Effects of a six-week combined tire-squat and explosive-kicking programme on roundhouse-kick performance in highly trained male Muay Thai athletes: a parallel-group controlled trial.

BACKGROUND: Muay Thai is a high-intensity striking sport requiring repeated roundhouse kicks performed with speed, force, and precision under fatigue. Although lower-limb resistance training is widely used in combat-sport conditioning, evidence for combined sport-specific programmes remains limited. This study investigated the effects of a six-week combined tire-squat and explosive-kicking programme on roundhouse-kick performance in highly trained male Muay Thai athletes. METHODS: Thirty-nine highly trained male Muay Thai athletes (15-25 years) participated in this parallel-group controlled trial. Participants were allocated to an experimental group (EXP, n = 20), which completed a six-week combined tire-squat and explosive-kicking programme in addition to usual training, or a control group (CON, n = 19), which continued usual training. Outcomes included stimulus-to-contact time, kick accuracy, repeated-kicking performance decrement (fatigue index; an indicator of repeated-kicking capacity), kicking consistency, dynamic balance, and inter-limb asymmetry. Longitudinal changes were analysed using linear mixed-effects models. RESULTS: Significant group × time interactions were observed for stimulus-to-contact time, repeated-kicking performance decrement, and kicking consistency (all BH-adjusted p = 0.001). Compared with CON, EXP showed greater improvements in stimulus-to-contact time (-0.05 s; g = 1.45), repeated-kicking performance decrement (-3.2%; g = 0.95), and kicking consistency (-1.8 percentage points; g = 0.88). A small interaction was observed for kick accuracy (unadjusted p = 0.048; BH-adjusted p = 0.072; g = 0.28); however, it did not remain statistically significant after Benjamini-Hochberg adjustment. No significant interactions were observed for dynamic balance (BH-adjusted p = 0.221) or inter-limb asymmetry (BH-adjusted p = 0.142). CONCLUSIONS: A six-week combined tire-squat and explosive-kicking programme was associated with improvements in stimulus-to-contact time, repeated-kicking capacity (reflected by a lower repeated-kicking performance decrement index), and kicking consistency in highly trained Muay Thai athletes. The programme was associated with improvements in selected aspects of repeated roundhouse-kick performance. Because the intervention combined tire-squat exercise with explosive-kicking practice, the independent effects of each component could not be determined.