In order to validate the physical fitness tests and anthropometric parameters of the AVENA multicenter study, a pilot study was carried out in 101 adolescents (48 girls and 53 boys) aged 15-18 years. Body composition was established by the sum of skinfolds (SS) in millimeters (biceps, triceps, subscapular, suprailiac) and body mass index (BMI, weight/height(2)) in kilograms per meters squared. Physical fitness was measured by means of the Course-Navette test (CNT). Median BMI was 22.5 and 20.3 for boys and girls, respectively, while their median SS was 32.5 and 47.47, respectively. The median CNT score was 8 and 4 for boys and girls, respectively. For both groups, there was a negative correlation between body fat and physical fitness, the correlation being stronger in boys (r=-0.65) than in girls (r=-0.43; p<0.01). SS appears to be more suitable than BMI in expressing body composition in this context. The CNT indicates physical fitness in adolescents satisfactorily. This subject will be explored in more depth during the final phase of the multicenter study.