Convergent validity of taekwondo high-intensity intermittent sport-specific tests and their relationship with lower limb muscle power performance

Objective: The interchangeability between multiple Frequency Speed of Kick Test (FSKTmult) and chest Taekwondo Anaerobic Intermittent Kick Test (TAIKT(chest)) has not been established, which prevents determining whether they reflect the same underlying construct of ability to repeat high-intensity kicks. Moreover, the relationship between the ability to repeat high-intensity kicks and lower limb muscle power requires further investigation. This study aimed to: establish the construct convergent validity between the FSKTmult and TAIKT(chest); investigate their relationship with countermovement jump (CMJ) test. Methods: Twenty-two national/international-level taekwondo athletes participated in this study. On the first day, they performed three CMJ followed by one of the intermittent tests in a randomized and counterbalanced order. After 48 hours, the other intermittent test was performed. During the FSKTmult and TAIKT(chest), heart rate (HR) was measured, while blood lactate concentration ([La]) and rating of perceived exertion (RPE) were recorded at the end of the tests. Results: FSKTmult total kick performance, as well as absolute and relative power performances, showed high shared variance (R-2 = 62-92%, p < 0.001) with respective TAIKT(chest) performances. HR, [La], and RPE responses were significantly higher (p <= 0.001, Cohen's d = 0.4-1.3) in the FSKTmult than in TAIKT(chest). Most high-intensity intermittent performances showed high significant correlations (r = 0.51-0.78, p < 0.05) with respective CMJ performances. Conclusions: FSKTmult performances can be predicted from the respective TAIKT(chest) performances and vice versa. However, the distinct methodological characteristics of the tests generate specific performance, physiological, and perceptual dynamics. Lower limb muscle power could influence performance in high-intensity kicks.