College of Medicine, University of Central Florida, 6850 Lake Nona Boulevard, Orlando, FL 32827-7408, USA.
Faculty of Health Sciences, Department of Performance, Neuroscience, Therapy and Health, MSH Medical School Hamburg, University of Applied Sciences and Medical University, Am Kaiserkai 1, 20457 Hamburg, Germany.
Int J Environ Res Public Health. 2021 Oct 3;18(19):10426. doi: 10.3390/ijerph181910426.
Eccentric cycling (ECC) has attracted attention as a method to improve muscle strength and aerobic fitness in populations unable to tolerate conventional methods. However, agreement on exercise prescription targets have been problematic. The current report is an initial exploration of a potentially useful tool, a nonlinear heart rate (HR) variability (HRV) index based on the short-term scaling exponent alpha1 of detrended fluctuation analysis (DFA a1), which has been previously shown to correspond to exercise intensity. Eleven male volunteers performed 45 min of concentric (CON) cycling and ECC separated by 1 month. Work rates were matched for HR (~50% of the maximal HR) during the first 5 min and remained stable thereafter. HRV, HR, oxygen consumption (VO), and cycling power were monitored and evaluated at elapsed times of 10 (T10) and 45 (T45) minutes duration. HR significantly increased between ECC T10 and ECC T45 ( = 0.003, d = 1.485), while DFA a1 significantly decreased ( = 0.004, d = 1.087). During CON, HR significantly increased ( < 0.001 d = 1.570) without significant DFA a1 change ( = 0.48, d = 0.22). Significantly higher HR was observed at T45 in ECC than in CON ( = 0.047, d = 1.059). A session of unaccustomed ECC lead to decreased values of DFA a1 at T45 in comparison to that seen with CON at similar VO. ECC lead to altered autonomic nervous system balance as reflected by the loss of correlation properties compared to CON.
离心运动（ECC）作为一种提高无法耐受传统运动人群肌肉力量和有氧适能的方法引起了关注。然而，在运动处方目标方面还存在一些问题。本报告是对一种潜在有用工具的初步探索，该工具是基于去趋势波动分析（DFA）短期标度指数 α1 的非线性心率变异性（HRV）指数，先前的研究表明，该指数与运动强度相对应。11 名男性志愿者在 1 个月内进行了 45 分钟的向心（CON）和离心（ECC）运动。在前 5 分钟内，HR （约最大 HR 的 50%）匹配工作率，之后保持稳定。监测和评估了心率变异性（HRV）、心率（HR）、耗氧量（VO）和骑行功率，并在 10 分钟（T10）和 45 分钟（T45）的时间间隔进行评估。ECC 的 T10 和 ECC 的 T45 之间 HR 显著增加（ = 0.003，d = 1.485），而 DFA a1 显著降低（ = 0.004，d = 1.087）。在 CON 期间，HR 显著增加（<0.001，d = 1.570），而 DFA a1 没有显著变化（ = 0.48，d = 0.22）。ECC 在 T45 时的 HR 明显高于 CON（ = 0.047，d = 1.059）。与 CON 相比，不熟悉的 ECC 会导致 T45 时 DFA a1 值降低，而 VO 相似。ECC 导致自主神经系统平衡发生改变，与 CON 相比，相关性丧失。
