Hamstring Injury Rehabilitation
Mathew Barreau explains how you can assist an athlete in the recovery from a hamstring injury.
A role of an athletic trainer is to return the athlete to full participation as quickly and as safely as possible. So, the helpful question to be asked is: "How can we speed up the healing process?"
According to Wolff's Law, the body "reacts and develops according to the stresses placed upon it" (Kidd 2001). With this in mind, we need to stress the body in a way that will induce the injured tissue to heal quickly and effectively. General treatment guidelines for any injury require us to consider the following (Kidd 2001):
The factors in the injury that we must consider are oedema (swelling), pain on palpation, decreased ROM, decreased strength, decreased function. Using the five guidelines, this paper will explain in detail the treatment program for our injured athlete. We assume that this athlete will be the only one in our care, and we will be able to devote our full attention to this athlete's needs.
We must first address the modality of treatment. Modalities are used to curtail the body's reaction to inflammation, which is excessive (Kidd 2001). An injured body will produce signals (swelling, pain, etc.) that will inhibit an athlete from performing at levels that may cause further damage. In doing this, it is overprotective of the injured area. Modalities can control the body's signals. The six modalities are cryotherapy, cryokinetics, thermotherapy, electrical stimulation, mechanical therapy, and pharmacological therapy (Kidd 2001).
"The initial treatment of acute injuries should use cold." (Kidd 2001) Having an analgesic effect, the ice will help reduce the pain of the injured area and, by causing vasoconstriction, any remaining swelling/inflammation will also be controlled. The recommendation is to ice for 20 minutes with a cup (ice massage) over the injured area immediately after the activity for the day. (See "mechanical therapy" for an explanation of the benefits of massage.) After swelling has subsided, we will favour thermotherapy before a workout with ice post-workout.
"Ice is nice, but motion is the potion." (Kidd 2001) Icing before the activity can cause numbness by overriding pain sensory information. This will allow us to have the injured athlete participate in some mild-to-moderate activity, which will help speed up the healing process by increasing the circulation to the injured area. Any exercises done should be active and progress from simple ROM exercises to full sport activity exercises. (These will be discussed in greater detail later.) The recommendation is not to use this modality (in favour of thermotherapy, described next). If pain levels become too high as to greatly prohibit training, then we will switch to cryokinetics over thermotherapy to precede exercise. In that case, we will ice for 10 to 15 minutes immediately before activity until the area is numb. Complete the daily activity in sets of 5 to 10 minutes (until numbness fades), and apply ice for 5 to 10 minutes between sets to "re-numb" (Kidd 2001). Cryokinetics would be preferred if it were a non-contractile injury.
Using ultrasound, we can penetrate deep into the muscle tissues. This will increase the extensibility of collagen (scar tissue; discussed in mechanical therapy), increase circulation, and decrease pain/spasm (Kidd 2001). Increasing circulation will give us greater repair capabilities due to the increased flow of oxygen and nutrients to the injured area. Since pain and spasm are limiting the ROM, then anything to decrease those problems will be of benefit to the athlete. The recommendation is to use ultrasound before the workout. The heat will help reduce pain/spasm, which will increase the ROM. We are choosing this over cryokinetics mostly because applying ice will be more likely to limit ROM even more (by causing muscles to contract - shorten - to heat the body back up (Kidd 2001)), which will limit our ability to complete activities for the day. Also, as swelling subsides (probably after only a few days), we will cease cryotherapy following the workout in favour of thermotherapy. This will allow us to begin dealing with collagen formation.
This modality will also reduce pain/spasm and increase circulation. It also helps with muscle re-education (Kidd 2001). The recommendation is not to use this modality as long as the athlete can perform active functions, based on the S.A.I.D. principle (Arnheim 2001). We will switch to this if weight-bearing exercises or dynamic movements cause too much pain (in which case we will try cryokinetics first). If other modalities are disruptive to the healing process, this modality will be used.
