We'd like to share with you an exercise which can prevent up to 70% of all hamstring injuries. Interestingly, this exercise also improves hamstring flexibility.
It's called the Nordic curl.
Most people will benefit from performing this exercise twice weekly, for 8-10 weeks. You should start at 2 sets of 4 repetitions and build up to 2 sets of 8-10 repetitions. Expect some hamstring soreness with starting this exercise, but this is normal and will improve with time and practice
We've prepared a video of this exercise which you can see below: