Rotator Cuff Training for Pitchers

This paper reviews the role of the rotator cuff during two key phases of the pitching sequence and presents a training program for these muscles. The program uses a periodization design consisting of three stages, beginning with a high-resistance/low-repetition eccentric strengthening stage. This is followed by a low-resistance/high-repetition stage for training muscular endurance. The core exercises for these two stages are prone external rotation in the 90/90 position, prone horizontal abduction, side-lying D2 flexion pattern, supine internal rotation in the 90/90 position, prone elevation with 100° of shoulder abduction and external rotation, and standing scapular plane elevation. The final stage of the program uses high-speed functional exercises: 90/90 external rotation, 90/90 internal rotation, D2 PNF flexion pattern, D2 PNF extension pattern, supine plyometric 90/90 internal rotation with a medicine ball, and the “arm whip” through the D2 PNF flexion pattern. The goal of this program is to prepare the muscles for the stresses of pitching and prevent shoulder injuries.

Download Full-text

Comparison of Shoulder Functions Between Workers With and Without Shoulder Impingement Syndrome

10.1101/2020.05.24.20109736 ◽

2020 ◽

Author(s):

Jun-hee Kim ◽

Oh-yun Kwon ◽

Chung-hwi Yi ◽

Hye-seon Jeon ◽

Woo-chol Joseph Choi ◽

...

Keyword(s):

Muscle Strength ◽

Internal Rotation ◽

External Rotation ◽

Impingement Syndrome ◽

Shoulder Abduction ◽

Shoulder Impingement Syndrome ◽

Asymmetry Ratio ◽

Shoulder Injuries ◽

Shoulder Impingement ◽

The Asymmetry

The occurrence of shoulder impingement syndrome (SIS) is associated with the frequent handling and lifting of heavy loads and excessive repetitive work above the shoulder level. Thus, assembly workers have a high prevalence of shoulder injuries, including SIS. The purpose of this study was to investigate differences in shoulder ROM, muscle strength, asymmetry ratio, function, productivity, and depression between workers with and without SIS.Sixty-seven assembly line male workers (35 workers with SIS and 32 workers without SIS) participated in this study. The four shoulder ROMs and the five muscle strengths were measured using a Smart KEMA system. The asymmetry ratios were calculated using the asymmetry ratio formula; shoulder functions were measured using the shoulder pain and disability index (SPADI), disabilities of the arm, shoulder, and hand (DASH), and visual analogue scale (VAS); and Endicott work productivity scale (EWPS). Severity of depression was measured using the Beck depression inventory (BDI). Independent t-tests were performed for statistical analysis.The SPADI, DASH, and VAS values of workers with SIS were significantly higher than those of workers without SIS. Also, workers with SIS had significantly smaller shoulder internal rotation and shoulder abduction compared to workers without SIS. In addition, workers with SIS exhibited significantly lower SIR muscle strength than workers without SIS. Workers with SIS had significantly higher asymmetry ratios in shoulder internal rotation, shoulder external rotation, and elbow flexion muscle strength than workers without SIS.The SPADI and DASH scores, which indicate shoulder function, were higher, and the intensity of self-aware pain was higher in workers with SIS. Also, workers with SIS exhibited reduced SIR and SAB ROMs; decreased SIR muscle strength. Particularly, the asymmetry ratios of SIR, SER, EF muscle strength are good comparable factors for workers with and without SIS. In addition, the asymmetry ratios of shoulder muscle strengths could provide an important baseline comparison for the workers with SIS.

Download Full-text

Força dos Músculos Rotadores do Ombro em Indivíduos Saudáveis/ Rotator Cuff Muscle Strength in Healthy Individuals

REVISTA CIÊNCIAS EM SAÚDE ◽

10.21876/rcsfmit.v1i1.19 ◽

1970 ◽

Vol 1 (1) ◽

pp. 78-82

Author(s):

Paulo José Oliveira Cortez ◽

José Elias Tomazini ◽

Mauro Gonçalves

Keyword(s):

