Originally Posted by
Gramercy
It takes a lot more power to average 22 or 23mph than 20mph. I can't say the exact percentage, but it's probably close to 25% more power. If you can squat 400lb I assume your lungs get tired before your legs. I would try longer rides to get your endurance up and you overall resting heart rate down.
A good rule of thumb is 3x the increase in speed. So to go from 20 to 22, i.e. 10%, will require approx 30% more power. 30% is a huge increase in FTP for someone who has been riding for a few years. You're much more likely to get those gains in speed by changing your position than a raw increase in power.