Holmer puts running impact at 7 to 8x body weight per step
One post, two numbers, and no study attached to either of them.
Brady Holmer says running hits you with 7 to 8 times body weight per step. Rucking, which is walking with a weighted pack, is closer to walking at around 3x, plus whatever you are carrying.
He credits the comparison to Michael Easter. Holmer says Easter reports that training injuries cost the military millions every year, and that the military consistently finds more soldiers get hurt running than rucking.
Holmer has changed his own habits off the back of it. In his words, he rarely goes for a walk now without his plate carrier.
What it actually means
This is a claim relayed from a second person, not a study anybody linked. Holmer does not cite the research behind the 7 to 8x figure, the 3x figure, or the military injury comparison, so treat all three as numbers worth checking rather than settled facts.
The load comparison also does not say what a lot of runners will read into it. More force per step is not the same thing as more injuries, and the military data Holmer describes compares soldiers running against soldiers rucking inside a military training program, not marathon runners against people who walk with a weighted vest. Nothing in the post says rucking replaces running, or that it builds the same fitness.
If you are reading this as a reason to swap easy miles for weighted walks, the post does not support that either. What it does offer is a rough sense of scale. Carrying weight at walking speed puts less peak force through the leg per step than running does, which is the argument for why rucking shows up as a lower injury training option in the setting Holmer is describing.
For marathon and ultra runners, the honest takeaway is small. One well known voice in running science repeated a comparison he finds convincing, and changed his own walking routine because of it. That is where the evidence stops for now.
I rarely go for a walk now without my plate carrier, largely thanks to Mike’s info!
Running hits you with 7–8x body weight per step.
Win the long run conversation
One email a day. Under three minutes. Marathon results, shoe fights and training arguments, settled.