New clothes is easy if you know how and if you have materials. Honestly, I took a template from my old sport pants which I accidentally messed up with paint during renovating a house. So, I just fold pants. put it on the paper and drew around. Fits perfectly.
I used overlock, because it is stretchy fabric and as you know, lots of sport clothes been made with overlock or overstitch. I needed cotton mixed with spandex, more than 1 yard, depends on your size and how long do you want your pants to be. I got some wide elastic and on the legs- ribbed cuff trim. Love this thing, so comfy.
If you have coverstitch, you can sew it without cuff trim.