Add a weight vest for push-ups and pull-ups to overload muscles. Perform negative reps by slowly lowering yourself from the top position of a pull-up or push-up, fighting gravity for 3-5 seconds.

I recently did a challenge that was 100 push ups a day AND 100 pull ups a day for a whole month. It was pretty tough at first ...

Similar to pull-ups, push-ups are very easy workouts that can be performed (nearly) anyplace and work a variety of muscle groups. You train with your own body weight for the basic exercises, so ...