Heart rate deflection point relates to second ventilatory threshold in a tennis test

Abstract

The relationship between heart rate deflection point (HRDP) and the second ventilatory threshold (VT2) has been studied in continuous sports, but never in a tennis-specific test. The aim of the study was to assess the relationships between HRDP and the VT2, and between themaximal test performance and the maximal oxygen uptake (V_ O2max) in an on-court specific endurance tennis test. Thirty-five high-level tennis players performed a progressive tennis-specific field test to exhaustion to determine HRDP, VT2, and V_ O2max. Ventilatory gas exchange parameters were continuously recorded by a portable telemetric breath-by-breath gas exchange measurement system. Heart rate deflection point was identified at the point at which the slope values of the linear portion of the time/heart rate (HR) relationship began to decline and was successfully determined in 91.4% of the players. High correlations (r = 0.79–0.96; p , 0.001) between physiological (HR and oxygen uptake [V_ O2]) and performance (Time, Stage, and Frequency of balls [Ballf]) variables corresponding to HRDP and VT2 were observed. Frequency of balls at the HRDP (BallfHRDP) was detected at 19.8 6 1.7 shots per minute. Paired t-test showed no significant differences in HR (178.9 6 8.5 vs. 177.9 6 8.7 b$min21 for HRDP vs. HRVT2, respectively) at intensities corresponding to HRDP and VT2. Maximal test performance and V_ O2max were moderately correlated (r = 0.56; p , 0.001). Heart rate deflection point obtained from this specific tennis test can be used to determine the VT2, and the BallfHRDP can be used as a practical performance variable to prescribe on-court specific aerobic training at or near VT2.