High rep squats are super tiring and I feel they are one of the best indicators as to not only how strong your legs are but also, how your cardio can cope with extreme demands in a very short period of time. Doing high rep heavy squats burns up your oxygen super fast making your lungs burn and testing your cardio to the max.
We where supposed to do 3 sets of 10 reps using 225 pounds but the boys I was with decided to get it over with and do 2 sets of 15 reps using 225 pounds. So of course I had to do the same. Except I showed them and on my last set I did an extra 5 reps making it 20 reps at 225 pounds. I did space them out a bit at the end only because I was struggling for air, not so much my legs, they felt good and I maybe even had another 5 reps in them if it wasn't for my cardio packing it in first.
We also did equal amounts of pull-ups between our squat sets which did not give us a lot of time to recover our lungs.
This Squat video was filmed at the CrossFit Gym I go to in Langley called Langley CrossFit, and was part of a three section workout that included:
Warmup (3 Rounds):
Main Back Squat Workout (3 Rounds):
Metcon Workout (3 Rounds):
You can see how this workout effected my heart rate and how many calories I burned by clicking on this link.