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  • Author: Serge Berthoin x
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Nicolas Olivier, Renaud Legrand, Jacques Rogez, FX Gamelin, Serge Berthoin and Thierry Weissland

Objective:

To analyze the consequences on heart rate variability (HRV) of a hospitalization period due to surgery of the knee in sportsmen.

Patients:

Ten soccer players who had undergone knee surgery took part in this study.

Design:

HRV was measured before and after hospitalization within a 7-day interval.

Results:

After the hospitalization phase, heart rate at rest increased significantly (3 beats/minute). A significant decrease of 7% in the cardiac inter beat interval (R-R interval), P < 0.05 and a 66% decrease in total power spectral density: −66%, P < 0.05 were observed. The disturbance of the autonomic nervous system could be due to a variation in cardiac vagal activity resulting in a 64% decrease in the high frequencies (P < 0.05). This variation was not associated with a modification in normalized markers (LFn.u., HFn.u.) and LF/HF ratio (P > 0.05).

Conclusion:

In sportsmen, a hospitalization period led to an increase in resting heart rate and was associated with a disturbance of the autonomic nervous system.

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Serge Berthoin, Georges Baquet, Fabienne Mantéca, Ghislaine Lensel-Corbeil and Michel Gerbeaux

A cross-sectional design was used to study the associations among sex, age, maximal aerobic speed (MAS), and running time to exhaustion at 100% of MAS (Tlim). The subjects were 1,448 schoolchildren (685 males and 763 females) ages 6 to 17 years. The MAS of males increased significantly (p < .001) from 6 (9.0 ± 0.8 km · h−1) to 17 years (14.1 ± 1.6 km · h−1). The MAS of females increased significantly (p < .001) from 6 (8.7 ± 0.6 km · h−1) to 12 years (10.7 ± 1.2 km · h−1), then remained relatively constant at approximately 11 km · h−1 between 12 and 17 years. Tlim increased significantly from 6 to 13 years for males and from 6 to 11 years for females, then remained relatively constant around 350 s for both males and females.

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Georges Baquet, Gregory Dupont, François-Xavier Gamelin, Julien Aucouturier and Serge Berthoin

This study aimed to compare the effect of active recovery (AR) versus passive recovery (PR) on time to exhaustion and time spent at high percentages of peak oxygen uptake (peakV˙O2) during short, high-intensity intermittent exercises in children. Twelve children (9.5 [0.7] y) underwent a graded test and 2 short, high-intensity intermittent exercises (15 s at 120% of maximal aerobic speed) interspersed with either 15 seconds of AR (50% of maximal aerobic speed) or 15-second PR until exhaustion. A very large effect (effect size = 2.42; 95% confidence interval, 1.32 to 3.52) was observed for time to exhaustion in favor of longer time to exhaustion with PR compared with AR. Trivial or small effect sizes were found for peakV˙O2, peakHR, and peak ventilation between PR and AR, while a moderate effect in favor of higher average V˙O2 values (effect size = −0.87; 95% confidence interval, −1.76 to −0.01) was found using AR. The difference between PR and AR for the time spent above 80% (t80%) and 90% (t90%) of peakV˙O2 was trivial. Despite the shorter running duration in AR, similar t80% and t90% were spent with AR and PR. Time spent at a high percentage of peakV˙O2 may be attained by running 3-fold shorter using AR compared with using PR.

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Erwan Leclair, Delphine Thevenet, Sophie C. Reguem, Benoit Borel, Georges Baquet, Serge Berthoin and Patrick Mucci

This study was designed to test the reproducibility of muscle oxygenation by NIRS in children during exercise. Twelve healthy non-obese and non-trained children performed one maximal graded test, and four 6-min constant load cycle exercises. Deoxy-hemoglobin (Hb/Mb-H+) data were averaged every 1, 5, 10, 20 and 30s. Hb/Mb-H+ data averaged every 5, 10, 20 and 30s showed good reproducibility. When averaged every second, Hb/Mb-H+ values were reproducible after the first minute of exercise. Based on 1s averaged signal modeling, time period and t values for Hb/Mb-H+ were not reproducible but mean response time values showed an acceptable reproducibility.

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Erwan Leclair, Benoit Borel, Delphine Thevenet, Georges Baquet, Patrick Mucci and Serge Berthoin

This study first aimed to compare critical power (CP) and anaerobic work capacity (AWC), to laboratory standard evaluation methods such as maximal oxygen uptake (V̇O2max) and maximal accumulated oxygen deficit (MAOD). Secondly, this study compared child and adult CP and AWC values. Subjects performed a maximal graded test to determine V̇O2max and maximal aerobic power (MAP); and four constant load exercises. In children, CP (W.kg−1) was related to V̇O2max (ml.kg−1.min−1; r = .68; p = .004). AWC (J.kg−1) in children was related to MAOD (r = .58; p = .018). Children presented lower AWC (J.kg−1; p = .001) than adults, but similar CP (%MAP) values. CP (%MAP and W.kg−1) and AWC (J.kg−1) were significantly related to laboratory standard evaluation methods but low correlation indicated that they cannot be used interchangeably. CP (%MAP) was similar in children and adults, but AWC (J.kg−1) was significantly lower in children. These conclusions support existing knowledge related to child-adults characteristics.