Build a progressive exercise program that adjusts to a real injury history instead of a generic template

You are drafting a phased exercise program for one specific person, not a generic "beginner workout plan" pulled from a template. The program has to account for what they can actually do this week, not an idealized version of them.

CURRENT ACTIVITY LEVEL
Walks about 20 minutes most days, hasn't done structured strength training in over a year.

GOAL
Build enough lower-body strength to comfortably hike a moderate trail in 10 weeks.

TIME AND EQUIPMENT AVAILABLE
3 sessions of 40 minutes a week, home setup with a set of dumbbells and a resistance band, no gym access.

RELEVANT INJURY OR HEALTH HISTORY
Mild recurring lower back tightness, no diagnosed disc issue; twisted right ankle badly two years ago, occasionally feels unstable on uneven ground.

WEEKS TO PLAN
10 weeks

STRUCTURE RULES
Build the program in phases, not a flat repeating week — each phase should progress load, duration, or complexity by a small, named increment from the phase before it, and state explicitly what triggers moving to the next phase (for example, completing a phase without pain above a stated threshold, not just "after two weeks"). For every phase, name at least one modification for the injury or health history given, rather than writing the ideal version of an exercise and leaving the person to guess how to adapt it themselves. Build in an explicit checkpoint after every phase asking the person to rate soreness, pain location, and energy, and state what changes if the answer is worse than the phase before (regress the load, extend the phase, or stop and check with a clinician) rather than assuming progress is always safe to continue. Do not invent a specific injury mechanism, rehab timeline, or clinical claim about what is or is not safe for the named condition — where the injury history matters to a specific exercise choice, say so and flag it as something to confirm with a physical therapist or physician rather than asserting it yourself.

MANDATORY DISCLAIMER
Open the program with a short, plain-language note that this is a general fitness planning aid, not a medical or physical therapy assessment, and that anyone with an existing injury, diagnosed condition, or recent surgery should have this reviewed by a physician or physical therapist before starting, especially the phases involving load progression.

OUTPUT FORMAT
1. The disclaimer, first, in plain language.
2. A phase-by-phase table: phase name, duration, sessions per week, key exercises with the stated modification, and the checkpoint question.
3. A one-paragraph note on what would make this plan stop being appropriate (a new symptom, a missed checkpoint, worsening pain) and what to do instead.