A Comparison of Incremental Running Field and Treadmill Tests in Young Soccer Players

The purpose of this study was to compare the incremental running tests performed by young soccer players on a treadmill (Tr) and in the field (FT_cod: 100 m change of direction and FT_cir: 100 m circle). Nineteen players (average age 17.4 ± 1.1 years; body height 172.0 ± 5.7 cm; body mass 68.9 ± 6.7 kg) volunteered to perform incremental Tr , FT_cod and FT_cir running tests. In all three tests, players ran for 3 min at 8, 10, 12 and 14 km∙h^-1 and were given a 1 min rest interval between subsequent stages. Blood lactate concentrations (La^-) were measured at 1 min rest intervals and the heart rate (HR) responses of players were recorded during the tests. After a 5 min recovery period, the second part of the test started; players ran at 15 km∙h^-1 with velocity increments of 1 km∙h^-1 every 1 min until exhaustion. This part was performed to determine maximum HR, maximum La^- and the players' final velocities. The results showed that players had significantly lower La^- (F = 6.93, p = 0.07, η² = 0.46, 95%CI_(TR-FTcir) = -1.91/-0.34, 95%CI_(TR-FTcod) = -1.59/-0.05) and HR (F = 9.08, p = 0.02, η² = 0.53, 95%CI_(TR-FTcir) = -6.98/-1.68, 95%CI_(TR-FTcod) = -7.19/1.08) responses in the Tr test than in the FT_cir and FT_cod tests at 14 km∙h^-1. It was also found that players completed the Tr test (F = 58.22, p = 0.00, η² = 0.87) at higher final running velocities than the FT_cir (95%CI_(TR-FTcir) = 1.67/2.78) and FT_cod (95%CI_(TR-FTcod) = 1.69/2.85) tests. In conclusion, when coaches or sports scientists plan to train at higher running velocities or according to the final velocity in the test, it is advisable to carry out testing in the circumstances under which training will be carried out (in the field or on a treadmill).