We hypothesized that the performance of prior heavy exercise would speed the phase 2 oxygen consumption (VO2) kinetics during subsequent heavy exercise in the supine position (where perfusion pressure might limit muscle O2 supply) but not in the upright position. Eight healthy men (mean +/- SD age 24 +/- 7 yr; body mass 75.0 +/- 5.8 kg) completed a double-step test protocol involving two bouts of 6 min of heavy cycle exercise, separated by a 10-min recovery period, on two occasions in each of the upright and supine positions. Pulmonary O2 uptake was measured breath by breath and muscle oxygenation was assessed using near-infrared spectroscopy (NIRS). The NIRS data indicated that the performance of prior exercise resulted in hyperemia in both body positions. In the upright position, prior exercise had no significant effect on the time constant tau of the VO2 response in phase 2 (bout 1: 29 +/- 10 vs. bout 2: 28 +/- 4 s; P = 0.91) but reduced the amplitude of the VO2 slow component (bout 1: 0.45 +/- 0.16 vs. bout 2: 0.22 +/- 0.14 l/min; P = 0.006) during subsequent heavy exercise. In contrast, in the supine position, prior exercise resulted in a significant reduction in the phase 2 tau (bout 1: 38 +/- 18 vs. bout 2: 24 +/- 9 s; P = 0.03) but did not alter the amplitude of the VO2 slow component (bout 1: 0.40 +/- 0.29 vs. bout 2: 0.41 +/- 0.20 l/min; P = 0.86). These results suggest that the performance of prior heavy exercise enables a speeding of phase 2 VO2 kinetics during heavy exercise in the supine position, presumably by negating an O2 delivery limitation that was extant in the control condition, but not during upright exercise, where muscle O2 supply was probably not limiting.

There is minimal research on the practices of strength and conditioning coaches in England.Information about training programme design could be useful in developing models of good practice and ecologically valid intervention studies. The aim of the research was to quantify the reported their rowers performed strength training, with 81% using Olympic lifting, and 91% employing a periodised training model. The clean (63%) and squat (27%) were rated the most important exercises prescribed within the training programme. Approximately 50% of coaches used plyometrics such as depth jumps, box drills and standing jumps. Ninety four percent indicated they conducted physical testing on their rowers, typically assessing cardiovascular endurance (80%), muscular power (70%), muscular strength (70%) and anaerobic capacity (57%). On average, testing was conducted by coaches in pre-season (88%) and inseason (91%), while only 31% preformed postseason testing. Coaches typically prescribed static stretching (97%), dynamic stretching (69%), PNF stretching (56%). This research provides detailed information on the current strength and conditioning provision in rowing within Great Britain.Future studies could use this information to develop experimental protocols to examine the effect of current or new strength and conditioning interventions on rowing performance.

Six weeks of low-intensity continuous training and high-intensity interval training were similarly effective in enhancing VO2 on-kinetics following step transitions to moderate and severe exercise in previously untrained subjects.

No abstract

We hypothesized that 4 weeks of recombinant human erythropoietin (RhEPO) treatment would result in a significant increase in haemoglobin concentration ([Hb]) and arterial blood O 2 -carrying capacity and that this would (1) increase peak pulmonary oxygen uptake (V O 2 ) during ramp incremental exercise, and (2) speedV O 2 kinetics during 'severe'-, but not 'moderate'-or 'heavy'-intensity, step exercise. Fifteen subjects (mean ± S.D. age 25 ± 4 years) were randomly assigned to either an experimental group which received a weekly subcutaneous injection of RhEPO (150 IU kg −1 ; n = 8), or a control group (CON) which received a weekly subcutaneous injection of sterile saline (10 ml; n = 7) as a placebo, for four weeks. The subjects and the principal researchers were both blind with respect to the group assignment. Before and after the intervention period, all subjects completed a ramp test for determination of the gas exchange threshold (GET) andV O 2 ,peak , and a number of identical 'step' transitions from 'unloaded' cycling to work rates requiring 80% GET (moderate), 70% of the difference between the GET anḋ V O 2 ,peak (heavy), and 105%V O 2 ,peak (severe) as determined from the initial ramp test. Pulmonary gas exchange was measured breath-by-breath. There were no significant differences between the RhEPO and CON groups for any of the measurements of interest ([Hb],V O 2 ,peak ,V O 2 kinetics) before the intervention. Four weeks of RhEPO treatment resulted in a 7% increase both in [Hb] (from 15.8 ± 1.0 to 16.9 ± 0.7 g dl −1 ; P < 0.01) andV O 2 ,peak (from 47.5 ± 4.2 to 50.8 ± 10.7 ml kg −1 ·min −1 ; P < 0.05), with no significant change in CON. RhEPO had no significant effect onV O 2 kinetics for moderate (Phase II time constant, from 28 ± 8 to 28 ± 7 s), heavy (from 37 ± 12 to 35 ± 11 s), or severe (from 33 ± 15 to 35 ± 15 s) step exercise. Our results indicate that enhancing blood O 2 -carrying capacity and thus the potential for muscle O 2 delivery with RhEPO treatment enhanced the peakV O 2 but did not influenceV O 2 kinetics, suggesting that the latter is principally regulated by intracellular (metabolic) factors, even during exercise where theV O 2 requirement is greater than theV O 2 ,peak , at least in young subjects performing upright cycle exercise.

We hypothesized that a period of endurance training would result in a speeding of muscle phosphocreatine concentration ([PCr]) kinetics over the fundamental phase of the response and a reduction in the amplitude of the [PCr] slow component during high-intensity exercise. Six male subjects (age 26 +/- 5 yr) completed 5 wk of single-legged knee-extension exercise training with the alternate leg serving as a control. Before and after the intervention period, the subjects completed incremental and high-intensity step exercise tests of 6-min duration with both legs separately inside the bore of a whole-body magnetic resonance spectrometer. The time-to-exhaustion during incremental exercise was not changed in the control leg [preintervention group (PRE): 19.4 +/- 2.3 min vs. postintervention group (POST): 19.4 +/- 1.9 min] but was significantly increased in the trained leg (PRE: 19.6 +/- 1.6 min vs. POST: 22.0 +/- 2.2 min; P < 0.05). During step exercise, there were no significant changes in the control leg, but end-exercise pH and [PCr] were higher after vs. before training. The time constant for the [PCr] kinetics over the fundamental exponential region of the response was not significantly altered in either the control leg (PRE: 40 +/- 13 s vs. POST: 43 +/- 10 s) or the trained leg (PRE: 38 +/- 8 s vs. POST: 40 +/- 12 s). However, the amplitude of the [PCr] slow component was significantly reduced in the trained leg (PRE: 15 +/- 7 vs. POST: 7 +/- 7% change in [PCr]; P < 0.05) with there being no change in the control leg (PRE: 13 +/- 8 vs. POST: 12 +/- 10% change in [PCr]). The attenuation of the [PCr] slow component might be mechanistically linked with enhanced exercise tolerance following endurance training.

Key points• Following the start of low-intensity exercise in healthy humans, it has been established that the kinetics of muscle O 2 delivery is faster than, and does not limit, the kinetics of muscle O 2 uptake.• Direct data are lacking, however, on the question of whether O 2 delivery might limit O 2 uptake kinetics during high-intensity exercise.• In this study, we made frequent measurements of muscle blood flow, arterial-to-venous O 2 difference (a-v O 2 difference) and O 2 uptake following the onset of multiple transitions of both low-intensity and high-intensity knee-extension exercise in the same subjects.• We show that although blood flow kinetics is slower for high-intensity compared with low-intensity exercise, this does not result in slower O 2 uptake kinetics.• These results indicate that muscle O 2 delivery does not limit O 2 uptake during knee-extension exercise in healthy humans.Abstract Following the start of low-intensity exercise in healthy humans, it has been established that the kinetics of skeletal muscle O 2 delivery is faster than, and does not limit, the kinetics of muscle O 2 uptake (V O 2 (m)

This systematic review and meta-analysis aimed to assess studies which have investigated cooling methodologies, their timing and effects, on endurance exercise performance in trained athletes (Category 3; VO2max ≥ 55 mL·kg·min−1) in hot environmental conditions (≥28 °C). Meta-analyses were performed to quantify the effects of timings and methods of application, with a narrative review of the evidence also provided. A computer-assisted database search was performed for articles investigating the effects of cooling on endurance performance and accompanying physiological and perceptual responses. A total of 4129 results were screened by title, abstract, and full text, resulting in 10 articles being included for subsequent analyses. A total of 101 participants and 310 observations from 10 studies measuring the effects of differing cooling strategies on endurance exercise performance and accompanying physiological and perceptual responses were included. With respect to time trial performance, cooling was shown to result in small beneficial effects when applied before and throughout the exercise bout (Effect Size: −0.44; −0.69 to −0.18), especially when ingested (−0.39; −0.60 to −0.18). Current evidence suggests that whilst other strategies ameliorate physiological or perceptual responses throughout endurance exercise in hot conditions, ingesting cooling aids before and during exercise provides a small benefit, which is of practical significance to athletes’ time trial performance.