Mobility vs. flexibility
You’ve probably heard both words and they frequently get used interchangeably. Knowing the differences between these two qualities can help you improve your overall health. The goal isn’t to necessarily choose one over the other, but develop both in a way to make each one more useful to you.
What is Mobility?
Mobility is the ability to move a joint actively (contracting the muscles) through its full range of motion with control. Its the combination of strength, coordination, and flexibility. You can think of mobility as how well you can move your body in various positions without needing to compensate (like with an injury) or feeling restricted. An example is performing a deep squat, with good body alignment, and without pain. This demonstrates good mobility in the hips, knees, and ankles.
Mobility is more about functional, dynamic movement and shows how well your body can perform in daily activities or athletic movements. It makes movements safe and efficient.
Mobility depends on more than just the muscles. Full joint mobility requires cooperation of the muscles, the connective tissue around the joint, the joint capsule, and the nervous system. The nervous system is one piece of the puzzle that most people underestimate. Your brain will often restrict your range of motion it thinks may be unstable or painful. There are protective reflexes, and one of the reasons that passive stretching alone won’t necessarily produce lasting mobility gains.
What is Flexibility?
Flexibility is more the ability of a muscle to lengthen passively (without contracting the muscle). It’s the range of motion available in your muscles and connective tissues when a force is applied, whether from another muscle group or an outside force like a partner. Flexibility doesn’t necessarily involve strength or active control, instead it’s more about how much stretch a muscle tolerate. An example is bending over to touch your toes without bending your knees. This is a test of the flexibility of the hamstring muscles in the back of the legs.
A person who has spent time stretching passively can develop impressive flexibility, getting muscles into long positions with assistance from something like gravity, a strap, or a partner. But they may not have much control or strength in those positions. They can get into a deep stretch, but might not be able to use that range of motion when they need to.
Flexibility is a component of mobility, it focuses more on the length of the muscles instead of how well they work together during movement. It’s still valuable as tight muscles still cause restrictions and tension on the joints they cross. Tight hamstrings contribute to posterior pelvic tilt and lower back issues. Tight pec and front shoulder muscles pull the whole shoulder girdle forward and can lead to the rounded upper back posture we associate with people who spend a lot of time at a desk.
The Short Version
Stretching and mobility training are related, but different, and you need both. Stretch to open up the ranges of motion your body has lost from years of sitting and repeated movement patterns.
Train mobility to build active control in those ranges. Move to the edge of your range and ask your muscles to work there, not just hang passively in a position.
