
==== Front
Int J Sports Phys Ther
Int J Sports Phys Ther
2159
International Journal of Sports Physical Therapy
2159-2896
NASMI Website: International Journal of Sports Physical Therapy

34123536
24244
10.26603/001c.24244
Original Research
Shoulder Strength and Closed Kinetic Chain Upper Extremity Stability Test Performance in Division III Collegiate Baseball and Softball Players.
Schilling David T. PT, DPT, OCS 1
Elazzazi Ashraf M. PT, PhD 1
1 Department of Physical Therapy Utica College, Utica, NY, USA
Corresponding Author: David T. Schilling, PT, DPT, OCS Department of Physical Therapy Utica College 1600 Burrstone Road Utica, NY 13502 Phone: 315-223-2561 Email: dtschill@utica.edu
1 6 2021
2021
16 3 844853
13 8 2020
15 12 2020
© The Author(s)
https://creativecommons.org/licenses/by-nc-sa/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike License (4.0) which permits non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited. If you remix, transform, or build upon this work, you must distribute your contributions under the same license as the original.

Background

Shoulder strength measured with a handheld dynamometer (HHD) and the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) are clinical tools that have been used to measure athlete’s performance and track their progress.

Purpose

The specific aims of this study were to describe baseball (BB) and softball (SB) players isometric strength measures and their performance on the CKCUEST; examine the relationships between strength and the CKCUEST; compare isometric strength measures of the throwing and non-throwing arms; and compare the strength and the CKCUEST measures between BB and SB players.

Study Design

Observational cohort study.

Methods

Participants included 50 DIII BB and 24 DIII SB players. Shoulder strength for the internal and external rotators were measured using a HHD and the CKCUEST was performed. The CKCUEST score and power were calculated. Descriptive statistics and paired t-tests were used to compare throwing and non-throwing shoulder strength. Independent t-test was used to compare BB and SB players shoulder strength and the CKCUEST measures.

Results

The BB players demonstrated significant strength differences between the throwing and non-throwing shoulders and the internal rotators were significantly stronger than the external rotators (p < 0.05), while the strength ratio of the internal and external rotators was not different between arms (p=0.87). The SB players demonstrated no significant strength differences between the throwing and non-throwing shoulders for the internal and external rotators or the strength ratio of the rotators (p > 0.05). There were no significant differences between the strength of the internal and external rotators of the non-throwing shoulder (p=0.075) or the throwing shoulder (p=0.096). The BB players throwing and non-throwing shoulders produced significantly more internal and external force than the SB players (p < 0.001), however, the internal/external rotators strength ratio were similar (p=0.32, p=0.30). The CKCUEST power had inverse and significant correlations (p=0.006, p=0.003) with SB players internal and external rotators, respectively. The CKCUEST power was significantly different between BB and SB players (p < 0.001).

Conclusion

This study presented shoulder rotator strength and CKCUEST reference values for DIII BB and SB players. BB players demonstrated more strength but overall, less symmetry compared to SB players. CKCUEST power may be considered for the evaluation of athletes.

Level of Evidence

Level III

movement system.
closed kinetic chain upper extremity stability test
shoulder strength
collegiate softball
collegiate baseball
==== Body
pmcINTRODUCTION

The physiological demands of overhead sports on the shoulder may predispose athletes to injuries.1–4 Shoulder impairments are common for collegiate baseball (BB) and softball (SB) players.2,5 Impaired rotator cuff muscle strength may alter glenohumeral joint mechanics, contribute to painful shoulder conditions or lead to shoulder injury during the season.1,6–8 Imbalances in muscle strength of the rotator cuff has been suggested to be related to the unilateral repetitive nature of overhead throwing activities. Specifically, increased muscle strength of the internal rotators as compared to the external rotators.1,4,9–13 The strength of the shoulder musculature can be objectively and reliably measured in the clinical setting using a handheld dynamometer (HHD).13

“Clinician-friendly” physical performance tests, such as the Closed Kinetic Chain Upper-Extremity Stability Test (CKCUEST), are increasingly being used to examine and screen overhead athletes.14–17 The CKCUEST is an objective, easy functional test that can be used to measure components of muscle performance of the shoulder complex in a closed-kinetic chain position and places high demands on its stabilizers. Moreover, the test movement requires coordination between muscles of the trunk, shoulder, elbow, wrist and hand.18 Performance on the CKCUEST has been reported for Division I (DI) college football players,15 recreational athletes16 as well as Division III (DIII) BB players.17

