Sleep, Stress, and Recovery as Predictors of Injury Risk in Soccer Players: A Systematic Review

Introduction. Sleep is an essential component in the recovery, performance, and injury prevention processes of soccer players. Associated psychological variables, such as the balance between stress and recovery, have been less explored, despite their potential influence on rest and injury vulnerability. This study aims to examine the relationship between sleep quality, quantity, and chronotype and injury risk in soccer players, also incorporating the modulating role of stress and recovery. Method. A PRISMA systematic review was conducted using searches in ScienceDirect, PubMed, Ovid, EBSCO, MDPI, Springer Nature Link, SPORTDiscuss (full text), and Dialnet. Original studies and reviews on sleep and its relationship with sports injuries in soccer players or comparable athletic populations were included. Eighteen studies were selected that addressed sleep indicators (quality, quantity, chronotype), injury incidence, and, to a lesser extent, measures of stress and recovery using instruments such as the RESTQ-Sport or wellness questionnaires. Results. There is evidence of an association between poor sleep quality or quantity and an increased risk of injury or illness. Chronotype is an emerging variable of interest, although still insufficiently researched. Regarding stress and recovery, direct evidence is limited, although studies that address this issue show that an imbalance between these two dimensions negatively impacts sleep quality and increases susceptibility to injury. Conclusions: Sleep and the stress-recovery balance are key and interdependent factors in the risk of injury in soccer players. Future research should consider including these variables to further understand the mechanisms underlying the injury process and optimize prevention and recovery strategies.