Acute neuromuscular, cognitive and physiological responses to a Japanese kickboxing competition in semi-professional fighters

BACKGROUND: Japanese kickboxing is a combat sport designed to accommodate fighters from different combat sports styles. However, the physiological profile of this discipline is unknown. Therefore, this study describes the neuromuscular, metabolic and cognitive responses to an official Japanese kickboxing (K-1) fight in 8 kickboxers. METHODS: Measurements before and after the competition involved a simple reaction time test (SRT), countermovement jump (CMJ), blood lactate (BLA) and rating of perceived exertion (RPE). Additionally, each participant’s volume of strikes was extracted from a match-analysis. RESULTS: CMJ height was unaffected by the fight (p = 0.230 max; p = 0.208 mean). SRT increased post-fight (p = 0.0036). Peak BLA concentration was 15.3 ± 1.6 mmol·L-1 at 2 minutes post-fight. RPE increased post-fight (p < 0.001). Match-analysis showed 86 ± 23 total blows. For rounds 1, 2, and 3, blow distribution was 32.7%, 32.6% and 34.7%, respectively. Total punches were significantly greater (p < 0.001) than knee-strikes. Total kicks were also significantly greater than knee-strikes (p = 0.002). No difference was found between numbers of punches and kicks (p = 0.952). There was a positive correlation (p = 0.029; r = 0.76) between the sum of all strikes in the first two rounds and ΔBLA. CONCLUSIONS: The data obtained here indicate that K-1 fighters need to improve tolerance to lactate accumulation to perform greater number of actions. Furthermore, the results of this study suggest that CMJ height was not sensitive to specific fatigue induced by fighting