Institute for Sports Medicine, Bispebjerg Hospital, Copenhagen and Centre for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
Eur J Appl Physiol. 2013 Feb;113(2):449-55. doi: 10.1007/s00421-012-2450-5. Epub 2012 Jul 13.
Mechanical loading of human tendon stimulates collagen synthesis, but the relationship between acute loading responses and training status of the tendon is not clear. We tested the effect of prolonged load deprivation on the acute loading-induced collagen turnover in human tendons, by applying the same absolute load to a relative untrained Achilles tendon (2-week immobilization period prior to acute loading) and a habitually loaded contra-lateral Achilles tendon, respectively, within the same individuals. Eight untrained, healthy males had one lower limb totally immobilized for 2 weeks, whereas the contra-lateral leg was used habitually. Following the procedure both Achilles tendons and calf muscles were loaded with the same absolute load during a 1-h treadmill run. Tissue collagen turnover was measured by microdialysis performed post-immobilization but pre-exercise around both Achilles tendons and compared to values obtained by 72-h post-exercise. Power Doppler was used to monitor alterations in intratendinous blood flow velocity of the Achilles tendon and MRI used to quantitate changes in tendon cross-section area. Acute loading resulted in an increased collagen synthesis 72 h after the run in both Achilles tendons (p < 0.05) with no significant difference. No signs of acute tendon overloading were demonstrated by Power Doppler, and tendon cross-section area did not change as a result of immobilization and reloading. The present study indicates that 2 weeks of tendon load deprivation is not sufficient to affect the normal adaptive response to loading determined as increased collagen synthesis of peritendinous Achilles tendon tissue in humans.
人体肌腱的机械负荷会刺激胶原蛋白的合成，但急性负荷反应与肌腱的训练状态之间的关系尚不清楚。我们通过在相同个体中分别对相对未训练的跟腱（急性负荷前 2 周固定期）和习惯性负荷的对侧跟腱施加相同的绝对负荷，测试了长时间负荷剥夺对急性负荷诱导的胶原蛋白转化的影响。8 名未经训练的健康男性将一条下肢完全固定 2 周，而对侧下肢则习惯性使用。在该程序之后，在 1 小时的跑步机跑步过程中，两条跟腱和小腿肌肉都加载相同的绝对负荷。在固定后但运动前，通过微透析测量周围的组织胶原蛋白周转率，并与运动后 72 小时获得的值进行比较。使用功率多普勒监测跟腱内血流速度的变化，并使用 MRI 定量测量肌腱横截面积的变化。急性负荷在跑步后 72 小时导致两条跟腱的胶原蛋白合成增加（p < 0.05），但无显著差异。功率多普勒未显示出急性肌腱过度负荷的迹象，并且固定和再负荷不会导致肌腱横截面积发生变化。本研究表明，2 周的肌腱负荷剥夺不足以影响正常的适应反应，这可以通过人类跟腱周围组织的胶原蛋白合成增加来确定。