DIII BB has the largest number of participating players (13,465) compared to DI (10,429) and DII (10,660) in the United States.19 Similarly, there were more SB players participating in DIII (7,646) compared to DI (6,042) and DII (5,992).19 A review of the literature showed that there are few reports that describe shoulder characteristics of DIII BB and SB players related to muscle strength and performance on the CKCUEST. Clinicians need to be able to identify the normal shoulder performance characteristics when examining and creating intervention strategies for DIII BB and SB players. A thorough review of the literature found no other studies that examined the relationship between the CKCUEST and shoulder strength or described the results of DIII BB and SB players.

The specific aims of this study were to: describe BB and SB players isometric strength measures and their performance on the CKCUEST; examine the relationships between strength and the CKCUEST; compare isometric strength measures of the throwing and non-throwing arms; and compare the strength and the CKCUEST measures between BB and SB players.

METHODS

Participants.

BB and SB players were recruited from one DIII college to participate in this study during the preseason. The inclusion criteria were: 1) BB or SB collegiate athletes; 2) who were over the age of 18 years; and 3) had no current shoulder injury or medical conditions that precluded them from participation in sports. The Institutional Review Board approved this study.

Data Collection.

Participants completed demographic and history information and then were randomly assigned to begin with either the CKCUEST or dynamometric strength testing. The order of the throwing and non-throwing shoulder testing also was randomly assigned.

Internal and External Rotator Isometric Strength Testing.

Study participants performed a 5-minute warm up which consisted of slowly lifting a submaximal weight through the full internal rotation and external rotation range of motion while in the testing position for 10 repetitions followed by a 3-minute rest period prior to strength testing. One investigator collected all strength measurements using a hand-held dynamometer (Lafayette Instrument, Lafayette, Indiana, USA). Strength was assessed in the prone position for the external rotators and internal rotators with the shoulder abducted to 90°, elbow flexed to 90° and the forearm pronated (Figure 1). A small towel was placed under the distal humerus. The examiner manually stabilized the humerus and placed the dynamometer on the distal radius 1 cm proximal to the wrist crease. The HHD was placed on the volar and dorsal aspects of the wrist to measure the strength of the internal and external rotators, respectively. To assess peak isometric force, the athletes were instructed to hold the arm against a gradually increasing force for a total of five seconds “make test”.1 The average peak force (kg) was divided by the athlete’s body mass in kg (BM) to calculate the standardized force production (%BM).

61298 Figure 1. Measurement of Isometric strength of the shoulder external rotators.

Good intrarater and interrater reliability of hand-held dynamometry (HHD) for strength testing of the internal and external rotators have been reported. 20,21 To ensure accurate reliability and validity of all included measures used in this study, a pilot study was performed utilizing 20 collegiate athletes. The shoulder strength of the internal and external rotators demonstrated high intra-rater and inter-rater reliability with intraclass correlation coefficients (ICC) of .95 and .99 for internal rotators and .98 and .98 for external rotators.

Closed Kinetic Chain Upper Extremity Stability Test.

The CKCUEST test has excellent test-retest reliability (ICC = 0.92).22 Additionally, a pilot study was performed and found the intra-rater and inter-rater for the CKCUEST to be ICC = .91 and .99, respectively. Two pieces of tape were placed 36 inches apart on the ground (Figure 2). The BB players were asked to assume the push-up position and the SB players used the modified push-up position with the shoulders kept directly over the hands. Participants were asked to make as many ‘touches’ of each piece of tape as possible within 15 seconds and the examiner counted the number of touches. Three trials were performed and the mean score of the three trials was calculated. A rest period of 45 seconds was given after each trial. The CKCUEST score and power were also calculated by using the following two formulas.23

Score= average number of touches performed on the CKCUEST/ height (m)

Power= 68% body weight (kg) x average number of touches performed on the CKCUEST

61299 Figure 2. Closed Kinetic Chain Upper Extremity Stability Testing position for female (top) and male (middle and bottom) subjects.

Data Analysis.

