>>13800058I do pull-ups with leg lifts (lifting my legs straight out after I have pulled myself up), but there are other ways to utilize exercises.
Try doing a one minute push-up for example. 30 seconds down, 30 seconds up.
The slower you do any exercise the more effective it will be at building strength.
Try multi-directional crunches/sit-ups too, and again, go as slow as you are able to go while still maintaining direction and motion.
Drink and eat healthy too etc.