What is a tendon?
A tendon connects muscle to bone and is designed to absorb force. They act as a spring that stores energy that allows a dancer to produce and absorb force, such as jumping higher. Tendons are made up of flat cells called tenocytes that lie in rows between collagen fibres. There is minimal blood and nerve supply in the normal tendon.
Tendons response to load
Like bones and muscles, tendons adapt to the load that is placed on them. Activities such as jumping and running are called plyometric activities and maximally load a tendon. This is due to the energy storage and quick release in the tendon (similar to if you flick a rubber band across the room). There are high load and low load activity types tendons go through.
Examples of high load activities in ballet would be petite and grand allegro (bigger jumps and greater distances traveled) as opposed to low loads such as barre work and adagio. Tendons have a specific capacity they can withstand in terms of load. The normal response to an increase in load, is to become stiffer. If the tendon is being loaded gradually with sufficient recovery time, it will be able to adapt to the demand being placed on it and it will be able to cope. If there is too much of an increase too quickly, and/or insufficient recovery time is being given, it will go through changes at the deep cellular level that are considered pathological changes.
This usually occurs with a sudden change in activity such as returning to a normal dance load after holidays or returning from injury, or increasing rehearsal and class hours for an upcoming performance. The response of the tendon in this stage is to draw water into the cells in order to thicken it by increasing the surface area so it’s able to withstand the new added forces. At this stage whilst it is technically swollen, there is generally no evidence of inflammation.
The tendon is able to recover in this stage which normally takes approximately 3 days which is done by reducing the load. If the load is not reduced, however, it will progress towards dysrepair (failed healing).
Proteins continue to increase in the tendon which can cause gradual separation of the tendon fibres and disorganization of the collagen. New blood vessels and nerves also begin to grow in the tendon during this phase and depending on load management and modification, the tendon can still heal.
If the tendon is continuously overloaded and unable to repair itself, it will then progress into degenerative tendinopathy. In this stage, the tissues have begun to break down and there is apparent cell death which is unlikely to be reversible. If there is still healthy tissue surrounding the damaged cells, it can be strengthened and the dancer can return to full work load without pain. If the tendon is continuously loaded, it can result in a rupture which will need surgery.
If a tendon is “unloaded” (where it is braced or placed in a cast) it can have a similar effect as if it was overloaded. This is because the tendon is unable to be strengthened, so the healthy tissue becomes weak. Additionally, once the pain has settled and the dancer goes back to training because the healthy tissue is now weaker, the tendon’s baseline strength has been
diminished and can be now overloaded much more easily. It is important to gradually strengthen and load the tendon to improve its capacity.
How do we manage and modify load appropriately?
Generally, tendons don’t like change and like consistent load. They respond well to strength training, particularly heavy, slow resistance training and don’t respond well to a sudden increase in jumping, running, and quick changes of direction.
- Slowly increase jumping, running and changes of direction in new choreography seasons and allow several days of recovery in between. This applies to students (particularly young students) who are progressing through levels and participating in workshops or intensives.
- Gradually increasing and decreasing activity should be applied at the start and end of term.
- A strengthening program should always be maintained to keep baseline tendon capacity at its highest.
- A dancer should never completely rest with tendon problems, they should have relative rest. This means avoiding provocative activities such as jumping but should participate in class as much as possible or participate in strength training as the injury allows.
But as always, it’s best to book in to see a physiotherapist for assessment and appropriate management.