Influence of glenohumeral internal rotation deficit on shoulder rotation torque in adolescent baseball players: An isokinetic comparative cross-sectional study
Restricted accessResearch articleFirst published online 2026
Influence of glenohumeral internal rotation deficit on shoulder rotation torque in adolescent baseball players: An isokinetic comparative cross-sectional study
Glenohumeral internal rotation range of motion deficit (GIRD) is linked to shoulder strength in the glenohumeral (GH) joint and to increased risk of throwing-related injuries. In adolescent overhead athletes, GIRD ≥25° has been associated with a four-fold higher risk of upper-extremity injury. However, from a functional perspective relevant to overhead throwing, the extent to which GIRD is related to the dynamic strength of the shoulder rotators has not been investigated.
Objective
This study compared internal rotation (IR) and external rotation (ER) torque between adolescent baseball athletes with and without GIRD, and examined factors associated with concentric and eccentric IR/ER torque, including GH joint range of motion (ROM).
Method
Eighty male adolescent baseball athletes participated. IR, ER, total rotational ROM, and GIRD were measured. Concentric and eccentric torque of IR and ER, as well as functional strength ratios, were assessed. Group differences were analyzed with independent t-tests, correlations with Pearson's coefficients, and predictors with Stepwise multiple regression analysis.
Results
Concentric IR and ER torques were significantly lower in the GIRD group than in the non-GIRD group (mean differences: 4.6% and 6.9% body weight, respectively; p < 0.05). Concentric torques showed poor to fair correlations with GH joint rotational ROM, particularly reduced IR ROM and increased GIRD. Eccentric torques did not differ significantly between groups. Regression analysis identified IR ROM and GIRD as significant predictors of concentric torque, while antagonist exhibited the greatest relative influence on the agonist.
Conclusions
Concentric shoulder strength (IR and ER torques) is reduced in adolescent baseball athletes with GIRD and is significantly associated with IR ROM loss. IR ROM and GIRD were key predictors of concentric torque, while antagonist strength exerted the greatest relative influence on agonist function. In contrast, eccentric torques showed no group differences or meaningful correlation with GH joint ROM.
LymanSFleisigGSAndrewsJR. Effect of pitch type, pitch count, and pitching mechanics on risk of elbow and shoulder pain in youth baseball pitches. Am J Sports Med2002; 30: 463–468.
2.
RechelJAYardEEComstockRD. An epidemiologic comparison of high school sports injuries sustained practice and competition. J Athl Train2008; 43: 197–204.
3.
SaperMGPierpointLALiuW, et al.Epidemiology of shoulder and elbow injuries among United States high school baseball players: school years 2005-2006 through 2014-2015. Am J Sports Med2018; 46: 37–43.
4.
TajikaTOyaNKuboiT, et al.Risk factors for throwing-related shoulder and elbow pain in adolescent baseball players: a prospective study of physical and developmental factors. Orthop J Sports Med2021; 9: 23259671211017129.
5.
FleisigGSBoltBFortenbaughD, et al.Biomechanical comparison of baseball pitching and long-toss: implications for training and rehabilitation. J Orthop Sports Phys Ther2011; 41: 296–303.
6.
GoesPKFloresDVDamerA, et al.Shoulder and elbow injuries in adult overhead throwers: imaging review. Radiographics2023; 43: e230094.
7.
BurkhartSSMorganCDKiblerWB. The disabled throwing shoulder: spectrum of pathology part I: pathoanatomy and biomechanics. Arthroscopy2003; 19: 404–420.
8.
DigiovineNMJobeFWPinkM, et al.An electromyographic analysis of the upper extremity in pitching. J Shoulder Elbow Surg1992; 1: 15–25.
9.
WilkKEMeisterKAndrewsJR. Current concepts in the rehabilitation of the overhead throwing athlete. Am J Sports Med2002; 30: 136–151.
10.
NakamizoHNakamuraYNobuharaK, et al.Loss of glenohumeral internal rotation in little league pitchers: a biomechanical study. J Shoulder Elbow Surg2008; 17: 795–801.
11.
