bielitzki R, Behrens M, Schega L. Acute performance, physiological, and perceptual changes in response to repeated cycling sprint exercise combined with systemic and local hypoxia in young males. Physiol Behav. 2023;267: 114217. 10.1016/j.physbeh.2023.114217.37127074 10.1016/j.physbeh.2023.114217
39. Mann TN Lamberts RP Lambert MI High responders and low responders: factors associated with individual variation in response to standardized training Sports Med 2014 44 1113 1124 10.1007/s40279-014-0197-3 24807838
Mann TN, Lamberts RP, Lambert MI. High responders and low responders: factors associated with individual variation in response to standardized training. Sports Med. 2014;44:1113–24. 10.1007/s40279-014-0197-3.24807838 10.1007/s40279-014-0197-3
40. Smith DJ A framework for understanding the training process leading to elite performance Sports Med 2003 33 1103 1126 10.2165/00007256-200333150-00003 14719980
Smith DJ. A framework for understanding the training process leading to elite performance. Sports Med. 2003;33:1103–26. 10.2165/00007256-200333150-00003.14719980 10.2165/00007256-200333150-00003
41. Vellers HL Kleeberger SR Lightfoot JT Inter-individual variation in adaptations to endurance and resistance exercise training: genetic approaches towards understanding a complex phenotype Mamm Genome 2018 29 48 62 10.1007/s00335-017-9732-5 29356897
Vellers HL, Kleeberger SR, Lightfoot JT. Inter-individual variation in adaptations to endurance and resistance exercise training: genetic approaches towards understanding a complex phenotype. Mamm Genome. 2018;29:48–62. 10.1007/s00335-017-9732-5.29356897 10.1007/s00335-017-9732-5
42. Bouchard C Rankinen T Timmons JA Genomics and genetics in the biology of adaptation to exercise Compr Physiol 2011 1 1603 1648 10.1002/cphy.c100059 23733655
Bouchard C, Rankinen T, Timmons JA. Genomics and genetics in the biology of adaptation to exercise. Compr Physiol. 2011;1:1603–48. 10.1002/cphy.c100059.23733655 10.1002/cphy.c100059
43. Millet GP Roels B Schmitt L Woorons X Richalet JP Combining hypoxic methods for peak performance Sports Med 2010 40 1 25 10.2165/11317920-000000000-00000 20020784
Millet GP, Roels B, Schmitt L, Woorons X, Richalet JP. Combining hypoxic methods for peak performance. Sports Med. 2010;40:1–25. 10.2165/11317920-000000000-00000.20020784 10.2165/11317920-000000000-00000
44. Périard JD Racinais S Sawka MN Adaptations and mechanisms of human heat acclimation: applications for competitive athletes and sports Scand J Med Sci Sports 2015 25 Suppl 1 20 38 10.1111/sms.12408 25943654
Périard JD, Racinais S, Sawka MN. Adaptations and mechanisms of human heat acclimation: applications for competitive athletes and sports. Scand J Med Sci Sports. 2015;25(Suppl 1):20–38. 10.1111/sms.12408.25943654 10.1111/sms.12408
45. Hughes L Patterson SD Haddad F Rosenblatt B Gissane C McCarthy D Examination of the comfort and pain experienced with blood flow restriction training during post-surgery rehabilitation of anterior cruciate ligament reconstruction patients: a UK National Health Service trial Phys Ther Sport 2019 39 90 98 10.1016/j.ptsp.2019.06.014 31288213
Hughes L, Patterson SD, Haddad F, Rosenblatt B, Gissane C, McCarthy D, et al. Examination of the comfort and pain experienced with blood flow restriction training during post-surgery rehabilitation of anterior cruciate ligament reconstruction patients: a UK National Health Service trial. Phys Ther Sport. 2019;39:90–8. 10.1016/j.ptsp.2019.06.014.31288213 10.1016/j.ptsp.2019.06.014
46. de Queiros VS Rolnick N Dos Santos ÍK de França IM Lima RJ Vieira JG Acute effect of resistance training with blood flow restriction on perceptual responses: a systematic review and meta-analysis Sports Health 2023 15 673 688 10.1177/19417381221131533 36415041
