Recreational soccer training improves heart-rate variability indices and physical performance in untrained healthy adolescent

The aim of this study was to evaluate the effects of soccer training on short-term heart-rate variability, blood pressure, and physical fitness in untrained healthy adolescents. Twenty-two adolescent boys took part in this study: 11 boys were randomly assigned to participate in an 8-week soccer training and 11 boys served as a control group. Soccer exhibited significant increases in high-frequency power (difference 52.9%, P = 0.03, effect size:...