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THE JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS
A Journal on Applied Physiology, Biomechanics, Preventive Medicine,
Sports Medicine and Traumatology, Sports Psychology
Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,111
The Journal of Sports Medicine and Physical Fitness 2016 Jan 21
Effectiveness of 2 weeks of high-intensity interval training on performance and hormone status in adolescent triathletes
Chia-Lun LEE 1, Meichich HSU 2, Todd A. ASTORINO 3, Ta-Wei LIU 4, Wen-Dien CHANG 5 ✉
1 Center for General Education, National Sun Yat-Sen University, Kaohsiung, Taiwan; 2 Department of Sports Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 3 Department of Kinesiology, California State University, San Marcos, San Marcos, CA, USA; 4 Chinese Taipei Triathlon Association, Taipei, Taiwan; 5 Department of Sports Medicine, China Medical University, Taichung, Taiwan
BACKGROUND: Weekly training volumes for triathlete are typically higher and may cause fatigue and musculoskeletal injury risk. High-intensity interval training (HIT) is a potent time-efficient strategy to induce adaptations normally associated with traditional endurance training. Therefore, the aim of this study was to investigate the effect of 2 weeks of in-season HIT on exercise capacity and hormonal responses in young triathletes.
METHODS: Twelve adolescent triathletes performed 18 sessions of HIT over 2 weeks including swim, cycle, and run events. The 6-day training blocks were separated by 1 day of recovery. Pre- and post-training, peak oxygen uptake (VO2peak) and exercise performance were assessed, and blood samples were obtained to detect changes in hormone and metabolite levels.
RESULTS: VO2peak was significantly higher (p =0.02) post-training (56.4 ± 8.1 ml·min-1·kg-1) versus pre-training (55.1 ± 7.5 ml·min-1·kg-1). Mean power and total work during 6 × 10 s repeated-sprint tests significantly increased (p = 0.03) after HIT. Additionally, 750 m swim time (pre- vs. post: 689.7 ± 102.5 s vs. 662.0 ± 75 s, p = 0.01) and 20 km cycling time (pre- vs. post: 1,856.6 ± 274.8 s vs. 1,705.4 ± 266.8 s, p = 0.02) were significantly lower post-training compared to pre-training, but there was no significant difference in 5 km run time after HIT (pre- vs. post: 1,315.8 ± 81.3 s vs. 1,292.0 ± 112.9 s, p = 0.31). In contrast to pre-training, ammonia concentration was significantly increased (p < 0.01) and creatine kinase concentration was significantly decreased (p = 0.02) post-training.
CONCLUSION: These findings suggest that two weeks of HIT using HRpeak as a monitor of physiological intensity improved VO2peak, sprint performance, and triathlon-specific performance in adolescent triathletes and attenuated levels of muscle damage.