Why You Need To Incorporate Fast-Twitch Exercises Into Your Routine STAT

"We train in the gym to get better at life," not just to perform better in the gym, says JJ Virgin, CNS, a certified holistic nutritionist and personal trainer.

According to Virgin, the work you put in at the gym pays forward in the most practical ways—independently standing up from a chair when you're 90 years old or playing pickleball like a pro at 65. 

In short, fast-twitch muscle fibers (also known as type II fibers) are those that fire off when you put explosive energy into a movement. These fibers are powerful but fatigue quickly. You'll trigger fast-twitch fibers when you sprint, jump onto a box, and so on.

Then, there are slow-twitch muscle fibers, which are activated during movements like walking, yoga, and slow strength training.

As you age, Virgin says, you tend to lose fast-twitch fibers more than slow-twitch fibers1, making intense movements more difficult. However, this doesn't have to be the case.

Interestingly, you also have some muscle fibers that adapt with age, tailoring themselves to whatever movements you do. For example, if you stick with only slow movements, they will become slow-twitch muscles to support that. If you incorporate sprints and jumps into your routine, they may become more fast-twitch, Virgin explains.

This, she says, is why you should add fast-twitch movements to your routine for strength longevity. "Whatever you train at is what you will be at," she adds, meaning that if you want to be able to do quicker movements as you age—like running around with grandchildren or throwing a baseball with your partner—you'll need to keep those fibers active.

This doesn't mean you need to abandon slow-twitch exercise routines you love, like yoga or Pilates. In fact, Virgin suggests the opposite: Incorporate all types of movement. Practice different elements like balance, mobility, and flexibility, along with endurance and strength training, to ensure that as you age, you can keep up with whatever kind of movement you want to do.

By working fast-twitch muscle fibers now, you'll prime your body to keep up with the quick pace of life as you age.

Keep workouts like box jumps, sprints, and medicine ball throws on the list in addition to those that work your balance and flexibility like yoga and Pilates.