Acute metabolic, hormonal and anxiety responses to two training load intensities of kumite (integrated approach training) in international level karate athletes

BACKGROUND: The endocrine-metabolic system and anxiety responses were assessed in 10 international level karatekas performing a novel form of kumite training (integrated approach training, IAT). METHODS: Six females and 4 males (16-25 yrs) performed two series of 4 matches each at two self-perceived effort levels (low and high). IAT provides continuous and dynamic actions and no score assignments. Metabolic and hormonal variables (blood glucose, insulin, cortisol, epinephrine and norepinephrine) and State-Trate Anxiety inventory Y-1 (STAI Y-1) were evaluated before and after the matches. The variables at different intensities were compared and correlations between STAI Y-1 and metabolic and hormonal variables were assessed. RESULTS: The high intensity IAT caused higher stress than the low intensity one, as demonstrated by high blood glucose, insulin, cortisol, epinephrine, norepinephrine and STAI Y-1 values (P<0.001). Moreover, anxiety levels were higher before the IAT sessions (pre-IAT) than after the IAT sessions (post-IAT) (P<0.05). An increase in metabolic and hormonal variables was observed from the pre-IAT measurements to the post-IAT ones (P<0.05). At low intensity, increments were detected only in blood glucose, insulin and norepinephrine (P<0.05). At high intensity, correlations were found between: norepinephrine pre-IAT and STAI Y-1 post-IAT (r=0.68, P=0.032); STAI Y-1 post-IAT with blood glucose (r=0.73, P=0.018), epinephrine (r=0.82, P=0.004) and norepinephrine (r=0.92, P<0.001) post-IAT. CONCLUSIONS: High intensity IAT elicits a stress-related response, demonstrated by correlations between anxiety levels and metabolic and hormonal parameters. At low intensity an initial activation of this stress-related response seems present. In relation to the athletes’ characteristics, training periodization and performance levels, these results can help in individualizing and designing specifics training programs.