The muscles comprising your back belong to the biggest and most complex groups of muscles in your body. (fitnessandpower.com)
Just like other muscles in your body, the older you get, the more help you need to keep the colon muscles strong and functioning properly. (liveinthenow.com)
The back muscles are not intended to replace the function of the glutes, one of the largest muscles in our body. (tomcoffeyfitness.com)