de Queiros VS, Rolnick N, Dos Santos ÍK, de França IM, Lima RJ, Vieira JG, et al. Acute effect of resistance training with blood flow restriction on perceptual responses: a systematic review and meta-analysis. Sports Health. 2023;15:673–88. 10.1177/19417381221131533.36415041 10.1177/19417381221131533
47. Scott BR Peiffer JJ Thomas HJ Marston KJ Hill KD Hemodynamic responses to low-load blood flow restriction and unrestricted high-load resistance exercise in older women Front Physiol 2018 9 1324 10.3389/fphys.2018.01324 30327609
Scott BR, Peiffer JJ, Thomas HJ, Marston KJ, Hill KD. Hemodynamic responses to low-load blood flow restriction and unrestricted high-load resistance exercise in older women. Front Physiol. 2018;9:1324. 10.3389/fphys.2018.01324.30327609 10.3389/fphys.2018.01324
48. Loenneke JP Kim D Fahs CA Thiebaud RS Abe T Larson RD The effects of resistance exercise with and without different degrees of blood-flow restriction on perceptual responses J Sports Sci 2015 33 1472 1479 10.1080/02640414.2014.992036 25555163
Loenneke JP, Kim D, Fahs CA, Thiebaud RS, Abe T, Larson RD, et al. The effects of resistance exercise with and without different degrees of blood-flow restriction on perceptual responses. J Sports Sci. 2015;33:1472–9. 10.1080/02640414.2014.992036.25555163 10.1080/02640414.2014.992036
49. Freitas EDS Miller RM Heishman AD Aniceto RR Silva JGC Bemben MG Perceptual responses to continuous versus intermittent blood flow restriction exercise: a randomized controlled trial Physiol Behav 2019 212 112717 10.1016/j.physbeh.2019.112717 31629764
Freitas EDS, Miller RM, Heishman AD, Aniceto RR, Silva JGC, Bemben MG. Perceptual responses to continuous versus intermittent blood flow restriction exercise: a randomized controlled trial. Physiol Behav. 2019;212: 112717. 10.1016/j.physbeh.2019.112717.31629764 10.1016/j.physbeh.2019.112717
50. Miller RM Galletti BAR Koziol KJ Freitas EDS Heishman AD Black CD Perceptual responses: clinical versus practical blood flow restriction resistance exercise Physiol Behav 2020 227 113137 10.1016/j.physbeh.2020.113137 32798570
Miller RM, Galletti BAR, Koziol KJ, Freitas EDS, Heishman AD, Black CD, et al. Perceptual responses: clinical versus practical blood flow restriction resistance exercise. Physiol Behav. 2020;227: 113137. 10.1016/j.physbeh.2020.113137.32798570 10.1016/j.physbeh.2020.113137
51. Farup J de Paoli F Bjerg K Riis S Ringgard S Vissing K Blood flow restricted and traditional resistance training performed to fatigue produce equal muscle hypertrophy Scand J Med Sci Sports 2015 25 754 763 10.1111/sms.12396 25603897
Farup J, de Paoli F, Bjerg K, Riis S, Ringgard S, Vissing K. Blood flow restricted and traditional resistance training performed to fatigue produce equal muscle hypertrophy. Scand J Med Sci Sports. 2015;25:754–63. 10.1111/sms.12396.25603897 10.1111/sms.12396
52. Norton K Norton L Sadgrove D Position statement on physical activity and exercise intensity terminology J Sci Med Sport 2010 13 496 502 10.1016/j.jsams.2009.09.008 20005170
Norton K, Norton L, Sadgrove D. Position statement on physical activity and exercise intensity terminology. J Sci Med Sport. 2010;13:496–502. 10.1016/j.jsams.2009.09.008.20005170 10.1016/j.jsams.2009.09.008
53. Mok E Suga T Sugimoto T Tomoo K Dora K Takada S Negative effects of blood flow restriction on perceptual responses to walking in healthy young adults: a pilot study Heliyon 2020 6 e04745 10.1016/j.heliyon.2020.e04745 32885079
Mok E, Suga T, Sugimoto T, Tomoo K, Dora K, Takada S, et al. Negative effects of blood flow restriction on perceptual responses to walking in healthy young adults: a pilot study. Heliyon. 2020;6: e04745. 10.1016/j.heliyon.2020.e04745.32885079 10.1016/j.heliyon.2020.e04745
54. Haouzi P Hill JM Lewis BK Kaufman MP Responses of group III and IV muscle afferents to distension of the peripheral vascular bed J Appl Physiol 1985 1999 87 545 553 10.1152/jappl.1999.87.2.545
