Role of Resistance Exercise in Reducing Risk for Cardiometabolic Disease

Associations of cardiorespiratory fitness, body composition, and blood pressure with arterial stiffness in adolescent, young adult, and middle-aged women

Few studies have investigated whether higher cardiorespiratory fitness (CRF) or favourable body composition are related to lower arterial stiffness in women. We therefore investigated the associations of CRF, body fat percentage (BF%), fat free mass index (FFMI), and mean arterial pressure (MAP) with arterial stiffness in 146 women aged 16-58 years. CRF was assessed by a maximal exercise test with respiratory gas analysis either on a cycle ergometer or a treadmill. Aortic pulse wave velocity (PWVao), augmentation index (AIx%), and MAP were assessed by a non-invasive oscillometric device and BF% and FFMI by a bioelectrical impedance or DXA device. CRF was inversely associated with PWVao (β =  - 0.004, 95% CI - 0.005 to - 0.002) and AIx% (β =  - 0.075, 95% CI - 0.102 to - 0.048) and these associations remained similar after adjustment for BF% or MAP, but not after the adjustment for age. FFMI was inversely associated with PWVao (β =  - 0.010, 95% CI - 0.019 to - 0.002) and MAP directly associated with PWVao (β = 0.005, 95% CI 0.003 to 0.006) and AIx% (β = 0.092, 95% CI 0.069 to 0.116) and the associations with PWVao also remained after further adjustments for BF% and age. In conclusion, a higher FFMI and a lower MAP were independently associated with lower arterial stiffness.

Low Muscle Strength Thresholds for the Detection of Cardiometabolic Risk in Adolescents

INTRODUCTION

There is an association between strength and health among adolescents, yet, what remains to be determined is sex-specific cut points for low strength in the detection of risk in this population. The purpose of this study was to determine thresholds of low grip strength in a large cohort (N=1,326) of adolescents.

METHODS

All data were collected between 2005 and 2008, and analyzed in 2014-2015. A cardiometabolic risk score (MetScore) was computed from the following components: percent body fat, fasting glucose, blood pressure, plasma triglyceride levels, and high-density lipoprotein cholesterol. A high-risk cardiometabolic phenotype was characterized as ≥75th percentile of the MetScore. Conditional inference tree analyses were used to identify sex-specific, low normalized strength (grip strength/body mass) thresholds and risk categories.

RESULTS

Lower strength was independently associated with increased odds of the high-risk cardiometabolic phenotype, such that for every 5% decrement of normalized strength, there were 1.48 and 1.45 increased odds (p<0.001) for boys and girls, even after adjusting for cardiorespiratory fitness and physical activity. Conditional tree analysis revealed a high-risk threshold for boys (≤0.33) and girls (≤0.28), as well as an intermediate threshold (boys, >0.33 and ≤0.45; girls, >0.28 and ≤0.36).

CONCLUSIONS

These sex-specific thresholds of low strength can be incorporated into a clinical setting for identifying adolescents that would benefit from lifestyle interventions to improve muscular fitness and reduce cardiometabolic risk.

Tennis for physical health: acute age- and gender-based physiological responses to cardio tennis

This study described physiological and perceptual responses to Cardio tennis for "younger" and "older" adult populations of both sexes for health-related outcomes. Thirty-one active participants, each with prior recreational tennis experience (∼2 years) (8 younger and 8 older males, and 7 younger and 8 older females) performed preliminary testing and a 50-minute instructor-led Cardio tennis session. Cardio tennis is a conditioning-based tennis program comprised of warm-up movements, drill-based exercises (set movement and hitting games), and competitive play scenarios. Participants performed the 20-m shuttle run test to determine maximal heart rate (HR) during preliminary testing. Before, after, and 30-minute post Cardio tennis session, HR, blood pressure (BP), rate pressure product (RPP), and capillary blood lactate and glucose were determined. Furthermore, HR and pedometer-derived step counts were measured throughout, while the session was filmed and coded for technical skill. After the session, ratings of perceived exertion, enjoyment, and challenge were obtained. Heart rate, systolic BP, and RPP were significantly increased by Cardio tennis (p ≤ 0.05), though returned to pre-exercise levels after 30 minutes (p > 0.05). Heart rate and BP did not differ between groups pre- or 30-minute postexercise (p > 0.05); however, these were lower in younger males during and higher in younger females postsession (p ≤ 0.05). Lactate and glucose concentrations were increased in all groups (p ≤ 0.05), with lactate being highest in male groups (p ≤ 0.05), without differences in glucose between groups (p > 0.05). Stroke and step counts were not different between groups (p > 0.05). Ratings of perceived exertion and perceived challenge were lowest in the younger male group compared with all other groups (p ≤ 0.05). Cardio tennis presents as an effective stimulus to invoke sufficient cardiovascular and metabolic load to benefit health and fitness, though age- and sex-based responses should be considered in prescription.

Strength capacity and cardiometabolic risk clustering in adolescents

OBJECTIVES

The purpose of this study was to determine the gender-specific independent association between muscular strength and cardiometabolic risk clustering in a large cohort (n = 1421) of children.

METHODS

Principal component analysis was used to determine the pattern of risk clustering and to derive a continuous aggregate score (MetScore) from various cardiometabolic risk components: percent body fat (%BF), fasting glucose, blood pressure, plasma triglycerides levels, and HDL-cholesterol. Gender-stratified risk and MetScore were assessed by using general linear models and logistic regression for differences between strength tertiles, as well as independent associations with age, BMI, estimated cardiorespiratory fitness (CRF), physical activity, and muscular strength (normalized for body mass).

RESULTS

In both boys (n = 670) and girls (n = 751), there were significant differences in cardiometabolic profiles across strength tertiles, such that stronger adolescents had lower overall risk. Age, BMI, cardiorespiratory fitness, physical activity participation, and strength were all individually correlated with multiple risk components, as well as the overall MetScore. However, in the adjusted model, only BMI (β = 0.30), physical inactivity (β = 0.30), and normalized strength capacity (β = -1.5) emerged as significant (P < .05) predictors of MetScore. %BF was the strongest loading coefficient within the principal component analysis-derived MetScore outcome.

CONCLUSIONS

Normalized strength is independently associated with lower cardiometabolic risk in boys and girls. Moreover, %BF was associated with all cardiometabolic risk factors and carried the strongest loading coefficient. These findings bolster the importance of early strength acquisition and healthy body composition in childhood.

A review of resistance exercise training in obese adolescents

Resistance training-also known as strength or weight training-has been well recognized by several national organizations as a safe and beneficial exercise modality for the health and well-being of children and adolescents. Resistance exercise improves muscular strength and can improve body composition (eg, increase lean body mass and decrease percent body fat) provided that a sufficient exercise stimulus is prescribed. Effects of resistance exercise training on body composition and metabolic profile are well established in obese adults, but warrant further investigation in obese youth. This article reviews the rationale for including a resistance training component with interventions geared toward overweight and obese adolescents by discussing the effects on various health measures. Shortcomings in published trials, including small, ethnic minority samples of short-duration and low-frequency exercise sessions primarily conducted in prepubertal youth (rather than postpubertal adolescents) limit the generalizability of the published literature on the effectiveness of resistance exercise in obese adolescents.