Marius Bakken on the Norwegian Method: Double Threshold, Lactate Control, and Muscle Tone (Science of Running, 2026)

A May 2026 Science of Running interview in which Marius Bakken, the Norwegian Olympian behind the lactate-controlled threshold model, sets out “muscle tone” (the baseline tension or stiffness of a muscle at rest) as a third monitored readiness variable alongside blood lactate and heart rate. He describes an inflection point above (sub)threshold intensity at which stiffness rises and subsequent recovery becomes unpredictable, which is part of the rationale for keeping double sessions sub-threshold, and uses tone to schedule the week (a Saturday hill session raises it; an easy Sunday and Monday lower it before a Tuesday double-threshold day). The broader claim is that high-intensity and heavy strength work carry a hidden muscular cost, and that the muscular system plays a larger part in fatigue, recovery and performance than the classical aerobic determinants capture. A practitioner framework resting on Bakken’s own training records and palpation-based monitoring rather than controlled trials, so filed as a signal from elite practice, not established physiology.