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Louis J.,University of Nice Sophia Antipolis | Hausswirth C.,Institute National Du Sport Et Of Leducation Physique Insep | Bieuzen F.,Institute National Du Sport Et Of Leducation Physique Insep | Brisswalter J.,University of Nice Sophia Antipolis
Applied Physiology, Nutrition and Metabolism | Year: 2010

The influence of vitamin and mineral complex supplementation on muscular activity and cycling efficiency was examined in elderly endurance-trained master athletes during a heavy cycling trial. Master athletes were randomly assigned in a double-blind process to 1 of 2 treatment groups: antioxidant supplementation (n = 8: As group) or placebo (n = 8: Pl group) for 21 days. After that time, each subject had to perform a 10-min session of cycling on a cycloergometer at a heavy constant intensity. Twenty-four to 48 h after this session, subjects performed an isometric maximal voluntary contraction before and immediately after a fatiguing strength training (leg press exercise) and the same 10-min cycling test after fatigue. Isometric maximal voluntary force (MVF) of knee extensors was assessed before and after fatigue. Electromyographic (EMG) activity of the vastus medialis, the vastus lateralis (VL), and the biceps femoris was recorded with surface EMG. The knee-extensors MVF after the fatiguing exercise was reduced in similar proportions for both groups (As, -10.9%; Pl, -11.3%, p < 0.05). This MVF loss was associated with a significant reduction in EMG frequency parameters for both groups, with a lower decrease for the As group. Muscular activity and cycling efficiency during the cycling bouts were affected by the treatment. Cycling efficiency decreased significantly and the oxygen uptake slow component was higher after the fatiguing exercise for both groups. Furthermore, a decrease in cycling efficiency was associated with an increase in VL activity. However, these changes were significantly lower for the As group. The results of the present study indicate an overall positive effect of vitamin and mineral complex supplementation on cycling efficiency after fatigue, in the endurance-trained elderly. Source


Bieuzen F.,Institute National Du Sport Et Of Leducation Physique Insep | Bieuzen F.,University of Toulon | Hausswirth C.,Institute National Du Sport Et Of Leducation Physique Insep | Louis J.,University of Nice Sophia Antipolis | Brisswalter J.,University of Nice Sophia Antipolis
Gerontology | Year: 2010

Background: Much attention has been focused on the need to design strategies to increase functional capacities in older populations. This has raised several questions regarding the ability of regular endurance training to preserve functional capacity with age. Objective: The purpose of this study was to examine the age-associated changes in neuromuscular function in endurance-trained men before and after a high-intensity, intermittent fatiguing task. Method: Twenty-six healthy endurance-trained male subjects: 16 older (59-79 years) and 10 young (20-34 years) men performed a high-intensity, intermittent fatiguing exercise corresponding to 10 sets of 10 repetitions on a horizontal leg press at 70% of the individual one-repetition maximum. Maximal voluntary contractions and evoked contractions of the knee extensor muscles were performed before and after the exercise. Results: Decreases in maximum voluntary contractions (older: -9.7%; young: -14.3%) and electromyographic activity were not different between groups. Peak twitch torque was reduced only for the older men and no changes in voluntary activation and M-wave properties were recorded in either group. Conclusion: The present study indicates that in endurance-trained men aged 59-79 years, muscle functional capacities are maintained despite losses in strength and contractile function related to the age. © 2009 S. Karger AG, Basel. Source

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