
1) Relief from tension/stress - training is hard and strenuous and the main reason for getting a massage is to relieve that stress. By allowing the mind to relax and the body to recover, an all around feeling of being "fresh" will give you the perception of starting anew.
2) Dilation of blood vessels - a massage dilates blood vessels which increases circulation which in turn flushes out toxins that can reduce muscle soreness and swelling.
3) Increases muscle tone - stimulating the muscles this way will increase muscle tone and prevent fatigue and muscle atrophy. Aiding this will also decrease risk of injury due to lower risk of tightened and/or strained muscle and increase flexibility.
Some other great benefits of a massage are: lower blood pressure, emphasis on elimination of metabolic toxic wastes, improved lymphatic system, releases endorphins, reduces pain, improves sleep, delivers more oxygen and nutrients to muscles, stimulates slower breathing, allows relaxation and repair of muscles, etc.
Even though now-a-days a professional massage can range you anywhere from $100-$300 pending on length and style, it is a definite must in the fitness world because of all the vast benefits. So go out, save up some money, and enjoy a massage because now you know all the great aspects it will bring to your life. It is well worth it.