Musculoskeletal fitness and weight gain in Canada

Muscle Strength Assessed by Handgrip Strength Moderates the Relationship Between Overweight and Obesity With Cardiometabolic Risk Markers Among Adults and Older Adults

Background and aims: Few population-based studies have studied whether muscle strength (MS) levels influence the relationship between cardiometabolic markers with excess body weight. We investigate the possible moderator role of MS in the relationship between overweight and obesity with cardiometabolic markers. Methods: Cross-sectional analysis using data from two studies in Florianópolis, Brazil (EpiFloripa Adult Cohort Study, n = 862, 39.3 ± 11.4 years; EpiFloripa Aging Cohort Study, n = 1,197, 69.7 ± 7.1 years). MS was assessed by handgrip strength. Body mass index (BMI) was classified as overweight or obesity (BMI 25.0-29.9 or ≥30.0 kg/m², respectively). Cardiometabolic markers included systolic (SBP) and diastolic blood pressure (DBP), C-reactive protein (CRP), lipids, glucose markers, and carotid intima-media thickness (CIMT). Linear regression models stratified by age groups (adults: <60 years; older adults: ≥60 years) and adjusted for confounders were used. Results: Compared to those with a normal BMI, overweight and obesity were related to higher SBP, DBP, lnCRP, ln triglycerides, fasting glucose (FG), and glicated hemoglobin (HbA1c), and inversely associated with HDL-C among adults and older adults (p value < .05 for all). Additionally, BMI was positively associated with LDL-C and CIMT only among adults (p value < .05). Among adults and older adults, elevated MS attenuated the adverse relationship between excess body weight with FG and HbA1c. Conclusion: Higher MS might help adults and older adults with overweight or obesity reduce their cardiovascular risk by keeping their FG and HbA1c at the same levels of those with a normal BMI.

Cardiorespiratory fitness is strongly linked to metabolic syndrome among physical fitness components: a retrospective cross-sectional study

BACKGROUND

Maintaining a good level of physical fitness from engaging in regular exercise is important for the treatment and prevention of metabolic syndrome (MetS). However, which components constitutive of physical fitness confer the greatest influence remains controversial. This retrospective cross-sectional study aimed to investigate the association between MetS and physical fitness components including cardiorespiratory fitness, muscle strength, flexibility, and agility and to identify which physical fitness components have the largest influence on MetS.

METHODS

A total of 168 Japanese adult males aged 25-64 years were allocated into non-MetS, pre-MetS, and MetS groups according to the criteria recommended by the Japanese Society of Internal Medicine. Anthropometric measurement of body composition by whole-body dual-energy X-ray absorptiometry and measures related to MetS, including waist circumference, triglyceride level, high-density lipoprotein cholesterol level, blood pressure, glucose level, and physical fitness components, were assessed. For evaluation of cardiorespiratory fitness, muscle strength, flexibility, agility, and balance, maximal oxygen consumption (VO_2peak) and oxygen uptake at anaerobic threshold (VO_2AnT), handgrip strength and vertical jumping, trunk extension and flexion, stepping side to side, and single-leg balance task with the eyes closed were assessed, respectively.

RESULTS

A progressive tendency of increasing body weight, body mass index, whole-body lean and fat mass, percentage of whole-body fat mass, trunk lean and fat mass, percentage of trunk fat mass, arm fat mass, waist circumference, triglyceride level, systolic and diastolic blood pressure, and blood glucose level from the non-MetS group to the MetS group was significant (P < 0.05). Conversely, the cardiorespiratory endurance parameters VO_2peak and VO_2AnT and the high-density lipoprotein cholesterol level showed a progressively decreasing tendency across the groups (P < 0.01). In addition, a VO_2peak below 29.84 ml·kg·min^-1 (P = 0.028) and VO2_AnT below 15.89 ml·kg·min^-1 (P = 0.011) were significant risk components for pre-MetS and MetS. However, there was no significant tendency with respect to muscle strength, agility, and flexibility.

CONCLUSION

Cardiorespiratory fitness is strongly linked to metabolic syndrome among physical fitness components.

