Everything you need to know about hamstring rehab exercises is the follow-up article, in a two part series on hamstring Injuries. The first article went into detail on the anatomy, bio-mechanics, and signs/symptoms of a hamstring injury. To read this article, click here.
Hamstring Injuries Prevention
The old saying, “an ounce of prevention is worth a pound of cure” rings especially true for hamstring injuries. Preventing hamstring injuries involves identifying the predisposing factors and then addressing them. Increasing hamstring muscle length and strength, active warm-up with sport-specific activities and proper running technique can all prevent hamstring injuries.
The type of activity being performed during a hamstring injury can also effect recovery. Hamstring injuries that occur while running (intramuscular tendon or aponeurosis and adjacent muscle fibres, usually the biceps femoris) typically heal faster than injuries that are involved with dancing and kicking (proximal free tendon, usually the semimembranosus) (Higashihara, A, et al 2010).
Hamstring Injuries Rehabilitation
The consensus among authors and healthcare practitioners is that early movement (mobilization) promotes the quickest recovery and prevention of future hamstring injuries. Research has shown that early mobilization promotes new muscle tissue growth (collagen fibres). Early mobilization also breaks-up (properly orientates) scar tissue and creates new blood vessel formation (re-capillarization) (Heiderscheit, et al, 2005).
Hamstring Rehab Exercises and Stretching
It is not uncommon to see athletes prior to a match doing a sit and reach stretch to loosen up their hamstrings. However, stretching might actually be doing more harm than good. This is because research has shown that a sit and reach stretch tensions the sciatic nerve. The sciatic nerve supplies the majority of the hamstrings.
A study by Mendiguchia, J, et al 2011, found that 14-19% of hamstring injuries had no muscle damaged when investigated with MRI. The authors concluded that tension placed on the sciatic nerve (neuromeningeal structures) was the cause of the hamstring irritation. Increased tension on the sciatic nerve has also been shown to be a risk factor for future hamstring injuries.
A safer alternative to the sit and reach, is a single legged stretch with a Pilates ball. With this stretch there is no flexion of the neck or foot, so the sciatic nerve is not placed under tension. If this stretch is too difficult you can try a straight leg raise while lying on your back. The goal of this stretch is to feel a gentle pull on the back of your hamstring. This position should be held for 30 seconds and repeated 3-4 times.
It is recommended that you warm up a muscle prior to stretching. This can include placing a damp, warm cloth over the muscle or performing an active warm-up such as the ‘ABC’ drills.
What is the Best Hamstring Rehab Exercise?
A proper stretching program and active warm-up can help to loosen up the hamstrings prior to activity. However, what are the best exercises to rehab a injured (strained) hamstring.
As stated previously, one of the greatest predisposing factors for future hamstring strains is a shortened muscle length. Therefore, it is important to avoid training the hamstrings at a shortened length.
Studies have shown that cycling produces training effects in the hamstrings at shorter muscle lengths than while running. Essentially, cycling makes the hamstrings strong but short.
If you want to increase the strength and length of a muscle, eccentric exercises are your best bet. Eccentric exercises have been shown to produce training effects at longer muscle lengths [Fig.4].
Nordic Hamstring Exercise
An eccentric exercise is when a muscle is contracting and lengthening at the same time. If you imagine a bicep curl, the eccentric portion would occur while you were straighten your arm.
Research has shown (fig 3) that Nordic hamstring exercises (NHE) are an effective way of increasing the length and strength of the hamstrings. NHE can significantly (2 cm) increase the length of the hamstring muscle (fascicle) in only 4-5 weeks. However, any gains in the length of the muscle are lost as soon as you stop exercising [Fig.5]. This is why individuals must adopt a maintenance routine if they want the results to last (Maintenance of 5 reps, 2 sets 1 a week indefinitely after).
Muscle strength increases are also seen with NHE. However, unlike hamstring muscle length research has shown that muscle strength gains persist after training has stopped [Fig.6].
In addition, to increased muscle strength and length. NHE have also demonstrated greater activation [electrical activation (EMG)] of the hamstrings (semitendinosus and semimembranosus) compared to hip extension exercises. However, biceps femoris activation was greater with hip extension exercises.
Nordic Hamstring Exercise Program
According to Dr. Daivid Opar, the minimum viable dosage for achieving increased hamstring muscle strength and length gains with NHE is 72 reps for the first two weeks. This initial acclimatization phase is followed by an indefinite maintenance phase of 8 reps per week.
So in the initial 2 week phase, an athlete could perform 18 reps, 1 time a day, 4 times a week. Or they could perform 9 reps, 2 sets a day, 4 times a week. The authors did not state a preference. Once the 2 weeks are up, the individual must do a maintenance program. This consists of 8 reps per week indefinitely to maintain the increased hamstring muscle length.
Other Eccentric Hamstring Rehab Exercises
There might be circumstances where the NHE is too difficult to perform. Whether it is an acute injury or coinciding knee and hip issues. In these circumstances, there are other eccentric exercises that can be used.
Patients can start off with either an double legged bridge or hip extension exercise. It is important focus on the eccentric portion while performing the exercise. The goal of these eccentric exercises is to train the endurance capability of the hamstrings. Therefore, high reps and low sets are recommended (15 x 3).
If an individual can perform the exercise in a pain-free ROM, then the difficulty should be increased. Progression for the bridge includes performing a single legged bridge, incline single legged bridge. Finally, incline single legged bridge on an unstable platform (TRX). The progression for hip extension is a single leg eccentric hip extension.
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