F. T. J. Verstappen

Effect of exercise training on total daily physical activity in elderly humans.

Abstract This study examined the effect of 12 weeks of exercise training on daily physical activity in elderly humans. Training consisted of a weekly group session and an individual session with cardio- and weight-stack machines. A group of 15 subjects served as the exercise group [EXER mean age 59 (SD 4) years], and 7 subjects as the controls [CONT mean age 57 (SD 3) years]. Physical activity and physical fitness were measured before the start of training (T), at week 6 and week 12 (T0, T6, T12 respectively) in EXER, and at T0 and T12 in CONT. Physical activity over 14 days was measured using a tri-axial accelerometer and physical fitness was measured during an incremental exercise test. At T12, mean maximal power output had significantly increased in EXER compared to CONT 8 (SD 12) vs −5 (SD 9) W; P < 0.02] and mean submaximal heart rate (at 100 W) had reduced [−10 (SD 7) vs −2 (SD 6) beats · min−1; P < 0.05]. No differences or changes in physical activity were observed between EXER and CONT. At T6, physical activity on training days was significantly higher than on non-training days (P < 0.001). When the accelerometer output of the training session was subtracted from the accelerometer output on training days, at T12 non-training physical activity was significantly lower than on non-training days (P < 0.004). Accelerometer output of the individual training session at T12 had significantly increased compared to T6 (P < 0.05), whereas, accelerometer output of the group training session had remained unchanged. In conclusion, in elderly subjects an exercise training programme of moderate intensity resulted in an improved physical fitness but had no effect on total daily physical activity. Training activity was compensated for by a decrease in non-training physical activity.

Variability and reliability of joint measurements

The purpose of this study was to determine the varia bility and reliability of joint measurements as carried out by three physician observers. The intratester variation and reliability of nine different joint measurements was determined in eight healthy subjects. The measure ments were taken in eight sessions by each tester. In this population also the intertester variation and relia bility was determined by the three observers. This was also done in a population of middle-aged athletes over a period of 2.5 years. The results indicate that it is difficult to show either an improvement or worsening of a joint motion of less than 5° to 10° for most joints measured by the same tester. The intertester variation is not consistent over a longer period of time, so differences between observers during long-term studies cannot be corrected on the basis of a single study at a single point in time. The reliability of all nine joint measurements is not very high, but is probably sufficient if the results are used to compare groups within a single population and for large studies with experienced observers. Because the reli ability strongly depends on the interindividual variation, it is preferable to determine the reliability for each study population.

Is Prevention of Sports Injuries a Realistic Goal? A Four-Year Prospective Investigation of Sports Injuries Among Physical Education Students

To assess the reliability of injury registration and to determine the incidence of injury in intramural (pro gram of the institution) and extramural (leisure time) sports activities, we prospectively recorded information on sports injuries for 4 years in a group of 136 physical education students. Registration forms were com pleted every 3 weeks, and data on medical consulta tions were recorded. During the last year, we asked 59 students to recall all injuries sustained to establish the reliability of retrospective injury registration. In the pro spective study, 525 sports injuries were recorded: 58% during intramural activities and 42% during extramural. The incident rate per 1000 hours of intramural activities (1.26) was significantly lower than that for extramural activities (1.77). A gradual decline in response rate from 98.4% the 1st year to 87.7% in the final year indicated a decreasing compliance during the study period. Eighteen percent of all injuries with recorded medical consultations were not reported by the stu dents. At the retrospective injury registration in the final year of the study, students had forgotten 54% of the recorded injuries and 50 injuries (20% of all recorded injuries) were mentioned that had not been recorded during the previous years. We conclude that, even in a well-supervised population, prospective injury registra tion is not complete, and the reliability of retrospective injury registration is even poorer.

