Physiological responses in tennis and running with similar oxygen uptake

The purpose of the study was to compare selected physiological responses during singles tennis match play and continuous running at a similar mean oxygen uptake (VO2). The study consisted of two main parts, which were separated by 1 week. In the first part, 12 nationally ranked senior tennis players [six females and six males; 47.2 (6.6) years old and 47.0 (5.4) years old, respectively] each completed a 2-h singles tennis match (TE). Mean VO2 during TE [23.1 (3.1) ml.kg(-1). min(-1) for the women and 25.6 (2.8) ml.kg(-1).min(-1) for the men] was measured by a portable spirometry-telemetry system and corresponded to 56% (women) or 54% (men) of their respective maximum VO2. In the second part, the relative VO2 data measured during TE were used to set a similar workload during a 2-h treadmill run at a constant level (RU). At the measured time points, heart rate [140.1 (15.5) beats.min(-1) vs 126.4 (15.1) beats. min(-1)], lactate concentration [1.53 (0.65) mmol.l(-1) vs 1.01 (0.38) mmol.l(-1)] and glucose concentration [5.45 (0.84) mmol.l(-1) vs 4.34 (0.56) mmol.l(-1)] in capillary blood, as well as the respiratory exchange ratio [0.93 (0.03) vs 0.88 (0.03)], were higher (P