Assessing asymmetries and predicting performance in semiprofessional soccer players

This study aimed to (a) detail the interlimb asymmetries during multi-directional jumping, change of direction and for ankle dorsiflexion range of motion and (b) determine how asymmetries and performance in multi-directional jumping and ankle dorsiflexion predict performance during change of direction tests. Twenty-two male semi-professional players completed a testing session which consisted of unilateral ankle dorsiflexion range of motion, vertical and horizontal unilateral and lateral countermovement jumps and left and right leg 90° (COD90_L&R) and 180° (COD180_L&R) change of direction tests. No significant differences between limbs were observed for any of the variables (P > 0.05), though vertical countermovement jump (11.1% ± 9.1%) and dorsiflexion range of motion (10.5% ± 10.3%) imbalances were greater than those during lateral (2.7% ± 2.2%) and horizontal (2.2% ± 1.9%) countermovement jumps, and 90° (3.6% ± 3.1%) and 180° change of direction (2.9% ± 3.6%). Subjects presented 3.4 ± 1.4 real asymmetries (i.e., one greater than the coefficient of variation) across the tests, with all subjects having at least one real asymmetry. Stepwise linear regression models explained a reasonable amount of variance in change of direction180_R (70%), COD90_L (57%), COD90_R (39%), COD180_L (23%) using the countermovement jump and dorsiflexion range of motion variables (P < 0.05). The current findings indicate that semi-professional soccer players have real bilateral asymmetries (particularly in countermovement jump and dorsiflexion range of motion), which practitioners should be cognizant of. Given the prediction value, change of direction performance can be predicted using performance and asymmetries during multi-directional jumping and ankle dorsiflexion.