Delphine Thevenet

Continuous vs. Interval Aerobic Training in 8- to 11-Year-Old Children

Baquet, G, Gamelin, F-X, Mucci, P, Thévenet, D, Van Praagh, E, and Berthoin, S. Continuous vs. interval aerobic training in 8- to 11-year-old children. J Strength Cond Res 24(5): 1381-1388, 2010-The aim of the present study was to show if the use of continuous-running training vs. intermittent-running training has comparable or distinct impact on aerobic fitness in children. At first, children were matched according to their chronological age, their biological age (secondary sexual stages), and their physical activity or training status. Then, after randomization 3 groups were composed. Sixty-three children (X 9.6 ± 1.0 years) were divided into an intermittent-running training group (ITG, 11 girls and 11 boys), a continuous-running training group (CTG, 10 girls and 12 boys), and a control group (CG, 10 girls and 9 boys). Over 7 weeks, ITG and CTG participated in 3 running sessions per week. Before and after the training period, they underwent a maximal graded test to determine peak oxygen uptake (peak &OV0312;o2) and maximal aerobic velocity (MAV). Intermittent training consisted of short intermittent runs with repeated exercise and recovery sequences lasting from 5/15 to 30/30 seconds. With respect to continuous training sessions, repeated exercise sequences lasted from 6′ to 20′. Training-effect threshold for statistical significance was set at p < 0.05. After training, peak &OV0312;o2 was significantly improved in CTG (+7%, p < 0.001) and ITG (+4.8%, p < 0.001), whereas no difference occurred for the CG (−1.5%). Similarly, MAV increased significantly (p < 0.001) in both CTG (+8.7%) and ITG (+6.4%) with no significant change for CG. Our results demonstrated that both continuous and intermittent-running sessions induced significant increase in peak &OV0312;o2 and MAV. Therefore, when adequate combinations of intensity/duration exercises are offered to prepubertal children, many modalities of exercises can successfully be used to increase their aerobic fitness. Aerobic running training is often made up of regular and long-distance running exercises at moderate velocity, which causes sometimes boredom in young children. During the developmental years, it seems therefore worthwhile to use various training modalities, to make this activity more attractive and thus create conditions for progress and enhanced motivation.

Effects of Playing Surface (hard and Clay Courts) on Heart Rate and Blood Lactate During Tennis Matches Played by High-level Players

Martin, C, Thevenet, D, Zouhal, H, Mornet, Y, Delès, R, Crestel, T, Ben Abderrahman, A, and Prioux, J. Effects of playing surface (hard and clay courts) on heart rate and blood lactate during tennis matches played by high level players. J Strength Cond Res 25(1): 163-170, 2011-The aim of this study was to compare tennis matches played on clay (CL) and resin (R) courts. Six matches were played (3 on CL courts and 3 on R courts) by 6 high-level players. Heart rate (HR) was monitored continuously while running time (4.66 m), and blood lactate concentration ([La]) were measured every 4 games. Mean duration of points and effective playing time (EPT) were measured for each match. Mean HR (154 ± 12 vs. 141 ± 9 b·min−1) and [La] values (5.7 ± 1.8 vs. 3.6 ± 1.2 mmol·L−1) were significantly higher on CL (p < 0.05). The [La] increased significantly during the match on CL court. Mean duration of rallies (8.5 ± 0.2 vs. 5.9 ± 0.5 seconds) and EPT (26.2 ± 1.9 vs. 19.5 ± 2.0%) were significantly longer (p < 0.05) on CL. Running time values in speed tests were not significantly different between CL and R. Running time performance was not significantly decreased during the match, whatever the playing surface. This study shows that the court surface influences the characteristics of the match and the players physiological responses. The court surface should be a key factor for consideration when coaches determine specific training programs for high-level tennis players.

Two months of endurance training does not alter diastolic function evaluated by TDI in 9–11-year-old boys and girls

Objective: Superior global cardiac performance (ie stroke volume) is classically reported after training in children. Current knowledge of the impact of exercise training on myocardial relaxation, a major component of left ventricular (LV) filling and subsequently stroke volume, is, however, limited in the paediatric population. This study aimed to investigate the effect of aerobic training on LV wall motion velocities by tissue Doppler imaging (TDI) in healthy children. Methods: 25 children (11 girls, 14 boys) were enrolled in a 2 month high-intensity aerobic training programme and 25 (12 girls and 13 boys) served as controls. The children (9–11 years old) performed a graded maximal exercise test on a treadmill to evaluate maximal oxygen uptake. Standard Doppler echocardiography and TDI measurements were performed at baseline and end of the study. Tissue Doppler systolic, early and late myocardial velocities were obtained at the mitral annulus in the septal, lateral, inferior and posterior walls. Results: Maximal oxygen uptake increased by 6.5% (before: 51.6 (SD 4.2), after: 55.0 (4.5) ml/min/kg p<0.001) after training. A modest but significant increase in left ventricular end-diastolic diameter was also noticed (before: 46.1 (3.4), after: 48.3 (4.3) mm.BSA-1/2, p<0.001), whereas left ventricular wall thickness and mass were unchanged. Neither transmitral inflow velocities nor early and late wall motion (Em: before = 18.4 (2.7), after = 18.0 (2.3) cm/s, Am: before = 6.8 (1.2), after = 6.7 (1.3) cm/s) were affected by training. Shortening fraction and regional systolic function (Sm: before = 10.1 (1.6), after = 10.2 (1.4) cm/s) by TDI were also unchanged. Conclusion: High-intensity aerobic sessions repeated over a 2 month period failed to improve regional diastolic function assessed by TDI in healthy young children.

Influence of recovery intensity on time spent at maximal oxygen uptake during an intermittent session in young, endurance-trained athletes

Abstract In this study, we examined the effects of three recovery intensities on time spent at a high percentage of maximal oxygen uptake (t90[Vdot]O2max) during a short intermittent session. Eight endurance-trained male adolescents (16 ± 1 years) performed four field tests until exhaustion: a graded test to determine maximal oxygen uptake ([Vdot]O2max; 57.4 ± 6.1 ml · min−1 · kg−1) and maximal aerobic velocity (17.9 ± 0.4 km · h−1), and three intermittent exercises consisting of repeat 30-s runs at 105% of maximal aerobic velocity alternating with 30 s active recovery at 50% (IE50), 67% (IE67), and 84% (IE84) of maximal aerobic velocity. In absolute values, mean t90[Vdot]O2max was not significantly different between IE50 and IE67, but both values were significantly longer compared with IE84. When expressed in relative values (as a percentage of time to exhaustion), mean t90[Vdot]O2max was significantly higher during IE67 than during IE50. Our results show that both 50% and 67% of maximal aerobic velocity of active recovery induced extensive solicitation of the cardiorespiratory system. Our results suggest that the choice of recovery intensity depends on the exercise objective.

Mechanical ventilatory constraints during incremental exercise in healthy and cystic fibrosis children

To analyze breathing pattern and mechanical ventilatory constraints during incremental exercise in healthy and cystic fibrosis (CF) children.

Comparison of mechanical ventilatory constraints between continuous and intermittent exercises in healthy prepubescent children

The aim of this study was to evaluate the occurrence and severity of mechanical ventilatory constraints in healthy prepubescent children during continuous and intermittent exercise.