- Warm up before activity. Leg swings front to back and alternate-leg bicycle action are two exercises to use. I don't recommend heavy stretching.
- Strengthen hamstring muscles with a weights program including some eccentric exercise such as the Nordic reverse curl or glute-ham exercise, and standing leg curl catches.
- Try to avoid intense running training while hamstrings are sore from weights work.
- Development of the quads with weight training exercises like the squat or leg extension should be balanced with suitable hamstring strengthening exercises.
- Fatigue over time may be a factor. Ensure an adequate intake of fuel in the form of carbohydrate in sports drinks during longer events or team sports.
- Stretch lightly, and preferably dynamically, with exercises similar to warm up at the end of an exercise training session or at intervals in a prolonged competitive session.
- Don't even think about returning to active competition until you are advised by a competent medical authority that you are fit to do so.
Sources
Mjolsnes R, Arnason A, Osthagen T, Raastad T, Bahr R. A 10-week randomized trial comparing eccentric vs. concentric hamstring strength training in well-trained soccer players. Scand J Med Sci Sports. 2004 Oct;14(5):311-7.
Sherry MA, Best TM. A comparison of 2 rehabilitation programs in the treatment of acute hamstring strains. J Orthop Sports Phys Ther. 2004 Mar;34(3):116-25.
Gabbe BJ, Bennell KL, Finch CF, Wajswelner H, Orchard JW. Predictors of hamstring injury at the elite level of Australian football.
Scand J Med Sci Sports. 2006 Feb;16(1):7-13.
Gabbe BJ, Branson R, Bennell KL. A pilot randomised controlled trial of eccentric exercise to prevent hamstring injuries in community-level Australian Football. J Sci Med Sport. 2006 May;9(1-2):103-9.
Gabbe BJ, Branson R, Bennell KL. Mason DL, Dickens V, Vail A. Rehabilitation for hamstring injuries. Cochrane Database Syst Rev. 2007 Jan 24;(1):CD004575. Review.