Most commonly known as massage, this modality also decreases the onset of pain and spasms. Deep tissue massages can also help realign collagen fibres that are forming as scar tissue (Arnheim 2001 and Kidd 2001)[1,2]. Even ice massages will influence the direction of scar tissue growth. Responses to massage are mechanical, physiological and psychological (Arnheim 2001). The recommendation is to use this form of therapy following a workout. While swelling is still present and cryotherapy is still in place, we will massage the injured area lightly immediately after the workout before applying ice. Once the swelling has subsided, and thermotherapy is in place immediately following the workout, we will use massage after ultrasound - this will allow the ultrasound to break up collagen (Kidd 2001) to enable us to influence its growth/alignment better.
This modality is mainly used to reduce pain and spasm and to decrease inflammation. I am against any chemical means of interaction unless necessary. With all the other forms of therapy we are introducing, the benefits of pharmacological therapy will be covered in other ways. The recommendation is to avoid this form of therapy in favour of the previous five modalities. If the pain becomes too high, then pain medication may be prescribed into the routine. Pharmacological therapy should only be used to allow an athlete the opportunity to perform rehabilitation therapy (Kidd 2001).
The goals of therapeutic exercise are for the development, improvement, restoration, and/or maintenance of ROM, strength, cardiovascular fitness, and coordination and skill (Kidd 2001). Each of these has been diminished in some capacity due to the injury, so each one must be addressed in the rehabilitation program
As stated previously, the pain/spasm within the muscle is causing a "guarding" of that muscle, subsequently creating a decreased ROM. Because ROM (in an athletic sense) is defined as the ability of a joint to move freely through its functional movements, any decrease in this will also harm the activity performed. ROM is performed based on two assumptions (Kidd 2001)
ROM is used to influence scar growth, rather than treat scar formation (Kidd 2001). Scar formation will cause a more permanent decrease in the ROM and subsequently the ability to perform the activity. In the early sub-acute stage of injury, passive ROM should be performed first, with a progression into active ROM "Let pain be your guide." Passive ROM will do the following (which will be directly beneficial to our injured athlete) (Kidd 2001):
If the pain is not too high, then active ROM can be used in place of passive ROM. Active ROM is used to (Kidd 2001)
The reasons for the use of active and passive ROM and their benefits have been described numerous times previously in this paper. There are contraindications to ROM, however, that we must consider. Most notably, ROM should not be performed when the motion is disruptive to the healing process (Kidd 2001).
Limitations of contractile tissue can also be treated with both inhibition techniques and passive stretching (ROM is not synonymous with stretching. However, stretching was mentioned here because it can help increase one's ROM.) Strain-Counter strain is an inhibition technique in which you "re-educate" the injured muscle. This technique is very gentle and non-traumatic for both the patient and the operator (Randall 2002). It involves moving the patient's limb away from pain, resulting in "maximal shortening of the involved muscle (hamstring, in this case) and its proprioceptors, and eventual reduction of neuromuscular firing to tonic levels." (Randall 2002). Then a slow return to the normal position (straightening of the leg) will increase the ROM. Slow movements are essential (especially in the first 15 degrees of motion), or the benefits from the positioning will be lost (Randall 2002).
Using the philosophy that a tight muscle is a weak muscle (Kidd 2001), we need to provide some forum for strength building for our injured muscle. In strength exercises, an AROM is used, which will help influence scar tissue development in the plane of movement desired. As the pain subsides (mainly due to scar tissue formation), we will be able to return to normal functioning activity. Isokinetic exercises are best for an injured tissue because we can control the speed of contraction and/or use manual resistance. (These require the athlete to make an active contraction of the muscle; if the pain is too great and activity is disruptive to the healing process; do not progress to strength training exercises.) Exercises, where we can control the speed (especially on a machine) can help us determine to what level the athlete is ready to perform his activity; if particular speeds are more painful than others, we will have a better idea as to what activities should or should not be prescribed. Speed is an important factor here. (Arnheim 2001)
Isotonic exercises will create resistance throughout the entire ROM, but we will not be able to control the speed as we can in isokinetics. Squats, deadlifts, lunges, and step-ups will all be incorporated into the workout regimen. We will repeat each exercise in sets of five to ten repetitions, beginning without any weights. Using only the athlete's body weight as resistance, we will complete one set of each exercise (as the injury allows). Once one set of each can be completed with ease, we will add additional sets. After the athlete can complete three sets without weight, we will slowly increase the resistance (i.e. add 25 to 50 pounds of resistance, keeping within a tolerable range and being careful not to cause further injury or disrupt the healing process).
