Although cycling has positive health effects, including improvement of cardiovascular fitness, it does not have a favourable effect on bone health. In professional cyclists, the bone mineral density (BMD) will actually have decreased at the end of an intensive season. As a professional cyclist's career progresses, there will be a further decrease in BMD particularly in the hip and lumbar spine. The forward leaning position, the repetitive movement at low intensity, and the fact that body weight is carried by the bicycle all contribute to non-stimulation of bone formation. The cyclists' low body weight, which is desirable for climbers in particular, and possibly their dietary pattern may exacerbate this negative effect. To reduce the risk of fractures both during and after a cycling career, it is desirable that more attention is paid to strengthening of the bones. The effectiveness of training programmes to strengthen the bones should be investigated in carefully designed research studies.