Lower limb joint sense, muscle strength and postural stability in adolescent Taekwondo practitioners

Background: Taekwondo (TKD) is a popular combat sport renowned for its kicking techniques. With repeated practice, it may enhance the sensorimotor performance and balance of its practitioners. Research question: This study aimed (1) to compare the effects of short-term and long-term TKD training on the lower limb joint proprioception, muscle strength and balance performance of adolescents, and (2) to explore the relationships among these three outcome measures. Type of study: Observational study. Methods: Thirty-one adolescents including long-term (n=11), short-term (n=10), and non-practitioners (n=10) of TKD participated in the study. The knee joint position sense, isokinetic strength of the quadriceps and hamstrings, and sway in prolonged single-leg standing were measured. Results: Long-term TKD practitioners made significantly smaller errors in the knee joint repositioning test than the control group (p<0.01). No significant difference was found in the body-weight-adjusted isokinetic peak torque of the quadriceps (p>0.01) or hamstrings (p>0.01) among the three groups. Both short and long-term TKD practitioners swayed significantly slower than control participants while standing on one leg (p<0.01). The accuracy of knee joint angle repositioning was significantly correlated with sway velocity (r = 0.499, p<0.01). Conclusions: More than one year of TKD training can improve single-leg standing balance. The better postural stability demonstrated by long-term TKD practitioners may be associated with better knee joint position sense rather than knee muscle strength. Physiotherapists may therefore suggest long-term TKD exercise for adolescents to improve balance.