Klausen K, Andersen L B, Pelle I
Acta Physiol Scand. 1981 Sep;113(1):9-16. doi: 10.1111/j.1748-1716.1981.tb06854.x.
Six male subjects exercised on a bicycle ergometer 30 min with left leg and 30 min with right leg 3 times a week for 8 weeks. This training resulted in a 14.6% increase in VO2 max with two-leg exercise and a 23.1% increase with one-leg exercise. A significant decrease towards pretraining VO2 max was seen during the following 8 weeks of detraining. Muscle biopsy samples were obtained at rest from m. vastus lateralis before and after training and 4 and 8 weeks after training. During training the number of capillaries per mm2 and the number of capillaries per fiber increased about 20%. The number of capillaries around each fiber type (CA) increased 20--30%. The average area of each fibre type increased only about 5%. The fibre area per CA decreased by about 10%. During 8 weeks of detraining decreases were seen in the number of capillaries per fibre, CA and in fibre area, while fibre area per CA and number of capillaries per mm2 were almost unchanged at the end of the detraining period. Pronounced increases in activities of oxidative enzymes were observed after training, while only minor increases were seen in glycolytic enzyme activities. All enzyme activities decreased towards pre-training levels during detraining. The results indicate that the training-induced improvement in oxidative capacity and in muscle capillarization expressed as capillaries per fibre and CA disappears within 8 weeks after cessation of training. However, the fibre area per CA and number of capillaries per mm2 point at a favourable long term effect on the average diffusion distance between capillaries and muscle fibres.
六名男性受试者每周三次在自行车测力计上分别用左腿和右腿各锻炼30分钟，持续8周。这种训练使得双腿锻炼时最大摄氧量增加了14.6%，单腿锻炼时增加了23.1%。在接下来8周的停训期间，最大摄氧量显著下降至训练前水平。在训练前、训练后以及训练后4周和8周，于静息状态下从股外侧肌获取肌肉活检样本。训练期间，每平方毫米的毛细血管数量以及每条肌纤维的毛细血管数量增加了约20%。每种肌纤维类型周围的毛细血管数量（CA）增加了20% - 30%。每种肌纤维类型的平均面积仅增加了约5%。每CA的肌纤维面积减少了约10%。在8周的停训期间，每条肌纤维的毛细血管数量、CA以及肌纤维面积均出现下降，而在停训期结束时，每CA的肌纤维面积和每平方毫米的毛细血管数量几乎未变。训练后观察到氧化酶活性显著增加，而糖酵解酶活性仅略有增加。在停训期间，所有酶活性均下降至训练前水平。结果表明，训练诱导的氧化能力改善以及以每条肌纤维和CA表示的肌肉毛细血管化在训练停止后的8周内消失。然而，每CA的肌纤维面积和每平方毫米的毛细血管数量表明对毛细血管与肌纤维之间的平均扩散距离具有有利的长期影响。
