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Buchheit M.,Academy for Sports Excellence | Buchheit M.,University of Picardie Jules Verne
International Journal of Sports Medicine | Year: 2012

To examine the respective associations between indices of aerobic fitness, metabolic control and locomotor function and repeated sprint-performance, 61 team sport players performed: a repeated-sprint sequence (RSS), an incremental test to exhaustion to determine maximal oxygen uptake (VO 2max) and peak incremental test speed (Inc. test speed), and 2-4 submaximal runs to determine the time constant of the primary phase of VO 2 kinetics at exercise onset (VO 2τ on) and cessation (VO 2τ off). The best (RS best) sprint times and mean sprint times (RS mean) and the percent sprint decrement (%Dec) were calculated. RS mean was almost perfectly correlated with RS best (r=0.92;90%CL(0.88;0.95)), largely correlated with Inc. test speed (r=-0.71;90%CL(-0.79;-0.59)) and moderately correlated with VO 2max (r=-0.58;90%CL(-0.70;-0.43)); the correlations with VO 2τ on or VO 2τ off were unclear. For%Dec, the correlations with Inc. test speed, VO 2max and VO 2τ on were moderate (r=-0.41;90%CL(-0.56;-0.23)), small (r=-0.26;90%CL(-0.43;-0.06)) and small (r=0.28;90%CL(0.09;0.46)), respectively. Stepwise multiple regression analyses showed that the only significant predictors of RS mean were RS best and Inc. test speed (r 2=0.88). Inc. test speed and RSbest were also the only significant predictors of %Dec (r 2=0.26). Present results obtained in a large sample of team sport players highlight that locomotor factors (i.e., RS best and Inc. test speed) show much larger associations with repeated-sprint performance than VO 2max and VO 2 kinetics. © Georg Thieme Verlag KG Stuttgart - New York. Source


Buchheit M.,Academy for Sports Excellence | Laursen P.B.,High Performance Sport New Zealand | Laursen P.B.,Auckland University of Technology
Sports Medicine | Year: 2013

High-intensity interval training (HIT) is a well-known, time-efficient training method for improving cardiorespiratory and metabolic function and, in turn, physical performance in athletes. HIT involves repeated short (<45 s) to long (2-4 min) bouts of rather high-intensity exercise interspersed with recovery periods (refer to the previously published first part of this review). While athletes have used 'classical' HIT formats for nearly a century (e.g. repetitions of 30 s of exercise interspersed with 30 s of rest, or 2-4-min interval repetitions ran at high but still submaximal intensities), there is today a surge of research interest focused on examining the effects of short sprints and all-out efforts, both in the field and in the laboratory. Prescription of HIT consists of the manipulation of at least nine variables (e.g. work interval intensity and duration, relief interval intensity and duration, exercise modality, number of repetitions, number of series, between-series recovery duration and intensity); any of which has a likely effect on the acute physiological response. Manipulating HIT appropriately is important, not only with respect to the expected middle- to long-term physiological and performance adaptations, but also to maximize daily and/or weekly training periodization. Cardiopulmonary responses are typically the first variables to consider when programming HIT (refer to Part I). However, anaerobic glycolytic energy contribution and neuromuscular load should also be considered to maximize the training outcome. Contrasting HIT formats that elicit similar (and maximal) cardiorespiratory responses have been associated with distinctly different anaerobic energy contributions. The high locomotor speed/power requirements of HIT (i.e. ≥95 % of the minimal velocity/power that elicits maximal oxygen uptake [v/p ̇V ̇ O2max] to 100 % of maximal sprinting speed or power) and the accumulation of high-training volumes at high-exercise intensity (runners can cover up to 6-8 km at v ̇ V ̇ O2max per session) can cause significant strain on the neuromuscular/musculoskeletal system. For athletes training twice a day, and/or in team sport players training a number of metabolic and neuromuscular systems within a weekly microcycle, this added physiological strain should be considered in light of the other physical and technical/tactical sessions, so as to avoid overload and optimize adaptation (i.e. maximize a given training stimulus and minimize musculoskeletal pain and/or injury risk). In this part of the review, the different aspects of HIT programming are discussed, from work/relief interval manipulation to HIT periodization, using different examples of training cycles from different sports, with continued reference to the cardiorespiratory adaptations outlined in Part I, as well as to anaerobic glycolytic contribution and neuromuscular/musculoskeletal load. © 2013 Springer International Publishing Switzerland. Source


Buchheit M.,Academy for Sports Excellence | Buchheit M.,Physiology Unit | Laursen P.B.,High Performance Sport New Zealand | Laursen P.B.,Auckland University of Technology
Sports Medicine | Year: 2013

