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ABSTRACT
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 (R^sup 2^ = 0.829-0.864), and with upper body muscular strength tests (R^sup 2^ = 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.
KEY WOKDS fitness, field tests, children, adolescents
INTRODUCTION
The role of muscular strength as a marker of health in adults (40) and in youth is well known (4,15,39). Longitudinal studies revealed that decreases in muscular strength from childhood to adolescence are negatively associated with changes in overall adiposity (23,47) and that levels of muscular strength during adolescence seems to track to adulthood (24,29). Taken together, these findings highlight the importance of assessing muscular strength from early ages (37).
Several dimensions of muscular strength (i.e., maximal isometric strength, muscular endurance, and explosive muscular strength) are included in the most important fitness test batteries for youth (3,7,10-12,41,46). Many tests were developed to assess these dimensions, but the information provided by each test is specific about one part of the body and one type of strength (e.g., the push-ups test assesses upper body muscular endurance, and the vertical jump (VJ) test assesses lower body explosive muscular strength). Whether field-based tests assessing upper body muscular strength are associated with that assessing lower body muscular strength in youth remains to be elucidated. We have recently performed a systematic review about criterionrelated validity of...