SPSS (IBM Corp. IBM SPSS Statistics for Windows, Version 26.0. Released 2019. Armonk, NY: IBM Corp.) was used to perform: 1) descriptive statistics for the strength of the internal and external rotators of the throwing and non-throwing shoulders and the CKCUEST; 2) paired t-tests to compare the strength measures of the throwing and non-throwing arms; 3) Pearson product-moment correlation coefficient to calculate the relationships between strength and the CKCUEST; 4) independent t-tests to compare the shoulder strength and the CKCUEST of BB and SB players; and 5) independent t-tests to compare the effects of the BB player’s field position on the shoulder strength and the CKCUEST variables. There was an insufficient number of SB pitchers (n=4) to complete a comparison between pitchers and other field positions. It was estimated that 30 participants would be sufficient to provide a good point estimate of isometric strength and the CKCUEST measures using a 95% confidence level and a population size of 13,465 DIII BB players.19

RESULTS

Seventy-four DIII collegiate athletes (50 BB and 24 SB players) with an age range of 18-21 years old agreed to participate (Table 1). All participants signed an institutionally approved informed consent. The strength expressed as %BM and the CKCUEST measures for BB and SB players are presented (Tables 2 & 3). All measurement values met the assumptions for parametric analysis.

There were significant differences between the BB players’ throwing and non-throwing shoulders for both the internal and external rotators (p = 0.012 & 0.047, respectively) with mean strength differences (95% CI) of 1.12 %BM (0.25, 1.96) and 0.92 %BM (0.01, 1.8), respectively. There were significant differences in the strength of the internal and external rotators within each shoulder (p = 0.008 & 0.013, respectively). The mean differences (95% CI) were 2.55 %BM (0.55, 4.56) for the internal rotators and 2.36 %BM (0.6, 4.09) for the external rotators of the throwing shoulder and non-throwing shoulders, respectively. However, the internal/external rotators strength ratio was not significantly different for either shoulder. When comparing BB pitchers to all other field positions there was no significant difference in any of the strength or CKCUEST measures (Table 4).

61300 Table 1. Participants Characteristics.

Participants Characteristics	Baseball (SD)	Softball (SD)	
Age (years)	19.3 (1.0)	19.2 (1.0)	
Years Competing (years)	13.8 (2.8)	13.6 (2.2)	
Height (m)	1.77 (.07)	1.64 (.06)	
Weight (kg)	84.2 (11)	69.8 (9.7)	
Sports Position (n)			
Pitcher	14	4	
Catcher	8	4	
Infield	18	9	
Outfield	10	7	
SD=Standard Deviation, m=Meter, kg=Kilogram

61302 Table 2. Strength Characteristics (Mean & SD) of and Differences Between Baseball and Softball Players Non-Throwing & Throwing Shoulders.

	Side	BB †	SB 	Mean Difference (BB - SB)	95% CI of the Difference	
Lower	Upper	
IR Strength as % BM*	Non-Throwing	23.75 (6.89)	17.73 (4.47)	6.02	3.36	8.69	
Throwing	24.86 (8.03)	18.46 (5.53)	6.40	3.20	9.60	
ER Strength as % BM*	Non-Throwing	21.39 (5.14)	16.46 (2.87)	4.93	3.07	6.79	
Throwing	22.31 (5.39)	17.10 (3.19)	5.21	3.21	7.21	
IR/ER Strength Ratio	Non-Throwing	1.14 (.30)	1.08 (.19)	.06	-.06	.18	
Throwing	1.14 (.31)	1.07 (.20)	.06	-.06	.18	
BM=Body Mass, SD=Standard Deviation, CI= Confidence Interval, IR=Internal Rotation, ER=External Rotation, BB=Baseball, SB=Softbal.

*Statistically significant difference between Baseball and Softball (p < .001).

†Statistically significant difference between throwing and Non-throwing arms.

61301 Table 3. Closed Kinetic Chain Upper Extremity Test (CKCUEST) Differences Between Baseball (N=50) and Softball (N=24) Players.

	BB Mean (SD)	SB Mean (SD)	Mean Difference	95% CI of the Difference	
Lower	Upper	
CKCUEST	18.89 (3.76)	17.54 (3.12)	1.35	-.4160	3.12	
CKCUEST Power*	71.35 (14.40)	55.37 (11.64)	15.98	9.26	22.70	
CKCUEST Score	10.73 (2.56)	10.72 (1.92)	.016	-1.039	1.07	
CI=Confidence Interval, SD=Standard Deviation, BB=Baseball, SB=Softball.

