Lifting with improper form reduces effectiveness and increases injury risk, but personal trainers are expensive.
Build an app that uses phone camera + AI to analyze key lifts (squats, deadlifts, etc.) and provide real-time form cues. Focus on the most common mistakes from scientific literature.
Freemium model - basic analysis free, detailed breakdowns and programs as subscription.
Start with 2-3 fundamental lifts before expanding the exercise library.
Risk: Hard to achieve medical-grade accuracy, and potential liability if users get injured.