Rotator Cuff ◽

Muscle Strength ◽

Internal Rotation ◽

Upper Limb ◽

Statistical Difference ◽

External Rotation ◽

Healthy Individuals ◽

Average Strength ◽

Strength Tests ◽

The Right

Introdução: A diminuição da capacidade de exercer esforços por parte dos músculos rotadores pode criar uma variedade de problemas. O conhecimento preciso do nível de força muscular de um indivíduo é importante, tanto para a avaliação da capacidade funcional ocupacional, como para uma apropriada prescrição de exercícios atléticos e de reabilitação. Percebe-se escassez de informação sobre as articulações do ombro, bem como os fatores envolvidos na força muscular dessa região. O objetivo deste estudo foi comparar a força gerada pelos músculos do manguito rotador entre o membro superior direito e o membro superior esquerdo em indivíduos saudáveis. Métodos: Participaram do estudo 22 sujeitos do sexo masculino, com idade de 18 e 19 anos, militares, saudáveis e sem história clínica de patologia ortopédica ou qualquer tipo de lesão no sistema musculoesquelético. Foram aplicados dois testes de força: Rotação Interna e Rotação Externa. Resultado : A força média de rotação interna no membro superior direito (MSD) foi maior que a força média de rotação interna no membro superior esquerdo (MSE) (p=0,723) e a força de rotação externa no MSD foi menor que a força média de rotação externa no MSE (p=0,788). Não houve diferença estatística na comparação dos valores de força de todos os testes de força isométrica. Conclusão: Para amostra estudada e metodologia utilizada na avaliação da força muscular, não houve diferença estatística na comparação da força gerada pelos músculos do manguito rotador do membro superior direito e do membro superior esquerdo.Rotator Cuff Muscle Strength in Healthy Individuals Introduction: Decreased ability to exert efforts by the rotator muscles can create a variety of problems. The precise knowledge of the level of muscular strength of an individual is important for both the functional capacity evaluation for occupational as an appropriate exercise prescription and rehabilitation of athletic. It is perceived scarcity of information on the shoulder joints as well as factors involved in muscle strength in this region. Objective: Develop a device for measuring the strength generated by the muscles of the upper limbs and the verification of efficiency and adaptability of this device through a comparative study of muscle strength in healthy subjects. Methods: The study included 22 male subjects, aged 18 and 19 years, military personnel, body mass between 57.7 and 93 kg (71.8 ± 9.45 kg) and height between 1.67 and 1.90 m (1.75 ± 0.06 m), healthy and without a history of orthopaedic disease or any kind of damage to the musculoskeletal system. Three strength tests were applied: Internal Rotation and External Rotation. For each type of effort three maximum voluntary contractions were required for 10 seconds, with an interval of 30 seconds between each contraction. Results: Internal rotation in the right upper limb (RUL) was higher than the average strength of internal rotation in the left upper limb (LUL) (p = 0, 723) and the external rotation strength in RUL was lower than the average strength of external rotation in the LUL (p=0,788). No statistical difference in comparing the strength values of all isometric strength tests. Conclusion: For sample and methodology used to assess muscle strength, there was no statistical difference in comparing the force generated by the muscles of the rotator cuff of the right and left upper limb.

Download Full-text

Chronic Adaptations of the Posterior Rotator Cuff in Professional Pitchers

The American Journal of Sports Medicine ◽

10.1177/0363546520988688 ◽

2021 ◽

pp. 036354652098868

Author(s):

Stephen J. Thomas ◽

Justin Cobb ◽

Scott Sheridan ◽

Joseph Rauch ◽

Ryan W. Paul

Keyword(s):

