On the Basic Training Protocol, HGH Phase — am I sprinting for 30 seconds? I don’t understand the counting part. What am I counting?

As for count­ing, I approx­i­mate sec­onds, or use a timer built into exer­cise equipment.

When I’m work­ing with oth­ers, I ver­bal­ly count down from 30 to help them main­tain pace, and remain aware the end is near. I try to approx­i­mate seconds.

If you don’t have a clock and you are work­ing alone, then count breaths as an approximation.