If you are not presently able to pull yourself up with your entire body weight, you can decrease the percentage of your body weight that you are pulling by using longer chains and lowering the baseballs closer to the floor and do body rows.
A body row is basically a reverse push-up. Initially hang the baseballs at a height where if you lay on your back with your chest directly underneath them and straighten your arms, you will barely be able to reach the baseballs. Pull your chest up to the baseballs and keep your body straight. It helps to imagine that your body is a board. If this is still too hard, you can raise the height of the baseballs. The higher the baseballs, provided that your feet are still on the ground, the lower the percentage of your body weight that you are required to pull.
Continue performing body rows until you can do a baseball pull-up with your entire body weight. If baseball pull-ups become too easy, you can increase the challenge in several ways:
• Add weight to your body.
• Do offset pull-ups by pulling your body towards one arm. Use the other arm only as much as necessary. You can even work towards a one arm baseball pull-up.
• Use softballs instead of baseballs. The softball will require more of an open hand which makes the grip more difficult.
Enjoy.