This study aimed to investigate the immediate effect of STM on shoulder pain, range of motion (ROM), posterior shoulder muscle stiffness, perceived improvement, scapular kinematics, and associated muscle activation in overhead athletes with PST and SPS.
This study has recruited thirty-two overhead athletes with PST and SPS. All participants were randomly assigned to the STM group, stretching (STR) group, or pure hot pack (HP) group. All groups received a hot pack application on the shoulder region, while the STM group received an additional STM, and the STR group received an additional stretching program. The primary outcome measures included shoulder pain, ROM, posterior muscle stiffness, and perceived improvement (global rating of change, GROC). The secondary outcome measures included scapular kinematics and muscle activation.
The change scores of horizontal adduction PROM exhibited significantly greater increases in both STM and STR groups compared to the HP group (p = 0.007- 0.011), while no significant differences were observed between the STM and STR groups (STM: 5.36±4.56, STR: 5.03±3.87, HP: -0.33±3.10). Additionally, the STM group demonstrated superior perceived improvement compared to the other two groups following the intervention (GROC ≥ 4, STM: 7, STR: 1, HP: 0, p = 0.004-0.024). In the kinematics of the scapular plane, all groups exhibited significantly increased scapular posterior tilt during shoulder elevation at 30° after intervention (p = 0.032). Additionally, all groups showed increased scapular external rotation at 90° (p = 0.033) and 120° (p = 0.002) elevation, and at 90° (p = 0.023) and 120° (p = 0.005) descending during shoulder flexion after intervention. Regarding the muscle activation, the infraspinatus activation from 30° to 90° of shoulder elevation (p = 0.014-0.017) showed significantly increased across all groups in the scapular plane after intervention. Furthermore, there was also significantly increased infraspinatus activation across all groups in the flexion plane during shoulder elevation from 30° to 120° (p = 0.004-0.047) and during shoulder descending from 90° to 30° (p = 0.022-0.036) after intervention.
The additional STM and STR resulted in better outcomes in horizontal adduction PROM. Moreover, the additional STM exhibited significantly more self-perceived improvement than other groups. Finally, all groups showed similar changes in scapular posterior tilt during shoulder elevation, as well as changes in scapular external rotation and infraspinatus muscle activation during both shoulder elevation and descending after treatment.
In addition to improved horizontal adduction ROM, adding STM to heat therapy may have more patient satisfaction in their treatment.
posterior shoulder tightness
soft tissue mobilization
