Impact of Three Strengthening Exercises on Dynamic Knee Valgus and Balance with Poor Knee Control among Young Football Players: A Randomized Controlled Trial

Abstract

The observed dynamic knee valgus and the limited dynamic balance described in the literature are modifiable risk factors for injuries in athletes. Therefore, identification and appropriate prevention are crucial in managing the development of young athletes. The aim of the study was to assess the effectiveness of three exercises strengthening the muscles: gluteal medius, popliteal and tibialis posterior to reduce dynamic knee valgus and improve the dynamic balance of the lower limbs in young football players with poor knee control. A total of 134 footballers were assessed for eligibility, and finally 45 participants (age 12-15) met the inclusion criteria. Participants were assessed with 2D video kinematic analysis during single-leg squats to assess the knee valgus angles and the dynamic balance (Y-Balance Test). No significant interactions between groups (Control and Exercise) and time (baseline and after 6 week) were noted for dynamic valgus for the left and right knee (p > 0.05). For the dynamic balance, there were statistically significant results, but not clinically relevant for anterior, posteromedial, and composite direction for the right lower limbs and for the anterior direction for left lower limbs in the exercise group. However, there were no significant differences (p > 0.05) in all of the YBT scores for both lower limbs between groups. This study demonstrated that there were no statistically significant differences in dynamic knee valgus angles and dynamic balance values after 6 weeks of exercise program in young footballers with poor knee control. Future randomized trials should focus on more comprehensive exercises, where possible using biofeedback methods to improve knee kinematics.

Keywords: Y-Balance test; injury prevention; knee kinetics; medial knee displacement; single leg squat.

Figure 1

CONSORT flow diagram of recruitment and retainment.

Figure 2

Video analyses of SLS test in the frontal and sagittal projection. (A,C)—starting angle, start of the test, (B,D)—maximum DKV, end of the test.

Figure 3

Initial and final exercise position. (A,B)—exercise of gluteus medium, (C,D)—exercise of politeus, (E,F)—exercise of posterior tibalis.

Figure 4

Mean with SD (°) for both groups at Pre-training and Post-training for the (a) right knee valgus, and (b) left knee valgus angles.