*Statistically significant difference p < .001.

61303 Table 4.  Comparison of Baseball Players Strength Measures (%BM) for Pitchers (N = 14) and Other Field Positions (N = 36).

	Position	Mean (SD)	95% CI	
Upper Limit	Lower Limit	
CKUEST	Pitcher	19.10 (4.51)	17.85	20.35	
Other	18.82 (3.50)	17.85	19.7	
CKUEST Power	Pitcher	72.73 (15.87)	68.33	77.13	
Other	70.81 (13.99)	66.93	74.69	
CKUEST Score	Pitcher	10.84 (2.73)	10.08	11.6	
Other	10.69 (2.04)	10.13	11.26	
IR Strength Throwing Shoulder as % BM	Pitcher	22.13 (5.90)	20.5	23.77	
Other	25.92 (8.56)	23.55	28.29	
ER Strength Throwing Shoulder as % BM	Pitcher	19.47 (4.65)	18.18	20.76	
Other	23.41 (5.30)	21.94	24.88	
Strength Ratio IR/ER Throwing Shoulder	Pitcher	1.16 (.28)	1.08	1.24	
Other	1.12 (.33)	1.03	1.21	
CKCUEST=Closed Kinetic Chain Upper Extremity Stability Test, BM=Body Mass, SD=Standard Deviation,

CI=Confidence Interval, IR=Internal Rotation, ER=External Rotation.

There were no significant differences between the SB players throwing and non-throwing shoulder strength for the internal (p=0.116) and external rotators (p=0.109). Moreover, there were no significant differences between the strength of the internal and external rotators of the non-throwing shoulder (p=0.075) or the throwing shoulder (p=0.096). There was an insufficient number of SB pitchers (n=4) to complete a comparison between the pitchers and other field positions (Tables 2).

The throwing and non-throwing arms of BB players produce significantly more internal and external rotation force than the SB players (p < 0.001). However, there was no statistically significant difference (p=0.31 & 0.30) in the internal/external rotators strength ratio of the throwing and non-throwing shoulders, respectively (Table 2). Among the CKCUEST measures, only the CKCUEST power showed significant differences (p < 0.001) between BB and SB players (Table 3).

Scatterplots were viewed to examine bivariate correlation and linearity between the strength and the CKCUEST measures. No curvilinear relationships were identified. There was no correlation between any measure of shoulder strength and the CKCUEST in BB players. Similarly, SB players also demonstrated no correlation between any of the throwing or non-throwing shoulder strength measures and the CKCUEST or CKCUEST score. However, SB players showed significant (p< 0.01) and moderate correlations between the CKCUEST power and strength of the internal rotators (r = -.54 & -.57) and external rotators (r=-.58 & -.58) of the throwing and non-throwing arm, respectively.

DISCUSSION

Descriptive studies enhance the ability of practitioners to accurately interpret examination data. One of the main purposes of this study was to describe the isometric shoulder strength measures of the internal and external rotators for DIII collegiate BB and SB players. Electromyographic analysis has shown that the shoulder internal rotators are the primary upper limb accelerators during overhead throwing while there is high supraspinatus, trapezius, and external rotator muscle activity during the follow-through phase.24,25 The rotator cuff strength of BB and SB players can be measured using a variety of tools including manual muscle testing, isokinetic dynamometry and HHD. HHD has been shown to be an effective alternative to manual muscle testing to improve objectivity in the clinical setting and is more readily available to clinicians than isokinetic dynamometry.

In this study, BB players demonstrated slightly higher levels of strength in their throwing shoulders compared to the non-throwing shoulders (Table 2). However, the ratio of strength between the internal and external rotators for the throwing and non-throwing arm not significantly different. The strength values for the throwing shoulder internal rotators reported in this study are consistent with other studies that reported on high school pitchers and professional players with average strength that ranged from 18.7 to 25% BM.10,11,26,27 Only one study by Mullaney et al.,4 who tested 13 collegiate BB pitchers, reported higher internal rotators strength values (Appendix A). The strength of the external rotators of the throwing shoulder in this study was slightly higher than those reported in the literature for high school and professional BB pitchers that reported average strength ranging from 16.1 to 17.5% BM.10,11,26,27 Mullaney et al.4 reported strength values of the external rotators that were consistent with the current results.

