When weight training, your muscles have three basic phases of strength. During a lift there is a concentric (shortening of the muscle), eccentric (lengthening of the muscle), and also a muscle has the ability to pause or hold the lift. Mechanically your muscle is stronger during the eccentric phase and weaker during the concentric phase. For example if you were to bench press, lowering the weight (eccentric) is easier than pressing the weight (concentric). OR you could keep a heavier weight from touching your chest but you would never be able to push it back up.
Apply it to your next workout to improve your chest when using push-ups with “negatives”.
*Perform a set of as many push-ups as you can with ideal form. When you can no longer press your chest back up from the floor perform “negatives”. Raise yourself to the starting (top) position of the push-up with help from your knees then slowly lower yourself back to the floor while counting backwards from 5. Perform 3 more push-ups with “negatives”. Now you’re done!