Soft Tissue ◽

Rotator Cuff ◽

Internal Rotation ◽

External Rotation ◽

Negative Relationship ◽

Muscle Thickness ◽

Pennation Angle ◽

Muscle Architecture ◽

Infraspinatus Muscle ◽

Teres Minor

Background: Because of the large forces and high frequency of throwing, the upper extremity experiences repetitive stresses that lead to acute and chronic adaptations. While the importance of pennation angle and muscle thickness as predictors of muscle force production has been shown in other populations and other joints, there has been little research done that examines these variables in the shoulders of baseball players. Purpose: (1) To examine the chronic effect pitching has on the rotator cuff muscle architecture (pennation angle and muscle thickness) in healthy professional baseball pitchers, and (2) to examine the correlation between muscle architecture and clinical measures of strength and range of motion (ROM). Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty-eight healthy professional pitchers were recruited during the 2019 spring training. Internal rotation (IR) and external rotation (ER) strength were measured with a handheld dynamometer and IR and ER ROM were measured with an inclinometer. A diagnostic ultrasound machine was utilized to capture images of humeral retroversion, as well as the pennation angle and muscle thickness of the infraspinatus and teres minor muscles. ImageJ software was used to quantify the pennation angle and muscle thickness. Results: There were no significant differences between the dominant and nondominant arms for ER or IR strength. Also, no pennation angle and muscle thickness differences were found between the dominant and nondominant arms. A weak positive relationship between infraspinatus muscle thickness (superficial and total) and ER strength ( P = .016, R = 0.287 and P = .009, R = 0.316) and a moderate negative relationship between soft tissue glenohumeral internal rotation deficit (GIRD) and the bilateral difference of the teres minor deep pennation angle ( R = −0.477, P = .008) were observed. No other significant relationships were noted. Conclusion: Our results are contrary to current literature as we expected to see a stronger dominant arm, with a larger pennation angle and greater muscle thickness. Interestingly, we found that ER strength was positively related to only the thickness of the infraspinatus muscle, and that soft tissue GIRD was positively related to only the side-to-side adaptation of the pennation angle within the deep portion of the teres minor. This suggests that when posterior shoulder tightness occurs, specifically the architecture of the teres minor muscle is involved. However, the organization to which these players belonged has a very extensive training protocol throughout the year that emphasizes bilateral training during a large majority of the exercises. Therefore, the results may not be generalizable to all professional players.

Download Full-text

Delayed Rehabilitation Protocol after Rotator Cuff Repair

Osteology ◽

10.3390/osteology1010003 ◽

2020 ◽

Vol 1 (1) ◽

pp. 29-38

Author(s):

Alessandra Berton ◽

Sergio De Salvatore ◽

Vincenzo Candela ◽

Gabriele Cortina ◽

Daniela Lo Presti ◽

...

Keyword(s):

Rotator Cuff ◽

Muscle Strength ◽

Internal Rotation ◽

Outcome Measures ◽

Rotator Cuff Repair ◽

External Rotation ◽

Shoulder Function ◽

Rehabilitation Protocol ◽

Patient Reported ◽

Cuff Repair

Rotator cuff tears are a frequent cause of shoulder pain that often require arthroscopic repair. After surgery an intense and well-studied rehabilitation protocol is needed to obtain the complete recovery of shoulder function. Fifty patients, who sustained arthroscopic rotator cuff repair for symptomatic, atraumatic and full-thickness supraspinatus tendon tear, were involved. According to our rehabilitation protocol, during the first four postoperative weeks, the arm was supported with an abduction sling pillow, and pendulum exercises, table slide and active elbow extension and flexion were conceded. Outcome measures (Oxford shoulder score (OSS), simple shoulder test (SST), patient-reported satisfaction), shoulder function (range of motion (ROM) and muscle strength), and MRI examination were evaluated. The mean OSS score and SST score increased from 16 to 30.2 and from 5.3 to 11.4, respectively. Patient-reported satisfaction was 96%. At 12 months, patients improved ROM and muscle strength. Postoperative passive anterior elevation was 176; external rotation averaged 47; internal rotation was 90. Postoperative muscle strength during anterior elevation was 8.3 ± 2.2 kg, internal rotation 6.8 ± 3 kg, external rotation 5.5 ± 2.3 kg. Five out of seven patients with recurrent tears evaluated their results as satisfactory. They reported improvements in terms of OSS and SST mean scores despite recurrent tears; therefore, they did not undergo revision surgery. The delayed postoperative physical therapy protocol was associated with improvements in the outcome measures and shoulder function compared to the preoperatory state and rotator cuff healing demonstrated by MRI.

Download Full-text

A NEW PARADIGM FOR THE IN VITRO SIMULATION OF SIDEWAYS FALL LOADING OF THE PROXIMAL HUMAN FEMUR

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519414500055 ◽

2014 ◽

Vol 14 (01) ◽

pp. 1450005 ◽

Cited By ~ 4

Author(s):

LORENZO ZANI ◽

LUCA CRISTOFOLINI ◽

MATEUSZ MARIA JUSZCZYK ◽

LORENZO GRASSI ◽

MARCO VICECONTI

Keyword(s):

