My legs feel dead before a long run — should I still do it?
The coach answer · Updated July 10, 2026
Check three things before deciding: last night's sleep, your last three days of training load, and this morning's resting heart rate. If two of the three are off, shorten the long run rather than skip it — 60–70% of the planned distance at a genuinely easy effort keeps the stimulus without deepening the hole. If all three are fine, start anyway: heavy legs often clear after fifteen easy minutes.
Dead legs are data, not a character flaw
Heaviness before a long run usually has a boring, mechanical cause: a load spike in the previous days, a short night, or accumulated weekly fatigue that hasn't cleared. The feeling is real — but it is a lagging, noisy signal on its own, which is why you cross-check it against the objective three.
The start-and-see rule matters: legs that loosen after 10–15 easy minutes were carrying ordinary stiffness. Legs that stay wooden after 20 minutes, or get worse, are telling you the recovery bill hasn't been paid — cut the run short without guilt.
Never test fitness on a long run
The long run is a deposit, not an exam. Its job is accumulating time on feet at an easy effort — arriving at it recovered matters more than hitting a pace. Turning a dead-leg day into a grind to "prove" fitness converts a deposit into a withdrawal, three days of extra fatigue included.
Source: Stephen Seiler's analyses of elite endurance training consistently show roughly 80% of volume at genuinely easy intensity — the long run's value is in easy accumulation, not effort, which is what makes shortening (not straining) the right adjustment.
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Educational content, not medical advice. If something hurts (rather than aches), or symptoms persist, see a professional.