Effect of impact exercise on physical performance and cardiovascular risk factors.

INTRODUCTION: Impact exercise is known to be beneficial for bones, but information regarding its effects on other health aspects is scarce. The aim of this study was to assess the effects of high-impact exercise on physical performance and glucose and lipid profiles. METHODS: We performed a 12-month, population-based, randomized controlled trial with 120 women (60 in the exercise group and 60 in the control group; ages 35-40 yr). The exercise regimen comprised supervised, progressive, high-impact exercises two to three times per week and an additional home program. Physical activity was continuously recorded using an accelerometer-based method and was analyzed as the daily number of impacts within five acceleration ranges between 0.3 and 9.2g (g = acceleration of gravity: 9.81 m x s(-2)). The changes in physical performance and in glucose and lipid profiles were determined. RESULTS: Thirty-nine women in the exercise group and 41 women in the control group completed the study. Maximal oxygen uptake (6.2 vs 3.1 mL x kg(-1) x min(-1); P = 0.008) and countermovement (2.3 vs -0.3 cm; P < 0.001) and static (1.4 vs -0.3 cm; P = 0.004) jump heights increased significantly more in the exercise group than in the control group. Exercise training also decreased waist (-1.1 vs 0.9 cm; P = 0.048) and hip circumference (-1.0 vs 1.1 cm; P = 0.037). Total cholesterol and LDL cholesterol decreased significantly more in women, with the highest number of impacts compared with the lowest quartile at intensities exceeding 1.1g, with differences being up to -0.5 mM (P = 0.005). Additionally, poor baseline values predicted greater exercise effects. CONCLUSION: The moderate-intensity exercise regimen, initially targeted at weight-bearing bones, improved cardiorespiratory fitness, speed-strength, and lipid profiles. In addition to bone health, impact exercise may be recommended for prevention of cardiovascular diseases.

Physical activity in the prevention of type 2 diabetes: the Finnish diabetes prevention study.

Clinical trials have demonstrated that lifestyle changes can prevent type 2 diabetes, but the importance of leisure-time physical activity (LTPA) is still unclear. We carried out post hoc analyses on the role of LTPA in preventing type 2 diabetes in 487 men and women with impaired glucose tolerance who had completed 12-month LTPA questionnaires. The subjects were participants in the Finnish Diabetes Prevention Study, a randomized controlled trial of lifestyle changes including diet, weight loss, and LTPA. There were 107 new cases of diabetes during the 4.1-year follow-up period. Individuals who increased moderate-to-vigorous LTPA or strenuous, structured LTPA the most were 63-65% less likely to develop diabetes. Adjustment for changes in diet and body weight during the study attenuated the association somewhat (upper versus lower third: moderate-to-vigorous LTPA, relative risk 0.51, 95% CI 0.26-0.97; strenuous, structured LTPA, 0.63, 0.35-1.13). Low-intensity and lifestyle LTPA and walking also conferred benefits, consistent with the finding that the change in total LTPA (upper versus lower third: 0.34, 0.19-0.62) was the most strongly associated with incident diabetes. Thus increasing physical activity may substantially reduce the incidence of type 2 diabetes in high-risk individuals.

Reliability of an inclinometric method for assessment of body sway.

Falling related injuries are associated with morbidity and mortality among older persons. An accurate and comparable assessment of postural sway may offer a method for detecting those at risk for falling. Our purpose was to assess the validity and repeatability of an inclinometric method in assessing postural sway during quiet standing. To assess repeatability, 51 elderly women (aged 72 to 74 years) were measured twice by the same tester. To assess validity, postural sway in 29 elderly subjects (aged 69 to 86 years) was assessed using simultaneously the inclinometric and a force platform method. The test-retest reliability correlation of the inclinometric method was high for sway path length (coefficient of determination r(2) = 0.683), and moderate for sway area (r(2) = 0.500) and the analysis revealed no sign of bias. The correlation was moderate between the values of the inclinometric sway path length and those of the force platform for antero-posterior (r(2) = 0.466), lateral (r(2) = 0.694) and combined lateral and antero-posterior (r(2) = 0.623) directional sway movements. The inclinometric method offers an accurate and repeatable method for assessing postural sway and may be a feasible method to be used in the risk stratification of falling.

Physical activity and aerobic fitness are positively associated with heart rate variability in obese adults.

BACKGROUND: Autonomic nervous system (ANS) dysfunction and obesity are intrinsically related to each other. In normal-weight subjects physical activity (PA) and fitness are related to cardiovascular autonomic regulation, providing evidence that aerobic training may improve ANS functioning measured by heart rate variability (HRV). The goal of this study was to investigate the association between lifetime PA, aerobic fitness and HRV in obese adults. METHODS: Participants included 107 (87 females) volunteers (mean age 44.5 years, median BMI 35.7) who completed health and lifestyle questionnaires and measurements of maximal aerobic performance, anthropometry and 24 h HRV. RESULTS: In the multivariate linear regression analyses, lifetime physical activity explained 40% of the variance in normal R-R intervals (SDNN). Each 1-category increase in the activity index increased SDNN by 15.4 (P = .009) and 24% of the variance in natural logarithmic value of ultra-low frequency power (P = .050). High measured VO2max explained 45% of the variance in natural logarithmic value of high-frequency power (P = .009) and 25% of the variance in low frequency/high frequency ratio (P < .001). CONCLUSIONS: Lifetime physical activity and aerobic fitness may reduce obesity-related health risks by improving the cardiac autonomic function measured by HRV in obese working-age subjects. This research supports the role of lifetime physical activity in weight management strategies and interventions to reduce obesity-related health risks.

Lifestyle risk factors for obesity in 7-year-old children.

OBJECTIVE: To evaluate the associates of obesity and overweight in 7-year-old children. DESIGN: Cross-sectional study. SUBJECTS: 855 children out of all 1278 school beginners in the city of Oulu, Northern Finland. METHODS: A questionnaire to be filled in by parents was delivered by the school nurses to 1278 children. The child's eating habits, dietary intake and physical activity patterns were enquired about. There were also questions about the household and parents' level of education and physical activity. Overweight and obesity were defined by BMI according to internationally accepted criteria. The χ(2) test was used to evaluate the significance of the differences between normal and overweight children. Multivariate logistic regression model was used to find the most predictive variables associated with overweight and obesity. The final models are reported using odds ratios (ORs) and their 95% confidence intervals (CI). RESULTS: The number of responders was 855 (66.9%). The prevalence of overweight was 16.7% and that of obesity 4.9%. Fifty-seven percent of the parents who had an overweight or obese child 7-year-old did not recognise their child's overweight. The factors associated with obesity were: mother's obesity (OR 13.04, CI 2.81-60.53), low physical activity (OR 10.95, CI 3.28-36.50), skipping breakfast (OR 10.12, CI 1.81-56.63), habitual overeating (OR 9.35, CI 2.58-33.82), father's overweight (OR 5.89, CI 1.23-28.10) and mother's age over 40 years (OR 2.91, CI 1.09-7.80). CONCLUSION: This cross-sectional study promotes the importance of child's eating behaviour and family's eating patterns. Parents should be helped to recognise their child's overweight, and educational strategies should be targeted at both children and their parents. Avoiding inactivity is essential in preventing obesity in children.

Muscular fitness in relation to physical activity and television viewing among young adults.

PURPOSE: To study how time spent in physical activity and that in television (TV) viewing are associated with muscular fitness among young adults. METHODS: The study population consisted of a cross-sectional sample of 381 males and 493 females aged 19.1 yr (SD 0.3) from the Northern Finland Birth Cohort 1986. Muscular fitness was measured by trunk muscle strength tests (trunk extension, flexion, and rotation) and jumping height test. Time spent on moderate- to vigorous-intensity physical activity and on TV viewing was self-reported by a questionnaire. RESULTS: The most physically active young adults performed significantly better in most trunk muscle strength tests and the jumping test than the least active subjects. The mean difference between the most and least active groups was at minimum 1.6 kg (95% confidence interval (CI) = -0.5 to 3.7) and at maximum 10.6 kg (95% CI = 4.7-16.5) for different trunk muscle strength tests and at minimum 4.4 cm (95% CI = 2.7-6.1) for the jumping height test. Males and females who watched TV for >or=2 h x d(-1) performed significantly worse in trunk extension and flexion tests and females also performed worse in the jumping test compared with those who watched TV <2 h x d(-1), independent of their physical activity level. The mean difference between low and high TV users was at minimum -3.8 kg (95% CI = -6.7 to -0.9) for trunk extension and flexion strength and -1.2 cm (95% CI = -2.0 to -0.4) for jumping height in females. CONCLUSIONS: Among young adults, daily TV viewing for >or=2 h, irrespective of physical activity level, was associated with poorer muscular fitness.