MODEL RELEASED. Cramp. View of a female physiotherapist treating a rugby player for calf cramp with cold spray. Cramp is a painful spasm in a muscle caused by excessive and prolonged contraction of the muscle fibres. It often occurs toward the end of a rugby game because of a build- up of lactic acid & other chemicals (caused by increased muscular activity) and small areas of muscle fibre damage. Cramps can also occur due to repetitive movements. Cooling the muscle with spray or cold water and massaging it relives the problem. Photographed in Pontefract, West Yorkshire, England.