TY  - JOUR
PY  - 2014//
TI  - The Yo-Yo IE2 Test: Physiological Response for Untrained Men vs Trained Soccer Players
JO  - Medicine and science in sports and exercise
A1  - Krustrup, Peter
A1  - Bradley, Paul S.
A1  - Christensen, Jesper F.
A1  - Castagna, Carlo
A1  - Jackman, Sarah
A1  - Connolly, Luke
A1  - Randers, Morten B.
A1  - Mohr, Magni
A1  - Bangsbo, Jens
SP  - 100
EP  - 108
VL  - 47
IS  - 1
N2  - PURPOSE: To examine the physical capacity and physiological response to the Yo-Yo Intermittent Endurance level 2 test (IE2) for untrained individuals and trained male soccer players, and to investigate the determinants of intense intermittent exercise performance. <br><br>METHODS: Thirty-four healthy untrained males (UTR) and fifteen age-matched trained soccer players (TR) performed a maximal incremental treadmill test (ITT) and a Yo-Yo IE2 test. Muscle biopsies and blood samples were obtained and HR were measured before, during and after tests. <br><br>RESULTS: UTR had a 67% lower (P<0.01) Yo-Yo IE2 performance (665±271 vs. 2027±298 m; ES:4.8), 34% lower (P<0.01) VO2max and 19% lower (P<0.05) resting muscle glycogen than TR. Blood lactate and heart rates during the first 560 m of the Yo-Yo IE2 test were higher (P<0.01) in UTR than TR (560 m: 7.4±2.8 vs. 2.4±0.8 mmol·L; 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 TR (1.0±1.1 vs. 6.3±2.9 min, ES:3.1). Mean rate of muscle creatine phosphate utilization (16.5±9.5 vs. 4.3±2.7 mmol·kgd.w·min), muscle lactate accumulation (16.8±9.1 vs. 4.2±2.9 mmol·kgd.w·min), and glycogen breakdown (29.6±14.2 vs. 7.7±5.4 mmol·kgd.w·min) were 4-fold higher (P<0.01,ES:1.4-1.7) in UTR than TR. For UTR, correlations (P<0.01) were observed between Yo-Yo IE2 performance and VO2max (r=0.77), ITT performance (r=0.79) and muscle citrate synthase activity (r=0.57), but not for TR (r=-0.12-0.50; P>0.05). <br><br>CONCLUSION: The Yo-Yo IE2 test was shown to possess high construct validity by showing large differences in performance, heart rates and anaerobic metabolism between untrained individuals and trained soccer players. Additionally, VO2max appeared to be important for intermittent exercise performance in untrained individuals, but not for trained soccer players.<p /> <p>Language: en</p>
LA  - en
SN  - 0195-9131
UR  - http://dx.doi.org/10.1249/MSS.0000000000000377
ID  - ref1
ER  -