David McCagg Takes Us Through the GMX7: The Future of Resistance Training For Swimming


Swimming World sat down with David McCagg at the American Swim Coaches Association World Clinic in Dallas, Texas earlier this month. McCagg is a former USA Swimming national team member, having won two gold medals at the 1979 Pan American Games in the 100 free and 4×100 free relay.

McCagg, World 100m freestyle champion in 1978 and winner of three golds (including 4x100m freestyle titles in 1978 and 1982), founded GMX7 in 2018, which is the future of resistance training for swimmers. The GMX7 device is shown in this interview and it is attachable to the lane line that tethers to a belt that the swimmer wears. The resistance is adjustable on the device itself and is fairly simple to use. McCagg also assured that the device will be able to correct a swimmer’s stroke since the line that runs parallel to the lane line and the swimmer will be able to hinder an athlete’s stroke if he or she is reaching too wide.

The GMX7 is not on the market yet since the company is still developing a patent for it, but McCagg said that they will make their first deliveries in November of this year. McCagg tested his device with Ryan Lochte and Caeleb Dressel and the rest of the Florida men’s and women’s teams (pro and amateur), who have been testing it for the last six months.

The device is made of aluminum and stainless steel so it will not rust. It is available for purchasing here.

1 Comment
Newest Most Voted
Inline Feedbacks
View all comments
Camillo Cametti
3 years ago

World Champion at Berlin 1978 in both 100m and 400m relay freestyle.