Prouteau Stephanie, Pelle Anne, Collomp Katia, Benhamou Laurent, Courteix Daniel
Bone Tissue Architecture and Physical Exercise (ATOSEP Laboratory) University of Orleans, Orleans, France.
Med Sci Sports Exerc. 2006 Apr;38(4):694-700. doi: 10.1249/01.mss.0000210207.55941.fb.
Weight cycling has been shown to exert negative effects on bone metabolism and bone mass, whereas weight-bearing activity is positively associated with bone mineral density (BMD). Bone health in judoists and effects of weight cycling on bone metabolism have not previously been investigated. To examine potential disrupter and stimulators of bone integrity, this study analyzed bone parameters at baseline and the effects of the first weight cycle of the season on bone metabolic status in 48 male and female elite judoists.
Body composition and lumbar, femoral, and total body BMD were evaluated by dual-energy x-ray absorptiometry. Cortisol, osteocalcin, C-terminal telopeptide of type I collagen (CTx), and bone uncoupling index (UI) were measured in judoists at normal body weight, after weight reduction, and after regaining weight. As a comparison, a control group of moderately active students was included at baseline. Training, menstrual status, and calcium intake were assessed by questionnaires.
EUweighted judoists displayed high BMD and an increased rate of bone formation. Precompetitive weight loss averaged 4 +/- 0.3% of body weight and induced an acute rise in cortisol (81%, P < 0.05) and CTx (33%, P < 0.0001), with a metabolic imbalance in favor of bone resorption. A 4 +/- 0.5% weight regain restored a positive UI in favor of bone formation. Metabolic responses were not dependent on gender. BMD was unaltered by weight cycling.
Increased bone formation rate pertaining to judo athletes lent protection from alterations in bone metabolic balance associated with weight cycling. This observation suggests that powerful osteogenic stimuli provided by judo's unique biomechanical environment may help prevent bone loss associated with weight loss.
体重循环已被证明对骨代谢和骨量有负面影响，而负重活动与骨矿物质密度（BMD）呈正相关。此前尚未对柔道运动员的骨骼健康以及体重循环对骨代谢的影响进行过研究。为了研究影响骨骼完整性的潜在干扰因素和刺激因素，本研究分析了48名男女精英柔道运动员在基线时的骨骼参数，以及本赛季首个体重循环对其骨代谢状态的影响。
采用双能X线吸收法评估身体成分以及腰椎、股骨和全身的骨密度。在柔道运动员体重正常、减重后和体重恢复后，测量其皮质醇、骨钙素、I型胶原C端肽（CTx）和骨解偶联指数（UI）。作为对照，在基线时纳入了一组中等活动水平的学生。通过问卷调查评估训练情况、月经状况和钙摄入量。
欧洲加权柔道运动员表现出较高的骨密度和增加的骨形成率。赛前平均减重4±0.3%的体重，导致皮质醇（81%，P<0.05）和CTx（33%，P<0.0001）急性升高，代谢失衡有利于骨吸收。体重恢复4±0.5%恢复了有利于骨形成的正UI。代谢反应不依赖于性别。体重循环未改变骨密度。
柔道运动员增加的骨形成率有助于保护其免受与体重循环相关的骨代谢平衡改变的影响。这一观察结果表明，柔道独特的生物力学环境提供的强大成骨刺激可能有助于预防与体重减轻相关的骨质流失。
