New studies show that the once forgiving legging may actually be working against you, in ways you didn’t even know possible.
Apparently, the tightness of the fabric in a legging causes the muscles in your legs to go lazy, whereas before you would have your own body’s muscles working to keep it flexed and taught. Leggings keep the muscle tight, and in allowing the muscle to sag and loosen.  Maybe it’s time for us to put our leggings to rest, and our muscles to work!
‘They hold in and support the quadriceps (thigh muscles), buttocks and core muscles in your tummy, and do the job the muscles are supposed to do.
‘As a result, the muscles are allowed to relax and switch off, so when we reveal our bodies for the first time as summer approaches, they are not as svelte or firm as they otherwise would be.’
Speaking only from personal experience, this makes a whole lot of sense as to why I’ve been sporting a mini buddha belly into spring. There’s always an upside though!  Retiring leggings might also retire lazy fashion(of which we are all victim to now and then). So do yourself a favor and save them for the gym when you’ll really be getting a work out.