Strain measures how much training load you have taken on today, on a 0–21 scale. It is calculated from every set you log: the weight, reps and sets you lift, how hard each set is relative to your estimated one-rep max, and the duration and intensity of any cardio. Harder, heavier and longer sessions score higher.

Recovery estimates how ready your body is to train, from 0 to 100%. It uses a fitness–fatigue model: each session adds fatigue that fades over time, with roughly half clearing every 30 hours of rest. Your score is measured against your own recent training capacity, so it is personal to you. As you rest, fatigue decays and your recovery climbs back up through the day.

The load ratio compares your last 7 days of training against your last 28 days — a method used in professional sport to flag when you are ramping up too fast (above ~1.3) or undertraining (below ~0.8). The sweet spot sits around 0.8 to 1.3.

These figures are modelled from your logged training, not from heart rate or sleep. They are a guide to help you train smart, not a medical measurement. For the most accurate strain, power users can turn on per-set effort logging in Account settings.