[Vincent Ragland is in his last semester as a student-athlete at East Carolina University, pursuing a Health Fitness Specialist Degree. He is currently in the Coaching Mentorship Program at Athletic Lab]

A hamstring strain is one of the most common injuries in all sports, specifically ones involving high intensity sprinting. Aside from the physical damage associated with a pulled hamstring, there are psychological damages associated with an injury as well. For example, a high-level sprinter who has strained their hamstring in the past will almost certainly never run a race again in their life without the thought of that pull being in the back of their mind.

As with many injuries, the major problem associated with a hamstring injury is the risk of a re-injury, with nearly 30% of strains resulting in such. There seem to be two main reasons why researchers believe there is such a high prevalence of re-injury. For one, muscle tissue will not completely regenerate after a strain has occurred, and two, a weakness of the hamstring muscle or hamstring/quadriceps imbalance. After a hamstring strain occurs, scar tissue emerges in the location of the injury. The emergence of scar tissue increases the likelihood of re-injury and also limits the range of motion in a strained muscle. The most common mechanism of re-injury is when an athlete returns back to sport before the injury is completely healed and fully functioning. A study by Brian Cammarota shows that nearly 83 percent of hamstring re-injuries occur because an athlete attempts to return too soon. Similar studies show that 20-55% of the original injury had not healed in six weeks. (Cammarota et.al, 2013).

Typically, when an athlete suffers an injury, they want to know how long an injury will affect them, and what damages may be associated with the injury long term. One of the more common and universal ways to measure strength and flexibility of muscles such as the hamstring is by using an isokinetic dynamometer. An isokinetic dynamometer is a device that measures muscle strength, torque, flexibility, and range of motion, often after an injured state. In a 2016 study, researchers examined the strength and flexibility of a hamstring after a strain (Maniar et. al, 2016). In addition to using an isokinetic dynamometer, these researchers also used MR Imaging and a biomechanical analysis of sprinting to examine whether there was significant bilateral differences post injury. As it turns out, there is no significant difference between the uninjured and previously injured muscles in terms of isometric strength, flexibility, gait patterns, and functional capacity 50 days post injury. As an aside, no grade 3 strains (avulsions), were in this study; other research has determined that with surgery and a recovery of 6+ months, that even an avulsion injury can return to its normal, functional state.

What exactly does this mean for an injured athlete or the coach of an injured athlete? Although a premature return to sport may lead to a re-injury, with the proper rest and rehabilitation, a hamstring injury does not necessarily have to have lasting effects. There can be different forms of rehabilitation, depending on the mechanism of injury (M.O.I) in which the strain occurred. The grade of the strain (I, II, or III) can also help determine the most effective rehabilitation. Even with all of this information, rehab protocols are not an exact science. Before they begin the actual rehabilitation protocol for return to play, they may follow an initial protocol, R.I.C.E. R.I.C.E is an acronym for Rest, Ice, Compression, and Elevation. Soon after following the R.I.C.E protocol for a short amount of time, athletes can begin to work on a more intensive rehabilitation protocol in order to get the muscle back to its fully functioning form. Individuals with a hamstring injury should view this protocol as a mechanism of protection for the injured tendon.

  • Rest: One of the initial things that an athlete must do immediately following a strain is rest. Any weight bearing activities, even activities as simple as walking, can inhibit the muscle from repairing itself. With each step, the knee extends, which ultimately puts additional pressure on the hamstring. This added pressure can keep the hamstring from healing altogether. Depending on the mechanism of injury, the athlete should rest for at least one week, potentially more.
  • Ice: The role of ice in hamstring rehab is to reduce swelling around the affected strained area. While ice should not be applied directly to the area, ice should be applied in the form of a wet towel or something similar, such as a cold pack. The strain also may cause internal bleeding, and the ice will help stop that.
  • Compression: Compression can be used as an additional aid to support the muscle and reduce swelling. Compression works by really shutting down the area to limiting blood flow to the area which prevents edema
  • Elevation: By elevating the leg and hamstring muscle above the heart after an injury, some of the fluid that is caused by inflammation can drain back to the center of the body, rather than pooling in the affected area.

Outside of the R.I.C.E protocol, swelling may be decreased, pain may be reduced and blood flow may be improved by some over the counter medications such as Ibuprofen and Advil. These are just some of the things that athletes can do at home to help themselves recover from a hamstring injury. As a result of this protocol, the muscle should heal to the point where athletes can begin some passive stretching and free exercising to strengthen the muscle.

