HIIT and small-sided games improve fitness comparably in youth soccer
Sport-specific games are an effective conditioning alternative to running intervals
Participants
n=232 young soccer players (mean age 16.2 ± 1.6 years) across nine studies comparing running-based HIIT with small-sided games (SSG) or other protocols (technical/soccer-specific training, high-volume endurance training).
Key Findings
HIIT and SSG produced similar positive effects on most endurance parameters: peak oxygen uptake, maximal running performance in incremental tests (Vmax / maximal aerobic speed), shuttle runs, time-trials, running economy and running velocity at the lactate threshold.
HIIT induced a moderate improvement in soccer-related tests (technical exercises with the ball, total distance covered, number of sprints, involvements with the ball).
Neuromuscular parameters were largely unaffected by either HIIT or SSG.
Authors' conclusion: HIIT and SSG have equally beneficial effects on endurance and soccer-specific performance in youth players, with little influence on neuromuscular performance.
Practical Application
In a meta-analysis of nine studies (n=232 youth soccer players, mean age 16.2), running-based HIIT and small-sided games gave similar gains in VO2peak, maximal aerobic speed, running economy and lactate-threshold speed — either can carry the conditioning load; neither develops neuromuscular qualities.
Inference, not tested: pick SSG vs running intervals by what else you want (game context vs precise dose control).
Limitations
Youth-soccer cohorts only; nine studies.
SSG load is harder to standardise than prescribed intervals.
How this entry was checked and changed
Content correction 2026-09-27
Removed "better skill transfer" for SSG: the abstract reports HIIT and SSG as equally beneficial for soccer-specific performance (and a moderate HIIT effect on soccer tests).
Added n=232 in nine studies, the list of endurance outcomes, and the null neuromuscular finding; Sport "conditioning" -> "running"; SSG-vs-intervals choice labelled as inference.