Active and Fit Communities. Associations between Neighborhood Walkability and Health-Related Fitness in Adults

There are many health benefits of regular physical activity and improving physical fitness levels can reduce the risk of chronic disease. Accumulating evidence suggests the neighborhood built environment is important for supporting physical activity; however, few studies have investigated the contribution of the neighborhood built environment to fitness levels. We examined the associations between objectively-determined and self-reported neighborhood walkability and overall and specific components of perceived health-related fitness (cardiorespiratory, muscular strength, and flexibility) in a random sample of 592 adults from two areas of Calgary (Canada). Participants provided complete data to an online questionnaire capturing perceived cardiorespiratory fitness (CRF), muscular strength (MST), flexibility, moderate-to-vigorous intensity physical activity (MVPA), resistance training, and sociodemographic characteristics. The questionnaire also captured participant’s perceptions of their neighborhood’s walkability (Physical Activity Neighborhood Environment Scale; PANES) and the physical activity supportiveness of neighborhood parks (Park Perceptions Index; PPI). Objectively-measured neighborhood walkability was estimated using Walk Score^®. The average (SD) age of participants was 46.6 (14.8) years and 67.2% were female. Participants, on average, participated in at least 30-minutes of MVPA on 3.4 (2.1) days/week and undertook resistance training 2.0 (1.8) days/week. Adjusting for covariates, Walk Score^® was not associated with any fitness outcomes. Adjusting for covariates, the PANES index was positively associated (p < 0.05) with CRF, MST, flexibility, and overall fitness and the PPI was positively associated (p < 0.05) with all fitness outcomes except MST. Our findings provide novel preliminary evidence suggesting the neighborhood built environment may be important for supporting higher health-related fitness levels in adults.

Prevalence of Underweight and Overweight and Its Association with Physical Fitness in Egyptian Schoolchildren

Underweight and overweight are serious health concerns for many children and could be associated with low physical-fitness levels. This study aimed (i) to evaluate the prevalence of underweight and overweight and (ii) to examine its association with the physical fitness levels in primary male and female schoolchildren. Including 13 government primary-schools, a cross-sectional survey was conducted between 2014 and 2017. Anthropometric characteristics together with the physical-fitness level were measured in 931 schoolchildren aged between 6- and 11-years old. The prevalence of under- and overweight children were 8.49% and 24.06%, respectively. These proportions were not significantly different between males and females and were affected by age (p < 0.001), with a higher prevalence of overweight and a lower prevalence of underweight at 9–11 years, compared to 6–8 years old. Concerning the physical fitness levels, statistical analysis showed a better performance among males compared to females, among participants aged 9–11 years, compared to 6–8 years old, and among underweight and normal-weight, compared to overweight children (p < 0.001). There was a higher prevalence of overweight and lower prevalence of underweight at 9–11 years compared to 6–8 years old. Physical fitness levels were better in (i) males, compared to females, (ii) schoolchildren aged 9–11 years, compared to 6–8 years old, and (iii) underweight and normal-weight, compared to overweight children.

Muscle fitness and its association with body mass index in children and adolescents aged 7-18 years in China: a cross-sectional study

BACKGROUND

The present study was the first one aimed to investigate the current muscle fitness and its associated factors among children and adolescents in mainland China.

METHODS

From Nov 2013 to Jul 2014, 2283 children and adolescents aged 7-18 were recruited in Hainan and Shaanxi Provinces in China by cross-sectional design. Information on anthropometry and muscle fitness, measured by hand grip strength (GS), vertical jump (VJ) and sit-and-reach (SR), were collected. Analysis of covariance was performed by using general linear regression models to identify the association between BMI and muscle fitness.

RESULTS

The means of GS, VJ and SR in boys were 22.30 ± 11.55 kg, 22.93 ± 6.80 cm and 3.58 ± 7.31 cm, respectively, and in girls were 16.61 ± 6.87 kg, 18.11 ± 4.08 cm and 7.18 ± 5.72 cm, respectively. GS (from 8.26 kg in the 7-8-year-old group to 27.91 kg in the 17-18 group) and SR (from 1.75 cm in the-8-year-old group to 10.12 cm in the 17-18 group) increased with age (both p for trend < 0.001). Boys had higher GS and VJ, but significantly lower SR than girls in each age group (p < 0.001). After adjusting for age, sex, residential areas and study regions, GS increased with elevated BMI (compared with normal weight group, the regression coefficient for thinness and overweight/obesity were - 2.997(95%CI: -3.693 to - 2.301) and 1.220 (95%CI: 0.285 to 2.155), respectively. With the p values less than 0.001 and 0.011, respectively). For VJ, there was no difference found between normal weight group and overweight/obesity group (p = 0.550), but the thinness group had the lowest performance (regression coefficient = - 2.681, 95%CI from - 3.965 to - 1.397, p < 0.001). For SR, compared with normal weight group, the regression coefficients for thinness and overweight/obesity were - 1.313(95%CI: -2.228 to - 0.399) and - 1.623(95%CI: -3.216 to - 0.030) respectively, both p < 0.05.

CONCLUSIONS

Increased body weight may have a positive association with isometric muscle strength measured by grip strength, but a negative one with strength of lifting the body. Sex difference was also found in the performance of flexibility.

