There are a few ways in which exercise can help.
One way is a term called Mechanotransduction or mechanotherapy and this the process of how exercise stimulates tissue repair and remodelling in tissue. This is an ongoing process in the human body just like respiration and circulation.
So what is it?
It is the process where the body converts the loading from exercise into cellular responses. These cellular responses promote structural change in the tissue - the muscles, tendons, cartilage and bone. A good example is weak bone can become stronger when put under appropriate load.
So this tissue goes through three stages, the first being the trigger and this is what your physio will call ‘load’. For example walking provides the achilles tendon with force which can elicit a change in the cells which can trigger a whole array of responses depending on the type, weight and sets and reps.
The second phase is the communication of the load throughout the tissue. This allows us to affect other tissue that may be in another location because of certain chemical reactions.
And finally the third part is the response at the cellular level to produce a tissue response and assemble the necessary material in correct alignment. In the absence of activity, mechanotansduction is weak and change in tissue is lost and will thus deteriorate - get weaker etc. When there is a load (exercise) above the tissues set point or capacity the body will adapt and change, becoming larger and stronger.
Research shows exercise and load helps to repair tendons, muscles, cartilage and bone.
This article was adapted from Khan and Scott, 2009, which is an open access article in the BJSM and can be accessed here: http://bjsm.bmj.com/content/43/4/247.long
Some examples of improvement can be seen below:
Muscle - Increased strength
Tendon - Improved capacity of muscle-tendon unit
Bone - Increased bone density
Joint - Regulation of synovial fluid, improved joint function