The BB players internal rotators were stronger than the external rotators bilaterally, which is consistent with previous studies of high school, collegiate and professional players.1,4,7,27 This strength differential between the internal and external rotators has been reported for BB pitcher and non-pitchers.8,9 Cook et al.9 suggested that this may be a natural imbalance of the shoulder musculature. Hurd et al.26 found that the strength of the internal rotators was positively associated with the peak shoulder external-rotation moment. They postulated that the demands on the posterior musculature during pitching are associated with the need to counterbalance the limb acceleration produced by the internal rotators.26

The results of this study demonstrated that the strength of the throwing and non-throwing shoulders in SB players were not statistically different. Also, the strength of internal and external rotators of each shoulder were similar. Only one study reported the strength of the internal and external rotators for 14 high school SB players (mean age 16.5 years) and had slightly lower values than those found in this study.28

The BB players demonstrated stronger but asymmetrical shoulder strength while the SB players had weaker but symmetrical shoulder strength. These findings were consistent with Riemann et al.20 who also found that healthy young men were stronger than women, while the strength ratio of the internal and external rotators for both the throwing or non-throwing arms of men and women were similar. The authors hypothesize that the differences between DIII Collegiate BB and SB players may be gender-related as opposed to sports related adaptations.

There are a growing number of performance measures that clinicians can use to screen and evaluate athletes. The CKCUEST has been found to have excellent reliability and agreement as well as good construct, convergent and discriminant validity.14 The CKCUEST performance of the BB and SB players in this study was similar to healthy collegiate males and females.29–31 Contrarily, the performance of BB players in this study were lower than those reported for collegiate DIII male BB players,17 DI collegiate football players15 and healthy collegiate males.22 No other study has reported the CKCUEST performance for collegiate SB players.

Among the CKCUEST measures (number of touches, power and score), only the CKCUEST power showed a significant difference between BB and SB players (Table 3) and was inversely correlated with the strength of the internal and external rotators in SB players. These observations may be partly explained by gender differences and/or the fact that the SB players performed the CKCUEST from the modified push up position. When comparing the CKCUEST performance of men and women, using the power may be considered for evaluation of athletes. However, more studies are needed to confirm this finding.

A review of the literature indicated that no other studies evaluated the relationship of the CKCUEST and shoulder strength in collegiate BB or SB players (Appendix B). In this study, there was no relationship between CKCUEST and any of the throwing or non-throwing shoulder strength measures for BB players. Negrete et al.30 found no relationship between the CKCUEST and maximal throwing distance in a group of healthy recreationally active men and women. Studies included in a recent systematic review indicated that the relationship between upper extremity strength and power measures in athletes is weak and positive.14 The negative relationship found in this study between the SB players’ CKCUEST power and strength measurements may be a spurious correlation. The utilization of body weight in the calculation of CKCUEST power and the standardization of the strength measures to the individual’s body weight may explain this negative relationship.

In this group of DIII BB players, the position on the field did not seem to make a difference in any of the strength or CKCUEST measures. The majority of research for high school, collegiate and professional BB players has focused on pitchers, thus making it difficult to compare the current results of other field players to similar studies (Appendix A and B). This highlights the need for additional research that includes all field positions for BB and SB at all levels of competition to help validate reference values for the entire team.

When evaluating reference values related to HHD it is important for researchers and clinicians to consider the testing procedure (make or break test), the device used, the subjects’ ages, genders, and level of athleticism.20,32–36 There are a variety of testing positions described in the literature for measuring the strength of the internal and external rotators using a HHD including prone, supine, sitting and standing positions (Appendix A).32,37 Riemann et al.20 reported that the prone testing position (90º shoulder abduction) was associated with more external rotation force for both men and women and less internal rotation force in women than the seated neutral or 30-30-30º positions. Their strength values were consistent with the results of this study and may indicate that DIII collegiate BB and SB players have similar shoulder strength as healthy college aged adults.20 It is recommended that there be a standardized methodology of HHD when screening the shoulder strength of BB and SB players to enhance the ability for researchers and clinicians to make comparisons between groups of athletes.32,37

The limitations of this study include the single site for data collection, the use of a sample of convenience and the smaller sample size of SB players. It should be noted that the participants of this study were measured during the preseason and there is a potential for strength changes throughout the season. The difference between the shoulder strength results using HHD of this study and those listed in Appendix A may be related to the different testing methods used.