Combined Aerobic and Resistance Training Effects on Glucose Homeostasis, Fitness, and Other Major Health Indices: A Review of Current Guidelines

The combination of aerobic and resistance training (AER + RES) is recommended by almost every major organization to improve health-related risk factors associated with sedentary behavior. Since the release of the Physical Activity Guidelines for Americans in 2008, several large well-controlled trials and ancillary reports have been published that provide further insight into the effects of AER + RES on health-related outcomes. The current manuscript examines the literature on the effects of AER + RES on major clinical outcomes, including glucose homeostasis, cardiorespiratory fitness (CRF), and muscular strength, as well as other important clinical outcomes, including metabolic syndrome, hypertension, dyslipidemia, and quality of life. Collectively, research suggests that AER + RES and AER or RES alone improves glycemic control and insulin sensitivity compared with continued sedentary behavior. Significant changes in CRF are also observed, suggesting a reduction in cardiovascular disease-related mortality risk. Reduced adiposity, especially abdominal adiposity, and increased strength may also interact with CRF to promote additional health benefits associated with AER + RES. While findings from our review support current physical activity guidelines, a paucity of research limits the generalizability of the results.

Overweight or Obesity, Gender, and Age Influence on High School Students of the City of Toluca's Physical Fitness

MATERIAL AND METHOD

This is a prospective, cross-sectional, and correlational study with a probabilistic sampling in which 150 teenagers from three different high schools from the city of Toluca, Mexico, aged 15-17, were assessed.

OBJECTIVE

To determine if weight, age, and gender have an influence on physical fitness evaluated with the EUROFIT and ALPHA-FITNESS batteries.

RESULTS

Women have a higher overweight and obesity rate than men (3 : 1). Adolescents who have normal weight have regular physical fitness (74.9%). When comparing genders we found that men have a higher mean than women in the tests, except for skinfold thickness and waist circumference. Age was only correlated with the plate tapping test (p = 0.001). There are significant differences in the standing broad jump test and the Course-Navette of the EUROFIT and ALPHA-FITNESS batteries (p = 0.000).

CONCLUSIONS

It is likely that regular physical activity, and not normal weight, helps generate healthy physical fitness. Male subjects had a higher mean than women, reporting a better physical fitness and more frequent physical activity.

Association of handgrip strength with hospitalization, cardiovascular events, and mortality in Japanese patients with type 2 diabetes

Handgrip strength is useful for the diagnosis of sarcopenia. We examined the associations of handgrip strength with all-cause mortality, cardiovascular events, and hospitalization in patients with type 2 diabetes. From April 2013 to December 2015, we conducted a retrospective cohort study to examine patients with type 2 diabetes whose handgrip strength was measured at our hospital. All patients were followed up until May 2016. A total of 1,282 patients (63.8 ± 13.9 years) were enrolled and followed up for 2.36 ± 0.73 years. During the follow-up period, 20 patients (1.6%) died, 14 (1.1%) experienced cardiovascular events, and 556 (43.4%) were admitted to our hospital for any diseases. Multiple regression analyses revealed that handgrip strength was favorably associated with abdominal obesity and renal function. Moreover, Cox proportional hazard analyses with adjustment for potential confounding variables revealed that handgrip strength was significantly associated with occurrence of CVD events and hospitalization in all subjects. In addition, handgrip strength was significantly associated with mortality and hospitalization in men and with hospitalization in women. Handgrip strength could be a prognostic indicator for health as well as a diagnostic marker of skeletal muscle mass loss in Japanese patients with type 2 diabetes.

Physical activity: Health impact, prevalence, correlates and interventions

OBJECTIVE

To provide a broad overview of the state of physical activity (PA) research in the form of (1) definitions of PA, (2) health benefits, (3) prevalence, (4) correlates and (5) interventions.

DESIGN

A high-level overview of published reviews of the literature.

RESULTS

Regular PA is an effective primary and secondary preventative strategy against at least 25 chronic medical conditions with risk reduction typically in the 20-30% range. While approximately 75% of adults meet recommended PA guidelines, the prevalence is slightly lower for women compared to men, and considerably lower for youth, older adults and those in higher income countries. Motivation, self-efficacy and self-regulation remain consistent correlates of PA. Interventions show PA changes in the small effect size range for adults and youth but the heterogeneity is considerable across studies. Only a few (aggregate of behavioural regulation strategies, supervision, high frequency of contact) reliable moderators of intervention success were identified across study quality, sample characteristics, theory/behaviour change techniques and delivery modes/settings.

CONCLUSION

PA research should continue to examine the mechanisms causing health outcomes, the dose that can lead to clinically relevant changes in health status, the scope and validity of PA surveillance and innovative behaviour change techniques, while improving the reach and duration of PA interventions.