Femoral Head ◽

Internal Rotation ◽

Proximal Femur ◽

High Speed ◽

External Rotation ◽

Frontal Plane ◽

New Paradigm ◽

Human Femur ◽

Sideways Fall

Although the direction of loads applied to the proximal human femur is unpredictable during sideways fall, most in vitro and numerical simulations refer to a single loading condition (15° internal rotation; 10° adduction), which has been anecdotally suggested in the 1950s. The aim of the present study was to improve in vitro simulations of sideways falls on the proximal femur. An in vitro setup was developed that allowed exploring a range of loading directions +/-90° internal–external rotation; 0°–50° adduction). To enable accurate control of the loading conditions (direction and magnitude of all load components applied to the femur), the setup included a number of low-friction linear and rotary bearings. The setup was instrumented with an axial and a torsional load cell, three displacement transducers and a rotation transducer to monitor the most significant components of load/displacement during testing. The strain distribution was measured on the bone surface (16 triaxial strain gauges, 2,000 Hz). Fracture was recorded with a high-speed camera. The setup was successfully tested on a cadaveric femur non-destructively (12 loading configurations) and destructively (15° internal rotation; 10° adduction). All measurements were highly repeatable (the displacements of the femoral head varied by < 2% between repetitions; the tilt in the frontal plane by < 0.05°; and strain varied on average 0.34% between repetitions). The displacement of the femoral head varied by over 50% when the same force was applied in different directions. Principal strains at the same location varied by over 70%, depending on the direction of the applied force. The high-speed video enabled the identification of the point of fracture initiation. This study has shown that a new paradigm for testing the proximal femur (including improved testing conditions and a variety of loading configurations) can provide more accurate and more extensive information about the state of strain.

Download Full-text

STRENGTHENING AND STABILIZATION EXERCISES IN PREVENTION OF SHOULDER INJURIES

sportlogia ◽

10.5550/sgia.201601.en.bl ◽

2020 ◽

Vol 16 (1) ◽

pp. 149-160

Author(s):

Bernarda Letnar ◽

Keyword(s):

Training Program ◽

Internal Rotation ◽

Shoulder Joint ◽

External Rotation ◽

Shoulder Injuries ◽

Serratus Anterior ◽

Warm Up ◽

Overhead Athletes ◽

Daily Training ◽

Stretching Exercises

The shoulder joint is the most flexible joint in the human body which experiences high loads during certain sport activities involving overhead motion. Overhead athletes experience rapid shoulder elevation, abduction and external rotation during the movement and rapid deceleration after the movement, making them susceptible to shoulder injuries. Due to the extreme ranges of motion, overhead athletes tend to develop increased external rotation, combined with decreased range of internal rotation, emphasizing the need for balanced shoulder care program in the training process to prevent such occurrences. The aim of the research paper was to develop training regimen for injury prevention and shoulder maintenance that can be incorporated in daily training activities of the athletes in order to decrease the occurrence of injuries. Three part training program was designed consisting of specific warm up, strengthening and stabilization exercises and stretching exercises. The aim of the specific warm up was to prepare the shoulder for the training loads, mimicking the overhead movements and stimulating the stabilization in the joint. Strengthening and stabilization exercises aimed to strengthen external rotators in the shoulder and improve the stabilization of the shoulder joint by targeting specific muscles such as serratus anterior. The focus of stretching exercises was to stretch internal rotation muscles, which experience high loads in the overhead athlete's training. An effective training program that can be performed with minimal equipment and in a short time frame was designed to enable its simple incorporation into the daily training of overhead athletes.

Download Full-text

Biomechanical characteristics of scapula and glenohumeral movements during pitching motion in injury-prone college baseball pitchers

10.1101/2021.11.22.469507 ◽

2021 ◽

Author(s):

Koji Miyashita ◽

Sentaro Koshida ◽

Taro Koyama ◽

Kenicihro Ota ◽

Yusuke Tani ◽

...

Keyword(s):

