The relationship between ankle joint mobility and knee valgus during jump in football players

Purpose: determine relationship between ankle joint mobility and knee valgus during jump. Goals of study: 1.Measure and compare active and passive movements amplitudes of the ankle joint. 2.Identify and compare knees displacements during different jumps. 3.Identify the correlation between active and passive movements amplitudes of the ankle joint with knee valgus. Methods: Twelve professional football players (age 23,1 ± 2,5 years, body mass 77,6 ± 6,1 kg; body index 23,3 ± 1,9) participated in the study. The ankle joint amplitudes were measured using a mechanical goniometer. Position of the knee valgus was detected using jumps video recording (video recording system Contemplas and video analysis software Kinovea were used). Countermovement and drop jumps were analysed. Drop jumps were performed from a height of 0.41 m. Results: there was no asymmetry between the right and left legs of the active and passive ankle joints movements (p>0,05). Results showed that the average of active foot plantar flexion was 55 ± 9,64 degrees, and passive 59,92 ± 10,86 degrees. The average of active foot eversion was 22,04 ± 2,54 degrees, and passive 24,42 ± 2,22 degrees. The active foot inversion was 25,54 ± 3,84 degrees, and passive 29,13 ± 3,92 degrees. The average of active foot dorsiflexion (knee flexion at 90°) was 16,96 ± 5,87 degrees, and passive 20,88 ± 4,29 degrees. Comparing the flexibility of active and passive ankle joint movements, a statistically significant difference was obtained (p<0,05). The average knees displacement during countermovement jump was -10,75 ± 3,56 cm – dynamic varus; during drop jump (slow) was -1,05 ± 3,33 cm – dynamic varus and during drop jump (fast) was 3,67 ± 2,30 cm – dynamic valgus. The knee valgus was significantly greater during drop jump (fast) (p<0,01). The significant negative correlation (r=-.506, p