Muscular Grip Strength Estimates of the U.S. Population from the National Health and Nutrition Examination Survey 2011-2012

The purposes of this study were to use the National Health and Nutrition Examination Study (2011-12) data to determine nationally representative combined handgrip strength ranges and percentile information by sex and age group, examine trends in strength across age by sex, and to determine the relative proportion of children and adults falling into established health benefit zones (HBZ). Results indicate that mean strength was greater among men than women and increased linearly for children and in a quadratic fashion among adults for both sexes. Grip strength peaked in the 30- to 39-year age group for both men (216.4 lbs) and women (136.5 lbs) with subsequent age groups showing gradual decline, p < 0.0001. Relative and absolute increases in grip strength were greater for men than for women, but relative decrease from peak strength was less among women than men. Although absolute strength was greater among men than women, HBZ data indicated that a higher percentage of men than women overall and at each age group fell into the needs improvement zone, with differences particularly pronounced during adolescence and older adulthood. These data provide the first nationally representative population estimates of combined handgrip strength and percentile information from childhood through senescence and suggest consideration of HBZ information in conjunction with grip strength to improve surveillance data interpretation and intervention planning.

Reflections on Physical Activity and Health: What Should We Recommend?

The health benefits of regular physical activity are irrefutable; virtually everyone can benefit from being active. The evidence is overwhelming with risk reductions of at least 20%-30% for more than 25 chronic medical conditions and premature mortality. Even higher risk reductions (ie, ≥ 50%) are observed when objective measures of physical fitness are taken. International physical activity guidelines generally recommend 150 minutes per week of moderate- to vigorous-intensity physical activity. A critical review of the literature indicates that half of this volume of physical activity might lead to marked health benefits. There is compelling evidence to support health promotion strategies that emphasize that health benefits can be accrued at a lower volume and/or intensity of physical activity. Public health policies are needed that reduce the barriers to physical activity participation such that everyone can reap the benefits of physical activity. It is also important to highlight that sedentary time (particularly sitting time) carries independent health risks. The simple message of "move more and sit less" likely is more understandable by contemporary society and is formed on the basis of a strong body of evidence. For practitioners who work directly with clients, it is recommended that an individualized prescription (dosage) that takes into consideration the unique characteristics and needs of the client is provided. Physical activity or exercise promotion should not be done in isolation; it should be part of an integrated approach to enhance healthy lifestyle behaviours.

Muscular strength is associated with self-esteem in college men but not women

Muscular strength is a well-known predictor of morbidity and mortality. Similarly, self-esteem is a predictor of health and well-being. The relationship between these two variables, however, is currently unknown. This study examined the cross-sectional relationship between maximal muscular strength (i.e. handgrip and one-repetition-maximum (1-RM) squat) and global self-esteem in 126 college students. Significant correlations were found between both measures of muscular strength and self-esteem. Further analyses revealed that these relationships were only significant for men. Based on these results, additional research is needed to further explore the relationship between muscular strength and self-esteem, especially in other demographic groups and longitudinally.

A statewide assessment of youth sports- and recreation-related injuries using emergency department administrative records

PURPOSE

Adequate levels of physical activity are essential for health, but participation in sports and recreational physical activities is associated with an increased risk of injury. The present study quantifies the impact of sports- and recreation-related injuries (SRIs) for middle and high school-aged Kentucky children.

METHODS

The study describes unintentional injuries in 2010-2012 Kentucky emergency department (ED) administrative records for patients age 10-18 years. SRIs were identified based on external codes of injuries, according to the International Classification of Diseases, Ninth Revision, Clinical Modification.

RESULTS

A total of 163,252 ED visits by 10- to 18-year olds occurred during the study period, of which 31,898 (20%) were related to participation in physical activity. Males accounted for 70% of the SRIs. The primary mechanisms for SRIs were strikings (55%), falls (26%), and overexertion (13%). Superficial contusions (25%), sprains/strains (33%), and fractures (18%) were the primary diagnoses. The total charges billed for SRIs exceeded $40 million, or 19% of the total charges billed for all unintentional injury-related ED visits in this age group.

CONCLUSIONS

The present study revealed one fifth of all Kentucky ED visits, and ED charges billed for unintentional injury among youth aged 10-18 years were related to sport and recreation. In the absence of a dedicated SRI surveillance system, ED administrative records provide meaningful utility for conducting statewide assessments of adolescent SRIs.

Trekking exercise promotes cardiovascular health and fitness benefits in older obese women

Trekking includes downhill walking and enhances lower limb strength. Muscle fitness is a predictor of mortality and is associated with cardiovascular risk factors in adults. The purpose of this study was to investigate the effects of trekking on cardiovascular health and fitness in older obese women. The participants were randomly assigned to an exercise group (EG, n= 32) and a control group (CG, n= 48). The EG participated in the trekking program for 12 weeks, 3 times per week, and 90 min per session, at a moderate intensity. Cardiovascular health (BMI, percentage of body fat, blood pressure, glucose, triglycerides, and total cholesterol) and fitness (muscle strength, muscle endurance, balance, and flexibility) were measured before and after the 12-week program. A twoway repeated ANOVA was used to compare and analyze the group differences. Body weight, systolic blood pressure, and muscle strength were significantly different between the groups. These results indicate that trekking played a significant role in the reduction of weight and systolic blood pressure in obese women. The results of this study can be utilized to reduce cardiovascular risk factors associated with aging.

