What are tendons?
Tendons are the tough tissue that joins the muscle to the bone. Tendons are at every joint and they help that joint to move. Regardless of where the tendon is in the body, it has the same role.
Tendons are the essential structural element that stores and releases energy that allow us to move powerfully. They behave much like a spring. The inner structure of the tendon slides, glides and rotates. This occurs as load (force) is applied to them.
In the Achilles tendon (see image above) this occurs when the heal hits the ground, the Achilles which is at the base of the calf rotates, glides and lengthens. As you move to a ‘push off’ position the calf muscle contracts and the power of the spring gliding and rotating back into a tight spring propels you forward, it ‘forces’ you forward. To get more ‘power’ and therefore move faster you need to make your Achilles ‘spring’ faster. The Achilles of a kangaroo is a great example of the very powerful spring mechanism. The same mechanism occurs at the elbow and wrist when you hit a tennis ball, at the hip when you step up a stair and your knee when you kick a ball.
Tendons generally have a poor direct blood supply (unlike muscles). They get their nutrients through the paratendon – the sheath around the tendon and circulating blood supply. This lack of direct blood supply is one of the reasons why they are one of the slowest tissues in the body to adapt to training loads.
How does a tendinopathy develop?
Tendons adapt to training (loads) – slowly. The more you make them work in their capacity as a spring the better they get at it. However, the key word here is ‘slowly’. Whereas a muscle will adapt to a steady increase in load really quickly anything from 6-12 weeks, tendons take much, much longer with most full tendon strength coming after no less than 4-6 months.
This poses a problem for those starting an exercise regime. Most fitness programs on the internet are for 12 weeks. There is rarely any allowance made for tendon strengthening. As a result, many programs ramp up the intensity and in particular the dynamic intensity quite quickly, not allowing the tendon time to adapt. Add in other factors such as age, hormones, physical or mental stress or illness and adaptability of the tendon can be slowed further. The problem occurs then that the tendon is just not ‘fit for purpose’. There is more load is placed upon it than it can cope with.
This affects the fundamental structure of the tendon and over time this can lead to degeneration or break down of the tendon so that it no longer behaves like a tendon, it’s no longer ‘springy’.
The tendinopathy continuum
In 2009 (reviewed and updated in 2016) Australian researchers Jill Cook and Craig Purdum described a continuum model of tendon injury.
In the initial stages of tendon injury, it is known as a reactive tendinopathy – too much load has been placed on the tendon and it has become irritated in response. The tendon will often become thickened and a bit stiffer. There may or may not be pain and in fact pain is not indicative of degree of injury. If load is optimised at this stage then the tissue will settle down and the tendon will remain ‘healthy’.
Tendon disrepair is the second stage of the tendon injury continuum where changes are starting to occur in the actual structure of the tendon. The tendon often has become thickened and very stiff. There may be ‘bumps’ along the tendon. Changes in load will help this tendon, however it is becoming limited in its ability to self-repair.
How to manage a tendinopathy
However, research has shown that the outer ‘healthy’ tendon structure can be developed. This is where we really must develop the strength and function. It’s much like a donut. Focus now needs to be on improving the remaining healthy fibres of the tendon research has shown that these healthy fibres can thicken and adapt such that the tendon can function optimally – even though the damaged component of the tendon will not change.This is why treatments that focus on trying to ‘fix’ the damaged portion of the tendon fail.
There is one, proven method of improving this tissue and that’s through specific and progressive strengthening exercises designed to work the local muscle, improve the mobility of the tendon and develop the spring. It does take time, remember at the beginning I said 4-6 months! The program needs to be specific to the tendon and to the task that you need to do. There is no short cut with this.
It is interesting to note that any ‘pain’ you may feel is NOT associated with the degree of ‘damage’ you have. Pain is a complex physical and emotional response and not a measure of damage. Pain that has been around for a long period of time is known as persistent pain and needs to be addressed as a separate entity to the actual injury – but more on this next time…
Talk to one of the Vital Core Physio’s about getting onto a tendinopathy rehab program Yes it will be hard work and yes it will take time, but the dedication will be worth it as you are able to return to the activities you have been missing out on.