It’s not magic. For example our very first program, the 2K PLAN, is based on conventional periodization cycles, with optimizations for days per week available and current fitness level. At a high level, that program optimizes towards improving performance for a 2km test/race. The reason we chose to start with the 2km was because it requires a combination of raw strength and aerobic endurance, and if an athlete can perform highly on this distance it will correlate well to both longer distances and sprints.
Today we have a variety of programs covering general fitness, interval training, and target distances (if that's your jam).
To provide appropriate and challenging effort levels for all athletes, we use a combination of age, resting heart rate (RHR), and a fitness test. With these inputs we can calculate target splits and heart rate zones for a variety of HIIT, steady-state, and medium-distance interval workouts. The very first workout on the program is a 500m or 2km fitness test, so even athletes who don’t know their current benchmark can find out on Day 1 and update their Training Zones accurately!
That’s what we call your personalized split and heart rate targets! It’s based on the concept of Heart Rate Training, where an athlete can accomplish different training objectives when their exertion level puts their heart in different ranges. Remember to check with your doctor before starting a new workout regimen!