ThacherRRVaradyNHKhilnaniT, et al.Current concepts on the management of shoulder instability in throwing athletes. Curr Rev Musculoskelet Med2024; 17: 353–364.
12.
BorsaPALaudnerKGSauersEL. Mobility and stability adaptations in the shoulder of the overhead athlete: a theoretical and evidence-based perspective. Sports Med2008; 38: 17–36.
13.
BurkhartSSMorganCDKiblerWB. The disabled throwing shoulder: spectrum of pathology. Part II: evaluation and treatment of SLAP lesions in throwers. Arthroscopy2003; 19: 531–539.
WilkKEMacrinaLCFleisigGS, et al.Correlation of glenohumeral internal rotation deficit and total rotational motion to shoulder injuries in professional baseball pitchers. Am J Sports Med2011; 39: 329–335.
16.
AldridgeRStephen GuffeyJWhiteheadMT, et al.The effects of a daily stretching protocol on passive glenohumeral internal rotation in overhead throwing collegiate athletes. Int J Sports Phys Ther2012; 7: 365–371.
17.
FairallRRCabellLBoergersRJ, et al.Acute effects of self-myofascial release and stretching in overhead athletes with GIRD. J Bodyw Mov Ther2017; 21: 648–652.
18.
MyersJBLaudnerKGPasqualeMR, et al.Glenohumeral range of motion deficits and posterior shoulder tightness in throwers with pathologic internal impingement. Am J Sports Med2006; 34: 385–391.
19.
ShanleyERauhMJMichenerLA, et al.Shoulder range of motion measures as risk factors for shoulder and elbow injuries in high school softball and baseball players. Am J Sports Med2011; 39: 1997–2006.
20.
TylerTFMullaneyMJMirabellaMR, et al.Risk factors for shoulder and elbow injuries in high school baseball pitchers: the role of preseason strength and range of motion. Am J Sports Med2014; 42: 1993–1999.
21.
KellerRADe GiacomoAFNeumannJA, et al.Glenohumeral internal rotation deficit and risk of upper extremity injury in overhead athletes: a meta-analysis and systematic review. Sports Health2018; 10: 125–132.
22.
ClarsenBBahrRAnderssonSH, et al.Reduced glenohumeral rotation, external rotation weakness and scapular dyskinesis are risk factors for shoulder injuries among elite male handball players: a prospective cohort study. Br J Sports Med2014; 48: 1327–1333.
23.
NeumannDA. Kinesiology of the musculoskeletal system: foundations for rehabilitation. 3rd ed.St Louis, USA: Elsevier, 2017.
24.
TrakisJEMcHughMPCaraccioloPA. Muscle strength and range of motion in adolescent pitchers with throwing-related pain: implications for injury prevention. Am J Sports Med2008; 36: 2173–2178.
25.
YamauraKMifuneYInuiA, et al.Relationship between glenohumeral internal rotation deficit and shoulder conditions in professional baseball pitchers. J Shoulder Elbow Surg2021; 30: 2073–2081.
26.
GuneyHHarputGColakogluF, et al.The effect of glenohumeral internal-rotation deficit on functional rotator-strength ratio in adolescent overhead athletes. J Sport Rehabil2016; 25: 52–57.
27.
FleisigGSAndrewsJRDillmanCJ, et al.Kinetics of baseball pitching with implications about injury mechanisms. Am J Sports Med1995; 23: 233–239.
28.
SeroyerSTNhoSJBachBR, et al.Shoulder pain in the overhead throwing athlete. Sports Health2009; 1: 108–120.
29.
BakKMagnussonP. Shoulder strength and range of motion in symptomatic and pain-free elite swimmers. Am J Sports Med1997; 25: 454–459.
30.
NgGYLamPC. A study of antagonist/agonist isokinetic work ratios of shoulder rotators in men who play badminton. J Orthop Sports Phys Ther2002; 32: 399–404.
31.
Andrade MdosSFleuryAMde LiraCA, et al.Profile of isokinetic eccentric-to-concentric strength ratios of shoulder rotator muscles in elite female team handball players. J Sports Sci2010; 28: 743–749.
32.
