Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights.

If your fitness goal is to up the ante on endurance, pack more power into your sprint, or supercharge your strength gains in the gym, it’s worth exploring – what are the different muscle fiber types?

Myotonic dystrophy type 1 (DM1) is the most common form of adult-onset muscular dystrophy, affecting about 1 in 8,000 people. While it is well known for causing muscle weakness and stiffness, DM1 also ...