Q I weigh 10st 12lb and am 5ft 3in. Am I too heavy for my height?

A The normal height-weight tables are very limited in their ability to assess whether a person is over- or underweight, as they do not take your frame and amount of muscle mass into account, and muscle really is heavier than fat. As a runner, you work the largest muscles in your body, and the more you train, the bigger and heavier your muscles will become.

However, even if your weight is predominantly muscle, it is still advisable to keep it in check, as the more weight you are carrying, the more load goes through your joints, particularly your knees, when running. It is also more of a strain on the body's cardiovascular system. When assessing a person's “normality” for their height, Body Mass Index (BMI) is considered to be the gold standard. It is calculated by dividing your body mass in kilograms by your height in metres squared. Your BMI works out as 26.9, which would be considered to be on the heavy side. A BMI of 19-25 is considered to be the ideal.

Bear in mind that in addition to this index not allowing for a person's increased muscle mass, the population used to research and formulate the equation was not an athletic one.

—Nicki de Leon, Physiotherapist and Clinical Director at Sports and Spinal Clinics (Moorgate)