Pushups with timed sets for stronger pecs super set with stretch between the sets!

I do 30 seconds of pushups to a bar to off load some of my body weight or I won't be able to keep going.

Keep the eyes on the timer, when I hit 30 seconds and extend the first set 10 seconds at a time, 40 seconds to finally 50 seconds.

What do I do if I can do 1 minute sets? I'm under loading it so that's then when I know I have to get into tougher versions of pushups.

On the second set can I keep going like it's easy?....How many seconds can I keep going without hitting muscle failure? I forgot to check the timer!

After the third set I go down on the floor to keep going for knee pushups..Can I last long? Nope, 20 seconds only!

Now I have to wait to get my strength back, but waiting too long and it'll be too easy for my chest muscles.