The peripheral neuromuscular continuum: Histological remodeling induced by physical training

Physical exercise induces structural adaptations that extend far beyond skeletal muscle, affecting virtually every component of the peripheral neuromuscular system. Although remodeling of peripheral nerves and the neuromuscular junction (NMJ) has been increasingly documented, current knowledge remains fragmented because researchers have largely studied these structures in isolation rather than as components of a continuous biological system. This review critically synthesizes evidence on histological, ultrastructural, and cellular adaptations induced by physical exercise throughout the peripheral neuromuscular system. It emphasizes remodeling of peripheral nerve fibers, Schwann cells, the blood-nerve barrier, the extracellular matrix, and the NMJ, as well as the cellular and molecular mechanisms that coordinate these responses. The review also examines how aging affects peripheral nerve and NMJ integrity, discusses current methodological limitations, and proposes an integrative framework that interprets exercise-induced adaptation as coordinated remodeling across the peripheral neuromuscular continuum. Collectively, the available evidence indicates that regular physical exercise preserves structural integrity throughout the neuromuscular system, providing a broader biological basis for its protective effects than skeletal muscle adaptations alone.