“…These data confirm the outcomes which emerged from O' Donoghue and Liddle (1998), in which the average duration of a tennis match is about 90-120 min on grass or concrete and from 120 to 180 min on clay. Nevertheless, the technical-tactical evolution of recent years has led to more similar playing times on both hard and clay courts (Fabre, Martin, Gondin, Cottin, & Gerlot, 2012 a result of the frequent active and passive recovery periods, the average effective playing time corresponds to 24% of the total (Christmass, Richmond, Cable, Arthur, & Hartmann, 1998;Botton, Hautier, & Eclache, 2011;Smekal et al, 2001) and it further decreases after the third consecutive day of match play (Gescheit et al, 2016). The average duration of rallies is about 5 s (Smekal et al, 2001;Botton et al, 2011), whereas 56% of them last from 1 to 6 s and 18% from 6 to 9 s (Mendez-Villanueva, Ferandez-Fernandez, Bishop, FernandezGarcia, & Terrados, 2007), with an average of 2 s of rest per each second of work (Christmass et al, 1998;Murias et al, 2007).…”