Short periods of support and relative rest do not meaningfully weaken the foot; prolonged immobilization without concurrent loading/rehab will.

Practical points

• Relative vs strict rest: Use relative rest (avoid provoking loads, allow pain‑free walking) rather than strict non–weight bearing whenever safely possible for most overuse problems and low‑risk stress injuries1, 4.
• Immobilization indications: Short-term immobilization (boot/cast 2–6 weeks) is appropriate for higher‑risk injuries (e.g., some stress fractures, significant ligament injuries), but plan early transition to protected loading1, 4.
• Deconditioning risk: Muscle atrophy and stiffness start within days–weeks of complete unloading; risk rises with longer immobilization and absence of strengthening/ROM work.
• Counteracting weakness: Add early pain‑limited ROM, intrinsic foot exercises, and progressive loading as symptoms allow to maintain strength and prevent chronic dysfunction1, 3, 4.
• Chronic pain context: In conditions like functional dystonia or chronic tendinopathy, prolonged guarding and underuse can perpetuate pain and disability; graded activity and rehab are central3, 5.

If you share the specific diagnosis/injury (e.g., stress fracture vs plantar fasciitis vs sprain), I can suggest a concrete rest/loading progression.