Human Performance Laboratory, São Paulo State University, Rio Claro, Brazil.
School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia.
Eur J Sport Sci. 2021 Jan;21(1):84-92. doi: 10.1080/17461391.2020.1727570. Epub 2020 Feb 23.
The present study investigated the relationships between changes in running economy (RE) and indirect muscle damage markers following downhill running (DHR) to test the hypothesis that decreased RE after DHR would be associated with decreases in muscle function. Forty-five young men ran downhill (-15%) for 30 min at the velocity corresponding to 70% of their peak oxygen uptake (VOpeak). Oxygen uptake (VO) and other parameters possibly associated with RE (blood lactate concentration, perceived exertion, stride length and frequency) were measured during 5-minute level running at the velocity corresponding to 80%VOpeak before, immediately after and 1-3 days after DHR. Knee extensor maximal voluntary contraction torque (MVC), rate of torque development, vertical jump performance, muscle soreness and serum creatine kinase activity were assessed at the same time points. The values of the dependent variables were compared among time points by one-way ANOVAs followed by Bonferroni post-hoc tests when appropriate. Pearson's correlation tests were used to examine relationships between changes in VO (RE parameter) and changes in muscle damage parameters. VO during the level run increased ( < 0.05) immediately after DHR (18.3 ± 4.6%) and sustained until 2 days post-DHR (11.7 ± 4.2%). MVC decreased ( < 0.05) immediately (-21.8 ± 6.1%) to 3 days (-13.6 ± 5.9%) post-DHR, and muscle soreness developed 1-3 days post-DHR. The magnitude of changes in VO did not significantly ( < 0.05) correlate with the changes in muscle damage makers (= -0.02-0.13) nor stride length (= -0.05) and frequency (= -0.05). The absence of correlation between the changes in VO and MVC suggests that strength loss was not a key factor affecting RE.
本研究旨在探讨下坡跑（DHR）后跑步经济性（RE）的变化与间接肌肉损伤标志物之间的关系，以验证 DHR 后 RE 降低与肌肉功能下降相关的假设。45 名年轻男性以 70%最大摄氧量（VOpeak）对应的速度下坡跑 30 分钟。在 DHR 前、后即刻和 1-3 天，以 80%VOpeak 对应的速度进行 5 分钟水平跑，测量 VO 和其他可能与 RE 相关的参数（血乳酸浓度、感觉用力程度、步长和步频）。在相同时间点评估膝关节伸肌最大自主收缩扭矩（MVC）、扭矩发展率、垂直跳跃性能、肌肉酸痛和血清肌酸激酶活性。通过单向方差分析比较各时间点的因变量值，适当情况下进行 Bonferroni 事后检验。采用 Pearson 相关检验分析 VO（RE 参数）变化与肌肉损伤参数变化之间的关系。DHR 后即刻，水平跑时的 VO 增加（ < 0.05）（增加 18.3%±4.6%），并持续至 DHR 后 2 天（增加 11.7%±4.2%）。MVC 即刻（-21.8%±6.1%）至 3 天（-13.6%±5.9%）下降（ < 0.05），肌肉酸痛于 DHR 后 1-3 天出现。VO 变化的幅度与肌肉损伤标志物（= -0.02-0.13）和步长（= -0.05）、步频（= -0.05）的变化无显著相关性（ < 0.05）。VO 和 MVC 的变化之间缺乏相关性表明，力量下降不是影响 RE 的关键因素。
