Man… I wouldn’t considerate animating at 20FPS, because it is really hard to take one minute of it. Try animating at 14-15FPS, it’s the midterm between fast, smooth & good.
Also, stretching is a must-have in any anim., otherwise it will loko robotic and lame. Check out how to make a punch and how to run with stretching, and you’ll be good to go 😉

Very fast. Plus to take out the sliding go near tweening and there should be a button saying like “loop” or something. Tick the check off.