(2)
Great Britain
Derek Redmond tore his hamstring around the 250m mark at the 1992 Barcelona Games and with his father's help, finished the race. He was a favorite to medal in the event. He required seven orthopedic surgeries in the next 2 years and his career as a professional runner was over. This displays the difficulty of returning to your sport after a hamstring injury of this magnitude.(1)
Hamstring injuries plague runners or sprinters, triathletes, football players, or any sport requiring high-end speed or acceleration. Over 10 seasons in the NFL the hamstring injury rate was 172 per season, with a majority of the injuries occurring in the preseason.(3) Feeley et al. reported that 12% of training camp injuries in the NFL are hamstring injuries, making it the second most common injury.(4) Athletes can loose out on large amounts of money due to these injuries, including Cardale Jones recently at the NFL Combine.
Cardale Jones, Ohio State Quarterback, suffered a hamstring strain during the 40 yd dash in the 2016 NFL Combine. The hamstring strain ended his workouts for the day and his potential for improving his draft stock at the combine.
(5)
Athletes can easily neglect the hamstrings for numerous reasons, and one potential reason the muscle group gets less work in the gym is because they are not "mirror muscles," (muscles on the front side of your body). However, when it comes to athletic performance, the "mirror muscles" are usually not the reason you are one of the fastest runners on your team. Training for speed, acceleration, and injury prevention mostly requires strengthening the backside of the legs: glutes, hamstrings, calves. See the right side of the picture below:
(6)So as a general rule in the gym:
Lower body - Every exercise for your quads (i.e. squats) needs to be balanced with two exercises for the Glutes/Hamstrings (i.e. deadlifts or stoops, and for runners: single leg Romanian Dead Lift, RDL).
(7)Why? The hamstrings are weaker than the quads, generally by around 20-50%. Research states when the hamstring is approximately 40% weaker than the quad, the risk of injury increases 17.4 fold.(8)
(9)The hamstrings are most active in the last picture, when they are trying to slow the leg down while it moves forward during a stride (terminal swing). Your hamstrings basically act as a brake, so your leg stops striding too far forward and can prepare the leg to hit the ground. The hamstring is "active" or "firing" while it is lengthened and this is when injury risk increases quickly. This explains why the risk of hamstring injury increases when the quads are >40% stronger than the hamstrings; they overpower the braking system and the hamstring can be strained or torn.
(2)
Derek Redmond's stride prior to the quads overpowering the hamstrings.
Think of the legs and arms as the engines that allow you to run and anything from the hips to the shoulders is your chassis or frame of your car. You need a sturdy frame for the engine to be effective. Therefore, you need to have a strong mid section or core for the legs to move your body quickly. This is evident in the final study:
Two groups of athletes with hamstring injuries.
The 1st group only did light hamstring exercises, neglecting to incorporate the rest of the body.
6 of the 11 reinjured the hamstring that year.
The 2nd group did strengthening exercises of the glutes, hamstrings, and core muscles. This included exercises that lengthened the hamstring while it was "active" and included moving in all planes of motion (side to side, forward and backward, and rotating) as well as the single leg dead lift exercise for the glutes and hamstrings (no squat exercise included in the program).
1 out of 13 reinjured the hamstring that year.
Clear evidence that you need to train muscles that support the hamstrings (the core and glutes) that can help unload the muscle. Also, you need to perform exercises that lengthen the hamstring while it is "active".(10,11)
In conclusion: To prevent a season ending (or career ending) hamstring injury, you need to perform glute/hamstring exercises that incorporate full body motions with lengthening of the hamstring, like the Romanian Dead Lift (see picture above) and exercises that strengthen your core muscles (back muscles as well as abdominals). For example, an exercise starting in the push-up position, then rotating your body to lift one arm toward the ceiling, pause, and switch sides.(3,8,10,11)
References:
1) Derek Redmond. 2016 Mar 29. http://derekredmond.com/about
2) Derek Redmond's Emotional Olympic Story - Injury Mid-Race | Barcelona 1992 Olympics. Youtube. https://www.youtube.com/watch?v=t2G8KVzTwfw
3) Elliot MC, Zarins B, Powell JW, Kenyon CD. Hamstring muscle strains in professional football players: a 10-year review. Am J Sports Med. 2011 Apr;39(4):843-50. PubMed 2016 Mar 29
4) Feeley BT, Kennelly S, Barnes RP, Muller MS, Kelly BT, Rodeo SA. Epidemiology of national football league training camp injuries from 1998 to 2007. Am J Sports Med, 36 (2008), pp. 1597–1603. PubMed 2016 Mar 29.
5) Legwold J. ESPN: QB Cardale Jones suffers hamstring injury at NFL combine. Joe Robbins/Getty Images. 2016 Feb 27. Accessed 2016 Mar 29. http://espn.go.com/nfl/draft2016/story/_/id/14858562/qb-cardale-jones-suffers-apparent-hamstring-injury-nfl-combine
6) Google Images: Accessed on 2016 Mar 29. https://classconnection.s3.amazonaws.com/107/flashcards/2796107/jpg/quads-glutes-hamstrings-calves-145106373ED6E75D766.jpg
7)Google Images: Accessed on 2016 Mar 29. https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoVJnwOQ-L2oRU6-aM4BN9RdpBxYlpTFVy42_ZMw9lOgfULC30Ygv4nrg9NGlNCzZ_maXtpWW3ITYMF0PFk0hmjV49QLQ0DTvNH-sC84qlmYbX662u7VMa_-HivGEq4mkpnzcn_VL7t4k/s1600/Romanian+Deadlift.jpg
7)Google Images: Accessed on 2016 Mar 29. https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoVJnwOQ-L2oRU6-aM4BN9RdpBxYlpTFVy42_ZMw9lOgfULC30Ygv4nrg9NGlNCzZ_maXtpWW3ITYMF0PFk0hmjV49QLQ0DTvNH-sC84qlmYbX662u7VMa_-HivGEq4mkpnzcn_VL7t4k/s1600/Romanian+Deadlift.jpg
8) Opar DA, Williams MD, Shield AJ. Hamstring Strain Injuries: factors that lead to injury and re-injury. Sports Med. 2012 Mar 1;42(3)209-26. PubMed 2016 Mar 29.
9) Digital Research Foundation. Google Search. 2016 Mar 29. http://movement-as-medicine.com/wp-content/uploads/2013/12/running-gait.jpg
10) 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. PubMed 2016 Mar 29.
10) 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. PubMed 2016 Mar 29.
11) Askling CM, Tengvar M, Tarassova O, Thorstensson A. Acute hamstring injuries in Swedish elite sprinters and jumpers: a prospective controlled clinical trial comparing two rehabilitation protocols. Br J Sports Med. 2014 Apr;48(7):532-9. PubMed 2016 Mar 29.
