Customers who ask for a topical painkiller will often be doing so as a result of physical activity having gone wrong. This may be because of an accident, exercising without first warming up, falling over, using equipment wrongly, having incorrect technique, or pushing the body beyond what it can cope with. Any of these can result in an injury, the most common of which are:

1. Sprains are the result of an abnormal or excessive force being applied to a joint, injuring the ligament. Commonly affected joints are the knees, ankles and wrists.

2. Strains are stretching or tearing of muscle fibres as a result of being forced to contract too strongly or being stretched beyond their limits. The legs and back are frequently affected.

3. A dislocation occurs as a result of a joint being moved beyond its normal range of motion (for example, the shoulder) and often results in ligament damage.

4. Tendonitis is inflammation of the tendon that attaches two bones. It is a common injury in the elbow for those who play tennis or golf.

5. A ruptured tendon is a serious condition that usually happens suddenly, causing severe pain because of a tear in the tissue. This commonly affects the Achilles tendon in the ankle.

6. Fractures are breaks in bones. Sometimes these may be tiny cracks, as is the case in shin splints, a painful but self-resolving condition that can affect runners. But the break may be much more severe and serious, causing extreme pain and resulting in the person being unable to use the affected area.

Some customers may also seek advice on topical pain relief because they suffer from osteoarthritis. This condition is the result of damage to the cartilage in a joint, most commonly the knee, which results in swelling, pain and stiffness.