Haouzi P, Hill JM, Lewis BK, Kaufman MP. Responses of group III and IV muscle afferents to distension of the peripheral vascular bed. J Appl Physiol. 1985;1999(87):545–53. 10.1152/jappl.1999.87.2.545.10.1152/jappl.1999.87.2.545
55. Jankowski MP Rau KK Ekmann KM Anderson CE Koerber HR Comprehensive phenotyping of group III and IV muscle afferents in mouse J Neurophysiol 2013 109 2374 2381 10.1152/jn.01067.2012 23427306
Jankowski MP, Rau KK, Ekmann KM, Anderson CE, Koerber HR. Comprehensive phenotyping of group III and IV muscle afferents in mouse. J Neurophysiol. 2013;109:2374–81. 10.1152/jn.01067.2012.23427306 10.1152/jn.01067.2012
56. Franz A Berndt F Raabe J Harmsen J-F Zilkens C Behringer M Invasive assessment of hemodynamic, metabolic and ionic consequences during blood flow restriction training Front Physiol 2020 11 617668 10.3389/fphys.2020.617668 33391036
Franz A, Berndt F, Raabe J, Harmsen J-F, Zilkens C, Behringer M. Invasive assessment of hemodynamic, metabolic and ionic consequences during blood flow restriction training. Front Physiol. 2020;11: 617668. 10.3389/fphys.2020.617668.33391036 10.3389/fphys.2020.617668
57. Ilett MJ Rantalainen T Keske MA May AK Warmington SA The effects of restriction pressures on the acute responses to blood flow restriction exercise Front Physiol 2019 10 1018 10.3389/fphys.2019.01018 31456694
Ilett MJ, Rantalainen T, Keske MA, May AK, Warmington SA. The effects of restriction pressures on the acute responses to blood flow restriction exercise. Front Physiol. 2019;10:1018. 10.3389/fphys.2019.01018.31456694 10.3389/fphys.2019.01018
58. Dean M White MB Amos J Gerrard B Stewart C Khaw KT Leppert M Multiple mutations in highly conserved residues are found in mildly affected cystic fibrosis patients Cell 1990 61 863 870 10.1016/0092-8674(90)90196-l 2344617
Dean M, White MB, Amos J, Gerrard B, Stewart C, Khaw KT, Leppert M. Multiple mutations in highly conserved residues are found in mildly affected cystic fibrosis patients. Cell. 1990;61:863–70. 10.1016/0092-8674(90)90196-l.2344617 10.1016/0092-8674(90)90196-l
59. Kilgas MA Yoon T McDaniel J Phillips KC Elmer SJ Physiological responses to acute cycling with blood flow restriction Front Physiol 2022 13 800155 10.3389/fphys.2022.800155 35360241
Kilgas MA, Yoon T, McDaniel J, Phillips KC, Elmer SJ. Physiological responses to acute cycling with blood flow restriction. Front Physiol. 2022;13: 800155. 10.3389/fphys.2022.800155.35360241 10.3389/fphys.2022.800155
60. Silva JCG Domingos-Gomes JR Freitas EDS Neto GR Aniceto RR Bemben MG Physiological and perceptual responses to aerobic exercise with and without blood flow restriction J Strength Cond Res 2021 35 2479 2485 10.1519/JSC.0000000000003178 31136546
Silva JCG, Domingos-Gomes JR, Freitas EDS, Neto GR, Aniceto RR, Bemben MG, et al. Physiological and perceptual responses to aerobic exercise with and without blood flow restriction. J Strength Cond Res. 2021;35:2479–85. 10.1519/JSC.0000000000003178.31136546 10.1519/JSC.0000000000003178
61. Proske U Gandevia SC The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force Physiol Rev 2012 92 1651 1697 10.1152/physrev.00048.2011 23073629
Proske U, Gandevia SC. The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force. Physiol Rev. 2012;92:1651–97. 10.1152/physrev.00048.2011.23073629 10.1152/physrev.00048.2011
62. Amann M Blain GM Proctor LT Sebranek JJ Pegelow DF Dempsey JA Group III and IV muscle afferents contribute to ventilatory and cardiovascular response to rhythmic exercise in humans J Appl Physiol 1985 2010 109 966 976 10.1152/japplphysiol.00462.2010
