The term 'muscles' is an umbrella term for the three solutions EG, Biceps and Abs. EG stands for Erector Spinae, which is a group of muscles located in the lower back that are responsible for posture and movement. Biceps are the muscles located in the upper arm that are used for flexing the elbow joint. Lastly, Abs are the muscles located in the abdominal area that are used for core stability and strength.