This randomized controlled trial aimed to investigate the effects of casein supplementation timing on post-exercise recovery and exercise performance in trained football players. Participants were allocated into three groups: pre-sleep casein ingestion, post-exercise casein ingestion, and control. The study compared the effects of pre-sleep and post-exercise casein intake on anaerobic performance, agility, and recovery markers following a standardized high-intensity resistance training session.
Casein is a slow-digesting protein commonly used as a dietary supplement to promote muscle recovery and adaptation. Although casein is traditionally consumed before sleep to maximize overnight muscle protein synthesis, limited evidence exists regarding the optimal timing of casein ingestion relative to exercise. This study employed a randomized controlled experimental design to compare the effects of pre-sleep versus post-exercise casein supplementation on recovery and performance outcomes in trained football players. Twenty-four male participants were stratified by playing position (defender, midfielder, forward) and randomized into three groups: pre-sleep casein ingestion group (PSCIG), post-exercise casein ingestion group (PECIG), and control group (CG). All participants first completed a familiarization session and pre-test assessments, including the countermovement jump (CMJ), Illinois Agility Test, and Running-based Anaerobic Sprint Test (RAST). After the pre-tests, all players performed a standardized high-intensity resistance training protocol designed to induce muscle fatigue. Participants in the PECIG consumed 30 g of micellar casein dissolved in 300 mL of water within 10-15 minutes post-exercise, while participants in the PSCIG consumed the same supplement 30-60 minutes before sleep. The control group did not receive any supplementation. Twenty-four ± 1 hours after the resistance training, post-tests were conducted using the same protocols as the pre-tests. The primary aim of this study was to determine whether casein supplementation timing (pre-sleep vs. post-exercise) differentially influences recovery and subsequent anaerobic performance. Outcomes from this trial may provide practical recommendations for athletes and coaches regarding optimal protein supplementation strategies to enhance recovery and performance.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
24
Participants consumed 30 g of micellar casein powder dissolved in 300 mL of water. Supplement timing varied by group: Post-Exercise Casein Ingestion Group (PECIG): Taken 10-15 minutes after completing the standardized high-intensity resistance training session. Pre-Sleep Casein Ingestion Group (PSCIG): Taken 30-60 minutes before bedtime on the same day as the training session. The control group received no supplementation. All supplements were prepared and monitored by the research team to ensure dosage accuracy and participant compliance.
Gumushane University, Faculty of Sport Sciences
Gümüşhane, Gümüşhane Province, Turkey (Türkiye)
Peak Power (RAST Test)
Peak power will be calculated using body mass and sprint times obtained during the RAST test to assess maximal anaerobic performance. Measurements will be taken at baseline and 24 hours post-training.
Time frame: Change from baseline (pre-test) to 24 hours post-training (post-test)
Mean Power (RAST Test)
Mean power will be calculated from total sprint time and body mass during the Running-based Anaerobic Sprint Test (RAST) to evaluate anaerobic endurance performance. Measurements will be collected pre- and 24 hours post-training.
Time frame: Change from baseline (pre-test) to 24 hours post-training (post-test)
Fatigue Index (RAST Test)
Fatigue index will be calculated using the difference between the highest and lowest sprint times divided by the total sprint time during the RAST test. It reflects fatigue and recovery capacity. Measurements will be collected pre- and 24 hours post-training.
Time frame: Change from baseline (pre-test) to 24 hours post-training (post-test)
Countermovement Jump (CMJ) Height
CMJ height will be measured using a validated jump mat system to assess lower-limb explosive power. Measurements will be collected pre- and 24 hours post-training under standardized conditions.
Time frame: Change from baseline (pre-test) to 24 hours post-training (post-test)
Illinois Agility Test Time
Agility performance will be assessed using the Illinois Agility Test to evaluate change of direction speed and overall agility. Measurements will be collected pre- and 24 hours post-training under standardized environmental conditions.
Time frame: Change from baseline (pre-test) to 24 hours post-training (post-test)
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.