Effects of a novel kinesio taping technique on lower extremity dynamic knee valgus during single-leg landing and squatting tasks with fatigue

Background: Excessive dynamic knee valgus is a commonly seen lower extremity malalignment associated with many sports injuries, such as patellofemoral pain syndrome, iliotibial band syndrome and anterior cruciate ligament injuries. Excessive dynamic knee valgus was consisted of greater hip adduction, hip internal rotation and knee abduction during dynamic weight bearing tasks. Insufficient hip muscle strength and/or abnormal neuromuscular control may contribute to excessive knee valgus. Greater knee valgus angles and moments were observed during single-leg landing, and it was considered at higher risk of knee injuries when compared to double-leg landing. Previous studies reported that fatigue will further increase muscle demands, alter neuromuscular control and increase knee valgus. Hip muscle strengthening and neuromuscular control training are proved to be beneficial in decreasing excessive knee valgus, however, it will take at least 4 to 8 weeks to complete these two training regimes. A immediately effective and fatigue-resistant protocol to prevent excessive knee valgus is still lacking. A novel kinesio taping technique (anti-valgus taping) has been used to prevent excessive dynamic knee valgus in clinical practice, however, the efficacy of anti-valgus taping has not been examined with biomechanical evaluations to date. Purpose: The purpose of this study was to investigate the effect of a novel kinesio taping technique (anti-valgus taping) on lower extremity biomechanical parameters during single-leg landing and squatting under the influence of fatigue. Methods: 18 healthy female participants with regular exercise habit were recruited in this study. Vicon motion capture system with 8 infra-red cameras, an AMTI force plate and wireless EMG system were used to collect joint movements, GRF and gluteus maximus and medius, vastus lateralis and biceps femoris muscle activities. Two taping conditions were tested: with and without anti-valgus taping. Subjects performed three consecutive single-leg landing and squatting tests before and after fatigue in both taping conditions. After the pre-fatigue session, subjects were asked to perform and repeat the fatigue protocol until reaching a reduction of 20 % maximal vertical jump height. Outcome measures including: joint angles and moments, time to stabilization, peak and average EMG amplitudes during descending and ascending phase of single-leg landing and squatting. Two-way repeated measures ANOVAs (taping X fatigue) were used to compare outcome variables in single-leg landing and squatting respectively with and without anti-valgus taping, before and after fatigue. Results: After fatigue, participants landed with greater hip internal rotation at initial contact, lesser hip rotation excursion, greater peak knee flexion, trunk flexion and ipsilateral lean angles. (hip IR at IC, p<0.001; hip rotation excursion, p<0.001; knee flexion, p=0.034; trunk flexion, p=0.044; trunk ipsilateral lean, p=0.031) There were lower peak knee adduction moments after fatigue in single-leg landing. (p=0.01) EMG amplitudes of Gmax, Gmed, VL and BF increased at peak and average in the fatigue condition. With anti-valgus taping, participants landed with less hip adduction, internal rotation, knee abduction angles and moments (hip ADD angles, p=0.004; hip IR angles, p=0.008; knee ABD angles, p=0.031; knee ABD moment, p=0.02). There were lower Gmed and VL EMG amplitudes at peak and in descending phase with taping. Two-way repeated measures ANOVA revealed that there were no interactions between fatigue and taping on lower extremity movements and muscle activations. Time to stabilization (TTS) in both AP and ML direction increased after fatigue, but there were no differences in TTS between taping conditions. (main effect of fatigue: AP, p=0.009; ML, p=0.031) Conclusion: Fatigue influenced landing movements, postural stability and muscle activations. Anti-valgus taping reduced dynamic knee valgus and muscle activations during single-leg landing. The effects of anti-valgus taping on preventing excessive knee valgus were immediate and fatigue-resistant.