Future research should focus on the shoulder performance characteristics and biomechanical analysis of the throwing motion of all DIII BB and SB field positions to determine the unique characteristics of these groups and their associated risk for injury. Future research should also focus on the clinical usefulness of the CKCUEST to determine how it could most effectively be utilized in the clinic and on the field.

CONCLUSION

The reference values presented in this study may be used to enhance the interpretation of the examination findings related to DIII BB and SB players. BB players demonstrated stronger internal and external rotators but overall, less symmetry between and within their throwing and non-throwing shoulders when compared to SB players. Although the CKCUEST number of touches or score were not correlated to the isometric strength of the internal or external rotators nor differentiated between BB and SB players, the CKCUEST power did and may be considered for the evaluation of athletes.

Conflict of Interest

Authors have no conflict of interest related to this manuscript

Supplementary Material

Appendix A

Appendix B
==== Refs
Preseason shoulder strength measurements in professional baseball pitchers The American Journal of Sports Medicine Byram Ian R. Bushnell Brandon D. Dugger Keith Charron Kevin Harrell Frank E. Jr Noonan Thomas J. SAGE Publications 20 5 2010
38 7 1375 1382 0363-5465 10.1177/0363546509360404 10.1177/0363546509360404
Descriptive epidemiology of collegiate women's softball injuries: National collegiate athletic association injury surveillance system, 1988–1989 through 2003–2004 J Athl Train Marshall S. Hamstra-Wright K. Dick R.. 2007
42 2 286 94
Performance demands in softball pitching: A comprehensive muscle fatigue study The American Journal of Sports Medicine Corben Jeffrey S. Cerrone Sara A. Soviero Julie E. Kwiecien Susan Y. Nicholas Stephen J. McHugh Malachy P. SAGE Publications 24 6 2015
43 8 2035 2041 0363-5465 10.1177/0363546515588179 10.1177/0363546515588179
Upper and lower extremity muscle fatigue after a baseball pitching performance The American Journal of Sports Medicine Mullaney Michael J. McHugh Malachy P. Donofrio Tom M. Nicholas Stephen J. SAGE Publications 1 2005
33 1 108 113 0363-5465 10.1177/0363546504266071 10.1177/0363546504266071
The incidence of shoulder injury among collegiate overhead athletes Journal of Intercollegiate Sport Laudner Kevin Sipes Rob 12 2009
2 2 260 268 1941-6342 10.1123/jis.2.2.260 10.1123/jis.2.2.260
Muscle strength and range of motion in adolescent pitchers with throwing-related pain The American Journal of Sports Medicine Trakis James E. McHugh Malachy P. Caracciolo Philip A. Busciacco Lisa Mullaney Michael Nicholas Stephen J. SAGE Publications 2 7 2008
36 11 2173 2178 0363-5465 10.1177/0363546508319049 10.1177/0363546508319049
Risk factors for shoulder and elbow injuries in high school baseball pitchers The American Journal of Sports Medicine Tyler Timothy F. Mullaney Michael J. Mirabella Michael R. Nicholas Stephen J. McHugh Malachy P. SAGE Publications 3 6 2014
42 8 1993 1999 0363-5465 10.1177/0363546514535070 10.1177/0363546514535070 24893778
Prospective multifactorial analysis of preseason risk factors for shoulder and elbow injuries in high school baseball pitchers Knee Surgery, Sports Traumatology, Arthroscopy Shitara Hitoshi Kobayashi Tsutomu Yamamoto Atsushi Shimoyama Daisuke Ichinose Tsuyoshi Tajika Tsuyoshi Osawa Toshihisa Iizuka Haku Takagishi Kenji Springer Science and Business Media LLC 2017
25 10 3303 3310 0942-2056 10.1007/s00167-015-3731-4 10.1007/s00167-015-3731-4
Shoulder antagonistic strength ratios: a comparison between college-level baseball pitchers and nonpitchers Journal of Orthopaedic & Sports Physical Therapy Cook Ellen E. Gray Victoria L. Savinar-Nogue Emily Medeiros John 3 1987
8 9 451 461 0190-6011 10.2519/jospt.1987.8.9.451 10.2519/jospt.1987.8.9.451 18797031
