What your heart rate data actually tells you
Heart rate data — Two athletes at 150 bpm can be in completely different physiological states. Here's
Lactate: from misconception to modern application
Lactate — Not a waste product, not the cause of soreness. What lactate testing actually measures.
VO2max as a Major Endurance Metric
VO2max — The ceiling metric everyone quotes — and why it alone won't predict your performance.