Reduced vasodilator function following acute resistance exercise in obese women

Obesity contributes to stress induced impairments in endothelium-dependent vasodilation (EDV), a precursor to atherosclerosis. Since obesity is associated with inflammation and oxidative stress, we sought to determine if a single bout of strenuous weight lifting (SWL) reduces EDV among sedentary obese adults. Participants included 9 obese (OB) (BMI 30.0–40.0 kg/m²) and 8 lean (LN) (BMI 18.5–24.9 kg/m²) sedentary young women. All participants underwent a single bout of SWL using a progressive leg-press protocol. Brachial artery flow-mediated dilation (FMD) (an index of EDV) was determined using ultrasonography before and after SWL. Sublingual nitroglycerin (NTG) was used to determine brachial artery endothelium-independent vasodilation following SWL. Brachial artery FMD was significantly reduced in OB and LN women (LN: 6.4 ± 1.6%, p = 0.22) after SWL. There was no difference in the magnitude of change pre- and post-SWL between groups (OB: −2.4 ± 0.6% and LN: −2.2 ± 1.6%, p = 0.84). Dilation to NTG was lower in OB (21.6 ± 1.3%) compared to LN women (27.6 ± 2.1%, p = 0.02) and associated with body weight (r = −0.70, p = 0.01). These data suggest that EDV is reduced in woman after acute resistance exercise. Dilations to NTG were lower in obese compared to lean woman and associated with body weight suggesting that changes in sensitivity of blood vessels to NO occurs during obesity. These findings may be important for understanding vascular risk following acute exercise in obesity.

A comparative controlled trial comparing the effects of yoga and walking for overweight and obese adults

Background

Walking and yoga have been independently evaluated for weight control; however, there are very few studies comparing the 2 with randomization.

Material/Methods

The present study compared the effects of 90 minutes/day for 15 days of supervised yoga or supervised walking on: (i) related biochemistry, (ii) anthropometric variables, (iii) body composition, (iv) postural stability, and (v) bilateral hand grip strength in overweight and obese persons. Sixty-eight participants, of whom 5 were overweight (BMI ≥25 kg/m²) and 63 were obese (BMI ≥30 kg/m²; group mean age ±S.D., 36.4±11.2 years; 35 females), were randomized as 2 groups – (i) a yoga group and (ii) a walking group – given the same diet.

Results

All differences were pre-post changes within each group. Both groups showed a significant (p<0.05; repeated measures ANOVA, post-hoc analyses) decrease in: BMI, waist circumference, hip circumference, lean mass, body water, and total cholesterol. The yoga group increased serum leptin (p<0.01) and decreased LDL cholesterol (p<0.05). The walking group decreased serum adiponectin (p<0.05) and triglycerides (p<0.05).

Conclusions

Both yoga and walking improved anthropometric variables and serum lipid profile in overweight and obese persons. The possible implications are discussed.

Muscle strength in adolescent men and risk of cardiovascular disease events and mortality in middle age: a prospective cohort study

BACKGROUND

Ischemic heart disease and stroke are two severe types of cardiovascular disease (CVD), a major contributor to the global burden of disease. The preventive framework currently includes promotion of both adequate cardiorespiratory and muscular fitness. Although muscle fitness is established as an indicator of health, it is currently unknown whether muscle strength is associated with later CVD independently of cardiorespiratory fitness.

METHODS

We studied 38,588 Swedish men who in 1969 to 1970 (typically aged 18 years) completed compulsory conscription. Using the mean standardized score of three isometric muscle strength tests performed at conscription (hand grip, elbow flexion and knee extension), we categorized the subjects into three groups with the 25th to 75th percentile defining the reference category. We followed the cohort until 2012 for diagnosed CVD events and mortality via national health care registers and the national cause of death register. To estimate hazard ratios (HR) for CVD events (coronary heart disease or stroke) and CVD mortality we used Cox proportional hazard models adjusted for body mass index, smoking, alcohol consumption, cardiorespiratory fitness and socioeconomic status.

RESULTS

Men with high muscle strength in adolescence had a decreased risk of later CVD events (HR 0.88, 95% confidence interval 0.77 to 0.99), whereas we observed no increased risk in men with low muscle strength (0.99, 0.86 to 1.13). However, low muscle strength was associated with increased risk of CVD mortality during middle age (1.31, 1.02 to 1.67).

