Guy Grover - Academia.edu (original) (raw)

Papers by Guy Grover

Medicine and Science in Sports and Exercise, May 1, 2006

Sports Biomechanics, Feb 6, 2020

In this study, a custom device was developed to analyse the pitching shoulder's external rotation... more In this study, a custom device was developed to analyse the pitching shoulder's external rotation (ER) and internal rotation (IR) passive flexibility. We analysed three novel measures: the resistance onset angle (ROA = angle where the shoulder begins stretching), rotational stiffness, and torque at the end range of motion (ROM). The purpose was to conduct a bilateral analysis to determine if there are significant differences between the throwing and nonthrowing shoulder. Participants were 30 upper level pitchers (13 division I, 17 minor league). During testing, pitchers laid supine on a treatment table and the arm was secured to a rotational wheel with the shoulder abducted 90°and elbow flexed 90°. Dependent t-tests revealed significant (p < 0.01) and relatively extreme bilateral differences for all three variables. The throwing shoulder had: increased ER ROA (9°), decreased IR ROA (5.3°), increased ER stiffness (17%), increased IR stiffness (34%), increased ER torque (21%), and increased IR torque (30%). Secondary correlation analysis was completed to determine if the torque-angle variables were good predictors of the end ROM. Stiffness correlations were weak for ER (r = 0.35, p = 0.048) and IR (r = 0.42, p = 0.017) but ROA correlations were strong for ER (r = 0.85, p < 0.001) and IR (r = 0.86, p < 0.001).

Physical Therapy in Sport, Sep 1, 2018

Objectives: 1) Thoroughly assess shoulder flexibility by establishing the passive torque-angle re... more Objectives: 1) Thoroughly assess shoulder flexibility by establishing the passive torque-angle relationship for internal and external rotation with the arm in an overhead athletics position (abducted 90°) and 2) test the reliability of four passive torque-angle measures. Design: Reliability study Setting: Data were collected in a university biomechanics laboratory. Participants: Bilateral shoulder flexibility of 15 male college students (20.7 ± 1.1 y) was evaluated twice in two sessions over 7-10 days. Main Outcome Measures: For both ER and IR, reliability was assessed bilaterally (intra-session, inter-session, and inter-tester) for the traditional range of motion measure and three novel kinetic measures: torque at end ROM, resistance onset angle, rotational stiffness. This resulted in 48 total assessments. Results: Thirty-four assessments had good to excellent reliability (ICC ≥ 0.8), 10 had fair reliability (0.7≤ ICC < 0.8), and 4 had poor reliability (ICC< 0.7). Three of the four flexibility measures had a good overall ICC score: ROM (0.83), torque at end ROM (0.84), and resistance onset angle (0.81). The fourth, stiffness, had a fair overall reliability score (0.74). Conclusions: The passive torque-angle measures should be assimilated into clinical and research settings to determine the relevance to injury, rehabilitation, and performance. HIGHLIGHTS  we establish the entire passive torque-angle plot for shoulder internal and external rotation  the overall reliability for the three novel flexibility measures was fair to excellent  the torque-angle measures can be used to thoroughly assess shoulder flexibility

Physical Therapy in Sport, 2018

It is important to monitor the throwing shoulder’s internal rotation (IR) flexibility. Interestin... more It is important to monitor the throwing shoulder’s internal rotation (IR) flexibility. Interestingly, pitchers with throwing arm problems often have drastically reduced IR mobility, likely because of excessive shoulder “posterior tightness” [1,2]. This condition is commonly referred to as glenohumeral internal rotation deficit or GIRD. To date, GIRD studies have focused on shoulder range of motion (ROM) only. In this study, we assess the torque that is generated by the shoulder as it is passively internally rotated to the end ROM. The purpose is to conduct a bilateral analysis on a group of pitchers who suffer from GIRD. We hypothesize that the throwing shoulder will have a reduced laxity zone, reduced resistance zone, and increased rotational stiffness. Studying the torque-angle relationship may help to better understand this altered ROM.

Medicine & Science in Sports & Exercise, 2007