A personal record is the most honest measure of athletic progress. It does not care how you feel that day, what the scale says, or whether you think you are getting stronger. A PR is a number, and numbers do not lie. Tracking your PRs systematically is one of the most motivating and informative practices a serious lifter or runner can build into their training.

Ask most gym-goers what drives muscle growth and they will say heavy weight. Ask exercise scientists and they will say volume. Both are right, but volume — the total amount of work done across a training session or week — turns out to be the primary driver of hypertrophy and the best predictor of long-term strength progress. If you are not tracking it, you are flying blind.

Body weight is a blunt instrument. Two people can weigh exactly the same and look completely different, feel completely different, and have completely different health profiles — because what matters is not just how much you weigh, but what that weight is made of. Body fat percentage tells you what the scale cannot.