The Role of Eccentric Strength in 180° Turns in Female Soccer Players

Previous studies have reported an association between eccentric strength (ECC-STR) and change of direction (COD) ability. Little is known about how ECC-STR facilitates COD maneuvers. The aim of this study was to examine the role of ECC-STR during a 180 degrees COD task in 18 female soccer players. Each player performed six trials of a 180 degrees COD task whereby three-dimensional motion data from 10 Qualisys Pro-Reflex infrared cameras (240 Hz) and ground reaction forces (GRFs) from two AMTI force platforms (1200 Hz) were collected. Relative eccentric knee extensor (ECC-EXT) and flexor (ECC-FLEX) peak torque was collected from both limbs at 60 degrees s(-1) using a Kin Com isokinetic dynamometer. Large correlations were revealed between COD performance (time to complete 5 m approach, 180 degrees turn, 5 m return) and ECC-EXT (R = -0.674) and ECC-FLEX (R = -0.603). Moderate to large correlations were observed between approach velocity (AV) and COD performance (R = -0.484) and ECC-EXT (R = 0.724). Stronger participants (n = 9) recorded significantly (p < 0.05) faster AV (4.01 +/- 0.18 vs. 3.74 +/- 0.24 ms(-1), d = 1.27) and a greater reduction in velocity (-1.55 +/- 0.17 vs. -1.37 +/- 0.21 ms(-1), d = -0.94) during penultimate contact than weaker (n = 9) subjects. Greater ECC-STR is associated with faster COD performance in female soccer players, as stronger players are better able to decelerate during penultimate contact from faster approach velocities.