To compare the kinematics and electromyography of the periscapular muscles in swimmers before and after a 3-min maximal effort test.
16 competitive swimmers.
MAIN OUTCOME MEASUREMENTS:
Infrared cameras were used to record kinematics in the scapular plane in synchronization with the electromyography system.
There was an increase in internal rotation in all angles (p < 0.05), an increase of the anterior tilt, with 120° of elevation (p = 0.04). The serratus anterior showed a decrease in the intervals of 120-90° and 60-30° (p = 0.04; p = 0.02). There was a linear relationship between the variation before and after the maximal effort of the anterior tilt in relation to the variation of muscular activation of the transverse trapezius (p = 0.01) and the lower trapezius (42%, p = 0.01); an internal rotation in 120° and 90° of elevation in relation to the transverse trapezius (p = 0.01); and an internal rotation in 60° and 30° of elevation in relation to the serratus anterior (p = 0.04, p = 0.03).
A maximal 3-min effort test resulted in altered scapular biomechanics. More studies are needed to verify if the changes correspond to a risk factor for injuries.
Practical Application by Erin Cameron DPT: This study highlights the importance of improving scapular and rotator cuff muscle strength and endurance in order to decrease the likelihood of altered kinematics with fatigue. A three minute, maximal effort can significantly alter scapular biomechanics in competitive swimmers. While this particular protocol was performed out of the water (on a swim bench), it is likely that similar fatigue pattern occurs in pool swimming. Altered scapular kinematics with fatigue increases injury risk.
1. Serenza FS1, Oliveira AS2, Bedo BLS3, Mariano FP4, Aquino R5, Warner M6, Santiago PRP7. Biomechanical analysis of the shoulder of swimmers after a maximal effort test. Phys Ther Sport. 2017 Nov 6;30:14-21.