WBV training is as efficient as a fitness program to increase isometric and explosive knee extension strength and muscle mass of the upper leg in community-dwelling older men. These findings suggest that WBV training has potential to prevent or reverse the age-related loss in skeletal muscle mass, referred to as sarcopenia.

OBJECTIVE: To investigate whether peripheral muscle strength is signi®cantly different between lean and obese women controlled for age and physical activity, using an allometric approach. DESIGN: Cross-sectional study of isometric handgrip and isokinetic leg and trunk muscle strength. SUBJECTS: 173 obese (age 39.9 AE 11.4 y, body mass index (BMI) 37.8 AE 5.3 kgam 2 ) and 80 lean (age 39.7 AE 12.2 y, BMI 22.0 AE 2.2 kgam 2 ) women. MEASUREMENTS: Anthropometric measures (weight, height) and body composition (bioelectrical impedance method), isometric handgrip (maximal voluntary contraction on the Jamar dynamometer), isokinetic trunk¯exion ± extension, trunk rotation, and knee¯exion ± extension (Cybex dynamometers). RESULTS: Absolute isokinetic strength output (that is, strength uncorrected for fat-free mass) was larger in obese compared to lean women, except for knee¯exion and isometric handgrip, which were not signi®cantly different (P b 0.05). Pearson correlation coef®cients between strength measures and fat-free mass (kg) were low to moderate both in lean (r 0.28 ± 0.53, P`0.05) and in obese (r 0.29 ± 0.49, P`0.001) women. There was no correlation with fat mass (kg) in the lean, whereas in the obese women a weak positive relation could be observed for most isokinetic data (r 0.21 ± 0.39, P`0.01). When correcting for fat-free mass (raised to the optimal exponent determined by allometric scaling), all strength measurements were at least 6% lower in obese when compared to the lean women, except for trunk¯exion, which was at least 8% stronger in obese women. DISCUSSION: The higher absolute knee extension strength measures of leg and the similar extension strength of the trunk in the obese sample compared to the lean might be explained by the training effect of weight bearing and support of a larger body mass. However when the independent effect of fat-free mass is removed, these strength measures, as well as oblique abdominal muscle and handgrip strength, turned out to be lower in obese women. These observations could be the re¯ection of the overall impairment of physical ®tness as a consequence of obesity and its metabolic complications.

The aim of this study was first, to assess the presence of medical conditions that might interfere with walking; second, to assess the differences in walking capacity, perceived exertion and physical complaints between lean, obese and morbidly obese women; and third, to identify anthropometric, physical fitness and physical activity variables that contribute to the variability in the distance achieved during a 6-minute walk test in lean and obese women. A total of 85 overweight and obese females (18-65 years, body mass index (BMI) > or = 27.5 kg m(-2)), 133 morbidly obese females (BMI > or = 35 kg m-2) and 82 age-matched sedentary lean female volunteers (BMI < or = 26 kg m(-2)) were recruited. Patients suffering from severe musculoskeletal and cardiopulmonary disease were excluded from the study. Prior to the test, conditions that might interfere with walking and hours of TV watching were asked for. Physical activity pattern was assessed using the Baecke questionnaire. Weight, height, body composition (bioelectrical impedance method), isokinetic concentric quadriceps strength (Cybex) and peak oxygen uptake (peakVO2_bicycle ergometer) were measured. A 6-minute walk test was performed and heart rate, walking distance, Borg rating scale of perceived exertion (RPE) and physical complaints at the end of the test were recorded. In obese and particularly in morbidly obese women suffering from skin friction, urinary stress incontinence, varicose veins, foot static problems and pain, wearing insoles, suffering from knee pain, low back pain or hip arthritis were significantly more prevalent than in lean women (P < 0.05). Morbidly obese women (BMI > 35 kg m(-2)N = 133) walked significantly slower (5.4 km h(-1)) than obese (5.9 km h(-1)) and lean women (7.2 km h(-1), P < 0.05), were more exerted (RPE 13.3, 12.8 and 12.4, respectively, P < 0.05) and complained more frequently of dyspnea (9.1%, 4.7% and 0% resp., P < 0.05) and musculoskeletal pain (34.9%, 17.7% and 11.4% resp., P < 0.05) at the end of the walk. In a multiple regression analysis, 75% of the variance in walking distance could be explained by BMI, peakVO2, quadriceps muscle strength age, and hours TV watching or sports participation. These data suggest that in contrast with lean women, walking ability of obese women is hampered not only by overweight, reduced aerobic capacity and a sedentary life style, but also by perceived discomfort and pain. Advice or programs aimed at increasing walking for exercise also need to address the conditions that interfere with walking, as well as perceived symptoms and walking difficulties in order to improve participation and compliance.

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The aim of this study was to assess the nature and magnitude of the differences in submaximal and maximal exercise capacity parameters between lean and obese women. A total of 225 healthy obese women 18-65 years (BMI> or=30 kg/m(2)) and 81 non-athletic lean women (BMI< or=26 kg/m(2)) were selected. Anthropometric measurements (weight and height), body composition assessment (bioelectrical impedance method) and a maximal exercise capacity test on a bicycle ergometer were performed. Oxygen uptake (VO(2)), carbon dioxide production (VCO(2)), expired ventilation (VE), respiratory quotient (RQ), breathing efficiency (VE/VO(2)), mechanical efficiency (ME) and anaerobic threshold (AT) were calculated. At a submaximal intensity load of 70 W, VO(2) (l/min) was larger in the obese women and was already 78% of their peak VO(2), whereas in the non-obese it was only 69% (P=0.0001). VE (l/min) was larger, VE/VO(2) did not differ and ME was lower in obese compared to the lean women. AT occurred at the same percentage of peak VO(2) in both lean and obese women. At peak effort, achieved load, terminal VO(2) (l min(-1) kg(-1)), VE, heart rate, RQ respiratory exchange ratio and perceived exertion were lower in obese subjects compared to the non-obese. Obese subjects mentioned significantly more musculoskeletal pain as a reason to end the test, whereas in lean subjects it was leg fatigue. Lean women recovered better as after 2 min they were already at 35% of the peak VO(2), whereas in the obese women it was 47% (P=0.0001). Our results confirm that exercise capacity is decreased in obesity, both at submaximal and peak intensity, and during recovery. Moreover, at peak effort musculoskeletal pain was an important reason to end the test and not true leg fatigue. These findings are important when designing exercise programs for obese subjects.