Are Flexibility and Mobility the Same Thing?
What a great question! I'm glad you asked because I've been thinking a lot about this lately. :)
No, they are not. If you have worked with me in person, you may or may not have noticed I focus more on mobility than flexibility. Let me explain why.
Flexibility is a muscle’s ability to lengthen passively, or without engagement. When you perform static (holding still) stretches using body weight, limb support, or props, you are working on muscular flexibility. In many instances we may get to the end range of our muscle flexibility and start relying on and stretching the connective tissue as well.
Mobility, on the other hand, is related to the joints and their ability to move actively through their full range of motion. Think of lifting your leg in the air to a 90-degree angle and bringing it back down again. That is active mobility. If you then grab your knee and pull it up towards your chest with any amount of force, that is flexibility.
While flexibility is a component of mobility, mobility is the key to strength and stability.
Flexibility without the strength to support the muscle length can actually create the potential for injury. I like to think of our muscles as the brakes on a car. We are able to use them over and over throughout the day to move safely as we drive and, though our seatbelts are there, we rarely have to rely upon them to keep us safe--but when we need them they do their job. I like to think of the connective tissues, like tendons and ligaments, as our seatbelts. If our brakes (muscles) are working well and moving us through different ranges of motion we will rarely rely on our seatbelts (connective tissue) to keep us within healthy boundaries. However, if our brakes (or muscles) are not able to activate and support us in all of our ranges of motion then we end up relying on our seatbelts (or connective tissue) way too much (both time and force) and set ourselves up for potential injury.
If you are someone who is extremely flexible, you may find that it is especially important not to push through to the end of your given range of motion because you are not able to support that range actively. That is such good information to have about yourself!
If you are someone who is less flexible you may find that you push and push and push yourself to become more flexible but make very little progress. That very well may be because your mobility simply cannot support that range of motion. The body is amazing!