Comparison of the Physical, Physiological, and Psychological Responses of the High-Intensity Interval (HIIT) and Small-Sided Games (SSG) Training Programs in Young Elite Soccer Players
Question
Do HIIT running and small-sided games produce different physical, physiological, and psychological responses in young elite soccer players?
Summary
In young elite male soccer players, 6 weeks of added HIIT running or small-sided games produced similar aerobic-fitness gains, but small-sided games were much more enjoyable and HIIT worsened mood markers. The study is most useful for comparing engagement and affect when the physiological training load is broadly similar.
Methodology
- Young elite male soccer players from the same national football league team, excluding goalkeepers.
- 24 participants.
- Outdoor shuttle-style running.
- Work intervals: 15 seconds.
- Recovery: 15 seconds passive recovery.
- Intensity: Individualized distance corresponding to 110% maximal aerobic speed.
- 25 minutes added after standardized warm-up.
- 2 sessions per week.
- 6 weeks.
- Randomized two-group training study
- PACES enjoyment, Mood, Maximal aerobic speed, and Jump performance were tracked.
Outcomes
Enjoyment
HIIT was much less enjoyable than small-sided games.
PACES HIIT 59.30 +/- 7.17 vs SSG 88.70 +/- 6.99, p<0.001, eta2=4.44.
Mood
HIIT increased total mood disturbance and decreased vigour, while SSG did not show the same deterioration.
Vigour group p<0.001, eta2=0.69; interaction p<0.001, eta2=0.70. TMD group p<0.01, time p<0.05, interaction p<0.05.
Aerobic fitness
Both groups improved maximal aerobic speed with no between-group difference.
Time p<0.001, eta2=0.81; group p=0.30; interaction p=0.98.
Jump power
The 5-jump test did not significantly change.
Group p=0.85; time p=0.20; interaction p=0.13.
Agility
Overall modified agility t-test effects were not significant, although SSG improved within group.
Group p=0.35; time p=0.14; interaction p=0.41.
Recovery
Training load, total quality of recovery, and Hooper well-being indices were not meaningfully different between groups.
No significant group difference in Hooper index, p>0.05; training load rose over time in both groups.
Insights
- For athletes, game-like HIIT can produce similar aerobic gains with better enjoyment than off-ball running intervals.
- A 15-second work and 15-second passive-rest format at 110% maximal aerobic speed is a clear running HIIT comparator, but it may carry poorer affective responses.
- Enjoyment and mood outcomes are important when judging whether a protocol is likely to be repeated, even when performance outcomes are similar.
Limitations
- Small sample of 24 elite youth male soccer players from one team.
- Athlete-only sample limits translation to general fitness users.
- Environmental conditions and competitive-season timing may have influenced results.
- The intervention was short and no longer-term adherence follow-up was reported.
- No non-exercise control group was included.
Safety
- No explicit adverse-event table was reported.
- Participants with disease, medical treatment, or injury were excluded.
- The authors described low well-being variability as indicating tolerability.