Background: The aim of the study was to compare the effects of high-intensity intermittent training (HIIT) versus small-sided games (SSG) in soccer on both the physiological responses and the mood state of players.
Methods: Sixteen professional soccer players took part in the study (age: 24.1±0.9 years). Testing of players was conducted on separate days in a randomized and counter-balanced order (each training session: 28 minutes: 4x4 minutes work with 3 minutes of passive recovery in-between). Effort: HIIT: intermittent 15-s runs at 110% maximal aerobic speed with 15 seconds of passive recovery in-between. SSG: 4 versus 4 players on a 25x35 meter pitch size with full-involvement play. Psychological responses before and after each training-session were assessed using the profile of mood-state (POMS: Tension, Depression, Anger, Vigor, Fatigue, and Confusion). The players' heart rate (HR) was continuously measured, whereas ratings of perceived exertion (RPE) and blood lactate concentration ([La]) were collected ~3-min after each training-session.
Results: HIIT and SSG showed no significant difference in HR, RPE and [La] responses. The HIIT compared with SSG resulted in: an increased total mood disturbance (P<0.001), tension (P<0.05), fatigue (P<0.01) and a decreased vigor (P<0.001).
Conclusions: Both HIIT and SSG sessions induced similar physiological responses, in contrast, HIIT produced a mood disturbance while SSG ensured mood balance. Practitioners could choose between these two exercises according to the objective of their training, keeping in mind the mood-related advantages of the SSG shown in the present study.