If you think about some muscles that most people or athletes do not train, what muscles come to mind? I am pretty sure you can cross out most of the muscles in the upper body. What muscle in the lower body can cause the most problems if it is weak or imbalanced? In my opinion, it is the hamstring muscles. I will admit that my least favorite muscle group to train is the lower body, but they need attention. As an athlete, I would put little to no effort in building my leg strength and power. This could be the reason why I have had so many knee surgeries. The hamstrings play a huge role in our performance (running, jumping and cycling) and should not be neglected.
The Anatomy of the Hamstrings
Every summer when we have our Kids Athletic Development Camp, one question I ask a lot are how many hamstring muscles do you have? Do not be afraid to say one, before I started my degree I thought we only had one.
There are three hamstring muscles (biceps femoris, semitendinosus and the semimembranosus) (Koulouris 2006).
| Name | Origin | Insertion | Action |
| Biceps Femoris(Long Head) | Ishial Tuberosity of the Ishium | Lateral Condyle of the Tibia, Head of the Fibula | External knee rotation, hip extension, knee flexion |
| Biceps Femoris(Short Head) | Lateral Condyloid Ridge of the Linea Aspera on the posterior surface of the Femur | Lateral Condyle of the Tibia and the Head of the Fibula | Knee Flexion and External Knee Rotation |
| Semimembranosus | Ishial Tuberosity of the Ishium | Medial Condyle of the Tibia | Hip extension, internal knee rotation and flexes knee |
| Semitendinosus | Ishial Tuberosity of the Ishium | Medial Condyle of the tibia | Hip extension, internal knee rotation, flexes knee |
What Can Cause a Hamstrings Injury?
If you have ever experienced a hamstring muscle injury and hamstring muscle rehabilitation? It can be very painful and frustrating to deal with. Have you seen or has it happened to you where you come back from that injury and you re-injure that same spot? If you are involved in any sports or activities that involve sprinting, kicking or high speed agility movements, then you can be at risk of a hamstring strain. A couple years ago I was playing an adult softball league double header and I was standing in the outfield and I had to sprint as hard as I could. Can you guess what happened? POP, my hamstring gave out and it swelled up like a balloon. After going to my Universities Athletic Trainer, I was diagnosed with a grade 3 strain.
There are three grades of strains (Koulouris 2006):
Grade I strain– In this mild strain, only a few muscle fibers are stretched or torn. Although the injured muscle is tender and painful, it has normal strength.
Grade II strain- This is a moderate strain, with a greater number of injured fibers and more severe muscle pain and tenderness. There is also mild swelling, noticeable loss of strength and sometimes a bruise.
Grade III strain- This strain tears the muscle all the way through, sometimes causing a “pop” as the muscle rips into two separate pieces or shears away from its tendon. Grade III strains are serious injuries that cause complete loss of muscle function, as well as considerable pain, swelling, tenderness and discoloration.
How to Evaluate Risk Factors for Hamstring Injuries?
If you have had a movement analysis screening or somebody has tested you for risk factors, consider yourself lucky. Having somebody test your strengths and weaknesses can keep you safe from future injury. This does not mean that you will completely avoid injury though. Studies suggest that a decrease in quadriceps flexibility was an independent risk factor for hamstring strains in Australian football players. Studies have also stated that hamstring flexibility when measured with the sit and reach test, passive straight leg raise and knee extension test have not had an effect on hamstring strains.
Strength Imbalances with the Hamstrings and Quadriceps
One big problem that occurs a lot is strength imbalances between the quadriceps and the hamstrings, this needs addressing during hamstring muscle rehabilitation. 
Croisier (2008) used 462 Belgian, Brazilian and French professional players over a five-year period. Isokinetic strength measurements of the hamstring and quadriceps muscles were made for each player at the start of each season. Strength imbalances were defined as a player having more than a 15% difference in hamstring strength between the right and left limb or hamstring strength less than 45% of quadriceps strength. Injuries were reported over the course of the season and were defined based on physical and diagnostic examination by the team’s medical staff and at least 4 weeks of missed playing time for each player. Of the 462 players, less than half were diagnosed with hamstring imbalance. The players who had hamstring imbalances were given a specific hamstring strengthening program designed to balance out the strength. In group of players only 4% suffered a hamstring injury. In players with an imbalance that was not corrected, more than 16% were injured. In the group of players that received training, only 6% were injured, reducing their risk to near normal.
What this study shows us is that having a pre-season, during season and end of the season assessment can be effective in decreasing the risk of hamstring injuries. This does not mean that this is the cure and nobody will get hurt, but if we can decrease the chances of occurrence then we can keep our kids on the field.
What Rehab/Prevention Program could we use to for Hamstring Injuries?
When we are rehabilitating for any injuries, it can be challenging and frustrating. If you have a serious injury, this process could last from a month to a year. I learned the hard way on how on how to be patient and smart. As an athlete, your main goal is to get back on the field as fast as possible. The problem this can cause is we can take short cuts or come back too soon. This is a good way to injure it again or even worse than it originally was.
There have been a couple of studies that have looked eccentric training (lengthening the muscle using body weight or a resistance) with a leg curl machine has a positive effect on decreasing hamstring injuries. These studies even suggested that using a single leg on both sides had significant improvements.
Neuromuscular training has been a topic of conversation for hamstring injuries. Neuromuscular training is designed to teach your body better habits for stability.
Cameron (2009) demonstrated that below-average neuromuscular control can predispose athletes to hamstring injury. He created the HamSprint program, this involves a number of drills (leg cycling, pawing, ankle pops, high knee marching, forward falling runs and explosive starts). For six weeks, this program was more beneficial than regular stretching.
Studies on trunk stabilization, three to four times a week can be beneficial for hamstring injuries. These studies used exercises that target trunk rotation, weight bearing and the different angles of hip flexion. These exercises included low to high and high to low chops, core planks, physioball bridges and single leg holds in different hip angles.
There are a lot of great ideas out there for hamstring muscle rehabilitation and prevention. If you are an athlete who plays a sport, especially the ones that involve quick bursts, changing directions and jumping, having an injury prevention program is advised. If you are rehabbing now, remember to be smart and take the program seriously so you can be back on the field.
Reference:
- Croisier J-L, GAnteaume S, Binet J, Gentry M, Ferret J-M (2008) Strength imbalances and prevention of hamstring injury in professional soccer players: A prospective study. American Journal of Sports Medicine, DOI:10.1177/0363546508316764.
- Cameron ML, Adams RD, Maher CG, and Misson D. Effect of the HamSprint Drills training program on lower limb neuromuscular control in Australian football players. J Sci Med Sport 12: 24–30, 2009.
- Brooks JH, Fuller CW, Kemp SP, and Reddin DB. Incidence, risk, and prevention of hamstring muscle injuries in professional rugby union. Am J Sports Med 34: 1297-1306, 2006.
- Koulouris G, Connell DA, Brukner P, Schneider-Kolsky M. (2007). “Magnetic resonance imaging parameters for assessing risk of recurrent hamstring injuries in elite athletes.”. Am J Sports Med. 35 (9): 1500–6.
Written by Chris Barber, CPT