2.3.1. Health-Related Physical Fitness (HRPF)

HRPF was measured based on the FITNESSGRAM [32] and EURO FIT [33] test batteries, both of which have demonstrated good reliability and validity for use in adults, as well as adolescents [34,35]. The measurements of HRPF included cardiovascular endurance, muscular strength, muscular endurance, flexibility, and body composition, and the entire testing process was conducted under the supervision of well-trained assistants. (1) Cardiovascular endurance was evaluated using a 15 m progressive aerobic cardiovascular endurance run (15 m PACER) and was performed once. The 15 m PACER is an alternative way to measure cardiovascular endurance and an easy-to-measure for a limited gymnasium, as evidence suggests that it provides a similar profile of the adolescent’s cardiovascular endurance compared to the 20 m PACER [36]. (2) Muscular endurance was evaluated through a 1 min sit-up test and performed once. (3) Muscular strength was evaluated using a hand-grip strength dynamometer with accuracy to the nearest 0.1 kg (Takei Scientific Instruments Co. Ltd., T.K.K. 5101 Grip D, Tokyo, Japan). The measurements, left-hand and right-hand grip strength, were taken two times and the average score was calculated. (4) Flexibility was measured using an Acuflex I modified flexibility sit-and-reach test box (PSYMTEC, Madrid, Spain). As muscular strength measurements, the sit-and-reach test was also measured two times for the left and the right leg, and the average scores were calculated from the measured test scores. (5) Body composition was measured by biometric impedance analysis (BIA, Tanita, TBF-543, Japan), and height (SECA S-208M, the United States) and weight (TANITA, BC-581, Japan) were measured directly. Additionally, body mass index (BMI) was calculated by dividing the weight (kg) by the square of the height (m²).