Sports Medicine ◽

High Speed ◽

Glenohumeral Joint ◽

External Rotation ◽

Three Dimensional ◽

Control Group ◽

Shoulder Injuries ◽

Pitching Motion ◽

College Baseball ◽

Baseball Pitchers

Coordination of glenohumeral and scapular movements plays an important role in the injury prevention of baseball pitchers. However, there is no objective data establishing the direct relationship between pitching injuries and associated glenohumeral and scapular movements. Therefore, the objectives of the present study were to demonstrate biomechanical differences in scapular and glenohumeral movements during pitching between injury-prone pitchers and healthy college baseball pitchers. Thirty collegiate baseball pitchers were classified into two groups according to their injury status: injury-prone group (N=15, 20.7±1.4 years, 180.1±6.5 cm, 78.9±5.4 kg) and control group (N=15, 20.9±1.1 years, 177.1±6.6 cm, 72.3±6.7 kg). We obtained the pitching motion data using the three-dimensional motion analysis technique with four high-speed cameras. The horizontal abduction angles of the glenohumeral joint during cocking and acceleration phases were significantly greater in injury-prone pitchers [19.0° (95% CI: 14.4–23.6) at foot contact, −4.0° (95% CI: −7.7 to −0.2) at maximum external rotation (MER), and −0.3° (95% CI: −4.8 to −4.2) at ball release] than in healthy controls [11.7 °(95%CI:7.1 to 16.3) at foot contact, −10.0°(95%CI: −13.7 to −6.3) at MER, and −6.9°(95%CI: −11.4 to −2.4)]( p <0.01). In addition, the external rotation angle (ER) of the scapula at MER was significantly greater in the injury-prone group [−0.1° (95% CI: −5.0 to 4.8)] than in the control group [−12.3° (95% CI: −17.2 to −7.4)] (p<0.01), but there was no difference in the scapular ER during foot contact between the two groups. These results suggests that injury-prone pitchers have less internal rotation of the scapula and more horizontal abduction of the glenohumeral joint during cocking and acceleration phases. Therefore, sports medicine practitioners may need to pay more attention to coordination of scapular and glenohumeral movements during the cocking and acceleration phases of pitching for prevention of shoulder injuries.

Download Full-text

Effect of a 6-Week Strengthening Program on Shoulder and Scapular-Stabilizer Strength and Scapular Kinematics in Division I Collegiate Swimmers

Journal of Sport Rehabilitation ◽

10.1123/jsr.21.3.253 ◽

2012 ◽

Vol 21 (3) ◽

pp. 253-265 ◽

Cited By ~ 29

Author(s):

Elizabeth E. Hibberd ◽

Sakiko Oyama ◽

Jeffrey T. Spang ◽

William Prentice ◽

Joseph B. Myers

Keyword(s):

Muscle Strength ◽

Internal Rotation ◽

Intervention Program ◽

External Rotation ◽

Division I ◽

Shoulder Injuries ◽

Scapular Kinematics ◽

Outcome Measurements ◽

Weight Room ◽

Stretching Exercises

Context:Shoulder injuries are common in swimmers because of the demands of the sport. Muscle imbalances frequently exist due to the biomechanics of the sport, which predispose swimmers to injury. To date, an effective shoulder-injury-prevention program for competitive swimmers has not been established.Objective:To assess the effectiveness of a 6-wk strengthening and stretching intervention program on improving glenohumeral and scapular muscle strength and scapular kinematics in collegiate swimmers.Design:Randomized control trial.Setting:University biomechanics research laboratory.Participants:Forty-four Division I collegiate swimmers.Interventions:The intervention program was completed 3 times per week for 6 wk. The program included strengthening exercises completed using resistance tubing—scapular retraction (Ts), scapular retraction with upward rotation (Ys), scapular retraction with downward rotation (Ws), shoulder flexion, low rows, throwing acceleration and deceleration, scapular punches, shoulder internal rotation at 90° abduction, and external rotation at 90° abduction—and 2 stretching exercises: corner stretch and sleeper stretch.Main Outcome Measurements:Scapular kinematics and glenohumeral and scapular muscle strength assessed preintervention and postintervention.Results:There were no significant between-groups differences in strength variables at pre/post tests, although shoulder-extension and internal-rotation strength significantly increased in all subjects regardless of group assignment. Scapular kinematic data revealed increased scapular internal rotation, protraction, and elevation in all subjects at posttesting but no significant effect of group on the individual kinematic variables.Conclusions:The current strengthening and stretching program was not effective in altering strength and scapular kinematic variables but may serve as a framework for future programs. Adding more stretching exercises, eliminating exercises that overlap with weight-room training and swim training, and timing of implementation may yield a more beneficial program for collegiate swimmers.

Download Full-text

Improved Rotator Cuff Footprint Contact Characteristics With an Augmented Repair Construct Using Lateral Edge Fixation

The American Journal of Sports Medicine ◽

10.1177/0363546519888182 ◽

2019 ◽

Vol 48 (2) ◽

pp. 444-449

Author(s):

Ekaterina Urch ◽

Charles C. Lin ◽

Yasuo Itami ◽

Nilay A. Patel ◽

Michelle H. McGarry ◽

...