Effect of weight-training on energy expenditure and substrate utilization during sleep

This study was performed to investigate the effect of weight-training (12 wk; 21 male subjects) on energy expenditure and substrate utilization during sleep. Sleeping metabolic rate (SMR) as measured in a respiration chamber was calculated according to three procedures: the lowest mean energy expenditure of a shiftable 3-h interval between 0:00 and 6:00 (SMR3) and SMR over predetermined intervals from 3:00 to 6:00 (SMR3-6) and from 0:00 to 6:00 (SMR0-6). In analogy with SMR the corresponding respiratory quotients were expressed as RQ3, RQ3-6, and RQ0-6. Changes in body composition were assessed from changes in body weight, body volume (densitometry), and total body water (deuterium dilution). Weight-training induced an increase in fat-free mass (+1.1 +/- 1.3 kg; P < 0.001) and a decrease in fat mass (-2.3 +/- 1.5 kg; P < 0.001) and body weight (-1.1 +/- 2.1 kg; P < 0.05). There was no significant change in SMR, irrespective of the way SMR was expressed. Only RQ3 decreased significantly (from 0.82 +/- 0.04 to 0.79 +/- 0.02; P < 0.05). Remarkably RQ3, RQ3-6, and RQ0-6 were highly negative correlated with the pre-training RQ (r = -0.93, -0.91, and -0.90, respectively: P < 0.001) resulting in a diminished variation in post-training RQ (P < 0.001). These results suggest that weight-training has no effect on SMR but increases relative fat utilization in low fat oxidizers and vice versa for individuals displaying high pre-training lipid oxidation.

Exercise capacity, energy metabolism, and beta-adrenoceptor blockade

SummaryThe effects of beta1 and beta1/2 blockade on exercise capacity were studied in 9 healthy normotensive subjects. Progressive maximal bicycle ergometer tests, followed by an endurance test at 80% of maximal work load, were performed during randomized, double-blind 3 day treatment periods with placebo, atenolol (beta1) and oxprenolol (beta1/2). The reduction of maximal work capacity (ca. 10%) was similar with atenolol and oxprenolol, despite a more pronounced maximal heart rate reduction with atenolol (from 175±2 to 132±3 beats · min−1) than with oxprenolol (to 138±2 beats · min−1). Exercise time during the endurance test was reduced from 36±4 min with placebo to 27±3 min with atenolol (p<0.05) and 24±3 min with oxprenolol (p<0.01) (atenolol vs. oxprenolol: p<0.05). During the endurance test, plasma glycerol and non-esterified fatty acid concentrations were reduced with both atenolol and oxprenolol. The glycerol reduction was more pronounced with oxprenolol than with atenolol, plasma NEFA concentrations being similar. Plasma glucose and lactate concentrations were reduced by oxprenolol but not with atenolol. These data show that submaximal exercise capacity at work loads representing similar relative exercise intensities is reduced during non-selective and beta1-selective beta blockade. This reduction may be related to the effects of beta1 blockade on energy metabolism, with possibly an additional effect of beta2 blockade.

Maximal aerobic power and blood pressure in normotensive subjects after acute and chronic administration of metoprolol

SummaryThe acute and long-term effects of the beta1-adrenoceptor blocking agent metoprolol on blood pressure and maximal aerobic power (Wmax) were studied in 10 healthy subjects. Progressive maximal bicycle ergometer tests were performed after intravenous administration of placebo and metoprolol (0.15 mg×kg−1 and 0.30 mg×kg−1), and at the end of 4-week treatment periods with placebo, conventional metoprolol (C-M) and slow-release metoprolol (SR-M).The reduction in maximal exercise heart rate (HRmax) was correlated with the log plasma metoprolol concentration. Despite a reduction in HRmax of 23 beats/min after 0.15 mg×kg−1 metoprolol, Wmax was unaffected. After 0.30 mg×kg−1 HRmax was reduced by 40 beats/min and Wmax by 5.0%. During chronic treatment, the reductions in HRmax and Wmax were 48 beats/min and 7.5% (C-M) and 45 beats/min and 6.9% (SR-M), respectively. Resting systolic blood pressure was not changed after acute administration of metoprolol but it was reduced during chronic beta-blocker treatment. Resting diastolic blood pressure was not affected after acute or chronic treatment. Exercise systolic blood pressure remained unchanged after 0.15 mg×kg−1 metoprolol i.v. The fall in exercise systolic pressure after 0.30 mg×kg−1 metoprolol i.v. (18±5 mmHg) was significantly smaller than that during chronic treatment (30±6 mmHg C-M; 30±6 mmHg, SR-M).During chronic metoprolol treatment a certain % HRmax corresponded to a higher % Wmax than during placebo treatment, but the shift appeared to be of minor practical importance.The results show that the reduction in maximal aerobic power was comparable after acute i.v. administration and after 4 weeks oral treatment with metoprolol, if the degree of beta blockade (i.e. reduction in maximal exercise heart rate) was similar.

