If you don't have time to go to the gym, make the most of your time at home. Dr. Brett McIff with the Utah Department of Health demonstrates how to do Counter Push-ups.
Place your hands on a counter or other solid surface, and move your feet backward so you are almost at a 45 degree angle. Your hands should be slightly wider than shoulder width, and on the edge in a comfortable position that won’t slip. With your elbows pointed out, lower yourself toward the counter. Go as far as you can comfortably, then return to the start position. Want to make it a little more challenging? Move your feet further from the counter, or lift one leg to really engage the abdominal muscles. Repeat about 8-12 times, 1-3 sets.