by Brett Holland. PT, DPT, CSCS 09/17/2015
Laymen’s Cliff Notes:
•In order to prevent hamstring pulls it is important to add specific hamstring strengthening exercises to your program.
•According to research, eccentric based hamstring exercises are effective in reducing hamstring injury rates.
•Using a program combining flexibility, strengthening, postural corrections, and local muscle endurance may provide the greatest protection against hamstring injuries.
Background:
-The hamstring musculature is generally considered to be composed of 3 muscles: the semimembranosus, the semitendinosis, and the biceps femoris.
-Action: The hamstrings can act upon two joints: the hip and the knee
Knee: When acting upon the knee the hamstrings produce knee flexion
Hip: When acting upon the hip the hamstrings produce hip extension
Let’s get dynamic:
How about hamstring activity during functional movements such as running and jumping?
Running: The hamstring muscles are loaded during both swing and stance phases (see below).
A 2010 study performed by Higashihara et al. showed that increasing sprinting speeds close to maximal increased activation of the hamstring muscles. Specifically, the biceps femoris increased in late swing phase while the semitendinosis activation increased during the middle of swing phase (important for rehab)[1].
Jumping: The biceps femoris shows greater activation during an eccentric landing task vs the eccentric portion of a counter-movement jump (lower version of depth jump). This is due to release of stored-elastic energy [2]. If you are unfamiliar with a depth jump see my page DEPTH JUMP.
-Hamstring injuries are prevalent in sports requiring high speed running such as football, baseball, soccer, and track and field.
Brief look at the evidence:
-In a study looking at injuries in NFL training camps from 1998-2007, Feeley et al found that hamstring strains were the most common muscular injury and second most common injury behind knee sprains [3].
-In soccer, hamstring injuries account for 12% of all injuries [4].
Mechanism of Injury:
-Most commonly an open chain injury (in other words your leg is not in contact with the ground)
– When looking at EMG data it would appear that if the injury occurs earlier in the swing phase, the medial hamstring group would be most vulnerable to injury. If the insult occurs later in swing phase, the lateral portion of the hamstring musculature is more susceptible to injury. In fact most injuries occur during the latter phases of swing. (Gait is a term used to describe human locomotion, it typically consists of a ground stage know as stance and a flight stage know as swing)
-The latter half of swing phase (think hip flexed and leg extending) is when most hamstring injuries are sustained [5].
-During the second half of swing the hamstrings are responsible for bracing the limb for ground contact, essentially slowing the forward propulsion of the limb by undergoing a strong eccentric contraction [6].
-To simplify, the hamstrings, specifically the biceps femoris, undergo a strong muscle contraction while elongating. This coupled with high velocity movement results in the biceps femoris being the most often injured muscle of the hamstring group (biceps femoris=greatest length change+greatest amount of negative work= most number of injuries in hamstring group)[6].
Risk Factors
1. Previous Hamstring Injury: A 2002 study by Orchard et al revealed that re-injury rate for Australian footballers over a 22 week season was 30.6% [7]! An astonishingly high number, however dealing with these types of injuries both personally and professionally I would say this number is roughly accurate, especially in sports involving bursts, fatigue, and lots of sprinting.
2. Decreased Quad Flexibility-using a modified thomas test
3. Older Age
Prevention
1. Improve optimal length-tension relationship via eccentric exercise
2. Develop local muscle endurance to combat fatigue during competition
3. Improve entire lower body flexibility
4. Establish Q:H ratios and rectify if needed (this one can be tricky, the optimal Q:H ratio is unknown for many sports although we use 3:2 as our best guess and balance between injury prevention and performance).
•Eccentrics a key component to hamstring prevention-shifting optimum length-tension relationship
•Magnitude of shift depends on volume, intensity, and length of muscle during exercise [8]
•In a review of current literature, Braghelli et al concluded that, “eccentric exercise can cause a shift in optimum length and that the magnitude of the shift depends on volume, intensity, and muscle length at which the individual exercises” [8].
AR’s top 3 Hamstring Prevention Exercises
1. Standing cable hamstring curl with working leg set in hip flexion (low or high velocity exercise)
2. Nordic Curl
•Brooks et al found that rugby players whom participated in a flexibility program, strength program, and performed the nordic curl reduced hamstring injury by 65%[9].
3. Single leg bridge with curl on physioball
Honorable mentions: zercher squats, lunges (forward and reverse), stiff-legged deadlifts, sumo squats and deadlifts, prone hamstring curls, seated hamstring curls
(Don’t forget trunk stabilization and neuromuscular control exercises)
References
1.HIGASHIHARA, A., T. ONO, J. KUBOTA, T. OKUWAKI, AND T. FUKUBUYASHI. “FUNCTIONAL DIFFERENCES IN THE ACTIVITY OF THE HAMSTRING MUSCLES WITH INCREASING RUNNING SPEED.” JOURNAL OF SPORTS SCIENCES 10 (2010): 1085-092. PUBMED. WEB. 5 MAY 2014. http://www.ncbi.nlm.nih.gov/pubmed/20672221
2. Padulo, Johnny, Alessandra Tiloca, Douglas Powell, Giampietro Granatelli, Antonino Bianco, and Antonio Paoli. “EMG Amplitude of the Biceps Femoris during Jumping Compared to Landing Movements.” Springerplus2 (2013): n. pag. Pubmed. Web. 13 May 2014. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3797910/
3. FEELEY BT, ET AL. EPIDEMIOLOGY OF NATIONAL FOOTBALL LEAGUE TRAINING CAMP INJURIES FROM 1998 TO 2007. THE AMERICAN JOURNAL OF SPORTS MEDICINE. 2008;36:1597–1603. http://www.ncbi.nlm.nih.gov/pubmed/18443276
4.Woods C, Hawkins RD, Maltby S, Hulse M, Thomas A, and Hodson A. The Football Association Medical Research Programme: An audit of injuries in professional football—Analysis of hamstring injuries.
Br J Sports Med Ovid. WEB. 30 MAY 2014 http://www.ncbi.nlm.nih.gov/pubmed/14751943
5.Schache AG, Wrigley TV, Baker R, and Pandy MG. Biomechanical response to hamstring muscle strain injury.
Gait Posture Ovid WEB 30 MAY 2014 http://www.ncbi.nlm.nih.gov/pubmed/19038549
6. Sherry, Marc A., Thomas M. Best, Amy Silder, Darryl G. Thelen, and Bryan C. Heiderscheit. “Hamstring Strains: Basic Science and Clinical Research Applications for Preventing the Recurrent Injury.” Strength and Conditioning Journal 33.3 (2011): 56-71. Web. 11 June 2014. http://revdesportiva.pt/files/para_publicar/Hamstring_Strains__Basic_Science_and_Clinical.5.pdf
7. Orchard JW and Best TM. The management of muscle strain injuries: An early return versus the risk of recurrence.? Clin J Sport Med 12: 3-5, 2002 Ovid WEB 31 MAY 2014 http://www.ncbi.nlm.nih.gov/pubmed/11854581
8. Brughelli, Matt, and John Cronin. “Preventing Hamstring Injury in Sport.” Strength and Conditioning Journal 30.1 (2008): n. pag. Web. 11 June 2014. http://journals.lww.com/nsca-scj/Abstract/2008/02000/Preventing_Hamstring_Injuries_in_Sport.9.aspx
9. Brooks, J, Fuller, C, Kemp, S, and Reddin, D. Incidence, risk, and prevention of hamstring muscle injuries in professional rugby union. Am J Sports Med 34: 1297–1306, 2006. http://www.ncbi.nlm.nih.gov/pubmed/16493170
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