With a massage gun you increase the horses performance, flexion happiness and physcial health as it realeases the lactic acid within the muscles that can be built up after an intense exercise.
By doing a massage on your horse you are allowing the blood to flow circulation to go back through the muscles which helps oxygen and nutirents enter the muscles.
This also relieves muscle spasms which is caused by the lack of blood flow within the tissue and by applying light pressure to the tendons, muscles ligaments you will result into helping them relax alot more.
There are many other health benefits to the massage gun, apart from relaxing the muscles and alleviating pain. This also includes increased mobility, improved rest and improved immunity.