Functional torque ratios and torque curve analysis of shoulder rotations in overhead athletes with and without impingement symptoms

Abstract

In this study, we evaluated the peak torque, functional torque ratios, and torque curve profile of the shoulder rotators in overhead athletes with impingement symptoms so as to examine possible alterations in response to sports training and shoulder pain. Twenty-one overhead athletes with impingement symptoms were compared with 25 overhead athletes and 21 non-athletes, none of whom were symptomatic for impingement. The participants performed five maximal isokinetic concentric and eccentric contractions of medial and lateral shoulder rotations at 1.57 rad · s(-1) and 3.14 rad · s(-1). Isokinetic peak torque was used to calculate the eccentric lateral rotation-to-concentric medial rotation and the eccentric medial rotation-to-concentric lateral rotation ratios. An analysis of the torque curve profiles was also carried out. The eccentric lateral rotation-to-concentric medial rotation torque ratio of asymptomatic athletes was lower than that of non-athletes at both test velocities. The concentric medial rotation isokinetic peak torque of the asymptomatic athletes, at 3.14 rad · s(-1), was greater than that of the non-athletes, and the peak appeared to occur earlier in the movement for athletes than non-athletes. These findings suggest that there may be adaptations to shoulder function in response to throwing practice. The eccentric medial rotation-to-concentric lateral rotation torque ratio was altered neither by the practice of university-level overhead sports nor impingement symptoms.

Posture and isokinetic shoulder strength in female water polo players

“…These findings are further indicated by the weakness seen in the ER muscles relative to the IR muscles in the reciprocal ratio. These results are lower than previously found in the assessment of the peak torque to body weight ratio in asymptomatic overhead athletes [19] and reciprocal ratio in water polo players. However, they were previously assessed at 30 o /sec, which could account for the differences.…”

Effects of Kinesio taping on scapular kinematics of overhead athletes following muscle fatigue

“…This hypothesis is reinforced by the moderate increase in scapular internal rotation at 30°of humeral elevation, position at which the lower trapezius presented the lowest increase in muscle activity. Previous studies have found alterations in the shoulder of asymptomatic overhead athletes that were considered beneficial adaptations for injury prevention and sports performance, as a decrease in the functional strength rotators ratio and an increase in torque fluctuation (Zanca et al, 2011(Zanca et al, , 2013. The lack of significant alterations in scapular kinematics following muscle fatigue could be interpreted in the same direction, as a possible positive adaptation.…”

A 12-week rehabilitation program improves body composition, pain sensation, and internal/external torques of baseball pitchers with shoulder impingement symptom

“…The subjects underwent a physical examination including medical history and orthopedic evaluation by an orthopedic surgeon. The inclusion criteria for baseball players with impingement symptoms were as follows: complaints of posterosuperior shoulder pain during the throwing motion; pain during the apprehension test and pain relief during the relocation test; or a positive response in one of the above-mentioned tests associated with another of the following diagnostic indicators: Neer, Hawkins, or Jobe (Zanca et al, 2011). An impingement syndrome can be usually diagnosed by subjects’ history and due to physical examination.…”