Middle distance interval:
3 x 10 minutes
Rest: 3 minutes

#1. 20 (+19), 22 (+17), 24 (+15), 26 (+13)
#2. 20 (+18), 22 (+16), 24 (+14), 26 (+12)
#3. 20 (+19), 22 (+17), 24 (+15), 26 (+13)

cool down