Rampinini E, Sassi A, Azzalin A, Castagna C, Menaspā P, Carlomagno D, Impellizzeri FM

Human Performance Laboratory, MAPEI Sport Research Center, Castellanza, Varese, Italy, physiolab@mapeisport.it.

The physiological determinants of performance in two Yo-Yo intermittent recovery tests (Yo-YoIR1 and Yo-YoIR2) were examined in 25 professional (n = 13) and amateur (n = 12) soccer players. The aims of the study were (1) to examine the differences in physiological responses to Yo-YoIR1 and Yo-YoIR2, (2) to determine the relationship between the aerobic and physiological responses to standardized high-intensity intermittent exercise (HIT) and Yo-Yo performance, and (3) to investigate the differences between professional and amateur players in performance and responses to these tests. All players performed six tests: two versions of the Yo-Yo tests, a test for the determination of maximum oxygen uptake ([Formula: see text]), a double test to determine [Formula: see text] kinetics and a HIT evaluation during which several physiological responses were measured. The anaerobic contribution was greatest during Yo-YoIR2. [Formula: see text] was strongly correlated with Yo-YoIR1 (r = 0.74) but only moderately related to Yo-YoIR2 (r = 0.47). The time constant (tau) of [Formula: see text] kinetics was largely related to both Yo-Yo tests (Yo-YoIR1: r = 0.60 and Yo-YoIR2: r = 0.65). The relationships between physiological variables measured during HIT (blood La(-), H(+), HCO(3) (-) and the rate of La(-) accumulation) and Yo-Yo performance (in both versions) were very large (r > 0.70). The physiological responses to HIT and the tau of the [Formula: see text] kinetics were significantly different between professional and amateur soccer players, whilst [Formula: see text] was not significantly different between the two groups. In conclusion, [Formula: see text] is more important for Yo-YoIR1 performance, whilst tau of the [Formula: see text] kinetics and the ability to maintain acid-base balance are important physiological factors for both Yo-Yo tests.

Eur J Appl Physiol. 2009 Oct 11. [Epub ahead of print]