In this article we take a look at a research project that was published in the American Journal of Sports Medicine (Vol. 26, No.3) 1998. The study investigated the role of resistance training in rehabilitation of chronic achilles tendonosis.
Overuse injuries involving the achilles tendon are common, particularly among middle aged runners. The symptoms include pain and discomfort during impact activities -- such as running and aerobics -- and there is often associated stiffness felt in the mornings and at the onset of exercise. These problems are often slow to resolve due to the poor healing rate of the tissues involved and the high loads they have to endure during impact exercise.
Recent work by Khan and co-workers studied the nature of the lesion within the achilles tendon. Their research revealed a lack of inflammatory cells in and around the involved site which led to a reclassification from tendonitis (inflamed tendon) to tendonopathy or tendinosis (terms that refer to the mechanical breakdown of tissues within the tendon). These studies provided an insight as to why these injuries require such a lengthy recovery period and helped to explain the relative ineffectiveness of anti-inflammatory modalities when dealing with these injuries.
The study in the American Journal of Sports Medicine took two groups of 15 individuals who each had an achilles tendinosis. In each case the diagnosis was confirmed by an ultrasound scan and the subjects had a history of discomfort for at least three months.
- Group 1 continued their conservative management of rest, non-steroidal anti-inflammatories, orthotics, physical therapy and standard rehabilitation programmes.
- Group 2 was placed on an eccentric loading programme.
Both groups were monitored for six months. Regular measurements were taken to determine levels of pain and strength within the calf-achilles unit over this period.
The results were significant.
After a 12 week period the group that was placed on the eccentric loading programme made a complete recovery and were back running at their pre-injury level. The other group undergoing conventional care went on to require surgery and subsequently a more lengthy recovery time. These results indicate that a correctly administered eccentric loading programme significantly reduces the recovery time of an achilles tendinosis.
So - what is an eccentric loading programme? Eccentric exercise emphasises the lowering or lengthening phase of a repetition. For example in a bicep curl - the upward phase of the motion is known as the concentric contraction - the downward phase (where the bar is slowly lowered to the starting position) is known as the eccentric phase. The muscle continues to contract during this action, however the muscle belly lengthens as it lowers the weight.
Eccentric exercise emphasises the lowering or lengthening phase of a repetition. For example in a bicep curl - the upward phase of the motion is known as the concentric contraction - the downward phase (where the bar is slowly lowered to the starting position) is known as the eccentric phase. The muscle continues to contract during this action, however the muscle belly lengthens as it lowers the weight.
With long term tendon injuries such as achilles tendinosis, it is thought that it is this eccentric type of load that gradually causes degeneration, resulting in tearing and subsequent breakdown of the cells within the tendon. However, placing eccentric loads on these effected tendons in a controlled manner, stimulates the tendon tissue to remodel in such a way as to assist in recovery and to help cope with these types of loads.
The eccentric loading group in this study had to perform a series of modified calf raises on the edge of a step using body weight as resistance. They were instructed to go up onto their toes on the good foot only - transfer all their weight across to the effected side - and lower down to the start position so that the heel of their effected leg was slightly below the level of the step. Therefore the side with the tendinosis performed the lowering or eccentric component of the action only.
This exercise was performed with the knee straight and then repeated with a bent knee to ensure both major muscles in the calf were worked. They performed these exercises for 3 sets of 15 reps, twice each day.
Once these exercises were too easy and there was no discomfort, weights were gradually added in a back pack or the exercise was performed on a calf raise machine (as shown for a tendonosis of the Left leg).
The results, as mentioned earlier, were quite dramatic, with complete recovery of the group undergoing this type of training after only 12 weeks.
Although this research focused solely on the Achilles - I have used the same eccentric loading philosophy when rehabilitating tennis elbow and supraspinatus tendonopathies with similar results. Initially clients may experience mild discomfort following the exercises - however, if they continue with the programme the results speak for themselves. Reassurance and close monitoring is often needed in the early phases to ensure compliance.
These types of rehab programmes should always be done under the guidance of a sports medicine professional.
- Alfredson, Pietila, Jonsson, Lorentzon, Heavy Load Eccentric Calf Muscle Training For The Treatment of Chronic Achilles Tendinosis. American Journal Of Sports Medicine , Vol 26 No 3 1998.
- Karim Khan, Course Proceedings , Sports Medicine New Zealand Annual Conference , October 1999.
- Illustrations , Frank Netter , Atlas Of Human Anatomy