The term 'overuse; is actually a bit of misnomer, but the term has stuck so it is still being used.
The term is also 'relative' - what constitutes overuse for one person may not be so for another. Really what we are referring to when we use this term is actually 'inappropriate exercise'.
What is overuse?
Most of the tissues in the body are simultaneously being broken down and repaired. During training the breaking down increases and so does the repairing, but the repair usually dominates allowing the muscles to get bigger.
However, when training, biomechanical and other factors lead to a situation where the rate of damage eceeds the rate of repair, the body's response if an acute inflammation leading to pain, swelling and stiffness.
If this is ignored the situation may become chronic and difficult to treat, not necessarily settling with rest.
Training errors leading to overuse problems
Certain sports lead to repeat loading, for example -
- track running places more stress on the outside of the 'inside' leg and the inside of the 'outside' leg. This leads to an asymmetric load on the bones.
- Running on cambered road surfaces leads also to more loading on one part of the knee than another.
- Cycling clipless puts constraints on the knee and inappropriate stress can cause problems.
- Running on hard surfaces such as concrete pavements can lead to considerable stress on joints.
Most of these problems can be overcome by a varied training programme involving a variety of sports and training on a variety of surfaces.
Faulty biomechanics leading to overuse problems
In the same way that everybody's faces are different, the shape of everyone's skeleton is also different, for example, the angle that the foot makes with the leg, or the femur makes with the tibia. These differences can become much more complex within the anatomy of the foot or with rotational alignments of the leg. Over-pronation of the foot (flat foot) is an underlying cause of many sports overuse injuries. Another common cause is valgus knees (knock knees) which are associated with problems with the patellofemoral joint and patellofemoral subluxation.
Some people's skeletal shape is simply better than others with regard to fitness to play sport.