A profile of glenohumeral internal and external rotation motion in the uninjured high school baseball pitcher, part II: Strength Journal of Athletic Training Hurd Wendy J. Kaplan Kevin M. ElAttrache Neal S. Jobe Frank W. Morrey Bernard F. Kaufman Kenton R. 1 5 2011
46 3 289 295 1062-6050 10.4085/1062-6050-46.3.289 10.4085/1062-6050-46.3.289 21669099
Comparison of shoulder range of motion, strength, and playing time in uninjured high school baseball pitchers who reside in warm and cold weather climates The American Journal of Sports Medicine Kaplan Kevin M. ElAttrache Neal S. Jobe Frank W. Morrey Bernard F. Kaufman Kenton R. Hurd Wendy J. 2011
39 2 320 328 0363-5465 10.1177/0363546510382230 10.1177/0363546510382230 21051421
The effects of anthropometric scaling parameters on normalized muscle strength in uninjured baseball pitchers Journal of Sport Rehabilitation Hurd Wendy J. Morrey Bernard F. Kaufman Kenton R. 8 2011
20 3 311 320 1056-6716 10.1123/jsr.20.3.311 10.1123/jsr.20.3.311 21828383
Shoulder weakness in professional baseball pitchers Medicine & Science in Sports & Exercise Magnusson PETER S. Gleim GILBERT W. Nicholas JAMES A. 1 1994
26 1 5 9 0195-9131 10.1249/00005768-199401000-00003 10.1249/00005768-199401000-00003
Clinician-friendly physical performance tests in athletes part 3: A systematic review of measurement properties and correlations to injury for tests in the upper extremity British Journal of Sports Medicine Tarara Daniel T Fogaca Lucas K Taylor Jeffrey B Hegedus Eric J BMJ 2016
50 9 545 551 0306-3674 10.1136/bjsports-2015-095198 10.1136/bjsports-2015-095198 26701926
Prediction of in-season shoulder injury from preseason testing in division I collegiate football players Sports Health: A Multidisciplinary Approach Pontillo Marisa Spinelli Bryan A. Sennett Brian J. 7 3 2014
6 6 497 503 1941-7381 10.1177/1941738114523239 10.1177/1941738114523239 25364482
Closed kinetic chain upper extremity stability test (CKCUES test): A reliability study in persons with and without shoulder impingement syndrome BMC Musculoskeletal Disorders Tucci Helga Tatiana Martins Jaqueline Sposito Guilherme de Carvalho Camarini Paula Maria Ferreira de Oliveira Anamaria Siriani Springer Science and Business Media LLC 3 1 2014
15 1 1471-2474 10.1186/1471-2474-15-1 10.1186/1471-2474-15-1 24387196
Reference values for the closed kinetic chain upper extremity stability test (CKCUEST) for collegiate baseball players N Am J Sports Phys Ther Roush J. R. Kitamura J. Waits M. C. 2007
2 3 159 163 21522211
Biomechanical analysis of the closed kinetic chain upper-extremity stability test Journal of Sport Rehabilitation Tucci Helga T. Felicio Lilian R. McQuade Kevin J. Bevilaqua-Grossi Debora Camarini Paula Maria Ferreira Oliveira Anamaria S. 1 2017
26 1 42 50 1056-6716 10.1123/jsr.2015-0071 10.1123/jsr.2015-0071
NCAA® sports sponsorship and participation rates report 1981-82 to 2015-16 Irick E. 2017-9-10 www.ncaapublications.com/productdownloads/pr1516.pdf Accessed September 10
Hand-held dynamometer testing of the internal and external rotator musculature based on selected positions to establish normative data and unilateral ratios Journal of Shoulder and Elbow Surgery Riemann Bryan L. Davies George J. Ludwig Lauren Gardenhour Helen 12 2010
19 8 1175 1183 1058-2746 10.1016/j.jse.2010.05.021 10.1016/j.jse.2010.05.021
Intraexaminer reliability of hand-held dynamometry in the upper extremity: A systematic review Archives of Physical Medicine and Rehabilitation Schrama Patrick P.M. Stenneberg Martijn S. Lucas Cees van Trijffel Emiel 12 2014
95 12 2444 2469 0003-9993 10.1016/j.apmr.2014.05.019 10.1016/j.apmr.2014.05.019
Test-retest reliability of the closed kinetic chain upper extremity stability test: A clinical field test Journal of Sport Rehabilitation Goldbeck Todd G. Davies George J. 2 2000
9 1 35 45 1056-6716 10.1123/jsr.9.1.35 10.1123/jsr.9.1.35
A comprehensive guide to multiple exercises Ellenbecker T. Davies G.Closed Kinetic Chain Exercises Human Kinetics Champaign, Illinois 2001

