5. Calf or Achilles tendon strain

Description: Pain in one of the muscles at the back of the lower leg (calf) or in the tendon that attaches the calf to the heel (Achilles tendon). Discomfort is often worse when running uphill, because uphill running can excessively stretch the calf – particularly if you aren't used to hill training. Overuse and poor flexibility are the most likely causes.

Treatment: Rest, sports massage to remove adhesions and align muscle fibres, and a programme of flexibility training and strengthening exercises. Specialist help and treatment is recommended.

Training and racing: Continued training or racing will only exacerbate the injury, which could eventually result in a snapped Achilles tendon – which would require surgery and lengthy rehabilitation. Instead, focus on the treatments we've given and maintain your fitness with non-calf-loading exercise such as swimming.