The score for this type of workout is the lowest number of reps performed in a 20 - second interval. (mindbodygreen.com)
The number of reps you perform in the fourth set decides whether or not you raise or lower your weight in the next workout, based on the guidelines below. (completehumanperformance.com)
Use the table below to estimate your one repetition maximum from reps performed at different weights. (fitnessdoctrine.com)