Can You Run With a Weighted Vest or Backpack? What the Research Actually Says

Short answer: a light vest, yes. A loaded backpack, not really.

Here's why.

Running with weight has a bad rap. And fair enough, it didn't come from nowhere. Australian Army injury data shows carrying load is a genuine source of lower limb and back injuries in soldiers.¹

But let's be honest. Soldiers are hauling heavy packs, for kilometres, while knackered. That's not you doing a few kilos on a Tuesday morning interval session.

Force doesn't stack up the way you'd think

This is the bit that surprised me.

Stanford researchers put 27 recreational runners in vests loaded to 10%, 20% and 30% of body weight.² Add 10% of body weight and peak impact force went up around 5%. Crank it to 30% and it still only rose about 13%.

Why? Your body's smarter than you give it credit for. Under load, runners stayed on the ground a touch longer and ran with more bend through the hips and knees. They spread the force out without being told to.

For context, a light running vest sits right at the bottom of that range. STRYDR comes in 4.5kg and 6.8kg, roughly 6% and 9% of body weight for a 75kg runner. The light end of the research. Nowhere near the military end.

So does it actually make you faster?

Maybe. Here's the most interesting study I've found.

Eleven well-trained distance runners added six 10-second strides in a weighted vest to their warm-up. Afterwards, top speed was up 2.9% and running economy was up 6% compared with the same warm-up without a vest.³ Note: they used 20% of body weight, which is heavy, and only measured the short-term effect.

How to start running with a light vest

• Use it for short, sharp efforts first: strides, intervals, hill reps, or the runs between HYROX stations. Earn the long runs.
• Short stride, quick feet.
• If your form falls apart, ditch the ego and remove the vest.
• Carrying an injury, pregnant or recently postpartum? Have a chat with your physio first.

Going heavier? Shuffle, don't run

Big weight is a different game. If you're loading up a RUKSAK for a proper ruck, walk. Or if you want to pick up the pace, shuffle: short, quick steps, feet low to the ground.

There's science behind it too. In runners without any load, bumping step rate 5 to 10% above their natural cadence reduced the work done by the knee, and at 10% the hip as well.⁴ Shorter, quicker steps mean less pounding on every landing.

So, is running with weight bad for you?

Heavy load, long distance, zero prep? It can be.

A light vest, used with a bit of intent? That's just training.

References

1. Orr RM, Johnston V, Coyle J, Pope R. Reported load carriage injuries of the Australian Army soldier. Journal of Occupational Rehabilitation. 2015;25(2):316-322. https://research.bond.edu.au/en/publications/reported-load-carriage-injuries-of-the-australian-army-soldier/

2. Silder A, Besier T, Delp SL. Running with a load increases leg stiffness. Journal of Biomechanics. 2015;48:1003-1008. doi:10.1016/j.jbiomech.2015.01.051. https://med.stanford.edu/content/dam/sm/ortho/documents/humanperformance/publications/Silder_JOB_2015.pdf

3. Barnes KR, Hopkins WG, McGuigan MR, Kilding AE. Warm-up with a weighted vest improves running performance via leg stiffness and running economy. Journal of Science and Medicine in Sport. 2015;18(1):103-108. doi:10.1016/j.jsams.2013.12.005. https://vuir.vu.edu.au/37060/

4. Heiderscheit BC, Chumanov ES, Michalski MP, Wille CM, Ryan MB. Effects of step rate manipulation on joint mechanics during running. Medicine & Science in Sports & Exercise. 2011;43(2):296-302. doi:10.1249/MSS.0b013e3181ebedf4. https://pubmed.ncbi.nlm.nih.gov/20581720/