Cycling injury prevention - does stretching help?

Dr Graham TheobaldSpecialist physio Dr Graham Theobald (thebodyrehab.co.uk) has a PhD in cycling-related knee pain:

Is stretching worthwhile for cyclists?
Yes, in my opinion it is, but the evidence indicates that the biggest benefit from static stretching is likely to come when it’s undertaken after exercise. Prior to cycling, I normally suggest dynamically warming-up rather than static stretching, as both the research and my clinical experience indicate that dynamic exercises have a greater effect on muscle length.

What are the physical effects?
Dynamically warming-up — that is, movement-based rather than static stretches — progressively warms the associated tissue and in turn allows the muscle to move further towards its maximum range of movement.
This also induces a more elastic state to the tendons attached to the muscles, which in turn prepares the muscles for the activity you are about to undertake. High-intensity warming-up for activities such as time trialling should be progressively worked towards in the warm-up.

When should a rider stretch, before or after riding, and how often?
Afterwards is generally best, when you are warm from the activity and before you fully cool down. This has been backed up by some evidence over the years, though the current trend seems to be moving away from stretching in general. Stretching before cycling seems to have very little effect, and some studies have shown a detrimental effect. In my opinion, stretching after some training rides is good practice, particularly for the quadriceps, in which excessive tightness can cause knee pain.

Which exercises are most useful?
I recommend focusing on the quads and hip flexors as the most important areas. You do however need to take care with how hard you stretch. Gently is best, in my experience — progress the stretch intensity over time.

Full article in Cycling Weekly 14.09.2016 ‘ Should cyclists stretch to prevent injury’.