An electromyographic analysis of the upper extremity in pitching Journal of Shoulder and Elbow Surgery DiGiovine Nick M. Jobe Frank W. Pink Marilyn Perry Jacquelin 1 1992
1 1 15 25 1058-2746 10.1016/s1058-2746(09)80011-6 10.1016/s1058-2746(09)80011-6
An EMG analysis of the shoulder in throwing and pitching: A preliminary report The American Journal of Sports Medicine Jobe Frank W. Tibone James E. Perry Jacquelin Moynes Diane SAGE Publications 1 1983
11 1 3 5 0363-5465 10.1177/036354658301100102 10.1177/036354658301100102
Glenohumeral rotational motion and strength and baseball pitching biomechanics Journal of Athletic Training Hurd Wendy J. Kaufman Kenton R. 1 5 2012
47 3 247 256 1062-6050 10.4085/1062-6050-47.3.10 10.4085/1062-6050-47.3.10 22892405
Assessment of shoulder strength in professional baseball pitchers Journal of Orthopaedic & Sports Physical Therapy Donatelli Robert Ellenbecker Todd S. Ekedahl Sheila R. Wilkes Joseph S. Kocher Keith Adam John Journal of Orthopaedic & Sports Physical Therapy (JOSPT) 9 2000
30 9 544 551 0190-6011 10.2519/jospt.2000.30.9.544 10.2519/jospt.2000.30.9.544 10994864
Effect of pitching consecutive days in youth fast-pitch softball tournaments on objective shoulder strength and subjective shoulder symptoms The American Journal of Sports Medicine Skillington S. Andrew Brophy Robert H. Wright Rick W. Smith Matthew V. SAGE Publications 1 2 2017
45 6 1413 1419 0363-5465 10.1177/0363546516688657 10.1177/0363546516688657 28298058
Exploration of the y-balance test for assessment of upper quarter closed kinetic chain performance Int J Sports Phy Ther Westrick R.B. Miller J.M. Carow S.D.. 2012
7 2 139 147
Can upper extremity functional tests predict the softball throw for distance: A predictive validity investigation Int J Sports Phy Ther Negrete R.J. Hanney W.J. Kolber M.J.. 2011
6 2 104 111
Closed kinetic chain testing techniques of the upper extremities Orthop Phys Ther Clin N Am Ellenbecker T.S. Manske R. Davies G.J. 2000
9 2 219 229
Establishing normative data on scapulothoracic musculature using handheld dynamometry Journal of Sport Rehabilitation Turner Nichole Ferguson Kristen Mobley Britney W. Riemann Bryan Davies George 11 2009
18 4 502 520 1056-6716 10.1123/jsr.18.4.502 10.1123/jsr.18.4.502
Make tests and break tests of elbow flexor muscle strength Physical Therapy Bohannon Richard W. 1 2 1988
68 2 193 194 0031-9023 10.1093/ptj/68.2.193 10.1093/ptj/68.2.193
Upper extremity strength and strength relationships among young women Journal of Orthopaedic & Sports Physical Therapy Bohannon Richard W. Journal of Orthopaedic & Sports Physical Therapy (JOSPT) 9 1986
8 3 128 133 0190-6011 10.2519/jospt.1986.8.3.128 10.2519/jospt.1986.8.3.128 18802233
Literature reporting normative data for muscle strength measured by hand-held dynamometry: A systematic review Isokinetics and Exercise Science Bohannon Richard W. 15 8 2011
19 3 143 147 1878-5913 10.3233/IES-2011-0415 10.3233/IES-2011-0415
Hand-held dynamometer measurements: tester strength makes a difference Journal of Orthopaedic & Sports Physical Therapy Wikholm Joan B. Bohannon Richard W. 4 1991
13 4 191 198 0190-6011 10.2519/jospt.1991.13.4.191 10.2519/jospt.1991.13.4.191 18796845
Muscle and sensory testing Reese N.B. Elsevier Health Sciences Louis, Missouri 2012