NoffalGJ. Isokinetic eccentric-to-concentric strength ratios of the shoulder rotator muscles in throwers and nonthrowers. Am J Sports Med2003; 31: 537–541.
33.
SaccolMFGracitelliGCda SilvaRT, et al.Shoulder functional ratio in elite junior tennis players. Phys Ther Sport2010; 11: 8–11.
34.
ScovilleCRArcieroRATaylorDC, et al.End range eccentric antagonist/concentric agonist strength ratios: a new perspective in shoulder strength assessment. J Orthop Sports Phys Ther1997; 25: 203–207.
35.
LeahyIFlorkiewiczEShotwellMP. Isokinetic dynamometry for external and internal rotation shoulder strength in youth athletes: a scoping review. Int J Sports Phys Ther2024; 19: 1521–1531.
36.
EllenbeckerTSDaviesGJ. The application of isokinetics in testing and rehabilitation of the shoulder complex. J Athl Train2000; 35: 338–350.
37.
CarvalhoHMCoelhoESilvaMJ, et al.Assessment of reliability in isokinetic testing among adolescent basketball players. Medicina (Kaunas)2011; 47: 446–452.
38.
MontiRFernandez-FernandezA. The Kerlan-Jobe orthopaedic clinic shoulder & elbow score used as a patient-reported outcome measure for the youth and high school aged baseball athlete. Int J Sports Phys Ther2022; 17: 879–886.
39.
MorrisseyDMorrisseyMCDriverW. Manual landmark identification and tracking during the medial rotation test of the shoulder: an accuracy study using three-dimensional ultrasound and motion analysis measures. Man Ther2008; 13: 529–535.
ForthommeBDvirZCrielaardJM, et al.Isokinetic assessment of the shoulder rotators: a study of optimal test position. Clin Physiol Funct Imaging2011; 31: 227–232.
42.
HillAMPramanikSMcGregorAH. Isokinetic dynamometry in assessment of external and internal axial rotation strength of the shoulder: comparison of two positions. Isokinet Exerc Sci2005; 13: 187–195.
43.
YuIYKangMHOhJS. The effects of posterior shoulder stretch on rotator cuff strength ratio in adolescent baseball players with scapular dyskinesis: a randomized controlled trial. Isokinet Exerc Sci2018; 26: 63–71.
44.
YildizYAydinTSekirU, et al.Shoulder terminal range eccentric antagonist/concentric agonist strength ratios in overhead athletes. Scand J Med Sci Sports2006; 16: 174–180.
45.
CarterABKaminskiTWDouexATJr, et al.Effects of high volume upper extremity plyometric training on throwing velocity and functional strength ratios of the shoulder rotators in collegiate baseball players. J Strength Cond Res2007; 21: 208–215.
46.
FowlesJRSaleDGMacDougallJD. Reduced strength after passive stretch of the human plantar flexors. J Appl Physiol2000; 89: 1179–1188.
47.
CavagnaGA. Elastic bounce of the body. J Appl Physiol1970; 29: 279–282.
48.
WilsonGJWoodGAElliottBC. Optimal stiffness of series elastic component in a stretch-shorten cycle activity. J Appl Physiol1991; 70: 825–833.
49.
LaudnerKGMolineMTMeisterK. The relationship between forward scapular posture and posterior shoulder tightness among baseball players. Am J Sports Med2010; 38: 2106–2112.
50.
DuncanPWChandlerJMCavanaughDK. Mode and speed specificity of eccentric and concentric exercise training. J Orthop Sports Phys Ther1989; 11: 70–75.
51.
WalmsleyRPPearsonNStymiestP. Eccentric wrist extensor contractions and the force velocity relationship in muscle. J Orthop Sports Phys Ther1986; 8: 288–293.
52.
KossevAChristovaP. Discharge pattern of human motor units during dynamic concentric and eccentric contractions. Electroencephalogr Clin Neurophysiol1998; 109: 245–255.
53.
LinnamoVMoritaniTNicolC, et al.Motor unit activation patterns during isometric, concentric and eccentric actions at different force levels. J Electromyogr Kinesiol2003; 13: 93–101.
