Sand-Based Locomotion and Exercise: Biomechanical, Neuromuscular, Balance, Proprioception, and Rehabilitation Perspectives—A Narrative Review

Sand is a deformable and mechanically variable substrate that alters foot–surface interaction, gait mechanics, energetic cost, and neuromuscular demands. This narrative review critically synthesizes evidence on sand-based locomotion and exercise, with emphasis on balance, sensorimotor control, proprioception, and rehabilitation. PubMed, Scopus, and Web of Science were searched through 12 August 2026. English-language peer-reviewed studies of walking, running, or exercise on sand were considered, together with the contextual literature on balance and sensorimotor control. Two authors independently screened records and resolved disagreements by consensus. Approximately 38 publications formed the core sand-specific evidence base. The review was prepared with reference to Scale for the Assessment of Narrative Review Articles criteria. Acute studies consistently show that sand modifies gait mechanics, foot sinking, propulsion, and energy expenditure, while neuromuscular responses are heterogeneous across muscles, populations, and substrate conditions. Repeated-exposure studies report improvements in selected balance, performance, and functional outcomes, but the effect of the substrate is not always separable from the effect of exercise itself. Direct measures of proprioceptive acuity are uncommon; therefore, improvements in functional balance should not be interpreted as direct evidence of enhanced proprioception. Sand characteristics, including moisture, compaction, depth, and sinking, further influence mechanical demand and study comparability. The strongest evidence supports acute biomechanical and physiological effects of sand-based locomotion. Evidence for persistent proprioceptive improvement and diagnosis-specific therapeutic efficacy remains limited. Sand is best regarded as a modifiable environmental constraint that may complement conventional training and rehabilitation, pending better-standardized controlled studies.