Cross-Education of Strength: From Theory to Practice in Contemporary Sports Rehabilitation—A Narrative Review and Clinical Implications

Background: Cross-education (CE) of strength refers to strength gains in the untrained limb after unilateral resistance training. Despite the long-standing recognition of this phenomenon, its potential implications in clinical and rehabilitation settings have only been studied extensively in recent decades. Main body: The implementation of unilateral resistance training in early-stage sports rehabilitation remains underrated, likely due to the lack of consensus on evidence-based guidelines. Thus, this narrative review provides a current overview of the CE of strength, analyzes its practical implications for sports rehabilitation, and examines the training modalities and parameters that should be modulated to optimize CE adaptations, thereby supporting early intervention against post-injury neuromuscular decline. Conclusions: Unilateral resistance training in the healthy limb appears to represent a cost-effective and accessible rehabilitation strategy for athletes who are unable to work on their injured limb from the early stages of rehabilitation. This strategy may ensure the maintenance of muscle strength levels in the trained limb while minimizing neuromuscular decline in the injured and immobilized limb. CE of strength may be implemented as an addition to traditional early-stage rehabilitation strategies, such as pain, swelling, and inflammation reduction, the progressive restoration of joint range of motion, and the progressive strength training in sports injury rehabilitation. Further research is required to make definitive recommendations.