Twitch muscle fibers which consist of two types, slow twitch and fast twitch, form the skeletal muscles. The fast twitch fibers provide rapid response to the body during explosive or highly intense movement. The slow twitch fibers are fatigue resistant and kick in during endurance activities. Both the muscle fibers are distributed throughout the body, but not in equal proportion.
Uses of slow and fast twitch muscles
“Twitch muscle fibers help create locomotion, balance and stability in the body,” says Ramji Srinivasan, former strength and conditioning coach of the Indian cricket team, and the founder of Sports Dynamix, Chennai. “It performs all the basic functions which are required [for the body], from crawling to walking or jogging.”
The antigravity muscles, which are constantly used to maintain posture, contain a slightly higher amount of slow twitch fibers. Muscle groups that facilitate fine motor work have more fast twitch fibers.
“Abdominal and lower back muscles are slow twitch muscle fibers as they maintain the posture stability,” adds Srinivasan. “So, you need to be mindful about where and how you train these muscle groups and identify whether you are a person with fast twitch muscle or a slow twitch muscle or a combination muscle in ratios.”
Your affinity towards a type of physical activity or sport depends on the type of muscle fibers you possess.
“Any physical activities that last for a short duration like jumping or throwing a ball are typically affected by fast twitch,” says Dr Vivekanand Upadhyay, head of Indian Army sports medicine centre in Hyderabad. “It includes activities like strength training and power training. Slow twitch activities include anything that a person is doing repetitively, with less intensity and for a prolonged period such as long-distance running.”
Slow twitch or fast twitch muscles, which do you have?
Muscle biopsy and how a person performs certain types of exercises, help in identifying the type of muscle fibers he or she predominantly possesses.
Muscle biopsy is a procedure through which a piece of muscle tissue is taken out and tested to determine advanced medical information. It is mostly performed on professional athletes and not recommended for the general population.
“If a person is exposed to certain types of exercises, it creates a general idea about whether the person has more endurance or more strength,” says Dr Upadhyay. “But these are only grossly indicative and not always accurate. Moreover, whatever the composition of muscles is, it does not prevent you from doing other activities.”
The type of twitch muscle fibers in your body does not prevent you from engaging in any type of physical activity. Of course, it may prevent you from becoming, let’s say an Olympic medalist!
If one has more slow twitch fibers, he or she will be good at endurance activities and should focus on such training. People who have slow twitch fibers do not gain too much muscle mass but have more blood vessels, again, ideal for endurance activities.
It is quite the opposite in the case of fast twitch fibers. They will have relatively less blood vessels but will see a lot of growth in muscle mass.
Training should focus on both
Training programmes should include both strength and endurance aspects. It will help maintain balance between the muscle types. In fact, sports such as football or badminton require both types of muscles in equal measure.
“Good level of interval training, circuit training, hybrid training or high intensity interval training combined with aerobic fitness helps maintain the balance in speed, agility and quickness,” says Srinivasan. “But the ratio of muscles will not be of equal proportion.”
General fitness and twitch muscles fibers
A normal person whose goal is to maintain general fitness need not worry about their type of twitch muscle fibers. Their goal should be to derive maximum benefits from the workout sessions or sports they play.
“It is much more important to focus on the enjoyment of the sports and exercises, rather than trying to focus on the type of muscles,” says Dr Upadhyay.
It is a different ball game when it comes to sportspersons, though. To take themselves to the next level, professionally, understanding their type of muscle helps.
“Sportspersons need to do physical testing, assessment and fitness testing to understand the predominant muscle group in their bodies,” says Srinivasan.
Takeaways
- Twitch muscles fibers, part of the skeletal muscles, help in stability and movement.
- Slow twitch muscle fibers facilitate low intensity endurance activities while fast twitch fibers are useful in fine motor movement and activities that require quick and explosive action.
- Any training that includes strength and endurance components is good enough to maintain the balance of both slow and fast twitch muscle fibers in the body.
