High School of Physical Education and Sport, Hitit University, Corum, Turkey.
J Strength Cond Res. 2011 Aug;25(8):2311-5. doi: 10.1519/JSC.0b013e3181f6b0dd.
Some studies reported testicular disorders associated with biking in mountain cyclists, which include injuries, erectile dysfunction, and higher scrotal temperatures. But none of these studies evaluated gonadal function. Therefore, the aim of this study was to evaluate gonadal function in male mountain bikers. Twenty-two male professional mountain bikers and 30 healthy noncyclist controls were included in the study. The mean age and body mass index were similar in both groups. Fasting blood samples for the measurement of the levels of total testosterone (TT), sex-hormone binding globulin (SHBG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were obtained from all study participants before any physical activity. In addition, because insulin sensitivity and leptin modulate gonadal function, the concentrations of insulin, glucose, and leptin were also measured in the same samples. Calculated free testosterone (cFT) and bioavailable testosterone (bioT) were calculated from SHBG and TT. Basal hormonal levels including insulin, leptin, LH, FSH, SHBG, TT, glucose, and homeostasis model assessment scores were similar between the groups. However, bioT and cFT levels were significantly lower (p ≤ 0.05) in the mountain bikers than those in the controls. Despite the lower mean testosterone levels in the study group, the levels of LH and FSH were similar to controls. Insulin and leptin do not contribute to lower testosterone levels. In conclusion, male mountain bikers have lower testosterone concentrations compared to controls. This alteration cannot solely be explained by testicular dysfunction. The etiology of lower testosterone levels in cyclists appears to be complex and requires further research. The influence of such a decline on the athlete's performance, quality of life, and muscle strength is not known as yet.
一些研究报道了与山地自行车运动相关的睾丸疾病，包括损伤、勃起功能障碍和阴囊温度升高。但这些研究都没有评估睾丸功能。因此，本研究旨在评估男性山地自行车运动员的睾丸功能。研究纳入了 22 名男性职业山地自行车运动员和 30 名健康的非自行车运动员作为对照组。两组的平均年龄和体重指数相似。所有研究参与者在进行任何体育活动前都空腹采集血样，用于测量总睾酮（TT）、性激素结合球蛋白（SHBG）、黄体生成素（LH）和卵泡刺激素（FSH）的水平。此外，由于胰岛素敏感性和瘦素调节睾丸功能，我们还在相同的样本中测量了胰岛素、葡萄糖和瘦素的浓度。通过 SHBG 和 TT 计算游离睾酮（cFT）和生物可利用睾酮（bioT）。两组之间基础激素水平（包括胰岛素、瘦素、LH、FSH、SHBG、TT、葡萄糖和稳态模型评估分数）相似。然而，山地自行车运动员的 bioT 和 cFT 水平明显低于对照组（p ≤ 0.05）。尽管研究组的平均睾酮水平较低，但 LH 和 FSH 水平与对照组相似。胰岛素和瘦素对降低睾酮水平没有影响。总之，与对照组相比，男性山地自行车运动员的睾酮浓度较低。这种改变不能仅用睾丸功能障碍来解释。自行车运动员的睾酮水平较低的原因似乎很复杂，需要进一步研究。这种下降对运动员的表现、生活质量和肌肉力量的影响目前尚不清楚。
