Foam rollers deliver self-myofascial release to relieve muscle tightness, soreness, and trigger points while boosting flexibility, circulation, and recovery. Smooth rollers (soft foam, 6-inch diameter) suit beginners for gentle quads/IT band rolling; textured/grid rollers (ridged surfaces) target deep knots in calves, back, glutes like a massage therapist; short rollers (12-24 inches) focus arms/legs; vibrating models add oscillation for faster relief. Technique: position roller under target (e.g., thighs), support with arms, roll slowly 20-30 seconds per tender spot, hold "hot spots" breathing deeply—pre-workout warms, post-workout recovers. Avoid joints/bones; enhances range 10-20%.