Background/Aims It is unclear if open kinetic chain and closed kinetic chain exercises differ in the ability to influence a change in torque and power of the shoulder. The purpose of this study was to compare peak torque and average power of shoulder rotation after 6 weeks of resistance tubing exercise in the open kinetic chain and closed kinetic chain positions. Methods A total of 30 injury-free participants were randomly assigned to one of three groups (open kinetic chain, closed kinetic chain, control). The open kinetic chain and closed kinetic chain groups performed glenohumeral internal rotation and external rotation 3 days a week for 6 weeks. The control group participated in their usual activities of daily living and did not participate in either protocol. Isokinetic dynamometry testing of shoulder internal rotation and external rotation was performed concentrically to determine peak torque and average power at 60° a second and 180° a second on the throwing dominant arm before and after the 6-week training period for all groups. Results Peak torque and average power increased following the 6-week period. A main effect of time was observed for peak torque during internal rotation at 180º a second (F 1,27 =7.69, P=0.01), with higher post-test values (36.6 ± 17.4 Newton-metres) compared to pre-test (34.2 ± 17.1 Newton-metres). For average power, significant main effects of time were found for internal rotation at 60º a second (F 1,27 =5.83, P=0.023; post-test: 30.66 ± 15.62 Watts; pre-test: 27.54 ± 15.28 Watts), internal rotation at 180º a second (F 1,27 =8.20, P=0.008; post-test: 57.38 ± 36.06 Watts; pre-test: 50.79 ± 35.4 Watts) and external rotation at 180º a second (F 1,27 = 4.42, P=0.045; post-test: 40.17 ± 18.84 Watts; pre-test: 38.04 ± 18.75 Watts). No significant group × time interactions were observed for peak torque at 60º a second (external rotation: F 2,27 = 1.97, P=0.159; internal rotation: F 2,27 =0.459, p = 0.637) or 180º a second (external rotation: F 2,27 = 1.921, P=0.166; internal rotation: F 2,27 = 0.153, P=0.859), nor for average power at 60º a second (external rotation: F 2,27 = 1.829, P=0.18; internal rotation: F 2,27 = 0.759, P=0.478) or 180º a second (external rotation: F 2,27 = 0.605, P=0.553; internal rotation: F 2,27 = 0.311, P=0.735).] Conclusions There were no differences in peak torque or average power between the groups. Given that the outcomes in both the open kinetic chain and closed kinetic chain groups were similar to the outcomes in the control group, the results suggest that the open kinetic chain and closed kinetic chain interventions were ineffective. Clinicians should consider other evidence-based, explanatory factors (such as the dose–response relationship of exercise training) when prescribing exercise programmes to improve the torque and power production of glenohumeral internal and external rotation. Future research efforts should focus on patients who warrant strengthening of the rotator cuff. Implications for practice Allied health professionals should prioritise exercise dosage, progression, and patient-specific factors over kinetic chain position when designing shoulder strengthening programmes in injury-free populations. For patients who require rotator cuff or shoulder strengthening, such as those recovering from injury or with identified muscle imbalances, exercise interventions may need to be more intensive, targeted and individualised to achieve clinically relevant outcomes.
Tucker et al. (Tue,) studied this question.