Identification of the optimal hiit protocol for fatigue resistance in adolescent athletes: a randomized controlled trial

Myong-Won Seo, Jung Min Lee, Hyun Chul Jung, Joon Young Kim, Jong Koon Song

Research output: Contribution to journalArticlepeer-review


The combat sports athletes developed great gains in both muscular function and fatigue resistance by
utilizing high-intensity interval training (HIIT). However, it has not been investigated fully whether different
work-to-rest ratios of HIIT show the effectiveness on muscle function in adolescent athletes. The purpose of the
study was to compare different work-to-rest ratios by applying different rest times in response to the identical
work time during HIIT on muscle function in adolescent taekwondo athletes. Forty-seven adolescent male
taekwondo athletes (mean age: 16.7±0.8 years) were randomly assigned to the control group (n=11) vs. three
HIIT groups by work-to-rest ratios; (1) 1:2 [30s:60s] (n=12), (2) 1:4 [30s:120s] (n=12), and (3) 1:8 [30s:240s]
(n=12). All groups completed 10 experimental sessions over four weeks, while the control group maintained
their regular taekwondo training. Muscular functions were measured by assessing isokinetic muscle strength
and endurance of the knee extensor and flexor. The participants performed three sets of twenty maximal
extension and flexion contractions at 120°s-1 with a 1-min interval between the sets for fatigue resistance.
Blood samples were collected to measure free-testosterone, cortisol, creatine kinase, and urea as stress-torecovery
indicators. A positive effect on improving muscle fatigue resistance was observed at the first set of
assessments in the HIIT with 1:4 (Δ10.2%, pexhibited fatigue resistance improvement in the second set (Δ7.7%, pindicators, while the other groups did not show any improvement. The 30s all-out work with 120s
rest time, lasting over a brief 4-week period, improved participants’ fatigue resistance. A certain amount of
rest time between high-intense movements is required to optimize muscle development in adolescent athletes
compared with insufficient rest time.
Original languageEnglish (US)
Pages (from-to)256-267
Number of pages12
Issue number2
StatePublished - Dec 31 2022


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