Another hot topic!
Coming from a yoga background, and of course it was drilled into our heads growing up (remember the 'sit & reach' in the Canada Fitness Testing?), flexibility & range of motion was a key aspect of our fitness regime. As a person who teaches yoga it is very common to hear, after announcing that aspect of my teaching/training, the words: 'Oh, I'm not flexible, I can't do yoga'. If only I had a $1 for every time I heard that...
The conversation after that statement is usually something that surprises them... flexibility isn't all it is cracked up to be. Yes, our range of motion is an important aspect of our health, but the ability to put your foot behind your head is not going to give you enlightenment. So what's the deal?
Flexibility is typically seen and worked on by performing passive stretches. Think of your hamstrings. Sit on the ground, legs straight in front of you, lean forward and find that 'stretch' sensation in the back of your legs. Feel tight? There is nothing wrong with that! Is it fun to sit there and 'patiently' wait for it to feel better? Not really.
Let's look at mobility... with the basic difference between the 2 being that our basic definition of stretching for flexibility is a passive movement, like the above hamstring stretch. While the idea of mobility is an active/stabile range of motion in the body. The basic idea of how high you can lift your leg straight in front of you from a standing position. Bet there is a noticeable difference in the range of motion between the active position and the passive 'stretch'. Try it... I'll wait.
You can also think of deadlifts. If you have been passively stretching your hamstrings, at that end point of the stretch your muscle isn't working to stabilize your joints so there will not likely be any stability/strength at that range.
If you go to do a deadlift you'll likely find that you need to engage more muscle groups (rather than mainly your hamstrings) to be able to lift at that full range (stretched) position. If you have been working actively with your hamstrings, you'll be able to use your full range of motion, and power, from your hamstrings to lift the weight. And if you train with active stretching (mobility work) you'll find that your range of motion improves. Something I bring awareness to when I teach Lagree.
Here is the kicker... they are both beneficial, but if you want to live your best life and not spend hours improving your health (time spent improving your health is never a waste of time, but I have other fun things to do with life as well), you may as well work on mobility or active stretching. It is an easy switch. With an estimated 59% of adults over 60 years of age (and 75%! of adults over 80) that have severe limitations in walking or climbing stairs, mobility is something that is key to ageing well (1).