what happen when squat?

From rep one, every lower-body joint is loading at once. Knees, hips, ankles, with quads, glutes and hamstrings firing together through a full range. Past 25 reps the burn arrives and you’re into strength endurance, the zone between lifting and cardio that most programmes never touch. That’s the zone your connective tissue cares about. Tendons, ligaments and cartilage build slower than muscle, and what builds them is blood pushed through them again and again. High reps do that.