Most of my recent studying has been related to movement patterns - as you saw in my most recent blog post "Posture" - alongside the kinetic chain / human movement system (HMS) it can be really important to understand the importance of mobility and flexibility within everyday life. This isn't just a concern for those who partake in regular exercise, or for dancers / gymnasts / athletes; having good mobility and flexibility across all walks of life can help to relieve general aches and pains, or more importantly to help try and avoid them in the first place!
Mobility and flexibility are defined as different things but go hand in hand in both training as well as our everyday movement habits. Mobility is related to the range of motion (ROM) available at the joint, for example, the amount of rotation around the shoulder when you circle the arm backwards or forwards. Flexibility is the ability to lengthen the muscles that surround the joints, for example, if you are able to reach your toes from standing with straight legs, then you would be considered to have good flexibility down the backs of the legs (hamstrings, gastrocnemius and soleus, among other muscles).It's also important to remember here that although you might have good flexibility, you may still have poor mobility since the structure of the joints may be limited whilst the tendons and ligaments holding the joint together are weak.
It can sometimes be seen that someone has "good" flexibility, when in fact they are overcompensating for poor posture or technique - from a dance background this can be seen when someone may be good at the front splits (right or left), but have limited mobility at the hips so struggle to do the side (box) splits. To put this into perspective from an adults point of view, when we regularly sit at desks, the hip flexors can become tight, whilst the gluteals/hamstrings become elongated and weakened due to not being used - an adult may be able to touch their toes due to better flexibility down the back of the legs, but struggle to stand up complete