Does eight-week neuromuscular warm-up improve knee isokinetic strength and the functional hamstring–quadriceps ratio in national team Para-taekwondo athletes? A randomized controlled trial

Background: Para-taekwondo demands explosive lower-limb actions that challenge knee stability and neuromuscular control. Athletes face an elevated risk of noncontact injuries, particularly hamstring strains and anterior cruciate ligament (ACL) rupture. Although neuromuscular warm-ups such as the MASS-12 are effective in able-bodied sports, their impact on Para-taekwondo remains unclear. To determine whether an eight-week neuromuscular warm-up (MASS-12) improves isokinetic knee strength and the functional hamstring–quadriceps (H/Q) ratio in national Para-taekwondo athletes. Methods: Twenty-four K44 athletes (12 men, 12 women; mean age 23.4 ± 3.9 years) were randomized into MASS-12 (n=12) or control (n=12) groups. The intervention included MASS-12 three times weekly (~20 min/session) for eight weeks, whereas the controls continued standard warm-ups. The isokinetic strength of the dominant leg was assessed on a Biodex System 4 Pro at 60°/s and 180°/s for concentric quadriceps and eccentric hamstrings. Group, time, and interaction effects were tested via 2×2 mixed ANOVA. Results: A significant group × time interaction was found for eccentric hamstring strength at 180°/s (F=5.79, P=0.02, η²=0.14; Cohen’s d=1.29), indicating large improvements in the MASS-12 group but not in the control group. No significant changes in concentric quadriceps strength or the functional H/Q ratio were detected (P>0.05). No adverse events were reported. Conclusions: MASS-12 warm-up significantly increased eccentric hamstring strength in national Para-taekwondo athletes, supporting its clinical relevance as a short, sport specific, and effective injury prevention strategy. However, the unchanged quadriceps strength and H/Q ratios suggest that extended or combined neuromuscular protocols may be required for broader muscular adaptations. Trial registration: The researchers registered this trial on 07/06/2025, with the identifier IRCT20250626066261N1 in the Iranian Registry of Clinical Trials (IRCT) at the following address: https://irct.behdasht.gov.ir. The study protocol was approved by the institutional ethics committee of Shahid Beheshti University (approval code: IR.SBU.REC.1404.055).