Moderate recovery unnecessary to sustain high stroke volume during interval training

IMG_20131125_081714Stanley J. & Buchheit M. Moderate recovery unnecessary to sustain high stroke volume during interval training, J Sport Sci & Med, 2014, In press.Recovery SV HIT

It has been suggested that the time spent at a high stroke volume (SV) is important for improving maximal cardiac function. The aim of this study was to examine the effect of recovery intensity on cardiovascular parameters during a typical high-intensity interval training (HIIT) session in fourteen well-trained cyclists. Oxygen consumption (VO2), heart rate (HR), SV, cardiac output (Qc), and oxygenation of vastus lateralis (TSI) were measured during a HIIT (3×3 min work period, 2 min recovery) session on two occasions. VO2, HR and Qc were higher during moderate-intensity (60%) compared with low-intensity (30%) (VO2, effect size; ES=+2.6; HR, ES=+2.8; Qc, ES=+2.2) and passive (HR, ES=+2.2; Qc, ES=+1.7) recovery. By contrast, there were no clear differences in SV between the three recovery conditions, with the SV during the two active recovery periods not being substantially different than during exercise (60%, ES=−0.1; 30%, ES=−0.2). To conclude, moderate-intensity recovery may not be required to maintain a high SV during HIIT.

Keywords: high-intensity interval training; cardiac output; cardiac function; arteriovenous oxygen difference

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Effects of age, maturity and body dimensions on match running performance in highly-trained under 15 soccer players

More vs less mature

Buchheit & Mendez-Villanueva. Effects of age, maturity and body dimensions on match running performance in highly-trained under 15 soccer players. Journal of Sports Science, In press

For a discussion about the stats used in this study see the comments here: don’t trust % differences

The aim of the present study was to compare, in 36 highly-trained under 15 soccer players, the respective effects of age, maturity and body dimensions on match running performance. Maximal sprinting (MSS) and aerobic speeds were estimated. Match running performance was analysed with GPS (GPSport, 1 Hz) during 19 international friendly games (n=115 player-files). Total distance and distance covered >16 km/h (D>16 km.h-1) were collected. Players advanced in age and/or maturation, or having larger body dimensions presented greater locomotor (Cohen’s d for MSS: 0.5-1.0, likely to almost certain) and match running performances (D>16 km.h-1: 0.2-0.5, possibly to likely) than their younger, less mature and/or smaller team-mates. These age-, maturation- and body size-related differences were of larger magnitude for field test measures vs. match running performance. Compared with age and body size (unclear to likely), maturation (likely to almost certainly for all match variables) had the greatest impact on match running performance. The magnitude of the relationships between age, maturation and body dimensions and match running performance were position-dependent. Within a single age-group in the present player sample, maturation had a substantial impact on match running performance, especially in attacking players. Coaches may need to consider players’ maturity status when assessing their on-field playing performance.

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