Peter Krustrup1, Paul S Bradley, Jesper F Christensen, Carlo Castagna, Sarah Jackman, Luke Connolly, Morten B Randers, Magni Mohr, Jens Bangsbo. 1. 1Department of Nutrition, Exercise and Sports, Copenhagen Centre for Team Sport and Health, University of Copenhagen, Copenhagen, DENMARK; 2Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UNITED KINGDOM; 3Department of Sport and Exercise Sciences, University of Sunderland, Sunderland, UNITED KINGDOM; 4Carnegie School of Sport, Leeds Metropolitan University, Leeds, UNITED KINGDOM; 5University Hospitals Centre for Health Research, Copenhagen University Hospital, DENMARK; 6Italian Football Referees Association, Rome, ITALY; 7Football Training and Biomechanics Laboratory, Italian Football Federation, Technical Department, Coverciano, Florence, ITALY; 8Faculty of Natural and Health Sciences, University of the Faroe Islands, FAROE ISLANDS; and 9Department of Food and Nutrition, and Sport Science, University of Gothenburg, Gothenburg, SWEDEN.
Abstract
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˙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·kg d.w·min), muscle lactate accumulation (16.8 ± 9.1 vs 4.2 ± 2.9 mmol·kg d.w.·min), and glycogen breakdown (29.6 ± 14.2 vs 7.7 ± 5.4 mmol·kg d.w.·min) 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˙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˙O2max seemed to be important for intermittent exercise performance in UTR but not for TR.
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˙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·kg d.w·min), muscle lactate accumulation (16.8 ± 9.1 vs 4.2 ± 2.9 mmol·kg d.w.·min), and glycogen breakdown (29.6 ± 14.2 vs 7.7 ± 5.4 mmol·kg d.w.·min) 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˙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˙O2max seemed to be important for intermittent exercise performance in UTR but not for TR.
Authors: Therese Hornstrup; F T Løwenstein; M A Larsen; E W Helge; S Póvoas; J W Helge; J J Nielsen; B Fristrup; J L Andersen; L Gliemann; L Nybo; P Krustrup Journal: Eur J Appl Physiol Date: 2018-11-24 Impact factor: 3.078
Authors: André M Londe; Moacir Marocolo; Isabela Coelho Marocolo; James Fisher; Octavio Barbosa Neto; Markus Vinicius Campos Souza; Gustavo Ribeiro da Mota Journal: Sports Med Int Open Date: 2018-06-05
Authors: Susana C A Póvoas; Carlo Castagna; Carlos Resende; Eduardo Filipe Coelho; Pedro Silva; Rute Santos; Rita Pereira; Peter Krustrup Journal: Biomed Res Int Date: 2018-10-03 Impact factor: 3.411
Authors: Therese Hornstrup; Johan M Wikman; Bjørn Fristrup; Susana Póvoas; Eva W Helge; Signe H Nielsen; Jørn W Helge; Jesper L Andersen; Lars Nybo; Peter Krustrup Journal: J Sport Health Sci Date: 2017-09-19 Impact factor: 7.179