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  • Author: Isabelle J. Dionne x
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Eric D.B. Goulet and Isabelle J. Dionne

The use of nutritional ergogenic aids containing Eleutherococcus senticosus (ES), a plant which is also known as ciwujia or Siberian ginseng, is relatively common among endurance athletes. Eleutherococcus senticosus has been suggested to improve cardiorespiratory fitness (CF) and fat metabolism (FAM) and, therefore, endurance performance (EP). This article reviews the studies that evaluated the effects of ES during endurance exercise, three of which suggest that ES substantially improves CF, FAM, and EP. However, each of these reports contains severe methodological flaws, which seriously threaten their internal validity, thereby rendering hazardous the generalization of the results. On the other hand, 5 studies that used rigorous research protocols show no benefit of ES on CF, FAM, and EP. It is therefore concluded that ES supplementation (up to 1000 to 1200 mg/d for 1 to 6 wk) offers no advantage during exercise ranging in duration from 6 to 120 min.

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Cédric R.H. Lamboley, Donald Royer and Isabelle J. Dionne

The aim of this study was to determine the effects of oral β-hydroxy-β-methylbutyrate (HMB) supplementation (3 g/d) on selected components of aerobic performance and body composition of active college students. Subjects were randomly assigned to either an HMB (n = 8) or a placebo (PLA) group (n = 8) for a 5-wk supplementation period during which they underwent interval training 3 times a week on a treadmill. Aerobic-performance components were measured using a respiratory-gas analyzer. Body composition was determined using dual-energy X-ray absorptiometry. After the intervention, there were significant differences (P < 0.05) between the 2 groups in gains in maximal oxygen consumption (+8.4% for PLA and +15.5% for HMB) and in respiratory-compensation point (+8.6% for PLA and +13.4% for HMB). Regarding body composition, there were no significant differences. The authors concluded that HMB supplementation positively affects selected components of aerobic performance in active college students.

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Eric D.B. Goulet, Mylène Aubertin-Leheudre, Gérard E. Plante and Isabelle J. Dionne

The authors determined, through a meta-analytic approach, whether glycerol-induced hyperhydration (GIH) enhances fluid retention and increases endurance performance (EP) significantly more than water-induced hyperhydration (WIH). Collectively, studies administered 23.9 ± 2.7 mL of fuid/kg body weight (BW) with 1.1 ± 0.2 g glycerol/kg BW, and hyperhydration was measured 136 ± 15 min after its onset. Compared with WIH, GIH increased fluid retention by 7.7 ± 2.8 mL/kg BW (P < 0.01; pooled effect size [PES]: 1.64 ± 0.80, P < 0.01, N = 14). The use of GIH was associated with an improvement in EP of 2.62% ± 1.60% (P = 0.047; PES: 0.35 ± 0.13, P = 0.014, N = 4). Unarguably, GIH significantly enhances fluid retention better than WIH. Because of the dearth of data, the effect of GIH on EP must be further investigated before more definitive conclusions can be drawn as to its ergogenic property.

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Mathieu L. Maltais, Karine Perreault, Alexandre Courchesne-Loyer, Jean-Christophe Lagacé, Razieh Barsalani and Isabelle J. Dionne

The decrease in resting energy expenditure (REE) and fat oxidation with aging is associated with an increase in fat mass (FM), and both could be prevented by exercise such as resistance training. Dairy consumption has also been shown to promote FM loss in different subpopulations and to be positively associated with fat oxidation. Therefore, we sought to determine whether resistance exercise combined with dairy supplementation could have an additive impact on FM and energy metabolism, especially in individuals with a deficit in muscle mass. Twenty-six older overweight sarcopenic men (65 ± 5 years old) were recruited for the study. They participated in 4 months of resistance exercise and were randomized into three groups for postexercise shakes (control, dairy, and nondairy isocaloric and isoprotein supplement with 375 ml and ~280 calories per shake). Body composition was measured by dual X-ray absorptiometry and REE by indirect calorimetry. Fasting glucose, insulin, leptin, inflammatory profile, and blood lipid profile were also measured. Significant decreases were observed with FM only in the dairy supplement group; no changes were observed for any other variables. To conclude, FM may decrease without changes in metabolic parameters during resistance training and dairy supplementation with no caloric restriction without having any impact on metabolic properties. More studies are warranted to explain this significant decrease in FM.