I recently made this gym bag. The green lining is an old army duffel bag that once belonged to my dad (he died when I was 8 yrs old). I altered the pattern I used to make my yoga mat bag. This bag is shorter (finished length approx 18 in, 8 in wide, 8 in high). This one has two center zippered pockets and two mesh pockets on the inside. I also added a strapped key hook. My only regret is not making the straps a little longer.
Mesh pocket with the key hook before I turned the bag right side out.I used a label from a nephew's old jeans (it says made in America) to cover a badly frayed area of the lining fabric.