Presleep Casein Protein Ingestion: Acceleration of Functional Recovery in Professional Soccer Players.

Abstract

To examine whether consuming casein protein (CP) before sleep would enhance recovery after a nighttime soccer match in professional players. In a randomized, crossover design, 10 professional soccer players from the reserve squad of a team in the highest tier of English soccer consumed 40g of CP or 40g of carbohydrates (CON) 30min presleep after a soccer match (kick off: 7 PM). To assess recovery, countermovement-jump height, reactive strength index, muscle soreness, and the adapted Brief Assessment of Mood (BAM+) Questionnaire were measured before and 12, 36, and 60h after each match. Dietary intake across the testing period was also recorded. There were unclear differences in external load in the matches and dietary intake between CON and CP. Casein protein had a most likely and likely beneficial effect on countermovement-jump recovery at 12 and 36h postmatch (CP -1.6; ±1.2% vs CON -6.6; ±1.7%; -4.1; ±2.3% vs -0.4; ±1.1%, respectively). Reactive strength index recovery was most likely enhanced with CP at 12 and 36h postmatch, and muscle soreness, as measured with a visual analog scale (in millimeters), was most likely greater in CON versus CP at 12h postmatch (72; ±17 vs 42; ±20mm). BAM+ was possibly lower in CON at 36h postmatch but unaffected at other time points. Presleep CP accelerates functional recovery in professional soccer players and, therefore, provides a practical means of attenuating performance deficits in the days after a match.