Muscular fitness and cardiorespiratory fitness are associated with health-related quality of life: Results from labmed physical activity study

Abstract Background/Objective Adolescents’ physical fitness levels are an important indicator of their lifestyle and seem to have positive consequences in health-related quality of life (HRQoL). The purpose of this study is to analyse the combined associations of cardiorespiratory fitness and muscular fitness with HRQoL and to assess the differences between HRQoL scores across groups of cardiorespiratory fitness and muscular fitness in Portuguese adolescents. Methods This is a cross-sectional analysis with 567 Portuguese adolescents aged 12-18 years-old. HRQoL was measured using the Kidscreen-10 questionnaire. Cardiorespiratory fitness was estimated with the 20-m shuttle-run test. Muscular fitness was evaluated using the handgrip and the standing long jump tests and a muscular fitness index was computed by means of standardized measures of both tests. Socioeconomic status was assessed using the Family Affluence Scale. Body composition (body mass and height) was measured according to standard protocols. Accelerometers were used to obtain objective physical activity time. Pubertal stage was assessed using Tanner stages. Adherence to the Mediterranean diet was assessed using the KIDMED index. Participants were divided into four groups based on low or high values of both cardiorespiratory and muscular fitness. Regression analysis, mediation analysis and ANCOVA were performed. Results HRQoL was positively associated with cardiorespiratory fitness (B = 0.112; p  Conclusions In adolescents, the combination of high cardiorespiratory fitness and high muscular fitness was positively associated with a better HRQoL.