Physical and physiological effects of game based and running based High Intensity Interval Training with equal volume: a 4 week quasi experimental study

Purpose High-intensity interval training (HIIT) is a well-established exercise method, known for its effectiveness in improving various aspects of fitness. This study aimed to assess the effect of five distinct HIIT protocols, including Small Sided Games Long Interval (SSG(LI)), Long Interval (LI), Small Sided Games Short Interval (SSG(SI)), Short Interval (SI), and Sprint Interval Training (SIT), on aerobic, agility, vertical jump performance, sprinting abilities, and heart rate variability (HRV) in amateur soccer players. Methods Forty participants were randomly assigned to one of five training groups, and a four-week training intervention was conducted. The pre- and post-training assessments included measurements of maximal oxygen uptake (VO 2max ), anaerobic power, reactive agility, vertical jump height, sprint times, and HRV parameters. Results Results showed that all training groups demonstrated significant improvements in VO 2max . Reactive agility performance significantly improved in the SSG(LI), SSG(SI), SI, and SIT groups, whereas no significant changes were observed in sprint times or anaerobic power. Leg-specific vertical jump performance showed significant improvements in the right and left legs. HRV parameters showed variable responses to the training protocols. Significant main effects of Time were observed for LF ( F = 3.592, p = 0.016, ηp 2 = 0.310) and low frequency/high frequency (LF/HF) ratio ( F = 5.699, p = 0.023, ηp 2 = 0.151), indicating overall changes across participants from pre- to post-training. Conclusions These findings underscore the adaptability of HIIT and its association with improvements in aerobic endurance, agility, and leg-specific vertical jumping capabilities across different training forms, while acknowledging that causation cannot be definitively established due to the quasi-experimental design.