The Hampering Hamstring

by G. John Mullen, DPT 2011 | mullen@myhousecallmd.com

Fantasy baseball drafts and spring training are in the air…you can almost smell the finely cut grass, taste the $10 hot dogs and feel the $20 beer in your hand.  At the same time, the beginning of the season comes with big question marks hanging over the heads of players with injuries: Tommy John surgery, alcohol related rehabilitation, and hamstring strains (aka “pulling a hammie”) to name a few.  Most regular folk have experienced a hamstring strain and know it does not get better without a fight and a bottle of Georgia Moon (maybe not the later for everyone).   Before we get into treatment lets hit the basics of the hamstring.

Stat Fact: One-third of hamstring strains will recur with the highest risk of recurrence occurring 2 weeks after the initial injury.

Getting to Know Your Hammies

The hamstring is the predominant muscle in the back of your thigh.  The hamstring is composed of three muscles (biceps femoris, semimembranosus, semitendinosis…in case you were wondering) and their primary collective action is to flex the knee.  The most common cause of a hamstring strain is from the “eccentric use of the hamstring” while running. The eccentric use of the hamstring is highest when your leg is extending, off the ground, and swinging forward prior to hitting the ground for your next step.  This stage is termed the “terminal swing” (and yes, we realize this sounds more like a carnival ride than a leg movement).  The eccentric load is highest due to the amount of stretch it places on the hamstring muscles (this is similar to the strain you feel in a straight leg raise).

How do you know if you’ve hurt your hamstring?

Hamstring injury usually presents with a pop, pain in the back of the leg and decreased strength and range of motion.  The strain can occur in any of the three hamstring muscles at any point in the muscle, but the most common site for a strain is either behind the knee or near the butt.  Hamstring strains are classified by the amount of pain, weakness and loss of range of motion associated with the injury.  They are commonly graded on a 1-3 scale with I being mild, II is moderate and III is severe.  The duration of the injury depends on the site and size of the injury.  If you have a large tear near your butt, you’re what we physical therapists call “pretty screwed.”


Stat Fact: The attachment of the biceps femoris is at the outside of the knee (where the complete tear is identified in the picture above).  This particular region is the most commonly strained part of the hamstring muscles because it undergoes the highest amount of stretch amongst the hamstring posse.

Hamstring Hangover

The goal of rehabilitation is to return the athlete to their prior level of performance while minimizing the risk of injury recurrence.  Multiple factors contribute to a high re-injury risk of the hamstring: (1) persistent weakness in the injured muscle, (2) reduced flexibility due to scar tissue, (3) impaired movement/biomechanics due to injury.  Strengthening the hamstring is a fundamental component of rehabilitation and needs to include eccentric (muscle lengthening) and concentric (muscle shortening) exercises.  In addition to strengthening your hamstrings, the muscles attached to the pelvis are often weak and require assessment and strengthening. Rehabilitation of grade I and II hamstring strains can be broken into three distinct phases:

Phase I:

The goal of the Phase I is to decrease swelling, pain and scar tissue formation. You should avoid excessive stretching of the hamstring in this phase since over stretching can increase scar tissue formation. To avoid over stretching, limit your knee flexion range of motion by taking shorter strides while walking or using of crutches.  Ice should be used 2-3 times per day for 15-20 minutes with an ice pack to decrease swelling and pain (no more than 15 minutes at a time as longer amounts of time may increase swelling).  Exercises in Phase I should not stress the injury site. The most common exercises prescribed during this phase are single leg balance (seen in the picture to the left), isometric abdominal exercises, and lateral stepping drills (grapevine/karaoke).  Advancement from the first stage of rehabilitation includes normal walking and stride length without pain, light jogging without pain, and a lack of pain while resistance is applied with the knee bent to 90 degrees (lay on your stomach with your knees bent to 90 degrees and have someone gently pull your ankle down to the floor…pain = no good). Phase I is typically 5 days long but as doctors love to specify that “it depends.”  It always depends.

Phase II:

The goal of Phase II is to increase intensity of exercises, increase range of motion and to begin eccentric exercises. Ice is typically used after training to decrease pain and inflammation associated with exercises.   In Phase II exercises, we increase speed and intensity of agility drills.  Side to side agility drills should be utilized to decrease the risk of overstretching the muscle.  At the end of Phase II, you can progress agility and strengthening drills to include forward and backward movements (supine bent knee bridge walk-outs…Google it).  Eccentric strengthening is initiated and incorporated as functional movements (light jogging, moderate high knees) instead of isolation exercises.  To progress to Phase III, the participant must be able to 1) pull with the full strength of your hamstring against resistance with your knee bent to 90 degrees and 2) forward and backward jogging at 50% of maximum speed without pain. Phase II typically last 1-2 weeks.

Stat Fact: Mobilization (lengthening) of skeletal muscle 5-7 days after injury can enhance fiber regeneration.

Phase III:

Phase III involves sport specific movements with no range of motion restrictions but sprinting and high accelerations should be avoided until return-to sport-criteria are met.  Ice should be used as needed after rehabilitation exercises.  Exercises in Phase III involve sport-specific exercises emphasizing quick direction changes and proper technique.  Trunk stabilization should be improved with movements in multiple planes of motion. Single leg bridges and single limb windmills (see picture) are examples of high intensity exercises.  In order to be cleared to return to the sports you need full range of motion, strength and functional abilities (cutting, running, jumping). Phase III usually lasts 1-2 weeks.  The total time for hamstring recovery is typically 3-5 weeks.

Prevention:

To prevent hamstring strain, we recommend a combination of stretching and strengthening exercises. Research studies have not shown any significant benefit to stretching your hamstrings therefore static hamstring stretching is not the best prevention tip.  However, scientists believe that an improper length of the quadriceps and hip flexors are a risk factor for hamstring strains.  Therefore, increasing flexibility of these muscles is mandatory to prevent hamstring strains.  Additionally, research showed that eccentric hamstring training prevents strains.  Eccentric hamstring training should be incorporated into a preseason and in-season training program for all athletes at risk for hamstring injuries.  An exercise routine for eccentric hamstring training can include Romanian dead lifts, knee fall downs and single leg Romanian dead lifts (see picture above). Lastly, exercises that incorporate the lower extremities and pelvis are associated with a decreased risk of hamstring strains.  Examples of these exercises include high knee marching, forward-falling running drills, and explosive starts.

Reiteration:

Prevention is the key here!  Make sure warm-up for 10-15 minutes (and by “warm-up” we mean activity that raises your heart rate and gets you sweating) before any work out.  Incorporating a proper warm-up, eccentric hamstring training and proper hip flexor and quadriceps muscle length will decrease your chance of the ending up with a hampering hamstring.  Everyone wins!

Questions?  E-mail G. John Mullen: mullen@myhousecallmd.com

References:

1. Heiderscheit B, Sherry M, Silder A, Chumanov E, Thelen D. Hamstring strain injuries: recommendations for diagnosis, rehabilitation, and injury prevention. J Orthop Sports Phys Ther. Feb 2010;40(2):67-81.

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02 2010

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