[Show abstract][Hide abstract] ABSTRACT: We analysed the secular trends in health-related physical fitness in Spanish adolescents between 2001-2002 and 2006-2007. Two representative population studies were conducted 5 years apart in adolescents (12.5-17.5 years) from Zaragoza (Spain) that participated in the AVENA study in 2001-2002 and in the HELENA-CSS study in 2006-2007. Both studies used the same tests to assess physical fitness: the handgrip strength, bent arm hang, standing broad jump, 4×10m shuttle run and 20m shuttle run tests. Performance in 4×10m shuttle run and 20m shuttle run tests was higher in 2006-2007 (Cohen's d ranging from 0.2 to 0.4, p<0.05), whereas performance in handgrip strength and standing broad jump tests was lower in 2006-2007 (Cohen's d ranging from 0.3 to 1.1, p<0.001). Adjustment for age, pubertal status, fat mass, fat free mass and parental education did not alter the results. The odds ratio (OR) of meeting the FITNESSGRAM Standards for healthy cardiorespiratory fitness was higher in 2006-2007 in both boys (OR, 95% CI: 2.123, 1.157-3.908) and girls (OR, 95% CI: 2.420, 1.377-4.255). The results indicate that levels of both speed/agility and cardiorespiratory fitness were higher in 2006-2007 than in 2001-2002, whereas muscular strength components were lower in 2006-2007.