Background: Lower limb prosthesis users commonly exhibit gait asymmetry that may increase metabolic demand. Gait asymmetry, therefore, is frequently targeted in rehabilitation to improve walking efficiency. This review aimed to investigate whether interventions that improve gait asymmetry reduce metabolic demand in unilateral lower limb prosthesis users. Methods: A search of relevant English-language articles was conducted using PubMed and CINAHL, yielding a total of 1067 records. Following title, abstract, and full-text screening, 10 studies met eligibility requirements and were included in the qualitative synthesis. Data extraction focused on participant characteristics, gait asymmetry measures, metabolic outcomes, and intervention characteristics. Results: Four main intervention categories were identified: advanced prosthetic knees and ankles, prosthetic mass manipulation, feedback-based gait interventions, and exercise-based training. Across studies, changes in gait symmetry were not consistently associated with reductions in metabolic demand. Interventions targeting ankle function showed the most consistent reductions in metabolic demand, particularly during demanding walking tasks. In contrast, distal prosthetic mass addition consistently increased metabolic demand and worsened gait symmetry. Conclusion: Current evidence does not support a consistent or direct relationship between gait symmetry and metabolic demand in lower limb prosthesis users. Gait asymmetry may not be inherently metabolically disadvantageous and may represent an energetically optimal adaptation.

Background/Objectives: Foot arch status and muscular strength may influence balance and physical performance. However, evidence regarding their associations with unilateral balance performance, walking performance, and lower limb functional capacity in healthy young adults, particularly in Saudi Arabia, remains limited. This study investigated the associations of foot arch status and handgrip strength with these outcomes in healthy young Saudi adults. Methods: In this cross-sectional study, 104 healthy young adults (mean age: 21.1 ± 1.2 years; 52.9% female) underwent assessment of foot arch status using the sit-to-stand navicular drop test (SSNDT) and of muscular strength using a digital hand dynamometer. Unilateral balance performance was assessed using the single-leg stance test (SLST) under eyes open and eyes closed conditions. Walking performance and lower limb functional capacity were assessed using the 10 m walk test (10-MWT) and the 30 s chair stand test (30 s-CST), respectively. Generalised estimating equations and multivariable linear regression models were used to examine adjusted associations. Results: Greater SSNDT scores were independently associated with shorter SLST duration for both the right (β = −0.46, p = 0.003) and left feet (β = −0.25, p = 0.048). Greater handgrip strength was independently associated with longer SLST duration for the right foot only (β = 0.17, p = 0.019). Neither SSNDT score nor handgrip strength was independently associated with 10-MWT or 30 s-CST outcomes after adjustment. Athletic participants demonstrated superior balance and chair-stand performance, while the male sex was associated with longer SLST duration. Conclusions: Greater functional lowering of the medial longitudinal arch was independently associated with poorer unilateral balance performance, whereas handgrip strength demonstrated a more limited association. These findings suggest that foot arch behaviour is more strongly related to balance performance than to walking performance or lower limb functional capacity.