I started lifting regularly when I was 14 years old. I would get unsolicited advice from lots of people, and one piece of advice I heard quite often was “Be careful, and make sure to take extra time to stretch, or you’ll be tight, muscle bound, and inflexible.” I was cautious about this, but I have learned over time that maintaining flexibility and mobility is not nearly as big of a deal as you would think and gaining it might be a little simpler than you would realize.

Flexibility is the ability of a joint and associated muscles to get into a range of motion passively. Mobility is the ability the muscles have actively.

Flexibility is a quality your muscles have, and can develop, just like strength and size. To gain it, you need to work on passive and active stretches frequently. Think of a dancer practicing each day to be able to perform a full split. Just like strength and size, you do not need to do nearly as much to maintain it as you did to gain it.

The most recent studies have shown that to maintain your size, you need to eat in a caloric maintenance range, meaning eating as much as you burn each day. To maintain your strength, you only need to train at 30-50% of the intensity as you did to gain that strength. Flexibility is unique in this aspect, because according to another recent study, you are likely to not need to specifically train flexibility in the gym to maintain the flexibility you do have. Rather — performing resistance training exercises with the fullest range of motion you safely can is enough to keep you from getting tight. This adheres to the common adage originally said about adaptation, “If you don’t use it, you lose it.”

Being flexible is important for resistance training for a few reasons. You are less likely to get injured if you are flexible, and you might have an easier time performing heavy compound movements. Getting flexible is a process just like getting stronger, and if you seek to do both at the same time, you will likely increase your ability as an athlete. This gives us more of a reason to train with a full range of motion often.

I prefer to see each part of the range of motion of any given exercise as a tool to produce different adaptations, and to adjust exercises to unique situations, but full range of motion is the most powerful tool in this section, allowing us to stay flexible, develop strength, and maintain muscle mass.