Cross step sit ups are one basketball drill that can help build strength, agility, and balance. To do this exercise, you'll need to start by lying flat on your back on the floor. Make sure your back is well-supported and completely flat. From there, slowly sit up while crossing one leg over the other across your body. Keep in mind not to use your arms for any extra support as you come up; focus solely on using your core muscles to lift yourself up until both feet are firmly planted on the ground. Aim for five repetitions and don't forget to switch sides when done!