Both pre-sleep and post-exercise casein ingestion enhanced anaerobic performance in highly trained soccer players, with each timing method favoring different performance outcomes, but neither strategy demonstrated superiority over the other.
Key Findings
Results
Significant group-by-time interaction effects were found for countermovement jump and multiple RAST performance variables.
CMJ showed a significant group-by-time effect (F = 8.21, p = 0.002, η²p = 0.36)
RAST peak power showed a significant group-by-time effect (F = 6.94, p = 0.003, η²p = 0.32)
RAST mean power showed a significant group-by-time effect (F = 7.42, p = 0.002, η²p = 0.34)
RAST fatigue index showed a significant group-by-time effect (F = 5.87, p = 0.008, η²p = 0.28)
No significant group-by-time effect was observed for the Illinois Agility Test
Results
Pre-sleep casein ingestion (PSCIG) significantly improved countermovement jump height and RAST mean power compared to the control group.
PSCIG improved CMJ by Δ = +1.45 cm compared to control (p < 0.001, d = 2.04), indicating a large effect size
PSCIG improved RAST mean power by Δ = +125.14 W compared to control (p = 0.002, d = 1.55)
Participants consumed 30 g of micellar casein dissolved in 300 mL of water 30–60 min before bedtime
Performance was assessed before and 24 h after a standardized high-intensity resistance training session
Results
Post-exercise casein ingestion (PECIG) significantly enhanced RAST peak power, mean power, and fatigue index compared to the control group.
PECIG improved RAST peak power by Δ = +205.79 W compared to control (p = 0.001, d = 1.64)
PECIG improved RAST mean power by Δ = +128.43 W compared to control (p = 0.013, d = 1.24)
PECIG improved RAST fatigue index by Δ = +4.12 W/s compared to control (p = 0.010, d = 1.29)
Participants consumed 30 g of micellar casein dissolved in 300 mL of water immediately after exercise
Results
No statistically significant performance differences were observed between the pre-sleep and post-exercise casein ingestion timing conditions.
All comparisons between PSCIG and PECIG yielded p > 0.05
This finding applied across all performance measures including CMJ, IAT, and all RAST variables
The study involved 24 highly trained male soccer players (mean age: 20.6 ± 1.8 years) with n = 8 per group
The authors concluded that 'casein timing may be flexibly applied according to athletes' preferences and training contexts'
Results
The two casein timing conditions favored different performance outcomes, with pre-sleep intake more associated with CMJ improvement and post-exercise intake more associated with sprint power variables.
PSCIG demonstrated significant improvement in CMJ (Δ = +1.45 cm, d = 2.04) but not RAST peak power relative to control
PECIG demonstrated significant improvement in RAST peak power (Δ = +205.79 W, d = 1.64) and fatigue index but CMJ improvement was not reported as significant relative to control
Both PSCIG and PECIG showed significant improvements in RAST mean power compared to control
The study design was a randomized controlled trial using repeated-measures ANOVA with assessments at baseline and 24 h post-training
Methods
The study population consisted of 24 highly trained male soccer players who completed a standardized high-intensity resistance training protocol.
Mean participant age was 20.6 ± 1.8 years
Participants were randomly assigned to three groups of n = 8 each: PECIG, PSCIG, and control group (CG)
The protein dose used was 30 g of micellar casein dissolved in 300 mL of water
Performance tests included the Countermovement Jump (CMJ), Illinois Agility Test (IAT), and Running-based Anaerobic Sprint Test (RAST)