Twenty-four hour effects of oxprenolol oros and atenolol on heart rate, blood pressure, exercise tolerance and perceived exertion

SummaryThe effects of oxprenolol, a non-selective beta-blocker with moderate intrinsic sympathomimetic activity (ISA), given by the Oros delivery system, on resting and exercise heart rate and blood pressure have been compared over a 24-h period with those of atenolol, a beta1-selective blocker without ISA. The effects on maximal and submaximal exercise tolerance and perceived exertion were studied in relation to the level of beta-blockade. 9 healthy subjects were treated with placebo, atenolol, 100 mg/day and oxprenolol Oros, 16/260 mg/day in random order, each for 5 days. Progressive maximal exercise tests and submaximal endurance tests at 80% of maximum aerobic exercise capacity were performed 2, 5 and 24 h after intake of the drugs.The reduction of blood pressure 2 and 5 h after drug intake was less pronounced after oxprenolol Oros than after atenolol, but by 24 h after the last dose the effects were similar. The peak level of beta-blockade (i.e. reduction in maximal exercise heart rate) was similar after oxprenolol Oros and atenolol. The minimal level of beta-blockade 24 h after the last dose was greater after oxprenolol Oros than after atenolol. Maximal exercise capacity and submaximal exercise tolerance were impaired after both beta-blockers. The subjective feeling of exertion did not differ between placebo, atenolol and oxprenolol Oros when related to the relative work load, except after the first minute of exercise, when the rating of perceived exertion was higher after atenolol.

Maximal heart rates and plasma lactate concentrations observed in middle-aged men and women during a maximal cycle ergometer test

SummaryThe purpose of this study was to investigate criteria for maximal effort in middle-aged men and women undertaking a maximal exercise test until they were exhausted if no measurements of oxygen uptake are made. A large group of 2164 men and 975 women, all active in sports and aged between 40 and 65 years, volunteered for a medical examination including a progressive exercise test to exhaustion on a cycle ergometer. In the 3rd min of recovery a venous blood sample was taken to determine the plasma lactate concentration ([la−]p, 3min). Lactate concentration and maximal heart rate (fc, max) were lower in the women than in the men (P<0.001). Multiple regression analyses were performed to assess the contribution of sex to [la−]p, 3 min, independent of age and fc max, It was found that [la−]p,3 min was about 2.5 mmol·l−1 lower in women than in men of the same age and fc, max. In our population 88% of the men and 85% of the women met a combination of the following fc, max and [la−]p, 3min criteria: fc, max equal to or greater than 220 minus age beats·min−1 and/or [la−]p, 3min equal to or greater than 8 mmol·l−1 in the men and fc, max equal to or greater than 220 minus age beats·min−1 and/or [la−]p, 3min equal to or greater than 5.5 mmol·1−1 in the women.

Influence of therapeutic doses of amoxicillin on aerobic work capacity and some strength characteristics

The purpose of this study was to investigate whether or not amoxicillin in therapeutic doses could have an influence on maximal aerobic work capacity and some strength character istics in trained subjects. Fifteen volunteers (men; age range, 21 to 38 years; mean, 28.8 years) were examined once weekly for 4 consecutive weeks, and on these occasions the following variables and parameters were measured: maximum workload attained on the bicycle ergometer, maximum heart rate, maximum serum lactate concentration, heart rate and serum lactate concentra tion after 10 min at 80% of the maximum workload attained, maximum isometric extension force of the legs, vertical jump height, and body weight. During the baseline period, the deter mined variables and parameters did not show any significant difference between Test 1 and Test 2. During the 3rd and 4th week of the test period, the subjects received at random either placebo (6-aminopenicillanic acid) or amoxicillin in therapeutic doses (375 mg, 3 times a day) every day for 5 days. After the third test in the 3rd week, there was a cross-over, ensuring that each volunteer was examined during placebo as well as during amoxicillin medication. The serum amoxicillin levels were de termined. After statistical analysis, no influence of amoxicillin or placebo on the parameters and physiologic variables was demonstrable.