trunk via multiple frequencies of 50 kHz. The system’s eight electrodes are in the form of footpads, and each footpad is divided in half so that the anterior and posterior portions form two separate electrodes. Impedance and body mass are automatically measured, and the subject’s height and age are manually entered into the system. Percent body fat measured using the Tanita BC-418 has been shown to correlate highly with the reference measure of dual-energy X-ray absorptiometry [34]. The participants were asked to observe the following before body composition measurement, as described by Rech et al. [35]: not to perform any physical exercises for 12 hours before testing; not to eat or drink anything for 4 hours before the evaluation; to urinate within 30 minutes of the evaluation; not to take any diuretics during the 7 days prior to testing; and not to consume alcohol for 48 hours before testing.
Training Programme
Outdoor training was performed three times per week over 12 weeks. The participants in the intervention groups performed a 12-week training programme, whereas the participants in CON continued normal everyday activities during the study period. All training sessions were supervised by trained exercise instructors who finished bachelor or master study of kinesiology. All instructors were familiar with both recreational soccer and running training methods and well educated to delivery practical lessons. One instructor per match was delegated to supervise training, perform duties of referee and careful records each participant’s workout performance.
Soccer sessions consisted of 60 minutes of ordinary five-a-side, six-a-side or seven-a-side matches on a 20–45 m wide and 45–60 m long plastic grass pitch, with adjustments of the pitch size to 80–100 m2 per players [36, 37]. All games were played without consideration for the player’s playing position. There were no modifications to the general rules of soccer. Each training session began with a 10-minute low-intensity warm-up period, following which the participants completed four playing periods each lasting 10 minutes separated by 2-minute recovery periods. The warm-up consisted of 5 minutes of light running and passing the ball between players, 3 minutes of dynamic and static stretching and another 2 minutes with 2–4 acceleration runs. The heart rate of the participants was measured continuously during