Chin-ups and pull-ups are one of the best upper body mass builders

Source: thetumblrgym.com via Healthy on Pinterest

Pull-up & Chin-up Technique. Start each rep from a dead hang with straight elbows. Clear the bar with your chin on every rep.

• Squeeze The Bar. And put the bar close to your fingers, not in the palm of your hand. It minimize callus formation.
• Breathe at The Bottom. It's easier to breathe at the bottom. Take a big breath before pulling yourself up.
• Chest Up. Don't let your shoulders go forward: it's unhealthy for your shoulders. Lead with your chest up & keep your shoulders back.
• Look Up. Never look down during Pull-ups & Chin-ups. Look at the bar. Look where you're pulling yourself up to.
• Elbows to The Floor. Drive with your elbows to the floor. This involves your stronger back muscles more.
• Bend Your Legs. And cross your feet. Letting your legs hang means less strength in my experience. Squeeze your glutes on the way up.

Common Errors. Most common error on Pull-ups & Chin-ups is cheating the range of motion by not going low or high enough on each rep.

• Not Straightening the Arms. Start from a dead hang with straight elbows, like on the picture above. No partial Pull-ups/Chin-ups.
• Shoulders Going Forward. It's bad posture & bad technique. Lead with your chest up while driving your elbows to the floor.
• Using The Hips. Keep your legs inline with your torso, unless you're doing Kipping Pull-ups.
• Chin Over Bar. Nose or forehead against the bar is a partial Pull-up/Chin-up. Chin over bar unless you're not strong enough yet.