If a particular point in our athlete's ROM is injured, then isometric exercises can help build strength at that point. While this may be helpful, it can be very dangerous as you are specifically targeting the injured position of the muscle and can potentially cause the most damage here. The athlete should push against the trainer's resistance (using hamstring muscle) for 10 seconds and repeat the contraction five to ten times per day (at points that need strength). (Arnheim 2001)
To work the hamstrings, there are two exercises we can use (and can be performed without a trainer). The first is a hamstring muscle "heel dig" where the patient digs the heel into the floor in various degrees of knee flexion. (Kidd 2001) Or, in "leg wrestling", the patient sits on the edge of the table with both legs hanging over the side. The uninvolved leg acts as the resistance and the involved leg pushes against that resistance, at various degrees of flexion. (Kidd 2001) These are both great exercises for the athlete to perform during the day, either sitting at home or during class if he/she is unable to make it to the training room that day (i.e. the weekend).
Because we have a prime athlete who is losing valuable training time, we must do what we can to maintain, develop, or even improve his cardiovascular fitness. We have nearly unlimited freedom in this area, with the only contraindication being an activity that is disruptive to the healing process. Swimming may be the best means of maintaining cardiovascular fitness because it is non-weight bearing and does not necessarily require the use of the legs. If the kicking motion in swimming (in any of the different strokes) does not cause pain, then those may be used. Should pain be to "questionable" levels, the legs can be held motionless and only arm action used?
Swimming workouts can be likened to running workouts in their intensity/duration; either endurance training or interval workouts can be implemented. Also, if the running motion is painful only because of the impact on the ground, then completing this motion in the pool with the aid of an Aqua Jogger may be beneficial. Weight routines can also be implemented to aid in cardiovascular fitness as well as their strength training benefits.
Cycling can help with ROM of the injured limb (strap it to pedal) but need not include that limb in exercising (can use only non-involved side for the source of power). However, a problem with that can be an even greater imbalance produced by continuing to exercise the healthy side.
Coordination and Skill
Neuromuscular involvement in the healing process is just as important as any of the previous treatments discussed. Not only does an athlete need to maintain, develop, and improve the ROM, strength, and cardiovascular aspects of the injured muscle, but the "muscle memory" of the skills involved must also be addressed. Closed chain exercises are recommended. A closed chain exercise refers to a movement that occurs in a closed kinematic chain where the body moves over a fixed distal segment. (Kidd 2001) The benefits of this are that it maintains proper joint movement, involves multiple joints with a normal physiological load, and is more functional. Recommended closed chain exercises include squats, deadlifts, lunges, and step-ups. (Kidd 2001) (See strength for specific amounts).
Open chain exercises (end segment of limb moving freely in space) can isolate the muscle but may provide false feedback. Open chain exercises include standing hamstring curls and hamstring curl machine. We will favour Closed chain due to the more physiologically-representative movements they provide. Ultimately the decreased function of our athlete is our main concern. We wish to return the athlete to pre-injury levels as quickly (and safely) as possible. Our treatment plan must be implemented with the controlling principles of positive adaptation in mind.
Also included in our treatment plan, but was not fitting into any category above, is the necessity of a warm-up and cool-down. Warming up will increase the elasticity of muscle and reduce the chance of any further damage to a muscle already "guarding" itself. Cooling down will help reduce any lactic acid (though this may not be produced at too high of levels since the activity level has been reduced) and stiffness that may result after activity.
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About the Author
Mathew Barreau is assistant Cross Country and Track coach in charge of distances at Portland State University, a USATF Level II certified Endurance Coach and a USATF Level II certified Sprints/Hurdles/Relays Coach. He can be contacted through his college website at www.goviks.com. This article has been produced here with his kind permission.