Rucking: what a loaded pack changes about walking, and a build-up

Rucking is walking with a weighted backpack, a rucksack, and the studies call it load carriage. Some of the studies below are of soldiers; each says who it measured. This page covers what a load changes in the lab, what the one study of recreational hikers found, what training did for carrying loads, and a build-up that starts light.

It's a page about what the studies measured and a practical way to start, not a promise about what rucking will do for you. The groups below were small and young, mostly men, and your own start depends on things a page can't see. For the same idea in a vest, see weighted vest.

1. A load makes the same walk cost more

In 10 healthy male Army officers walking on a treadmill for 30 minutes at 6 km/h, carrying 30%, 50% and 70% of their lean body mass in a rucksack, oxygen use, ventilation and heart rate rose significantly between the trials, and perceived exertion was higher at 70% than at 30% or 50%.¹ The study was in military men carrying heavy loads, so read it for the direction, not the numbers: more weight, more effort.

2. What lighter loads felt like

The closest study to a civilian ruck had 15 experienced female recreational hikers, average age about 22, walk 8 km at their own pace carrying 0%, 20%, 30% and 40% of their body weight. Heart rate wasn't significantly affected by the load or the distance. Perceived exertion was: "fairly light" on average at 20%, and "hard" at 40%; even the 20% load brought significant changes in trunk posture and reported shoulder discomfort compared with no pack. The authors recommended a backpack load limit of 30% of body weight for female recreational hikers.² That's one small study of young women walking on their own pace, and a limit its authors set for that group, not a rule for everyone. It does give a reference point: 20% of body weight was rated "fairly light" over 8 km but still changed posture and comfort compared with no pack.

3. A 10% hill outweighed an 18.2 kg pack in one study

In 11 participants aged 19 to 27 walking at 4 km/h with an 18.2 kg (40 lb) pack, on 0% and 10% gradients, gradient had a greater effect on oxygen use and heart rate than the backpack load did.³ That study was run on a treadmill at temperatures from 20 to -10 °C, with one pack weight and one gradient, so it's a direction and not a rule: a hill can add more than a pack, and more weight isn't the only way to make a walk harder.

4. Compendium estimates, not measurements of you

The Compendium of Physical Activities lists an energy cost in METs for walking with loads. The rows use different paces and grades, so this isn't a controlled comparison, just a sense of range:⁴

These are group averages from the Compendium's sources. I haven't turned them into calories: the walking calorie calculator does that for a walk without a pack, from your pace and weight.

5. What training did for carrying loads

A 2012 systematic review, framed around soldiers carrying heavy loads, reviewed 10 studies of physical training and the time to cover a set distance carrying an external load, mostly in a backpack. Its meta-analysis found large training effects when progressive resistance training was combined with aerobic training and done at least 3 times a week for at least 4 weeks. In it, programs that included progressive load-carriage exercise had much larger effects, and aerobic training alone or resistance training alone had smaller and more variable ones.⁵ So the studies point at the same three parts a ruck week can have: walking with a load, getting stronger (the leg day workout), and walking without one. The World Health Organization also asks adults for muscle-strengthening on 2 or more days a week.⁶

How to start (practical)

• Start light. Put a few kilos in a backpack you can wear comfortably, 5 to 10% of your body weight to begin (a practical figure, not a finding). Nothing on this page needs a particular pack or product.
• Walk at a talking pace. The talk test is a rule of thumb for intensity: if you can't say a sentence, slow down.⁷
• Change one thing at a time. The WHO advises starting with small amounts and gradually increasing frequency, intensity and duration.⁶ For a ruck that's minutes, or weight, or hills, never all three in the same week.

After that, keep adding to one thing at a time. Fit the lifting around it: cardio and lifting covers the order and spacing, and rest days what to do between. If the pack is for a trail, hiking training adds hills and long walks.

Common questions

How much weight should I ruck with?

Start light. In the one recreational study here, a load of 20% of body weight was rated "fairly light" over 8 km and 40% "hard", and the authors recommended a limit of 30% for female recreational hikers.² That is a study's limit for one group; the practical start on this page is 5 to 10%.

Is rucking harder than walking?

In the lab, heavier loads (30 to 70% of lean body mass) raised oxygen use and heart rate at a set speed in 10 male Army officers.¹ In 15 female recreational hikers carrying 0 to 40% of body weight at their own pace, heart rate wasn't significantly affected by the load, though perceived exertion was.² Whether a loaded walk is right for you depends on what you want from the walk. Running vs walking compares walking with running the same way.

Is rucking good for building muscle?

No study cited here measured muscle size from rucking. In the load-carriage meta-analysis, resistance training combined with aerobic training improved carrying performance more than either alone,⁵ which is why lifting sits in the week beside the ruck.

Do I need a special pack?

This page doesn't recommend one: none of the studies cited here tested a product, so there's nothing for me to cite. A pack that sits comfortably on your back is what the practical plan assumes.

Rucking or running?

They're different jobs. In one study of 75 volunteers without symptoms, aged 19 to 72, the average load under the foot, as a percentage of body weight, was about 201% jogging over the ground and about 112% walking (an average percentage of body weight on the foot);⁸ that was without a pack. Running for beginners starts the other one.

I'm a fitness coach, not a doctor: if you have pain, an injury or a medical condition, ask a doctor or a physical therapist before you add weight to a walk.

If you'd rather have the week planned

A ruck, two lifting days and the rest of your life only work when they land in the right order, and that's a scheduling problem as much as a training one. Coaching is the version where your workouts are built around the days you actually have, and a weekly call looks at the week you just had and rebuilds the next one around what's coming. Coaching for a week that doesn't hold still explains how that works, and apply is the first step. Otherwise: do two 20-minute walks this week with a light pack.