Effect of ramp slope on intensity thresholds based on correlation properties of heart rate variability during cycling

Figures

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  FIGURE 1. Plotting of DFA a1 over time in seconds during a 30 W · min−1 RI (a) and DFA a1 versus HR (bpm) in a representative participant performing three types of incremental cycling ramp tests (b). Circle: 15 W · min−1; Square: 30 W · min−1; Triangle: 45 W · min−1 RI slopes. The solid line denotes the line of regression for heart rate variability threshold assessment for the 30 W·min−1 ramp values. DFA, detrended fluctuation analysis; HR, heart rate; RI, ramp incremental.

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  FIGURE 2. Box and whisker plots of individual participant ramp responses: HRVT1 (a, c); HRVT2 (b, d); both as either V̇O2 (mL · kg−1 · min−1) or HR (bpm); box edges represent first and third quartiles, the central line is the median, and the whiskers are the minimum and maximum values; 15 W · min−1 (15w), 30 W · min−1 (30w), and 45 W · min−1 (45w) refer to ramp slope. N = 17. HRVT, heart rate variability threshold.

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  FIGURE 3. Bland–Altman plots of ramp responses: HRVT1; HRVT2; both as either V̇O2 (mL · kg−1 · min−1) or heart rate (bpm); mean; SD (standard deviation); 15 W · min−1 (15w), 30 W · min−1 (30w), and 45 W · min−1 (45w) refer to ramp slope. Mean bias (solid line) and limits of agreement (dashed line) indicated. N = 17. HRVT, heart rate variability threshold.