Marathons, ultra-running, and longer course triathlon pulls in mostly slow-twitch muscle fibers. “Type I, slow-twitch muscle fibers, are also known as aerobic muscle fibers due to their ability to create energy from oxygen, allowing them to produce force over an extended period of time
Slow-twitch (type 1) muscle fibers. These fibers have a slow contraction speed, utilize aerobic glycolysis, and is fatigue and injury resistant, making them perfect for long distance events/activities.