 Doctors say, look, there's little evidence that stretching prevents injuries and that functional and strength training and cardiovascular exercise offer wider benefits for most people than just stretching alone. Stretching can increase your flexibility and your range of motion, but if you're injured, stiff, or lacking flexibility, stretching could actually make things worse. It's likely a sign of muscle weakness or another impairment and should be seen by a physical therapist or a qualified health care provider.