CONCLUSIONS

Muscle strength in adolescent men is inversely associated with later CVD events and CVD mortality in middle age, independently of cardiorespiratory fitness and other important confounders. Thus, the role of muscle fitness in the prevention and pathogenesis of CVD warrants increased attention.

Low weight and overweightness in older adults: risk and clinical management

The prevalence of individuals who are overweight or obese is growing exponentially in the United States and worldwide. This growth is concerning, as both overweightness and obesity lead to impaired physical function, decreased quality of life, and increased risk of chronic diseases. Additionally, overweightness and obesity are related to increased mortality among young and middle-aged adults. This weight-related risk of mortality is more ambiguous among older adults. In fact, obesity may be protective in this population, a relationship described as the "obesity paradox". In this review we discuss the effects of overweightness and obesity among the elderly on cardiovascular disease and all-cause mortality, along with the risks of low weight. We conclude by discussing the goal of weight management among older adults, focusing particularly on benefits of preserving lean body mass and muscular strength while stabilizing body fat. Ideally, overweight or mildly obese elderly individuals should devise a plan with their physicians to maintain their weight, while increasing lean body mass through a plan of healthy diet, behavioral therapy, and physical activity.

[Association of muscle strength with early markers of cardiovascular risk in sedentary adults]

OBJECTIVE

To assess the association between muscle strength and early cardiovascular risk (CVR) markers in sedentary adults.

MATERIALS AND METHODS

A total of 176 sedentary subjects aged 18-30 years were enrolled. Body mass index and fat percentage were calculated, and waist circumference, grip strength by dynamometry, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and maximal oxygen uptake by VO2max were measured as CVR markers. A multivariate logistic regression analysis was used to assess associations between muscle strength and CVR markers.

RESULTS

Inverse correlations were found between muscle strength and adiposity (r=-.317; P=.001), waist circumference (r=-.309; P=.001), systolic blood pressure (r=-.401; P=.001), and mean arterial pressure (r=-.256; P=.001). Subjects with lower levels of muscle strength had a 5.79-fold (95% CI 1.57 to 9.34; P=.008) risk of having higher adiposity levels (≥25%) and a 9.67-fold (95% CI=3.86 to 19.22; P<.001) risk of having lower physical capacity values for VO2max (≤31.5mL/kg/min(-1)).

CONCLUSIONS

In sedentary adults, muscle strength is associated to early manifestations of CVR. It is suggested that muscle strength testing is added to routine measurement of VO2max and traditional risk factors for prevention and treatment of cardiovascular risk.

Effects of muscular strength on cardiovascular risk factors and prognosis

Physical fitness is one of the strongest predictors of individual future health status. Together with cardiorespiratory fitness (CRF), muscular strength has been increasingly recognized in the pathogenesis and prevention of chronic disease. We review the most recent literature on the effect of muscular strength in the development of cardiovascular disease, with special interest in elucidating its specific benefits beyond those from CRF and body composition. Muscular strength has shown an independent protective effect on all-cause and cancer mortality in healthy middle-aged men, as well as in men with hypertension and patients with heart failure. It has also been inversely associated with age-related weight and adiposity gains, risk of hypertension, and prevalence and incidence of the metabolic syndrome. In children and adolescents, higher levels of muscular fitness have been inversely associated with insulin resistance, clustered cardiometabolic risk, and inflammatory proteins. Generally, the influence of muscular fitness was weakened but remained protective after considering CRF. Also, interestingly, higher levels of muscular fitness seems to some extent counteract the adverse cardiovascular profile of overweight and obese individuals. As many of the investigations have been conducted with non-Hispanic white men, it is important to examine how race/ethnicity and gender may affect these relationships. To conclude, most important effects of resistance training are also summarized, to better understand how higher levels of muscular fitness may result in a better cardiovascular prognosis and survival.

No association between COL3A1, COL6A1 or COL12A1 gene variants and range of motion

Approximately 64-70% of the variability in joint range of motion (ROM) is heritable. A common variant within a type V collagen (COL5A1) gene is associated with joint range of motion. Like type V collagen, types III, VI and XII collagen are also involved in fibril assembly and/or diameter regulation. Mutations within the genes that encode these proteins, COL3A1, COL6A1 and COL12A1, also cause connective tissue hypermobility disorders and phenotypes. The aim of this study was to determine if variants within these genes are associated with measures of joint range of motion. Three hundred and fifty apparently healthy and physically active Caucasian participants were recruited. Anthropometric measurements were taken. Sit-and-reach (SR), straight leg raise (SLR) and total shoulder rotation (ShTR) range of motion were measured. All participants were genotyped for COL3A1 rs1800255, COL6A1 rs35796750 and COL12A1 rs970547. COL3A1 rs1800255, COL6A1 rs35796750 and COL12A1 rs970547 were not significantly associated with sit-and-reach, straight leg raise or total shoulder rotation range of motion. Furthermore, no significant age-genotype interaction effects were identified between the variants and range of motion measurements. None of the variants investigated in this study were significantly associated with any of the measures of range of motion used. Further studies are required to identify additional intrinsic and extrinsic factors that may determine range of motion, including the genetic component.

