This semi-experimental study employed a pre-test–post-test design with a control group to investigate the effects of an eight-week sport metric training program on selected hematological indices and physical performance variables in adolescent male soccer players. Thirty participants (aged 13–16 years) were randomly assigned to either an experimental group (n = 15) or a control group (n = 15). The experimental group performed sport metric training three sessions per week for eight weeks, in addition to their routine soccer training. The control group continued only their standard soccer sessions. Hematological indices (hemoglobin, hematocrit, and blood viscosity) were measured from venous blood samples, while physical performance was assessed using the 36-meter sprint test (for speed) and the Illinois agility test. Following the intervention, the experimental group showed significant improvements compared to the control group. Hemoglobin and hematocrit levels increased meaningfully (P ≤ 0.05), suggesting enhanced oxygen-carrying capacity of the blood. Blood viscosity decreased significantly (P ≤ 0.05), which may indicate improved blood flow and reduced circulatory resistance. In terms of physical performance, the experimental group exhibited substantial reductions in sprint time (36-meter sprint) and agility time (Illinois test), both reaching statistical significance (P ≤ 0.05) with large effect sizes. In conclusion, eight weeks of sport metric training produced favorable changes in hematological profiles and marked enhancements in speed and agility performance among adolescent male soccer players. The findings suggest that targeted, sport-specific training programs can serve as a valuable supplement to routine soccer training during adolescence, supporting both physiological development and on-field performance.
Fereidani et al. (Sun,) studied this question.
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