Try a little cardio to warm you up first, then roll out your muscles with a ball or foam roller.
You can stand facing the bar or turn so that the bar is next to your lifting arm. Try different techniques to see what feels comfortable.
Think of your non-lifting arm as the “support arm” and only use it as needed. Try to rely on the lifting arm to do most of the work, but use the support arm to help pull yourself up.
This will give your body momentum, which makes that first rep a bit easier. [3] X Research source
Lift all the way up, until your head passes the bar. Be careful not to hit yourself on the chin on your way down! It can help to bend your legs under you, crossing your ankles. This gives your body more stability than if you let your legs flail.
Wait three minutes before trying another set.
Work on one armed lat pulldowns. You need to train on a lat pulldown or cable pull machine to execute this move, which involves pulling a weighted handle down to your chest. [5] X Research source Start at comfortable weight (which will vary depending on your fitness level), but work up to two to three repetitions using 20 or 30 percent more weight than your body weight. For example, if you weigh 150, your goal will be to accomplish 2-3 repetitions lifting 180-195 pounds. [6] X Research source Be sure to work both arms equally at each training session. Try the bench press. Bench pressing weight engages both your chest and your arms, which are both players in proper pull-ups. You can start with just the bar if you have no arm strength, or as much weight as you can manage. Gradually add more weight over the course of 3-5 weeks to increase muscle mass and strength. [7] X Research source Master push-ups. Push-ups engage your arms, chest, and back, and can help strengthen your arms for pull-ups. Once you’ve mastered regular push-ups, learn the one armed push up and be sure to master it with both arms.
Soften the SA and surrounding muscles first, by using a lacrosse ball, tennis ball, or foam roller to release tension and get your muscles in the right position. Laying on a mat or rubber floor, or leaning against a wall, roll the ball hard against your muscles across your pectorals (your chest), teres muscles (directly behind and in your armpits), and SA muscles. Roll gently at first, then increase pressure in tender spots. [9] X Research source Strengthen your back and particularly your SA muscles by focusing on back exercises such as downward facing dog, push ups, reverse flys, and cable rows.
Using an overhand grip and keeping your hands about shoulder-distance apart, hang from a pull-up bar with your arms extended. Slowly raise your body by bending the elbows, bringing your chest as close to the bar as you can. Slowly lower yourself back to arms extended. [10] X Research source Be sure to exercise different grips. You can do chin-ups, which are like typical pull-ups but with your hands slightly closer together and your palms facing towards you. You can also try widening your grip to engage the back muscles. Once you’ve mastered regular pull-ups, introduce a new challenge by raising yourself with two arms but lowering yourself with only one, alternating arms at each pull. This gets you one step closer to full one armed pullups. [11] X Research source
Start with a very small amount of additional weight (only one or two pounds) then gradually add more as you master each level. You can wear leg weights, attach weight to a belt, or even put it in a backpack.
Having a regular exercise schedule and a plan for increasing your weights and repetitions can be helpful. It can also be helpful to enlist a trainer or friend to motivate you and keep you accountable.
Start with just a bit of weight. One or two pounds makes a lot of difference with this difficult move.
Make sure to use proper form and no swinging and to progress slowly with the weights. Do them slowly with more time under tension.
This will train the muscles to be able to endure a lot of pressure with time under tension which is important in the one arm pull up/chin up.
Every person who can do at least a single one arm pull up will be tough in arm wrestling. It is not a coincidence. If you want to get better at either exercise, do the other one. Grab a friend or a relative who is stronger than you and practice.