Effects of combined training or moderate intensity continuous training during a 3‑week multidisciplinary body weight reduction program on cardiorespiratory fitness, body composition, and substrate oxidation rate in adolescents with obesity

This study aimed to investigate the effects of combined training (COMB, a combination of moderate intensity continuous training-MICT and high-intensity interval training-HIIT) vs. continuous MICT administered during a 3-week in-hospital body weight reduction program (BWRP) on body composition, physical capacities, and substrate oxidation in adolescents with obesity. The 3-week in-hospital BWRP entailed moderate energy restriction, nutritional education, psychological counseling, and two different protocols of physical exercise. Twenty-one male adolescents with obesity (mean age: 16.1 ± 1.5 years; mean body mass index [BMI] 37.8 ± 4.5 kg m2) participated in this randomized control trial study (n:10 for COMB, n:11 MICT), attending ~ 30 training sessions. The COMB group performed 3 repetitions of 2 min at 95% of peak oxygen uptake (V′O2 peak) (e.g., HIIT ≤ 20%), followed by 30 min at 60% of V′O2 peak (e.g., MICT ≥ 80%). Body composition, V′O2 peak, basal metabolic rate (BMR), energy expenditure, and substrate oxidation rate were measured during the first week (W0) and at the end of three weeks of training (W3). The two training programs were equivalent in caloric expenditure. At W3, body mass (BM) and fat mass (FM) decreased significantly in both groups, although the decrease in BM was significantly greater in the MICT group than in the COMB group (BM: − 5.0 ± 1.2 vs. − 8.4 ± 1.5, P < 0.05; FM: − 4.3 ± 3.0 vs. − 4.2 ± 1.9 kg, P < 0.05). V′O2 peak increased only in the COMB by a mean of 0.28 ± 0.22 L min−1 (P < 0.05). The maximal fat oxidation rate (MFO) increased only in the COMB group by 0.04 ± 0.03 g min−1 (P < 0.05). COMB training represents a viable alternative to MICT for improving anthropometric characteristics, physical capacities, and MFO in adolescents with obesity during a 3-week in-hospital BWRP.

本研究旨在探讨联合训练（COMB，即中等强度持续训练（moderate intensity continuous training, MICT）与高强度间歇训练（high-intensity interval training, HIIT）的组合方案）与单纯中等强度持续训练（MICT），在为期3周的住院体重减轻项目（body weight reduction program, BWRP）中，对肥胖青少年身体成分、运动能力及底物氧化的影响。为期3周的住院减重项目包含适度能量限制、营养教育、心理咨询以及两种不同的运动训练方案。本随机对照试验共纳入21名肥胖男性青少年（平均年龄：16.1±1.5岁；平均体质量指数（body mass index, BMI）37.8±4.5 kg·m⁻²），其中联合训练组（COMB）10人，单纯MICT组11人，所有受试者共完成约30次训练课程。联合训练组的训练方案为：依次完成3组时长2分钟、强度为峰值摄氧量（peak oxygen uptake, V′O2 peak）95%的训练（对应高强度间歇训练占比≤20%），随后进行30分钟、强度为V′O2 peak 60%的训练（对应中等强度持续训练占比≥80%）。分别于训练首周（W0）及3周训练结束时（W3），测量受试者的身体成分、V′O2 peak、基础代谢率（basal metabolic rate, BMR）、能量消耗与底物氧化速率。两种训练方案的能量消耗相当。训练3周后，两组受试者的体质量（body mass, BM）与脂肪量（fat mass, FM）均显著下降，但MICT组的体质量下降幅度显著大于联合训练组（体质量：-5.0±1.2 相较于 -8.4±1.5，P<0.05；脂肪量：-4.3±3.0 相较于 -4.2±1.9 kg，P<0.05）。仅联合训练组的V′O2 peak平均提升0.28±0.22 L·min⁻¹（P<0.05）。仅联合训练组的最大脂肪氧化速率（maximal fat oxidation rate, MFO）提升0.04±0.03 g·min⁻¹（P<0.05）。在为期3周的住院减重项目中，联合训练可作为单纯MICT的可行替代方案，用于改善肥胖青少年的人体测量学特征、运动能力与MFO。