Changes in Isokinetic Strength and Power of Lower Limbs in Young Female Soccer Players in Training Microcycle of Competitive Season

Muscle fatigue is a critical factor influencing athletic performance in soccer. The aim of the present study was to investigate changes in isokinetic torque and power of lower limbs, in young female soccer players, in training microcycle of competitive season. The sample consisted of eleven female soccer players U17 (age: 16.3 ± 0.8 years, height: 166.4 ± 6.4 cm, body weight: 64.7 ± 11.7 kg) who competed in the 3rd national division championship. Participants knee extensors/flexors muscles were assessed in three concentric angular speeds (60°/s, 180°/s, 300°/s) and in counter movement jump, 72 hours before 24, 48 and 72 hours after the match. Statistically significant differences were revealed (F = 5,681, p = 0.038) in isokinetic assessment. Extensors significantly decreased at 60°/s between initial measurements and 48 hours after the match (p = 0.008), as well as 48 to 72 hours postmatch (p = 0.017). Flexors significantly decreased between the measurements at 24 to 48 hours at 300°/s (p = 0.025). Analysis of the Counter Movement Jump (CMJ) data revealed that both CMJ with and without arm swing had no statistically significant differences in performance between all four measurements. Knee muscles isokinetic assessment is a sensitive method for detecting post-match muscle fatigue. Structuring of training microcycle should consider the recovery time-lines and the physiological characteristics of female soccer players to optimize performance.