To compare the difference of S-HSA during spiking between volleyball players with and without SAIS.To compare the difference of S-HSA during spiking between volleyball players with and without SAIS.
Fourteen elite high school volleyball players, seven players with and another seven without SAIS, were recruited to evaluate the range of thoracic rotation (RTR) and spiking kinematics. A motion capture system was employed to measure the thoracic, pelvic, shoulder, and scapular kinematics during spiking. The S-HSA were extracted at the timing of maximum shoulder external rotation (MER) and ball contact (BC) as well as the maximal amplitude. The Mann-Whitney U test examined differences in RTR, ball speed, and spiking kinematics between the two groups.
No significant difference in RTR and ball speed was found between the two groups. SAIS group exhibited less S-HSA than non-SAIS group at MER and BC events (maximal S-HSA: 16.15° ± 8.18° vs. 25.63° ± 3.55°, p= 0.025; S-HSA at MER: 9.24° ± 4.81° vs. 18.06° ± 2.58°, p= 0.002; S-HSA at BC: -2.23° ± 5.56° vs. 7.89° ± 5.41°, p= 0.009). In addition, the SAIS group showed more internal rotation of the scapula than the control group at BC (-22.44° ± 10.37° vs. -3.20° ± 16.55°, p= 0.048).
Although there was no significant limitation in spinal rotation, volleyball players with SAIS showed less S-HSA during spiking. The increased scapular internal rotation at BC may be a compensatory strategy and may raise the risk of SAIS.
Future study needs to compare the effects of shoulder- and spinal-focused intervention on clinical symptoms and spiking kinematics in volleyball players with SAIS.
Shoulder-hip separation
Overhead sports
