Rogers Bruce, Berk Sander, Gronwald Thomas
College of Medicine, University of Central Florida, 6850 Lake Nona Boulevard, Orlando, FL 32827-7408, USA.
Dutch Triathlon Federation, Papendallaan 49, 6816 VD Arnhem, The Netherlands.
Sports (Basel). 2022 Feb 18;10(2):25. doi: 10.3390/sports10020025.
A non-linear index of heart rate (HR) variability (HRV) known as alpha1 of Detrended Fluctuation Analysis (DFA a1) has been shown to change with increasing exercise intensity, crossing a value of 0.75 at the aerobic threshold (AT) in recreational runners defining a HRV threshold (HRVT). Since large volumes of low-intensity training below the AT is recommended for many elite endurance athletes, confirmation of this relationship in this specific group would be advantageous for the purposes of training intensity distribution monitoring. Nine elite triathletes (7 male, 2 female) attended a training camp for diagnostic purposes. Lactate testing was performed with an incremental cycling ramp test to exhaustion for the determination of the first lactate threshold based on the log-log calculation method (LT1). Concurrent measurements of cardiac beta-to-beat intervals were performed to determine the HRVT. Mean LT1 HR of all 9 participants was 155.8 bpm (±7.0) vs. HRVT HR of 153.7 bpm (±10.1) ( = 0.52). Mean LT1 cycling power was 252.3 W (±48.1) vs. HRVT power of 247.0 W (±53.6) ( = 0.17). Bland-Altman analysis showed mean differences of -1.7 bpm and -5.3 W with limits of agreement (LOA) 13.3 to -16.7 bpm and 15.1 to -25.6 W for HR and cycling power, respectively. The DFA a1-based HRVT closely agreed with the LT1 in a group of elite triathletes. Since large volumes of low-intensity exercise are recommended for successful endurance performance, the fractal correlation properties of HRV show promise as a low-cost, non-invasive option to that of lactate testing for identification of AT-related training boundaries.
一种称为去趋势波动分析（DFA）的α1的心率（HR）变异性（HRV）非线性指标已被证明会随着运动强度的增加而变化，在休闲跑步者的有氧阈值（AT）处超过0.75的值，从而定义了一个HRV阈值（HRVT）。由于许多精英耐力运动员建议进行大量低于AT的低强度训练，在这一特定群体中确认这种关系将有利于训练强度分布监测。九名精英铁人三项运动员（7名男性，2名女性）参加了一个用于诊断目的的训练营。通过递增式自行车功率测试至疲劳进行乳酸测试，以基于对数-对数计算方法确定第一个乳酸阈值（LT1）。同时进行心脏逐搏间期测量以确定HRVT。所有9名参与者的平均LT1心率为155.8次/分钟（±7.0），而HRVT心率为153.7次/分钟（±）（ = 0.52）。平均LT1自行车功率为252.3瓦（±48.1），而HRVT功率为247.0瓦（±53.6）（ = 0.）。布兰德-奥特曼分析显示，HR和自行车功率的平均差异分别为-1.7次/分钟和-5.3瓦，一致性界限（LOA）分别为13.3至-16.7次/分钟和15.1至-25.6瓦。在一组精英铁人三项运动员中，基于DFAα1的HRVT与LT1密切一致。由于成功的耐力表现建议进行大量低强度运动，HRV的分形相关特性有望成为一种低成本、非侵入性的选择，用于识别与AT相关的训练界限，替代乳酸测试。