Keyword(s):

Rotator Cuff ◽

Gold Standard ◽

External Rotation ◽

Contact Forces ◽

Rotator Cuff Tears ◽

Shoulder Abduction ◽

Average Difference ◽

Double Row ◽

Lateral Edge ◽

Contact Pressures

Background: The transosseous-equivalent (TOE) rotator cuff repair construct has become the gold standard for the repair of medium and large rotator cuff tears. Repair failure, however, continues to be a problem. One contributing factor may be the inability of the TOE repair to replicate the native footprint contact characteristics during shoulder movement, especially in rotation. This results in higher strain across the repair, which leads to gapping and predisposes the construct to failure. In an effort to better reproduce the native compression forces throughout the footprint, an augmented TOE construct supplemented with lateral edge fixation is proposed, and the contact characteristics were compared with those of the gold standard TOE construct. Hypothesis: The augmented TOE repair will demonstrate improved footprint contact characteristics when compared with the classic TOE repair. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen cadaveric shoulders underwent supraspinatus repair using both the classic TOE double-row construct and the augmented TOE repair. For the augmented repair, 2 luggage tag sutures were used to secure the lateral edge and incorporated into the lateral row anchors. A Tekscan pressure sensor (Tekscan Inc) placed under the repaired tendon was used to collect footprint contact area, force, peak pressure, and contact pressure data for each construct. Results: The augmented construct demonstrated significantly greater contact forces (average difference, 4.9 N) and significantly greater contact pressures (average difference, 23.1 kPa) at all degrees of abduction and all degrees of rotation. At 30° of internal and 30° of external rotation at both 0° and 30° of shoulder abduction, the augmented construct demonstrated significantly greater peak contact pressures. Conclusion: The augmented construct showed superior contact characteristics when compared with the classic TOE technique. The addition of lateral edge fixation to the classic TOE repair significantly improves bone-tendon contact characteristics with minimal additional surgical effort. Clinical Relevance: The results of this study indicate that lateral augmentation of the classic TOE repair produces a biomechanically superior construct that may optimize tendon healing.

Download Full-text

Gluteus Medius Muscle Activation During Isometric Muscle Contractions

Journal of Sport Rehabilitation ◽

10.1123/jsr.20.2.174 ◽

2011 ◽

Vol 20 (2) ◽

pp. 174-186 ◽

Cited By ~ 14

Author(s):

Catriona O’Dwyer ◽

David Sainsbury ◽

Kieran O’Sullivan

Keyword(s):

Internal Rotation ◽

Outcome Measures ◽

Lower Limb ◽

Repeated Measures ◽

Muscle Activation ◽

External Rotation ◽

Gluteus Medius ◽

Isometric Contractions ◽

Main Effect

Context:Functional subdivisions are proposed to exist in the gluteus medius (GM) muscle. Dysfunction of the GM, in particular its functional subdivisions, is commonly implicated in lower limb pathologies. However, there is a lack of empirical evidence examining the role of the subdivisions of the GM.Objectives:To compare the activation of the functional subdivisions of the GM (anterior, middle, and posterior) during isometric hip contractions.Design:Single-session, repeated-measures observational study.Setting:University research laboratory.Participants:Convenience sample of 15 healthy, pain-free subjects.Intervention:Subjects performed 3 maximal voluntary isometric contractions for hip abduction and internal and external rotation on an isokinetic dynamometer with simultaneous recording of surface electromyography (sEMG) activity of the GM subdivisions.Main Outcome Measures:sEMG muscle activity for each functional subdivision of the GM during each hip movement was analyzed using a 1-way repeated-measures ANOVA (post hoc Bonferroni).Results:The response of GM subdivisions during the 3 different isometric contractions was significantly different (interaction effect; P = .003). The anterior GM displayed significantly higher activation across all 3 isometric contractions than the middle and posterior subdivisions (main effect; both P < .001). The middle GM also demonstrated significantly higher activation than the posterior GM across all 3 isometric contractions (main effect; P = .027). There was also significantly higher activation of all 3 subdivisions during both abduction and internal rotation than during external rotation (main effect; both P < .001).Conclusions:The existence of functional subdivisions in the GM appears to be supported by the findings. Muscle activation was not homogeneous throughout the entire muscle. The highest GM activation was found in the anterior GM subdivision and during abduction and internal rotation. Future studies should examine the role of GM functional subdivisions in subjects with lower limb pathologies.

Download Full-text