Physiological fitness and health adaptations from purposeful training using off-road vehicles

The purpose of this study was to evaluate fitness and health adaptations from a training program riding all-terrain vehicles (ATV) and off-road motorcycles (ORM) as the exercise stimulus. Participants (n = 58) were randomized to a control group (n = 12) or one of four experimental groups; 2 days/week ATV (n = 11), 2 days/week ORM (n = 12), 4 days/week ATV (n = 11), or 4 days/week ORM (n = 12). Aerobic fitness, musculoskeletal fitness, body composition, clinical health, and quality of life (QOL) were compared at baseline and following 6 weeks of training. In all riding groups, there were improvements in blood pressure (SBP = 9.4 ± 10.1, DBP = 5.8 ± 6.2 mmHg), fasting glucose (0.5 ± 0.7 mmol/l), subcutaneous adiposity (0.9 ± 1.1%), body mass (0.7 ± 2.7 kg), waist circumference (1.3 ± 2.5 cm), and isometric leg endurance (26 ± 44 s). All changes were of moderate to large magnitude (Cohen's d 0.52-0.94) with the exception of a small loss of body mass (Cohen's d = 0.27). Although changes occurred in the riding groups for aerobic power (2.9 ± 4.6 ml kg(-1) min(-1)), leg power (172 ± 486 w), and curl-ups (13.2 ± 22.7), these changes were not significantly different from the control group. No significant alterations occurred in resting heart rate, trunk flexibility, back endurance, hand grip strength, long jump, pull/push strength, or push-up ability as a result of training. Physical domain QOL increased in all 2 days/week riders but mental domain QOL increased in all ORM, but not ATV riders regardless of volume. Ambient carbon monoxide levels while riding (<30 ppm) were within safe exposure guidelines. Positive adaptations can be gained from a training program using off-road vehicle riding as the exercise stimulus.

Muscular strength is inversely related to prevalence and incidence of obesity in adult men

The purpose of the study was to determine the relation between quintiles of muscular strength after adjustment for age and body weight, and excessive body fat (EBF) and excessive abdominal fat (EAF) when controlling for cardiorespiratory fitness (CRF) and other potential confounders. A two-phased cross-sectional and longitudinal study was conducted assessing the prevalence and incidence of EBF and EAF across quintiles of muscular strength. The sample included 3,258 men (mean age = 42.2 ± 8.9; weight (kg) = 81.2 ± 11.0; BMI = 25.3 ± 2.9; %fat = 19.4 ± 5.8; waist girth (cm) = 91.2 ± 9.0) who completed at least two clinical examinations as part of the Aerobics Center Longitudinal Study (ACLS). Muscular strength was assessed with tests of upper and lower body muscular strength using rack-mounted weights with participants placed into strength quintiles. CRF was measured by a modified Balke treadmill test, %fat via underwater weighing or seven-site skinfold measurements, and waist girth measured at the level of the umbilicus. EBF was defined as ≥25% and EAF was defined as >102 cm. There was a strong inverse gradient across quintiles of muscular strength for prevalence and incidence of EBF and EAF (P trend <0.01, each). With the lowest quintile serving as the referent, reductions in risk of EBF and EAF exceeded 70% for the highest strength quintile. Evidence suggests muscular strength may provide protection from EBF and EAF and their related comorbidities.

A systematic review of the evidence for Canada's Physical Activity Guidelines for Adults

This systematic review examines critically the scientific basis for Canada's Physical Activity Guide for Healthy Active Living for adults. Particular reference is given to the dose-response relationship between physical activity and premature all-cause mortality and seven chronic diseases (cardiovascular disease, stroke, hypertension, colon cancer, breast cancer, type 2 diabetes (diabetes mellitus) and osteoporosis). The strength of the relationship between physical activity and specific health outcomes is evaluated critically. Literature was obtained through searching electronic databases (e.g., MEDLINE, EMBASE), cross-referencing, and through the authors' knowledge of the area. For inclusion in our systematic review articles must have at least 3 levels of physical activity and the concomitant risk for each chronic disease. The quality of included studies was appraised using a modified Downs and Black tool. Through this search we identified a total of 254 articles that met the eligibility criteria related to premature all-cause mortality (N = 70), cardiovascular disease (N = 49), stroke (N = 25), hypertension (N = 12), colon cancer (N = 33), breast cancer (N = 43), type 2 diabetes (N = 20), and osteoporosis (N = 2). Overall, the current literature supports clearly the dose-response relationship between physical activity and the seven chronic conditions identified. Moreover, higher levels of physical activity reduce the risk for premature all-cause mortality. The current Canadian guidelines appear to be appropriate to reduce the risk for the seven chronic conditions identified above and all-cause mortality.

