Rapid increase of muscle in a person is an abnormal condition where there is sudden increase in the muscle mass of a person. This condition is known as muscle hypertrophy syndrome. It is a rare genetic condition which increases muscle growth by two times the normal growth. The most common kind of muscle hypertrophy is myostatin - related muscle hypertrophy. In this type of muscle hypertrophy the people suffer from a deficiency of MSTN gene which is responsible for the manufacture of the protein myostatin. The protein myostatin is responsible for the growth and the development of tissues. Infants inherit an MSTN gene from each parent. A mutation in both MSTN gene copies causes significant increase in muscle and strength. Doctors test for myostatin - related muscle hypertrophy by measuring the size of skeletal muscle through ultrasound examination, MRIs and other tests. They may also use a caliper to measure fat pad thickness. The most common symptoms that people experiences are muscle cramps, back spasms, and muscle spasms. Depending upon your condition your doctor would either prescribe medication or injections to improve your condition. Physiotherapy also plays a key role in speeding your recovery.