The classic pull-up is among the heavy hitters for upper-body training, working the shoulders, arms, back and chest. Most gyms have pull-up bars, but it's also quite simple to install one at home. A sturdy wood doorway is a fine place to put one, allowing you to do a pull-up whenever you pass through the door. Additionally, you should plan to add pull-ups to your strength training routine two or more days a week.
Choose a sturdy doorway that is free of cracks or loose trim. You're going to be putting your weight onto the pull-up bar, so the place where you'll install the bar needs to be structurally sound.
Measure the width of the doorway and then cut a 1-inch piece of metal pipe at the width of the doorway, minus 1/4 inch. If you don't have a power saw that can do the job, have your pipe cut at the hardware store.
Measure 3 inches down from the top of the doorway on both vertical sides of the doorway. Make a pencil mark at the 3-inch mark.
Set a U-shaped flange against the doorway, with the top of the flange meeting the mark you've made and the open side of the flange facing up. Drive 1.5-inch screws through the holes on the flange and into the doorway, securing the flange in place. Repeat the process on the opposite side of the doorway, so that you have two U-shaped flanges on opposite sides of the doorway at the same height.
Slide the metal pipe onto the flanges, so that the pipe rests inside the bottom of the "U."