High-intensity interval training (HIT), in a variety of forms, is today one of the most effective means of improving cardiorespiratory and metabolic function and, in turn, the physical performance of athletes. HIT involves repeated short-to-long bouts of rather high-intensity exercise interspersed with recovery periods. For team and racquet sport players, the inclusion of sprints and all-out efforts into HIT programmes has also been shown to be an effective practice. It is believed that an optimal stimulus to elicit both maximal cardiovascular and peripheral adaptations is one where athletes spend at least several minutes per session in their 'red zone,' which generally means reaching at least 90 % of their maximal oxygen uptake ( VO2max). While use of HIT is not the only approach to improve physiological parameters and performance, there has been a growth in interest by the sport science community for characterizing training protocols that allow athletes to maintain long periods of time above 90 % of VO2max (T@VO2max). In addition to T@VO2max, other physiological variables should also be considered to fully characterize the training stimulus when programming HIT, including cardiovascular work, anaerobic glycolytic energy contribution and acute neuromuscular load and musculoskeletal strain. Prescription for HIT consists of the manipulation of up to nine variables, which include the work interval intensity and duration, relief interval intensity and duration, exercise modality, number of repetitions, number of series, as well as the between-series recovery duration and intensity. The manipulation of any of these variables can affect the acute physiological responses to HIT. This article is Part I of a subsequent II-part review and will discuss the different aspects of HIT programming, from work/relief interval manipulation to the selection of exercise mode, using different examples of training cycles from different sports, with continued reference to T@VO2max and cardiovascular responses. Additional programming and periodization considerations will also be discussed with respect to other variables such as anaerobic glycolytic system contribution (as inferred from blood lactate accumulation), neuromuscular load and musculoskeletal strain (Part II). © Springer International Publishing Switzerland 2013. Source


Billaut F.,Institute national du sport du Quebec | Buchheit M.,Academy for Sports Excellence
Scandinavian Journal of Medicine and Science in Sports | Year: 2013

This study examined the influence of muscle deoxygenation and reoxygenation on repeated-sprint performance via manipulation of O2 delivery. Fourteen team-sport players performed 10 10-s sprints (30-s recovery) under normoxic (NM: FIO2 0.21) and acute hypoxic (HY: FIO2 0.13) conditions in a randomized, single-blind fashion and crossover design. Mechanical work was calculated and arterial O2 saturation (SpO2) was estimated via pulse oximetry for every sprint. Muscle deoxyhemoglobin concentration ([HHb]) was monitored continuously by near-infrared spectroscopy. Differences between NM and HY data were analyzed for practical significance using magnitude-based inferences. HY reduced SpO2 (-10.7±1.9%, with chances to observe a higher/similar/lower value in HY of 0/0/100%) and mechanical work (-8.2±2.1%; 0/0/100%). Muscle deoxygenation increased during sprints in both environments, but was almost certainly higher in HY (12.5±3.1%, 100/0/0%). Between-sprint muscle reoxygenation was likely more attenuated in HY (-11.1±11.9%; 2/7/91%). The impairment in mechanical work in HY was very largely correlated with HY-induced attenuation in muscle reoxygenation (r=0.78, 90% confidence limits: 0.49; 0.91). Repeated-sprint performance is related, in part, to muscle reoxygenation capacity during recovery periods. These results extend previous findings that muscle O2 availability is important for prolonged repeated-sprint performance, in particular when the exercise is taken in hypoxia. © 2013 John Wiley & Sons A/S. Source


Buchheit M.,Academy for Sports Excellence
European Journal of Applied Physiology | Year: 2010

In this study, the performance and selected physiological responses to team-sport specific repeated-sprint and jump sequence were investigated. On four occasions, 13 team-sport players (22 ± 3 year) performed alternatively six repeated maximal straight-line or shuttle-sprints interspersed with a jump ([RS+j, 6 × 25 m] or [RSS+j, 6 × (2 × 12.5 m)]) or not ([RS, 6 × 25 m] or [RSS, 6 × (2 × 12.5 m)]) within each recovery period. Mean running time, rate of perceived exertion (RPE), pulmonary oxygen uptake ( $$ \dot{V} $$ O2), blood lactate ([La]b), and vastus lateralis deoxygenation ([HHb]) were obtained for each condition. Mean sprint times were greater for RS+j versus RS (4.14 ± 0.17 vs. 4.09 ± 0.16 s, with the qualitative analysis revealing a 82% chance of RS+j times to be greater than RS) and for RSS+j versus RSS (5.43 ± 0.18 vs. 5.29 ± 0.17 s; 99% chance of RSS+j to be >RSS). The correlation between sprint and jump abilities were large-to-very-large, but below 0.71 for RSSs. Jumps increased RPE (Cohen's d ± 90% CL: +0.7 ± 0.5; 95% chance for RS+j > RS and +0.7 ± 0.5; 96% for RSS+j > RSS), $$ \dot{V} $$ O 2 (+0.4 ± 0.5; 80% for RS+j > RS and +0.5 ± 0.5; 86% for RSS+j > RSS), [La]b (+0.5 ± 0.5; 59% for RS+j > RS and +0.2 ± 0.5; unclear for RSS+j > RSS), and [HHb] (+0.5 ± 0.5; 86% for RS +j > RS and +0.5 ± 0.5; 85% for RSS+j > RSS). To conclude, repeated-sprint and jump abilities could be considered as specific qualities. The addition of a jump within the recovery periods during repeated-sprint running sequences impairs sprinting performance and might be an effective training practice for eliciting both greater systemic and vastus lateralis physiological loads. © 2010 Springer-Verlag. Source

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