[Evidence-based guidelines for physical activity of adult Canadians]

This review of the literature provides an update on the scientific biological and psychosocial bases for Canada's Physical Activity Guide for Health Active Living, with particular reference to the effect of physical activity on the health of adults aged 20-55 years. Existing physical activity guidelines for adults from around the world are summarized briefly and compared to the Canadian guidelines. The descriptive epidemiology of physical activity and inactivity in Canada is presented, and the strength of the relationship between physical activity and specific health outcomes is evaluated, with particular emphasis on minimal and optimal physical activity requirements. Finally, areas requiring further investigation are highlighted. Summarizing the findings, Canadian and most international physical activity guidelines advocate moderate-intensity physical activity on most days of the week. Physical activity appears to reduce the risk for over 25 chronic conditions, in particular coronary heart disease, stroke, hypertension, breast cancer, colon cancer, type 2 diabetes, and osteoporosis. Current literature suggests that if the entire Canadian population followed current physical activity guidelines, approximately one-third of deaths related to coronary heart disease, one quarter of deaths related to stroke and osteoporosis, 20% of deaths related to colon cancer, hypertension, and type 2 diabetes, and 14% of deaths related to breast cancer could be prevented. It also appears that the prevention of weight gain and the maintenance of weight loss require greater physical activity levels than current recommendations.

Prescribing physical activity: applying the ACSM protocols for exercise type, intensity, and duration across 3 training frequencies

When physicians advise patients to attain more physical activity, they usually recommend a walking program. However, in a similar way to no exercise, those embarking on a walking program will typically lose 4 to 6 lb of lean weight and reduce their resting metabolic rate 2% to 3% every decade. These effects may be mitigated by the inclusion of resistance exercise. The American College of Sports Medicine (ACSM) minimum exercise guidelines recommend 20 minutes of aerobic activity 3 days per week, and 1 set (8-12 repetitions) of 8 to 10 resistance exercises to train the major muscle groups 2 days per week. However, large-scale testing of these recommendations in a field setting has been minimal. Men and women between 21 and 80 years (N = 1725) [corrected] participated in a 10-week combined strength and aerobic activity program based on the ACSM protocols for exercise intensity and duration across 3 training frequencies (1, 2, or 3 sessions/week). Across all training frequencies, mean changes included a reduction in body fat of 1.97%, a decrease in fat weight of 1.7 kg, an increase in lean weight of 1.35 kg, a reduction in systolic blood pressure of 3.83 mm Hg, and a reduction in diastolic blood pressure of 1.73 mm Hg. More frequent weekly training sessions were associated with greater improvements in body fat percent, fat weight, and lean weight. Participants responded favorably to the ACSM exercise program with a 91% completion rate and a 95% satisfaction rating. This article presents recommendations for prescribing safe, effective, and time-efficient exercise programs.

Evidence-informed physical activity guidelines for Canadian adultsThis article is part of a supplement entitled Advancing physical activity measurement and guidelines in Canada: a scientific review and evidence-based foundation for the future of Canadian physical activity guidelines co-published by Applied Physiology, Nutrition, and Metabolism and the Canadian Journal of Public Health. It may be cited as Appl. Physiol. Nutr. Metab. 32(Suppl. 2E) or as Can. J. Public Health 98(Suppl. 2)

This review of the literature provides an update on the scientific biological and psychosocial bases for Canada’s physical activity guide for healthy active living, with particular reference to the effect of physical activity on the health of adults aged 20–55 years. Existing physical activity guidelines for adults from around the world are summarized briefly and compared with the Canadian guidelines. The descriptive epidemiology of physical activity and inactivity in Canada is presented, and the strength of the relationship between physical activity and specific health outcomes is evaluated, with particular emphasis on minimal and optimal physical activity requirements. Finally, areas requiring further investigation are highlighted. Summarizing the findings, Canadian and most international physical activity guidelines advocate moderate-intensity physical activity on most days of the week. Physical activity appears to reduce the risk for over 25 chronic conditions, in particular coronary heart disease, stroke, hypertension, breast cancer, colon cancer, type 2 diabetes, and osteoporosis. Current literature suggests that if the entire Canadian population followed current physical activity guidelines, approximately one third of deaths related to coronary heart disease, one quarter of deaths related to stroke and osteoporosis, 20% of deaths related to colon cancer, hypertension, and type 2 diabetes, and 14% of deaths related to breast cancer could be prevented. It also appears that the prevention of weight gain and the maintenance of weight loss require greater physical activity levels than current recommendations.