Abstract
OBJECTIVES:
To compare the kinematics and electromyography of the periscapular muscles in swimmers before and after a 3-min maximal effort test.
PARTICIPANTS:
16 competitive swimmers.
MAIN OUTCOME MEASUREMENTS:
Infrared cameras were used to record kinematics in the scapular plane in synchronization with the electromyography system.
RESULTS:
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).
CONCLUSION:
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.
Reference:
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.