Resumen de Validity and reliability of field test to assess physical fitness related to health in adults. The adult-fit project
Physical fitness is considered a powerful health marker in different populations (i.e., preschool, childhood, adolescence, adults, and older adults). Epidemiological studies have demonstrated an inverse association between cardiorespiratory and muscular fitness, with morbidity and all-cause mortality. Consequently, physical fitness assessment is considered an important prevention and diagnosis tool. Physical fitness can be objectively and accurately measured through laboratory tests. However, due to their high cost, the necessity of sophisticated instruments, qualified technicians, and time constraints, their use is limited in population-based studies. Field-based physical fitness tests provide a reasonable alternative since they are easy to administer, involve minimal equipment, are low in cost, and a large number of participants can be evaluated in a relatively short period of time and simultaneously. Valid, reliable, feasible, safe, and responsiveness are characteristics that need to be assured for any measurement tool. Longitudinal studies have recently contributed to the existing health-related fitness batteries archiving those characteristics in children and adolescents (The ALPHA Study), and preschool children (The PREFIT Study). However, researchers, clinicians, and sport practitioners do not have enough information about which field-based physical fitness tests are more reliable, valid, and informative from the health point of view to be implemented in adults.
Therefore, the general aim of this International Doctoral Thesis was: to propose a battery of field-based tests to assess physical fitness related to health in adults based on scientific evidence, valid (i.e. predictive validity and criterion-related validity) and reliable, depending on sex, age, and physical activity level: The ADULT-FIT project [Plan nacional I D i 2017-2020, (ref.: DEP2017-88043-R)].
Likewise, the specific aims were: (i) to comprehensively analyze the predictive validity of the existing motor fitness and flexibility tests in relation to several health outcomes in adults and older adults (study I); (ii) to comprehensively study the criterion-related validity of the existing field-based physical fitness tests used in adults aged 18-64 years (study II), and to identify studies evaluating the criterion-related validity of existing field-based methods and equations for body composition estimation used in adults aged 18-64 years (study III); (iii) to systematically review studies conducted to examine the reliability of field-based physical fitness tests used in adults aged 18-64 years (study IV); (iv) to analyze the criterion-related validity and the reliability of the 2-km walk test and the 20-m SRT for evaluating cardiorespiratory fitness in the adult population, according to sex, age, and physical activity level (study V), and to analyze the criterion-related validity and reliability of the SLJ test to assess the lower-body explosive muscular fitness in adults, according to sex, age, and physical activity level (study VI).
The main results showed that there is strong evidence indicating that: (i) slower gait speed, impaired balance, and worse TUG performance are good indicators of health outcomes in both adults and older adults; and limited evidence about the predictive validity of flexibility tests exists (study I). (ii) To assess cardiorespiratory fitness, the 20-m shuttle run test (using Leger?s equation), 1.5-mile run/walk test, 12-minute run/walk test, 6-minute walk test, YMCA step test, and the 2-km walk test (using Oja?s equation) are valid; to assess muscular fitness, the handgrip test (using the TKK dynamometer), and the Biering?Sørensen test are valid; to assess flexibility, the sit-and-reach test (and its different versions), and that the toe-to-touch tests are not valid; limited evidence about the criterion-related validity of motor fitness exists (study II). (iii) The field-based methods, waist circumference, body adiposity index, and body mass index are valid indicators of body adiposity in adult population; classical equations, such as Durnin/Womersley equation, Jackson/Pollock equation, Jackson, Pollock and Ward equation, and estimation equations implying skinfolds, alone or combined with circumferences, are most valid to estimate total body fat mass or body fat percentage in adult population (study III). (iv) To assess cardiorespiratory fitness, the 20-m shuttle run test, the step tests and the 6-minute walk test are reliable; to assess musculoskeletal fitness, the handgrip test (using a JAMAR dynamometer), back-leg test, Biering-Sørensen (and its modified versions), trunk flexion sustained, 5-reps sit-to-stand, bilateral side and prone bridge, the sit-and-reach (and its modified versions), and the toe-to-touch test are reliable; to assess motor fitness, the T-test (and its modified version) is reliable, and the single-leg stand test (and its modified versions) is not reliable (study IV). (v) The 2-km walk test (using) and the 20-m shuttle run test, as well as their corresponding Oja?s and Leger?s equations, are valid and reliable for estimating cardiorespiratory fitness in adults aged 18-64 years. However, the 20-m shuttle run test obtained slightly greater criterion-related validity and reliability, regardless of sex, age, and physical activity level (study V). (vi) The standing long jump test may be a valid tool to assess the lower-body explosive muscular fitness in the adult population, independently of age, and physical activity levels. The standing long jump test may be used when controlling the possible learning effect to provide reliability (study VI).
This International Doctoral Thesis provides evidence to propose a battery of field-based tests to assess physical fitness related to health in adults based on valid and reliable scientific evidence, depending on sex, age, and physical activity levels. Future methodological studies are still necessary to establish the validity and/or reliability of those field-based physical fitness tests identified in systematic reviews having insufficient or strong evidence that have not been developed in this International Doctoral Thesis, as well as the feasibility and safety of those field-based physical fitness test identified (in the systematic reviews) as valid and reliable, and the responsiveness of those field-based physical fitness test identified as valid, reliable, feasible and safe, in adult population.
