Understanding Your Fascia as a Runner Fascia is densely packed collagen fibers that wrap around individual internal parts, allowing them to slide easily with your movements. David Jaewon Oh You’ve got this injury you just can’t shake. You take time off. You ice and stretch and do all the right things but you’re still limping home. You spend too much time trying to articulate your particular brand of hurt to those loved ones who still put up with you. You follow referrals to physical therapists and massage therapists and you’d go to an aromatherapist if it’d help you run again, but nothing does. You diagnose yourself on WebMD: You’re structurally flawed, and recovery is impossible.