Liao Yi-Hung, Sung Yu-Chi, Chou Chun-Chung, Chen Chung-Yu
Department of Exercise and Health Science, National Taipei University of Nursing and Health Sciences, Taipei City, Taiwan.
Department of Chinese Martial Arts, Chinese Culture University, Taipei City, Taiwan.
PLoS One. 2016 Jul 27;11(7):e0160167. doi: 10.1371/journal.pone.0160167. eCollection 2016.
Changes in an athlete's physiological and health metabolic profiles after detraining have not been studied in elite Taekwondo (TKD) athletes. To enable a better understanding of these physiological changes to training cessation, this study examined the effects of 8-weeks detraining on the aerobic capacity, body composition, inflammatory status and health metabolic profile in elite TKD athletes. Sixteen elite TKD athletes (age: 21.0 ± 0.8 yrs, BMI: 22.4 ± 3.9 kg/m2; Mean ± SD; 11 males and 5 females) participated in this study. Physical activity level assessment using computerized physical activity logs was performed during the competitive preparation season (i.e. one-week before national competition) and at two week intervals throughout the detraining period. Participant aerobic capacity, body fat, and blood biomarkers were measured before and after detraining, and the blood biomarker analyses included leukocyte subpopulations, blood glucose, insulin, dehydroepiandrosterone-sulfate (DHEA-S), and cortisol. Eight-week detraining increased DHEA-S/cortisol ratio (+57.3%, p = 0.004), increased insulin/cortisol ratio (+59.9%, p = 0.004), reduced aerobic power (-2.43%, p = 0.043), increased body fat accumulation (body fat%: +21.3%, p < 0.001), decreased muscle mass (muscle mass%: -4.04%, p < 0.001), and elevated HOMA-IR (the biomarker of systemic insulin resistance; +34.2%, p = 0.006). The neutrophil-to-lymphocyte ratio (NLR), a systemic inflammatory index, increased by 48.2% (p = 0.005). The change in aerobic capacity was correlated with the increased fat mass (r = -0.429, p = 0.049) but not with muscle loss. An increase in the NLR was correlated to the changes in HOMA-IR (r = 0.44, p = 0.044) and aerobic capacity (r = -0.439, p = 0.045). We demonstrate that 8-week detraining suppresses physiological stress but rapidly results in declines in athletic performance and health metabolic profiles, including reduced aerobic capacity, increased body fat, muscle loss, insulin resistance development and elevated systemic inflammatory status in these young elite TKD athletes. The inflammation state was positively associated with insulin resistance development, fat mass, WHR (the index for central fat accumulation), and the decline in VO2max.
尚未对精英跆拳道（TKD）运动员停训后的生理和健康代谢状况变化进行研究。为了更好地了解这些因停止训练而产生的生理变化，本研究考察了8周停训对精英TKD运动员有氧能力、身体成分、炎症状态和健康代谢状况的影响。16名精英TKD运动员（年龄：21.0±0.8岁，体重指数：22.4±3.9kg/m²；均值±标准差；11名男性和5名女性）参与了本研究。在竞技准备赛季（即全国比赛前一周）以及整个停训期间每隔两周，使用计算机化身体活动日志进行身体活动水平评估。在停训前后测量参与者的有氧能力、体脂和血液生物标志物，血液生物标志物分析包括白细胞亚群、血糖、胰岛素、硫酸脱氢表雄酮（DHEA-S）和皮质醇。8周停训使DHEA-S/皮质醇比值升高（+57.3%，p=0.004），胰岛素/皮质醇比值升高（+59.9%，p=0.004），有氧能力降低（-2.43%，p=0.043），体脂积累增加（体脂百分比：+21.3%，p<0.001），肌肉量减少（肌肉量百分比：-4.零零4%，p<0.001），并且胰岛素抵抗稳态模型评估（HOMA-IR）升高（全身胰岛素抵抗的生物标志物；+34.2%，p=0.零零6）。全身炎症指数中性粒细胞与淋巴细胞比值（NLR）升高了48.2%（p=0.005）。有氧能力的变化与脂肪量增加相关（r=-0.429，p=0.049），但与肌肉量减少无关。NLR升高与HOMA-IR的变化相关（r=0.44，p=0.044）以及与有氧能力相关（r=-0.439，p=0.045）。我们证明，8周停训会抑制生理应激，但会迅速导致运动表现和健康代谢状况下降，包括有氧能力降低、体脂增加、肌肉量减少、胰岛素抵抗发展以及这些年轻精英TKD运动员全身炎症状态升高。炎症状态与胰岛素抵抗发展、脂肪量、腰臀比（中心脂肪积累指标）以及最大摄氧量下降呈正相关。
