The hamstrings are composed of three groups of muscles at the back of the thigh. Overstretching the hamstrings can cause them to tear, causing a hamstring strain. If just one of these muscles in the group is overstretched, a hamstring strain can develop. The pain can be mild or severe. An injury to the hamstring usually occurs near the tendon or in the muscle belly, which is the thickest part of the muscle. This injury most often occurs in athletes or fairly active people.

Hamstring strains can be categorized into three types:

1. Grade I is a hamstring pull, which is usually mild and heals quickly. 
2. Grade II is a partial tear, which includes moderate pain swelling. 
3. Grade III is a complete tear of the hamstring muscle causing the hamstring muscle to separate completely from the bone. Depending on the severity of the tear, this grade could take months to heal.

Hamstring strain risk factors

Injuries to the hamstring are more likely to happen if you fall into one of these categories: 

1. Play sports involving sprinting or running, such as soccer, basketball, football, and track.
2. Older athletes that mainly walk for exercise
3. Dancers 
4. Adolescent athletes that are still growing: Growing pains are a real issue for adolescents who are growing at a fast rate. When bones grow faster than muscles, muscles can’t keep up with growth, so they become stretched out as a result. 

Symptoms

Pain has a quality, including sharp, aching, deep, throbbing, and pulsating. However, a hamstring injury typically causes a sudden and sharp pain in the back of the thigh. Other symptoms can include swelling, reduced mobility, hamstring weakness, and bruising on the back of the leg. 

Causes

Hamstring strains can be caused by overloading the muscle. It can also be caused by a sudden acceleration or deceleration when running. 

Treatment of hamstring strains  

If you have a grade I or II hamstring strain, you can use the RICE method (Rest, Ice, Compression, Elevation), along with some immobilization if you need to, such as a knee brace. Hamstrings are responsible for extending the leg as well as bending the knee. It is a two-joint muscle since it crosses the hip and the knee. Braces or immobilizers may be sufficient in most cases to allow the muscle to rest. Depending on the severity, casting may be used as another option. 

Hamstring strains are often also treated with nonsteroidal anti-inflammatory drugs (NSAIDs) as well as painkillers. Physiotherapy is administered to individuals with grades I and II hamstring strains. When the pain subsides, physiotherapy will consist of gentle stretching and strengthening exercises and walking without crutches. 

A grade III hamstring strain could be treated non-surgically or surgically. The ischial tuberosity is where the hamstrings attach, so if the hamstring tears and is pulled away with enough force, it can break off a piece of the bone with it. This is referred to as an avulsion fracture. When this occurs, surgery is required. As part of the procedure, the surgeon pulls the hamstring tendon back to its original position at the hip base and reattaches it with anchors. During this process, the surgeon may cut away scar tissue that’s formed, since it may have been a few weeks since the original injury.

Platelet-rich plasma is a newer treatment that is available. However, there is still much research to be done. Nevertheless, it’s something that is available and that people can utilize as more of an experimental treatment. In addition, the plasma created from the patient’s own blood contains growth factors that could contribute to faster recovery.

Five mistakes that can cause a hamstring strain. 

1. Not stretching daily: a daily regimen of stretching is beneficial, especially for athletes and people with high levels of activity.
2. Muscle imbalance: Due to the quadriceps overpowering the hamstrings during high-speed activities, the hamstrings may become easily fatigued and strain.
3. Poor conditioning of the leg muscles: Weak muscles may not be able to handle the loads or stress of intense physical activity as well as strong ones. 
4. Poor endurance: When a muscle becomes fatigued, it loses its ability to absorb energy, which leads to injury.
5. A failure to consider other sports and activities with a lower risk of hamstring strain.

Hopefully you found this useful and can take the above into consideration whether you are an athlete, parent of an athlete or an active adult.

Disclaimer: The preceding information is not to be taken as medical advice. It is general information only. Always seek out your primary care physician prior to making any changes to your fitness or eating regimen.