What kind of muscle can stretch or maintain tension for long periods time?

Slow-twitch muscle fibers, also known as Type I muscle fibers, have the ability to stretch or maintain tension for extended periods of time. Slow-twitch muscle fibers are found in muscles that are responsible for endurance activities, such as long-distance running or swimming. These muscle fibers are characterized by their ability to generate force slowly but maintain it for a long duration. They contain a higher concentration of mitochondria, which are the organelles responsible for energy production in cells, allowing them to utilize oxygen efficiently and sustain prolonged activity. Slow-twitch muscle fibers also have a higher capillary density, which ensures an adequate supply of oxygen and nutrients to support their energy demands during endurance activities.