The 2v2 small-sided game format significantly reduced bout-to-bout heart rate variability compared to the 4v4 format (2.05% vs 2.85%, p=0.016), producing more stable cardiovascular responses.
RCT (n=40)
Open-label
Computer-generated block randomization stratified by team
No
Do physiological markers explain mean heart rate and bout-to-bout variability during 2v2 and 4v4 small-sided games in football players?
Submaximal warm-up heart rate recovery is associated with internal load during 4v4 small-sided games, while 2v2 formats produce more stable cardiovascular responses in amateur football players.
Effect estimate: Mean difference -0.80% (95% CI -1.44 to -0.16)
Absolute Event Rate: 2.05% vs 2.85%
p-value: p=0.016
Purpose Injury prevention in sport is increasingly recognized as a health priority, and monitoring internal load during routine training offers a pragmatic pathway to reduce overuse risk and support long-term athlete health. This study examined the extent to which three practical physiological markers (resting heart rate (HRrest), submaximal warm-up heart rate after 60-s recovery (HRR), and Yo-Yo IR1 HRmax) explain mean heart rate (HRmean) and bout-to-bout variability (CV%) during two commonly used small-sided game (SSG) formats (2v2 and 4v4) in football players. Methods Forty male amateur players completed HRrest, HRR, and Yo-Yo IR1 testing, followed by randomized, counterbalanced 2v2 and 4v4 SSG sessions (3 × 3-min bouts). HRmean and CV% were computed for each format. Associations were assessed using Pearson correlations and multiple linear regression. Results HRmean did not differ significantly between 2v2 and 4v4 (166.9 ± 5.1 vs. 165.3 ± 6.0 bpm; t₃₉ = 1.35, p = 0.19), whereas CV% was lower in 2v2 (2.05 ± 1.16%) than 4v4 (2.85 ± 1.43%; t₃₉ = −2.52, p = 0.016). In 2v2, no physiological marker correlated with HRmean (all p 0.30). In 4v4, HRR showed a moderate significant correlation with HRmean ( r = 0.36, p = 0.023). Regression models explained 3.1% (2v2) and 16.3% (4v4) of HRmean variance, with HRR emerging as the only significant predictor in 4v4 ( β = 0.20, p = 0.047). In a repeated-measures linear mixed-effects model (random intercept for player; fixed effect for format), the resting HR × format interaction for CV% was significant ( p = 0.016). Conclusion HRR is the sole physiological marker meaningfully associated with internal load during SSGs (and only in 4v4) while neither HRmean nor CV% in 2v2 is explained by the tested markers. More constrained formats (2v2) produce more stable cardiovascular responses. By identifying simple heart-rate–based indicators and game formats that yield more stable cardiovascular responses, these findings can inform scalable load-management strategies that help mitigate maladaptive overreaching and contribute to broader injury-prevention efforts in athletic populations, although future studies are necessary to confirm such hypothesis.
Kisilewicz et al. (Fri,) conducted a rct in Healthy amateur football players (n=40). 2v2 small-sided game (SSG) format vs. 4v4 small-sided game (SSG) format was evaluated on Bout-to-bout heart rate variability (CV%) (Mean difference -0.80%, 95% CI -1.44 to -0.16, p=0.016). The 2v2 small-sided game format significantly reduced bout-to-bout heart rate variability compared to the 4v4 format (2.05% vs 2.85%, p=0.016), producing more stable cardiovascular responses.