The objective of the present systematic review was to investigate whether physical fitness in childhood and adolescence is a predictor of cardiovascular disease (CVD) risk factors, events and syndromes, quality of life and low back pain later in life. Physical fitness-related components were: cardiorespiratory fitness, musculoskeletal fitness, motor fitness and body composition. Adiposity was considered as both exposure and outcome. The results of 42 studies reporting the predictive validity of health-related physical fitness for CVD risk factors, events and syndromes as well as the results of five studies reporting the predictive validity of physical fitness for low back pain in children and adolescents were summarised. Strong evidence was found indicating that higher levels of cardiorespiratory fitness in childhood and adolescence are associated with a healthier cardiovascular profile later in life. Muscular strength improvements from childhood to adolescence are negatively associated with changes in overall adiposity. A healthier body composition in childhood and adolescence is associated with a healthier cardiovascular profile later in life and with a lower risk of death. The evidence was moderate for the association between changes in cardiorespiratory fitness and CVD risk factors, and between cardiorespiratory fitness and the risk of developing the metabolic syndrome and arterial stiffness. Moderate evidence on the lack of a relationship between body composition and low back pain was found. Due to a limited number of studies, inconclusive evidence emerged for a relationship between muscular strength or motor fitness and CVD risk factors, and between flexibility and low back pain.

The present study summarises the work developed by the ALPHA (Assessing Levels of Physical Activity) study and describes the procedures followed to select the tests included in the ALPHA health-related fitness test battery for children and adolescents. The authors reviewed physical fitness and health in youth findings from cross-sectional studies. The authors also performed three systematic reviews dealing with (1) the predictive validity of health-related fitness, (2) the criterion validity of field-based fitness tests and (3) the reliability of field-based fitness tests in youth. The authors also carried out 11-methodological studies to determine the criterion validity and the reliability of several field-based fitness tests for youth. Finally, the authors performed a study in the school setting to examine the reliability, feasibility and safety of the selected tests. The selected fitness tests were (1) the 20 m shuttle run test to assess cardiorespiratory fitness; (2) the handgrip strength and (3) standing broad jump to assess musculoskeletal fitness, and (4) body mass index, (5) skinfold thickness and (5) waist circumference to assess body composition. When there are time limits, the authors propose the high-priority ALPHA health-related fitness test battery, which comprises all the evidence-based fitness tests except the measurement of the skinfold thickness. The time required to administer this battery to a group of 20 youth by one physical education teacher is less than 2 h. In conclusion, the ALPHA fitness tests battery is valid, reliable, feasible and safe for the assessment of health-related physical fitness in children and adolescents to be used for health monitoring purposes at population level.

Cardiorespiratory fitness (CRF) is not only an objective measure of habitual physical activity, but also a useful diagnostic and prognostic health indicator for patients in clinical settings. Although compelling evidence has shown that CRF is a strong and independent predictor of all-cause and cardiovascular disease mortality, the importance of CRF is often overlooked from a clinical perspective compared with other risk factors such as hypertension, diabetes, smoking, or obesity. Several prospective studies indicate that CRF is at least as important as the traditional risk factors, and is often more strongly associated with mortality. In addition, previous studies report that CRF appears to attenuate the increased risk of death associated with obesity. Most individuals can improve their CRF through regular physical activity. Several biological mechanisms suggest that CRF improves insulin sensitivity, blood lipid profile, body composition, inflammation, and blood pressure. Based on the evidence, health professionals should encourage their patients to improve CRF through regular physical activity.

Background—: The combined associations of changes in cardiorespiratory fitness and body mass index (BMI) with mortality remain controversial and uncertain. Methods and Results—: We examined the independent and combined associations of changes in fitness and BMI with all-cause and cardiovascular disease (CVD) mortality in 14 345 men (mean age 44 years) with at least 2 medical examinations. Fitness, in metabolic equivalents (METs), was estimated from a maximal treadmill test. BMI was calculated using measured weight and height. Changes in fitness and BMI between the baseline and last examinations over 6.3 years were classified into loss, stable, or gain groups. During 11.4 years of follow-up after the last examination, 914 all-cause and 300 CVD deaths occurred. The hazard ratios (95% confidence intervals) of all-cause and CVD mortality were 0.70 (0.59–0.83) and 0.73 (0.54–0.98) for stable fitness, and 0.61 (0.51–0.73) and 0.58 (0.42–0.80) for fitness gain, respectively, compared with fitness loss in multivariable analyses including BMI change. Every 1-MET improvement was associated with 15% and 19% lower risk of all-cause and CVD mortality, respectively. BMI change was not associated with all-cause or CVD mortality after adjusting for possible confounders and fitness change. In the combined analyses, men who lost fitness had higher all-cause and CVD mortality risks regardless of BMI change. Conclusions—: Maintaining or improving fitness is associated with a lower risk of all-cause and CVD mortality in men. Preventing age-associated fitness loss is important for longevity regardless of BMI change.

The objective of this systematic review was to comprehensively study the criterion-related validity of the existing field-based fitness tests used in children and adolescents. The studies were scored according to the number of subjects, description of the study population and statistical analysis. Each study was classified as high, low and very low quality. Three levels of evidence were constructed: strong evidence, when consistent findings were observed in three or more high quality studies; moderate evidence, when consistent findings were observed in two high quality studies; and limited evidence when consistency of findings and/or the number of studies did not achieve the criteria for moderate. The results of 73 studies (50 of high quality) addressing the criterion-related validity of field-based fitness tests in children and adolescents indicate the following: that there is strong evidence indicating that the 20 m shuttle run test is a valid test to estimate cardiorespiratory fitness, that the hand-grip strength test is a valid measure of musculoskeletal fitness, that skin fold thickness and body mass index are good estimates of body composition, and that waist circumference is a valid measure to estimate central body fat. Moderate evidence was found that the 1-mile run/walk test is a valid test to estimate cardiorespiratory fitness. A large number of other field-based fitness tests presented limited evidence, mainly due to a limited number of studies (one for each test). The results of the present systematic review should be interpreted with caution due to the substantial lack of consistency in reporting and designing the existing validity studies.

Castro-Piñero, J, Ortega, FB, Artero, EG, Girela-Rejón, MJ, Mora, J, Sjöström, M, and Ruiz, JR. Assessing muscular strength in youth: usefulness of standing long jump as a general index of muscular fitness. J Strength Cond Res 24(7): 1810-1817, 2010-The purpose of the present study was to examine the association among different measures of lower body muscular strength in children, and the association between measures of lower- and upper-body muscular strength. The study population comprises 94 (45 girls) healthy Caucasian children aged 6-17 years. Children performed several lower body explosive muscular strength tests (i.e., standing long jump [SLJ], vertical jump, squat jump, and countermovement jump) and upper body muscular strength tests (i.e., throw basketball, push-ups, and isometric strength exercises). The association among the study tests was analyzed by multiple regression. The SLJ was strongly associated with other lower body muscular strength tests (R2 = 0.829-0.864), and with upper body muscular strength tests (R2 = 0.694-0.851). The SLJ test might be therefore considered a general index of muscular fitness in youth. The SLJ test is practical, time efficient, and low in cost and equipment requirements.