What's the biggest myth in fitness? "Stretching prevents injury."
Can you touch your toes? If you can, congratulations! If you can't, who cares? The reality is, you only need so much flexibility to be healthy and to perform well.
What about preventing injury? According to 30 years of meta-research, static stretching might give you one percent better injury prevention. Dynamic stretching isn't much better. Most now agree that coaches and trainers may want to avoid using stretching as a means of injury risk prevention immediately prior to athletic activities.
The truth is, you're already as flexible as you need to be. Under anesthesia, an 80 year-old sedentary man is able to do the splits. So what is flexibility, really? It's a neuromuscular state that helps limit your movement to prevent injury.
You're actually not making a muscle longer when you stretch. Instead, your nervous system interprets the stretch as potential injury and shuts the muscle down. In turn, this causes instability of the joints attached to the muscle thus making you more susceptible to injury before the activity even starts.
Save stretching for after exercise, to relax the nervous system, and learn to move better to prevent injury.