Amann M, Blain GM, Proctor LT, Sebranek JJ, Pegelow DF, Dempsey JA. Group III and IV muscle afferents contribute to ventilatory and cardiovascular response to rhythmic exercise in humans. J Appl Physiol. 1985;2010(109):966–76. 10.1152/japplphysiol.00462.2010.10.1152/japplphysiol.00462.2010
63. Allen DG Lamb GD Westerblad H Skeletal muscle fatigue: cellular mechanisms Physiol Rev 2008 88 287 332 10.1152/physrev.00015.2007 18195089
Allen DG, Lamb GD, Westerblad H. Skeletal muscle fatigue: cellular mechanisms. Physiol Rev. 2008;88:287–332. 10.1152/physrev.00015.2007.18195089 10.1152/physrev.00015.2007
64. Pageaux B Perception of effort in exercise science: definition, measurement and perspectives Eur J Sport Sci 2016 16 885 894 10.1080/17461391.2016.1188992 27240002
Pageaux B. Perception of effort in exercise science: definition, measurement and perspectives. Eur J Sport Sci. 2016;16:885–94. 10.1080/17461391.2016.1188992.27240002 10.1080/17461391.2016.1188992
65. Loenneke JP Kim D Fahs CA Thiebaud RS Abe T Larson RD Effects of exercise with and without different degrees of blood flow restriction on torque and muscle activation Muscle Nerve 2015 51 713 721 10.1002/mus.24448 25187395
Loenneke JP, Kim D, Fahs CA, Thiebaud RS, Abe T, Larson RD, et al. Effects of exercise with and without different degrees of blood flow restriction on torque and muscle activation. Muscle Nerve. 2015;51:713–21. 10.1002/mus.24448.25187395 10.1002/mus.24448
66. Yasuda T Abe T Brechue WF Iida H Takano H Meguro K Venous blood gas and metabolite response to low-intensity muscle contractions with external limb compression Metabolism 2010 59 1510 1519 10.1016/j.metabol.2010.01.016 20199783
Yasuda T, Abe T, Brechue WF, Iida H, Takano H, Meguro K, et al. Venous blood gas and metabolite response to low-intensity muscle contractions with external limb compression. Metabolism. 2010;59:1510–9. 10.1016/j.metabol.2010.01.016.20199783 10.1016/j.metabol.2010.01.016
67. Cai Z-Y Chen W-C Wu C-M Acute effects of whole body vibration combined with blood restriction on electromyography amplitude and hormonal responses Biol Sport 2018 35 301 307 10.5114/biolsport.2018.77830 30449948
Cai Z-Y, Chen W-C, Wu C-M. Acute effects of whole body vibration combined with blood restriction on electromyography amplitude and hormonal responses. Biol Sport. 2018;35:301–7. 10.5114/biolsport.2018.77830.30449948 10.5114/biolsport.2018.77830
68. Dankel SJ Jessee MB Mattocks KT Buckner SL Mouser JG Bell ZW Perceptual and arterial occlusion responses to very low load blood flow restricted exercise performed to volitional failure Clin Physiol Funct Imaging 2019 39 29 34 10.1111/cpf.12535 29938892
Dankel SJ, Jessee MB, Mattocks KT, Buckner SL, Mouser JG, Bell ZW, et al. Perceptual and arterial occlusion responses to very low load blood flow restricted exercise performed to volitional failure. Clin Physiol Funct Imaging. 2019;39:29–34. 10.1111/cpf.12535.29938892 10.1111/cpf.12535
69. Bell ZW Buckner SL Jessee MB Mouser JG Mattocks KT Dankel SJ Moderately heavy exercise produces lower cardiovascular, RPE, and discomfort compared to lower load exercise with and without blood flow restriction Eur J Appl Physiol 2018 118 1473 1480 10.1007/s00421-018-3877-0 29725755
Bell ZW, Buckner SL, Jessee MB, Mouser JG, Mattocks KT, Dankel SJ, et al. Moderately heavy exercise produces lower cardiovascular, RPE, and discomfort compared to lower load exercise with and without blood flow restriction. Eur J Appl Physiol. 2018;118:1473–80. 10.1007/s00421-018-3877-0.29725755 10.1007/s00421-018-3877-0
70. Kolind MI Gam S Phillip JG Pareja-Blanco F Olsen HB Gao Y Effects of low load exercise with and without blood-flow restriction on microvascular oxygenation, muscle excitability and perceived pain Eur J Sport Sci 2023 23 542 551 10.1080/17461391.2022.2039781 35125067
