Impact of Tennis-Specific Hitting and Running Loads on Respiration Patterns Compared to Treadmill Running With Similar Oxygen Uptake.

This study aimed to compare respiratory patterns and gas exchange during tennis and treadmill running at similar oxygen uptake. On three experimental days, 15 elite players (7 female, 8 male) completed a standardized tennis protocol (TP), a treadmill-based incremental running test (RT), and a metabolically matched running protocol (RP). TP (Day 1) included low or high running loads (RL, RH) and low or high stroke velocities (SL, SH) which were combined in four incremental ball-machine stages (TP1:RL + SL; TP2:RL + SH; TP3:RH + SL; TP4:RH + SH). RT (Day 2) determined running speeds matching the oxygen uptake of each TP stage. RP (Day 3) replicated TP's mean oxygen consumption and stage duration through treadmill running. Metabolic and respiratory responses (portable spirometry) and external loads (stroke velocity) were compared between TP and RP. In tennis, mean oxygen uptake (p < 0.001), energy expenditure (p < 0.001), and respiratory exchange ratio (p < 0.001) as well as respiratory responses increased significantly between Stage 1-4. No differences in metabolic responses as well as in breathing frequency (bf), ventilation ( V ˙ $\dot{\mathrm{V}}$ 'E), inspiration (tI), and expiration time (tE) were observed between TP and RP. In contrast, the number of breathing plateaus per stage (NP) was significantly higher in TP compared to RP during TP2 (5.9 ± 3.8 vs. 0.4 ± 0.5 times, p < 0.001), TP3 (2.6 ± 2.7 vs. 0.3 ± 0.6 times, p = 0.04), and TP4 (4.6 ± 4.1 vs. 0.3 ± 0.6 times, p < 0.001). Breathing plateaus appear characteristic for tennis when hitting hard without affecting metabolism. Exploring individual breathing patterns can be recommended in practice.