Hamstring Strains

1. Hamstring Strains Alex Solomon Matt DeAngelis

2. Hamstring • One of main muscles in lower extremity. • Frequently injured in high speed skill movements. • Injury could reoccur at any time if not properly stretched. • Most injuries occur along the proximal musculotendon Junction (MTJ).

3. Muscles • Hamstring consist of posterior leg muscles. • Semitendinosus, semimembranosus, and biceps femoris are the three that make up the hamstring. • Gluteus maximus plays a role where it allows extension to occur in hamstring. • http://www.youtube.com/watch?v=t4HLKQWo1Ts

4. Injuries • Hamstring injuries are common in sports that involve: • Kicking • Sprinting • High speed skill movements • National Collegiate Association Injury Surveillance System found that male college athletes are 62% more likely to sustain the injury than female college athletes. • More common in field sports than court sports.

5. Studies • 4 year study for a Division 1 football team show that hamstring strains are 3rd most common orthopedic problem behind knee and ankle injuries. • 2 year study of a professional soccer team show that 12% of all injuries occur in hamstring. • In addition to high speed sports, there’s an increased risk for hamstring strains in sports involving slow stretching type maneuvers, such as dancing.

6. Studies (Con’t) • Even after recovery and full hamstring strength, you are still at risk for re-injury.

7. Hamstring Risks • Risk factors for not properly taking care of the hamstring include; • Previous injury • Older age in competition • Decrease in Quadriceps muscles • Decrease in flexibility • Muscle imbalances of the thigh. • Recently injured players are more than twice as likely to sustain a new hamstring injury when feeling like they can still compete and not fully rest.

8. To realize one has sustained a hamstring injury, there will be feeling of sudden onset posterior thigh pain, tenderness of palpation, feeling pain when stretching the hamstring muscle, and feeling of pain on contraction of the hamstring muscle group.

9. Mechanism • Most hamstring strain injuries happen while running. • It is generally believed that they occur during terminal swing phase. During the second half of the swing, the hamstrings undergo an eccentric contraction and absorb energy from the swing limb before foot contact. • The hamstrings are stretched while subjected to eccentric contraction with the biceps femoris acquiring the greatest amount of length change and performing the maximum amount of negative work. • As a result, the contraction may contribute to the predisposition of the biceps femoris to be more often injured than the semimembranosus and semitendinosus.

10. Physiology of Hamstring Injury • Most injuries occur where muscle fibrils intersect with the tendon. • Immediately after injury, there’s an acute inflammatory response that is followed by muscle and collagen regeneration. • MRI’s can confirm the presence and severity of muscle fiber damage and can also provide estimate of rehabilitation period. • 18 of 58 cases showed no positive identification of MRI images.

11. Physiology of Hamstring Injury (Con’t) • Injuries such as this can result in fibrous scar formation. • Animal models show that growth of fibrous tissue prevails over muscle regeneration. • Scar tissue can limit the stretch of the muscle and can be persistent in some people until 2 years. • Residual scar tissue at the sight of a previous injury may aversely affect local tissue mechanics in a way that could contribute to re-injury list.

12. Recondition/Rehabilitation • Eccentric exercise and sarcomeres are suggested. Stretching and exercising the hamstrings will allow the muscle to operate at longer lengths and decrease the magnitude of the stretch absorbed. • The rehabilitation strategies listed are • the YoYO flywheel ergometer • HamSprint program • Nordic curl

13. Strategies YoYo fly wheel Nordic Curl

14. Rehabilitation (con’t) • The hamstrings get tugged and pulled on by other muscles affecting their range of motion and strength. So working out the entire range of muscles in the lumbopelvic area is important. • When creating your personal warm-up, make sure to include specific drills shown to improve running technique, lumbopelvic control, and hamstring function. In addition, trunk stabilization and neuromuscular control exercises are needed. • These two things should be worked on at least 3-5 time s a week • Different ways to practice these two exercise types is to try weight bearing activities, practice trunk rotation and try multiple angles of hip flexion.

15. Dynamic Warm Up • Athletes should incorporate a dynamic warm up before any competition. • Dynamic agility drills can improve lower limb motor control. This has a relationship to hamstring injury. • Programs should include specific drills to improve • Running technique • Lumbopelvic control • Hamstring function

16. Dynamic Warm Up Drills Marching skipping

17. Short stride cariocas Side Shuffles

18. Leg cycling Ankle pops

19. Quick support running drills

20. Trunk Stabilization Low to high wood chops High to low wood chops

21. Rotating core planks Physioball

22. Single leg stand

23. Eccentric Training Exercises Eccentric box drop Eccentric loaded lunge drops

24. Eccentric forward pull Split-stance Zerchers

25. Single leg deadlifts

26. Great stretch video http://www.youtube.com/watch?v=C-wiOqYcxoI&feature=related

27. References Sherry, Marc A. (2011). Hamstring Strains: Basic Science and Clinical Research Applications for Preventing the Recurrent Injury. Strength and Conditioning Journal. Retrieved November 2011. Volume 33 - Issue 3 - pp 56-71. http://journals.lww.com/nsca-scj/Fulltext/2011/06000/Hamstring_Strains__Basic_Science_and_Clinical.5.aspx Gabbe, Barry M. (2005). Risk factors for Hamstring Injuries in Community Level Sports. British Journal of Sports Medicine. Retrieved November 2011. Volume 39-Issue 2-pp.106-110. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC17/