Kolind MI, Gam S, Phillip JG, Pareja-Blanco F, Olsen HB, Gao Y, et al. Effects of low load exercise with and without blood-flow restriction on microvascular oxygenation, muscle excitability and perceived pain. Eur J Sport Sci. 2023;23:542–51. 10.1080/17461391.2022.2039781.35125067 10.1080/17461391.2022.2039781
71. Behringer M Heinke L Leyendecker J Mester J Effects of blood flow restriction during moderate-intensity eccentric knee extensions J Physiol Sci 2018 68 589 599 10.1007/s12576-017-0568-2 28889225
Behringer M, Heinke L, Leyendecker J, Mester J. Effects of blood flow restriction during moderate-intensity eccentric knee extensions. J Physiol Sci. 2018;68:589–99. 10.1007/s12576-017-0568-2.28889225 10.1007/s12576-017-0568-2
72. Buckner SL Jessee MB Dankel SJ Mattocks KT Mouser JG Bell ZW Acute skeletal muscle responses to very low-load resistance exercise with and without the application of blood flow restriction in the upper body Clin Physiol Funct Imaging 2019 39 201 208 10.1111/cpf.12557 30506882
Buckner SL, Jessee MB, Dankel SJ, Mattocks KT, Mouser JG, Bell ZW, et al. Acute skeletal muscle responses to very low-load resistance exercise with and without the application of blood flow restriction in the upper body. Clin Physiol Funct Imaging. 2019;39:201–8. 10.1111/cpf.12557.30506882 10.1111/cpf.12557
73. Willis SJ Alvarez L Borrani F Millet GP Oxygenation time course and neuromuscular fatigue during repeated cycling sprints with bilateral blood flow restriction Physiol Rep 2018 6 e13872 10.14814/phy2.13872 30295004
Willis SJ, Alvarez L, Borrani F, Millet GP. Oxygenation time course and neuromuscular fatigue during repeated cycling sprints with bilateral blood flow restriction. Physiol Rep. 2018;6: e13872. 10.14814/phy2.13872.30295004 10.14814/phy2.13872
74. Peyrard A Willis SJ Place N Millet GP Borrani F Rupp T Neuromuscular evaluation of arm-cycling repeated sprints under hypoxia and/or blood flow restriction Eur J Appl Physiol 2019 119 1533 1545 10.1007/s00421-019-04143-4 31011807
Peyrard A, Willis SJ, Place N, Millet GP, Borrani F, Rupp T. Neuromuscular evaluation of arm-cycling repeated sprints under hypoxia and/or blood flow restriction. Eur J Appl Physiol. 2019;119:1533–45. 10.1007/s00421-019-04143-4.31011807 10.1007/s00421-019-04143-4
75. Willis SJ Borrani F Millet GP Leg- vs arm-cycling repeated sprints with blood flow restriction and systemic hypoxia Eur J Appl Physiol 2019 119 1819 1828 10.1007/s00421-019-04171-0 31187281
Willis SJ, Borrani F, Millet GP. Leg- vs arm-cycling repeated sprints with blood flow restriction and systemic hypoxia. Eur J Appl Physiol. 2019;119:1819–28. 10.1007/s00421-019-04171-0.31187281 10.1007/s00421-019-04171-0
76. Pignanelli C Petrick HL Keyvani F Heigenhauser GJF Quadrilatero J Holloway GP Burr JF Low-load resistance training to task failure with and without blood flow restriction: muscular functional and structural adaptations Am J Physiol Regul Integr Comp Physiol 2020 318 R284 R295 10.1152/ajpregu.00243.2019 31823670
Pignanelli C, Petrick HL, Keyvani F, Heigenhauser GJF, Quadrilatero J, Holloway GP, Burr JF. Low-load resistance training to task failure with and without blood flow restriction: muscular functional and structural adaptations. Am J Physiol Regul Integr Comp Physiol. 2020;318:R284–95. 10.1152/ajpregu.00243.2019.31823670 10.1152/ajpregu.00243.2019
77. Bielitzki R Behrendt T Behrens M Schega L Time to save time: beneficial effects of blood flow restriction training and the need to quantify the time potentially saved by its application during musculoskeletal rehabilitation Phys Ther 2021 10.1093/ptj/pzab172 34228788
Bielitzki R, Behrendt T, Behrens M, Schega L. Time to save time: beneficial effects of blood flow restriction training and the need to quantify the time potentially saved by its application during musculoskeletal rehabilitation. Phys Ther. 2021. 10.1093/ptj/pzab172.34228788 10.1093/ptj/pzab172
78. Mouser JG Mattocks KT Buckner SL Dankel SJ Jessee MB Bell ZW High-pressure blood flow restriction with very low load resistance training results in peripheral vascular adaptations similar to heavy resistance training Physiol Meas 2019 40 35003 10.1088/1361-6579/ab0d2a
Mouser JG, Mattocks KT, Buckner SL, Dankel SJ, Jessee MB, Bell ZW, et al. High-pressure blood flow restriction with very low load resistance training results in peripheral vascular adaptations similar to heavy resistance training. Physiol Meas. 2019;40:35003. 10.1088/1361-6579/ab0d2a.10.1088/1361-6579/ab0d2a
79. Counts BR Dankel SJ Barnett BE Kim D Mouser JG Allen KM Influence of relative blood flow restriction pressure on muscle activation and muscle adaptation Muscle Nerve 2016 53 438 445 10.1002/mus.24756 26137897
Counts BR, Dankel SJ, Barnett BE, Kim D, Mouser JG, Allen KM, et al. Influence of relative blood flow restriction pressure on muscle activation and muscle adaptation. Muscle Nerve. 2016;53:438–45. 10.1002/mus.24756.26137897 10.1002/mus.24756
80. Dankel SJ Jessee MB Buckner SL Mouser JG Mattocks KT Loenneke JP Are higher blood flow restriction pressures more beneficial when lower loads are used? Physiol Int 2017 104 247 257 10.1556/2060.104.2017.3.2 28956640
Dankel SJ, Jessee MB, Buckner SL, Mouser JG, Mattocks KT, Loenneke JP. Are higher blood flow restriction pressures more beneficial when lower loads are used? Physiol Int. 2017;104:247–57. 10.1556/2060.104.2017.3.2.28956640 10.1556/2060.104.2017.3.2
81. Hughes L Patterson SD The effect of blood flow restriction exercise on exercise-induced hypoalgesia and endogenous opioid and endocannabinoid mechanisms of pain modulation J Appl Physiol 1985 2020 128 914 924 10.1152/japplphysiol.00768.2019
Hughes L, Patterson SD. The effect of blood flow restriction exercise on exercise-induced hypoalgesia and endogenous opioid and endocannabinoid mechanisms of pain modulation. J Appl Physiol. 1985;2020(128):914–24. 10.1152/japplphysiol.00768.2019.10.1152/japplphysiol.00768.2019
82. Hughes L Grant I Patterson SD Aerobic exercise with blood flow restriction causes local and systemic hypoalgesia and increases circulating opioid and endocannabinoid levels J Appl Physiol 1985 2021 131 1460 1468 10.1152/japplphysiol.00543.2021
Hughes L, Grant I, Patterson SD. Aerobic exercise with blood flow restriction causes local and systemic hypoalgesia and increases circulating opioid and endocannabinoid levels. J Appl Physiol. 1985;2021(131):1460–8. 10.1152/japplphysiol.00543.2021.10.1152/japplphysiol.00543.2021
83. Cerqueira MS Lira M Mendonça Barboza JA Burr JF Wanderley E Lima TB Maciel DG de BritoVieira WH Repetition failure occurs earlier during low-load resistance exercise with high but not low blood flow restriction pressures: a systematic review and meta-analysis J Strength Cond Res 2021 10.1519/JSC.0000000000004093 34319945
Cerqueira MS, Lira M, Mendonça Barboza JA, Burr JF, Wanderley E, Lima TB, Maciel DG, de BritoVieira WH. Repetition failure occurs earlier during low-load resistance exercise with high but not low blood flow restriction pressures: a systematic review and meta-analysis. J Strength Cond Res. 2021. 10.1519/JSC.0000000000004093.34319945 10.1519/JSC.0000000000004093
84. Jessee MB Buckner SL Mattocks KT Dankel SJ Mouser JG Bell ZW Blood flow restriction augments the skeletal muscle response during very low-load resistance exercise to volitional failure Physiol Int 2019 106 180 193 10.1556/2060.106.2019.15 31262205
Jessee MB, Buckner SL, Mattocks KT, Dankel SJ, Mouser JG, Bell ZW, et al. Blood flow restriction augments the skeletal muscle response during very low-load resistance exercise to volitional failure. Physiol Int. 2019;106:180–93. 10.1556/2060.106.2019.15.31262205 10.1556/2060.106.2019.15
