BigMac no wonder you are out of breath. The cadence is fine, you are working the muscles properly. The only slight suggestion towards cadence would be to use 4-2-4 on peak contraction exercises like leg extensions, pec dek, hamstring curls, bicep curls and only one compound movement, the close grip underhanded pulldown. Otherwise use 4-1-4 on non peak contraction exercises. The reason for that is so you won′t be resting on the movements that don′t offer any true work at the top of the movement. On the 4-1-4 moves don′t reverse too quickly, make it a smooth transition. When it comes to the superset, Mike suggested that if at first you fail endurance wise then take a 30 second or so rest. You will work up to it eventually. The repetitions for legs should be similar for the upper body. In other words if you are achieving a total of somewhere between 9-12 reps for supersetting your chest (both sets combined into one), then that is what you should do for legs. An example would be to use the Nautilus Optimum Range test, to find out your bodies preferred repetition range, and then set it up to be somewhere around or slightly above it. Basically doing it the way you were was way too long and exhausting. No wonder you were out of breath. Here′s the optimum range test if you want to try it.
This was published by Nautilus many times.
Warm up with 6 very light reps.
Continue warming up by doing 3 reps at a weight that you normally do 10.
Add 10-15% to the weight and try for 1 rep.
Rest two minutes.
Add 5% more and try for 1 rep.
Rest two minutes.
Add 2.5 to 5% more and try for 1 rep.
Continue resting and adding until you can no longer do 1 perfect rep. Remember dont cheat or throw up the weight. Always slow repetitions.
Record your 1 rep max.
Rest at least 5 minutes.
Take 80% of your 1 rep max and perform as many perfect repetitions as possible.
Multiply the number by .15. Add this number to the maximum number of reps that you did at 80%. This is your high rep count.
Subtract the same number from the 80% count and this is your low side number.
If you did 10 reps then 8-12 or 9-11 is a good rep count. If you did 8 then 7-9 is good. If you did 12 then 10-14 is called for.
This will keep you around the 80% range.
Nautilus claims that 30% of trainees do not fall into the 8-12 category.
Ferrari gave me this. I hope it helps you. Do pretty much the same reps scheme that you do for upper body to your lower body. Good luck!