Resistance exercise and bone turnover in elderly men and women

Etude de l'effet de six mois de musculation sur la densité osseuse et les marqueurs biochimiques de la vitesse de renouvellement osseux chez des adultes âgés de 60 à 83 ans

Measurement of acute dynamic anaerobic muscle fatigue using a novel fatigue resistance index

Développement d'un nouveau protocole de test de la fatigue isocinétique sur dynamomètre isocinétique : vitesse unique de 90 degrés par seconde, mode concentrique/excentrique, 35 répétitions

Comparison of 2 vs 3 Days/Week of Variable Resistance Training During 10- and 18-Week Programs

0.05) than groups that trained 2 days/week (10 weeks = 13.5%; 18 \nweeks = 20.9%). We conclude that resistance training 2 days/week \nsignificantly improves knee extension isometric strength; however, the \nmagnitude of strength gain is greater when training is performed 3 \ndays/week. These data indicate that the adult exerciser (18 to 38 years)\n training 2 days/week may derive approximately 80% of the isometric \nstrength benefits achieved by those training 3 days/week. } data-sheets-userformat= { 2 :771, 3 :{ 1 :0}, 4 :{ 1 :2, 2 :16777215}, 11 :4, 12 :0} style= font-size: 10pt; font-family: Arial; \u3eThe purpose of this study was to evaluate the effectiveness of resistance training performed either 2 days/week or 3 days/week. One hundred and seventeen sedentary volunteers were randomly assigned to one of the two training groups or a control group. Twenty-two men (27 ± 5 years) and 22 women (26 ± 5 years) trained for 10 weeks. Twenty-five men (26 ± 5 years) and 22 women (24 ± 5 years) trained for 18 weeks. Twenty-six subjects served as controls and did not train. Training consisted of a single set of variable resistance bilateral knee extensions performed to volitional fatigue with a weight load that allowed seven to ten repetitions. Prior to and immediately following training, isometric strength was evaluated at 70, 85, 100, 115, 130, 145, 160, and 171 degrees of knee extension with a Nautilus knee extension tensiometer. All groups who trained showed a significant increase in peak isometric strength when compared with controls (P \u3c 0.01). Groups that trained 3 days/week increased peak isometric strength (10 weeks = 21.2%; 18 weeks = 28.4%) to a greater extent (P \u3e 0.05) than groups that trained 2 days/week (10 weeks = 13.5%; 18 weeks = 20.9%). We conclude that resistance training 2 days/week significantly improves knee extension isometric strength; however, the magnitude of strength gain is greater when training is performed 3 days/week. These data indicate that the adult exerciser (18 to 38 years) training 2 days/week may derive approximately 80% of the isometric strength benefits achieved by those training 3 days/week

Role of cardiac–renal neural reflex in regulating sodium excretion during water immersion in conscious dogs

The present study was undertaken to determine the role of cardiopulmonary mechanoreceptors in inducing the sustained reduction of renal sympathetic nerve activity (RSNA) and concomitant changes in sodium excretion occurring during water immersion (WI) in intact dogs. Seven cardiac-denervated dogs were chronically instrumented for measuring RSNA, systemic arterial (Pa), central venous (Pcv) and left atrial pressures (Pla). WI initially decreased RSNA in cardiac denervated dogs by 10.0 ± 5.5 %; thereafter the RSNA fell to a nadir of 18.5 ± 5.6 % (P < 0.05) at 40–80 min of WI and then returned toward the pre-immersion level. Renal sodium excretion increased significantly by 211 ± 69 % (P < 0.05) only during the first 20–40 min of WI. WI increased Pa, Pcv and Pla in a step manner from 94 ± 3 to 108 ± 3 mmHg (P < 0.05), from 1.4 ± 0.5 to 12.3 ± 1.0 mmHg (P < 0.05) and from 4.9 ± 0.6 to 15.4 ± 1.2 mmHg (P < 0.05), respectively. These responses in RSNA and sodium excretion to WI in the cardiac-denervated dogs were significantly (P < 0.05) attenuated compared with those in a previous group of intact dogs. These data suggest that the attenuated responses of neural and excretory response to WI observed in cardiac-denervated dogs can be attributed to an interruption of afferent input originating from the cardiopulmonary mechanoreceptors to the central nervous system