Resumen de The Yo-Yo IE2 Test: Physiological Response for Untrained Men versus Trained Soccer Players.
Peter Krustrup, Jens Bangsbo, Paul S. Bradley, Magni Mohr, Jesper F. Christensen, Morten B. Randers, Carlo Castagna, Luke Connolly, Sarah R. Jackman
AB Purpose: This study aimed to examine the physical capacity and physiological response to the Yo-Yo Intermittent Endurance level 2 test (IE2) for untrained individuals (UTR) and trained male soccer players (TR) and to investigate the determinants of intense intermittent exercise performance. Methods: Thirty-four healthy UTR males and 15 age-matched TR performed a maximal incremental treadmill test and a Yo-Yo IE2 test. Muscle biopsies and blood samples were obtained, and heart rate (HR) was measured before, during, and after tests. Results: UTR had a 67% lower (P < 0.01) Yo-Yo IE2 performance (665 +/- 271 vs 2027 +/- 298 m; effect size (ES), 4.8), 34% lower V[spacing dot above]O2max (P < 0.01), and 19% lower resting muscle glycogen (P < 0.05) than those of TR. Blood lactate concentration and HR during the first 560 m of the Yo-Yo IE2 test were higher (P < 0.01) in UTR than those in TR (560 m, 7.4 +/- 2.8 vs 2.4 +/- 0.8 mM; ES, 1.7-2.8; 188 +/- 11 vs 173 +/- 8 bpm; ES, 0.9-1.5), with no differences at exhaustion. Time >95% HRmax was lower (P < 0.01) in UTR than that in TR (1.0 +/- 1.1 vs 6.3 +/- 2.9 min; ES, 3.1). Mean rates of muscle creatine phosphate utilization (16.5 +/- 9.5 vs 4.3 +/- 2.7 mmol[middle dot]kg-1 d.w[middle dot]min-1), muscle lactate accumulation (16.8 +/- 9.1 vs 4.2 +/- 2.9 mmol[middle dot]kg-1 d.w.[middle dot]min-1), and glycogen breakdown (29.6 +/- 14.2 vs 7.7 +/- 5.4 mmol[middle dot]kg-1 d.w.[middle dot]min-1) were fourfold higher (P < 0.01; ES, 1.4-1.7) in UTR than those in TR. For UTR, correlations (P < 0.01) were observed between Yo-Yo IE2 performance and V[spacing dot above]O2max (r = 0.77), incremental treadmill test performance (r = 0.79), and muscle citrate synthase activity (r = 0.57) but not for TR (r = -0.12 to 0.50; P > 0.05). Conclusions: The Yo-Yo IE2 test was shown to possess high construct validity by showing large differences in performance, HR, and anaerobic metabolism between UTR and TR. In addition, V[spacing dot above]O2max seemed to be important for intermittent exercise performance in UTR but not for TR.