85. Jacobs E Rolnick N Wezenbeek E Stroobant L Capelleman R Arnout N Investigating the autoregulation of applied blood flow restriction training pressures in healthy, physically active adults: an intervention study evaluating acute training responses and safety Br J Sports Med 2023 57 914 920 10.1136/bjsports-2022-106069 36604156
Jacobs E, Rolnick N, Wezenbeek E, Stroobant L, Capelleman R, Arnout N, et al. Investigating the autoregulation of applied blood flow restriction training pressures in healthy, physically active adults: an intervention study evaluating acute training responses and safety. Br J Sports Med. 2023;57:914–20. 10.1136/bjsports-2022-106069.36604156 10.1136/bjsports-2022-106069
86. Rolnick N Kimbrell K de Queiros V Beneath the cuff: often overlooked and under-reported blood flow restriction device features and their potential impact on practice—a review of the current state of the research Front Physiol 2023 14 1089065 10.3389/fphys.2023.1089065 37064884
Rolnick N, Kimbrell K, de Queiros V. Beneath the cuff: often overlooked and under-reported blood flow restriction device features and their potential impact on practice—a review of the current state of the research. Front Physiol. 2023;14:1089065. 10.3389/fphys.2023.1089065.37064884 10.3389/fphys.2023.1089065
87. Head P Waldron M Theis N Patterson SD Acute neuromuscular electrical stimulation (NMES) with blood flow restriction: the effect of restriction pressures J Sport Rehabil 2020 30 375 383 10.1123/jsr.2019-0505 32736338
Head P, Waldron M, Theis N, Patterson SD. Acute neuromuscular electrical stimulation (NMES) with blood flow restriction: the effect of restriction pressures. J Sport Rehabil. 2020;30:375–83. 10.1123/jsr.2019-0505.32736338 10.1123/jsr.2019-0505
88. Rhodes RE Kates A Can the affective response to exercise predict future motives and physical activity behavior? A systematic review of published evidence Ann Behav Med 2015 49 715 731 10.1007/s12160-015-9704-5 25921307
Rhodes RE, Kates A. Can the affective response to exercise predict future motives and physical activity behavior? A systematic review of published evidence. Ann Behav Med. 2015;49:715–31. 10.1007/s12160-015-9704-5.25921307 10.1007/s12160-015-9704-5
89. Spitz RW Wong V Bell ZW Viana RB Chatakondi RN Abe T Loenneke JP Blood flow restricted exercise and discomfort: a review J Strength Cond Res 2022 36 871 879 10.1519/JSC.0000000000003525 32058360
Spitz RW, Wong V, Bell ZW, Viana RB, Chatakondi RN, Abe T, Loenneke JP. Blood flow restricted exercise and discomfort: a review. J Strength Cond Res. 2022;36:871–9. 10.1519/JSC.0000000000003525.32058360 10.1519/JSC.0000000000003525
90. Neto GR Novaes JS Salerno VP Gonçalves MM Piazera BKL Rodrigues-Rodrigues T Cirilo-Sousa MS Acute effects of resistance exercise with continuous and intermittent blood flow restriction on hemodynamic measurements and perceived exertion Percept Mot Skills 2017 124 277 292 10.1177/0031512516677900 27837041
Neto GR, Novaes JS, Salerno VP, Gonçalves MM, Piazera BKL, Rodrigues-Rodrigues T, Cirilo-Sousa MS. Acute effects of resistance exercise with continuous and intermittent blood flow restriction on hemodynamic measurements and perceived exertion. Percept Mot Skills. 2017;124:277–92. 10.1177/0031512516677900.27837041 10.1177/0031512516677900
91. Freitas EDS Miller RM Heishman AD Ferreira-Júnior JB Araújo JP Bemben MG Acute physiological responses to resistance exercise with continuous versus intermittent blood flow restriction: a randomized controlled trial Front Physiol 2020 11 132 10.3389/fphys.2020.00132 32256374
Freitas EDS, Miller RM, Heishman AD, Ferreira-Júnior JB, Araújo JP, Bemben MG. Acute physiological responses to resistance exercise with continuous versus intermittent blood flow restriction: a randomized controlled trial. Front Physiol. 2020;11:132. 10.3389/fphys.2020.00132.32256374 10.3389/fphys.2020.00132
