Modeling the dose-response rate/associations between VO2max and self-reported Physical Activity Questionnaire in children and adolescents

Background'. This study sought to explore the dose—response rate/association between aerobic fitness (VC)2max) and self-reported physical activity(PA) and to assess whether this association varies by sex, age, and weight status.Methods. VO2max was assessed using the 20・m shuttle・run test. PA was assessed using the Physical Activity Questionnaire (PAQ) for Adolescents(aged > 11 years, PAQ-A) or for Children (aged <11 years, PAQ-C). The associations between V02raax and PAQ were analyzed using analysisof covariance (ANCOVA), adopting PAQ and PAQ2 as covariates but allowing the intercepts and slope parameters of PAQ and PAQ2 tovary with the categorical variables sex, age group, and weight status.Results: ANCOVA identified a curvilinear association between VO2max and PAQ, with positive linear PAQ terms that varied for both sex andweight status but with a negative PAQ2 term of —0.39 (95% confidence interval (CI): —0.57 to —0.21) that was common for all groups in regardto age, sex, and weight status. These curvilinear (inverted U) associations suggest that the benefits of increasing PA (same dose) on VO2max isgreater when children report lower levels of PA compared to children who report higher levels of PA. These dose-response rates were alsosteeper for boys and were steeper for lean children compared to overweight/obese children.Conclusion'. Health practitioners should be aware that encouraging greater PA (same dose) in inactive and underweight children will result ingreater gains in V02max (response) compared with their active and overweight/obese counterparts.

Affective responses to supervised 10-week programs of resistance exercise in older adults

Background:Resistance exercise has numerous,well-documented benefits on the health and functional performance of older adults.However,little information exists on the affective responses to resistance exercise in this population.As affective responses can predict continued exercise behavior,examining if and how they differ between resistance exercise intensities and frequencies in older adults may provide important data to improve resistance exercise prescription.Methods:We monitored the affective responses of older adults when performing high-velocity,low-load(HVLL)or low-velocity,high-load(LVHL)resistance exercise once or twice weekly.A total of 40 moderately to highly active,but resistance-exercise naïve,older adults(60-79 years)completed 1 of 4 randomly assigned progressive resistance exercise conditions:HVLL once weekly(HVLL1:n=10),HVLL twice weekly(HVLL2:n=10),LVHL once weekly(LVHL1:n=10),or LVHL twice weekly(LVHL2:n=10).The Physical Activity Affect Scale,Felt Arousal Scale,Feeling Scale,rating of perceived exertion,Visual Analog Scale,and the Physical Activity Enjoyment Scale were used to assess enjoyment and affective responses.Results:The results from Physical Activity Enjoyment Scale(out of 35)suggest that all exercise conditions were largely and similarly enjoyable to older adults(HVLL1:30.9±2.4;LVHL1:31.9±3.6;HVLL2:30.9±3.5;LVHL2:30.2±3.7)despite greater fatigue(p=0.033;ηp^2p=0.22)and perceived workload(p=0.042;ηp^2=0.20)in LVHL(results from Visual Analog Scale).Conclusion:Moderately to highly physically active older adults may tolerate higher intensities of resistance exercise performed once or twice weekly without experiencing a negative impact on enjoyment.However,the role that supervision and social interaction played in shaping the participants’responses is unclear.