While the R.I.C.E protocol is an effective protocol for initial treatment of a strain, that protocol is just the beginning of the rehabilitation process that should take place. The period of rest will help the injury heal, but that rest will also cause a decrease in flexibility and strength. The next step would be to try to strengthen the area around the hamstring, such as the surrounding tendons and muscles. This is not necessarily a continuum of the order in which these athletes follow, but there should be an emphasis on the listed order.

Force Production

In an attempt to help an athlete return to play, the first thing an athlete should do is to strengthen the surrounding muscles by doing compound exercises, as opposed to exercises that isolate the muscle and put too much direct strain on it. By doing compound exercises, the hamstrings are able to be worked without being overworked. Two example exercises could be the squat and deadlift. The squat and deadlift may be used to help the muscles gain some of the strength that they lost due to injury. For a sprinter, these exercises will also recruit fast twitch motor units and accomplish a high neuromuscular output (Davis, 2017). While these lifts should not be maximal effort, they should be challenging enough to apply some load to the muscles. These and similar exercises are focused on producing force.

Force Absorption

Following these force producing activities should be some form of force absorption activities. A great way to train the body to absorb force would be by performing fast, eccentric movements. As far as exercises go, you or the athlete that you are rehabbing should do things such as depth drops to improve force absorption. In depth drops, the athlete should be standing atop of a platform, (height depends on the level of athlete and the level of injury), and have them jump off of the platform and land on the ground. In this movement, the athlete indirectly uses their hamstrings to absorb the forces applied by the ground from their jump. These depth drops can be performed with a stiff legged landing or regular, bent knee landing. Studies by Killgallon et. Al and Mjolsnes et. Al have shown that eccentric exercises increase strength in muscles at longer muscle lengths more than concentric exercises do.

Force Storage and Release

Next, the athlete should focus on storing and releasing force in order to get the muscle back to its original pre-injured state. During this phase, the athlete can begin to incorporate plyometrics into their rehabilitation process. Storing and releasing force is similar to absorbing force, but in the storage and release of force, you are coupling an explosive concentric movement with that fast-eccentric movement. Looking at a depth jump, for example, an athlete performs a quick eccentric movement to lower their bodies off of the box before they perform an explosive concentric movement to jump into the air. The landing portion is storing energy, and the jumping portion of the depth jump is releasing the stored energy. During this storage and release, the athlete is activating the stretch-shortening cycle, causing them to utilize the elastic energy that they have stored. In a hamstring, dominant plyometric exercise, it is very important that these muscles can work in a concentric and an eccentric manner before they are able to return to sport.

If the athlete is able to perform these movements efficiently and successfully, they may be ready for more sport specific movements. For a runner, this may be a jogging and light sprinting progression. Once they are comfortable and pain-free during these types of movements, they may be able to progress to strides and faster sprints before they ultimately return to their full speed running. Each sport will have specific movements that should be done in the form of a progression, but the general idea is that you want to start sport specific movements at a lower intensity at which they are typically done. As time goes on, these movements can gradually progress to the level that they were performed at pre-injury.

While the recovery from a grade III strain (complete rupture) is a lot different, these strains can also still be treated and ultimately returned to their fully functional state. These types of strains may require surgery because the muscle has become detached from the tendon and sometimes may need to be manually reattached to it. For a more specific rehabilitation process, an athlete/coach should follow the advice of an orthopedic professional.

If possible, an athlete should seek the help of a physical therapist following an injury in order to optimize their rehabilitation process. Access to a physical therapist may not be available to every athlete, so in those cases, they must adhere to protocols such as the R.I.C.E to help get them back to their original, pre-injured state. It is important that, if an athlete wants to return to the level that they were at before injury, they must be cautious and patient with their rehabilitation. Returning from an injury too soon will only increase the chances of a re injury. With the adequate rehab and rest, it is quite possible that they can return to being the fully functioning athlete that they once were.

References

Hamstring Injury (Hamstring Muscle Strain) Rehabilitation – Hip & Thigh Sports Injury Products & Physiotherapy Advice. (2017). Retrieved July 01, 2017, from https://www.physioroom.com/injuries/hip_and_thigh/hamstring_strain_exer.php

J. B. (2009, January 23). How to Avoid and Treat Hamstring Strains. Retrieved July 07, 2017, from https://www.coreperformance.com/knowledge/injury-pain/hamstring-strain.html

W. (2016, July 21). How to Safely Strengthen Hamstrings After an Injury. Retrieved July 10, 2017, from https://www.wikihow.com/Safely-Strengthen-Hamstrings-After-an-Injury

Cammarota, , B. (2013, December 03). Hamstring injuries: Frequency, re-injury and length of recovery. Retrieved July 10, 2017, from https://www.philly.com/philly/blogs/sportsdoc/Hamstring-injuries-frequency-re-injury-and-length-of-recovery.html