The benefits of rucking, and what the evidence supports

The strongest rucking benefits are cardiovascular and behavioural. Adding load to a walk raises its metabolic and heart-rate cost without making the walk faster or more technical, and the barrier to doing it is close to zero. The muscle-building case is weak. The core-strength case runs against the measurement data we could find. The bone-density case is thinner than the marketing.

Below we grade each claimed benefit against what we could actually find, and we mark each one as well supported, plausible but thin, or marketing. Some held up better than we expected. One of them — the near-universal claim that a ruck is a core workout — points the other way once you look at what the trunk muscles are doing under a pack. If you are beginning a rucking practice, the setup, kit and first-month structure live there; this article is only about what the load buys you. One caveat we mean sincerely: if you are pregnant, managing a health condition, or returning from an injury, whether to carry weight at all is a question for a doctor or a qualified coach before it is a question for an article.

How we graded the evidence

Rucking sits in an awkward research position. Nobody runs randomised trials on recreational rucking. What exists instead is a large military load-carriage literature built on heavy packs over long distances, a smaller weighted-vest literature built on treadmills, and an enormous walking literature. Every popular rucking claim borrows from at least one of those three, and the borrowing is where claims go wrong.

So we have sorted them three ways:

• Well supported. Directly measured, in a population close enough to a recreational rucker to matter.
• Plausible but thin. The mechanism is sound, the direct evidence is missing or is an inference from something adjacent.
• Marketing. Widely asserted, and either unsupported or contradicted by what we found.

| Claimed benefit | Our grade | | --- | --- | | Raises cardiovascular demand versus unloaded walking | Well supported | | Increases energy expenditure | Well supported | | Builds muscular endurance and carrying capacity | Plausible but thin | | Is a core or full-body workout | Marketing | | Builds muscle | Marketing | | Improves bone density | Plausible but thin | | Is easy to stick with | Well supported, indirectly |

Is rucking good for you? The cardiovascular case is the strongest one

Yes, in the specific sense that it makes an easy walk harder without making it faster. The cleanest recent measurement we found is a 2025 study in Bioengineering by Jing and colleagues, who put 31 healthy young men — mean body mass 68.5 kg — on a treadmill across vest loads from 0 to 30 kg. Note the carrier: that was a vest rather than a pack, and the two do not cost the same to carry, which is the vest-versus-rucksack comparison in a sentence.

At 5 km/h on level ground, net metabolic rate rose from 3.87 W/kg unloaded to 6.29 W/kg at 30 kg, roughly a 60 percent increase. Heart rate went from about 111 beats per minute to about 136. The shape of those two curves is the part worth remembering: the authors report that "the net metabolic rate exhibited a quadratic relationship with the vest load weight," while "heart rate displayed a linear relationship with the vest load weight."

Metabolic cost accelerates as load grows; heart rate does not. The first ten pounds in the pack are cheap. The last ten are not. That is a good argument for the modest loads in most published beginner guidance, and it is one reason we treat the question of how much weight to ruck with as the most consequential decision in the whole practice.

A second finding from the same study is worth flagging because it cuts against received wisdom. At a 10 kg load, the researchers found no significant difference in metabolic rate (p = 0.989) or heart rate (p = 0.998) across different load positions on the torso. Load placement is widely sold as a comfort and safety variable, and it may well be one. On this evidence it is not an intensity variable.

The military laboratories find the same nonlinearity at much heavier loads. In a 2022 paper in Medicine and Science in Sports and Exercise, Looney and colleagues built the US Army's load-carriage backpacking equation from 30 military-age adults walking under packs of 0, 22, 44 and 66 percent of body mass, and state plainly that walking energy expenditure "rises nonlinearly with increased load relative to body mass." Two independent groups, two very different populations, the same curve.

For context on what that buys you: the CDC's adult guidance is 150 minutes of moderate-intensity physical activity a week plus at least two days of muscle-strengthening activity. A loaded walk is a cheap way to move a walk you were already taking from light into that moderate band. We have compared the two side by side in rucking versus plain walking, where the load is the only variable that changes.

Energy expenditure: real, and smaller than the internet claims

One paragraph, because a sibling article owns the arithmetic. The quadratic relationship above is the whole story: doubling the weight in your pack does not double the extra energy you spend, and at recreational loads the additional burn is a modest percentage on top of a walk, not a multiplier. Most of the energy cost of a ruck is the walking. We work through how many calories rucking burns separately, with the numbers; treat any figure that implies a light pack doubles your calorie burn with suspicion.

Does rucking build muscle? Not much, and the best study says so

Rucking builds tolerance for carrying things. It does not build appreciable muscle, and the training study most often cited as proof that it does cannot actually separate the two.

That study is a 2023 paper in Military Medicine by Wills, Saxby, Glassbrook and Doyle. Twenty-eight healthy civilians, 15 men and 13 women, completed 10 weeks of lower-body resistance training plus progressive treadmill load carriage, and were tested before and after on a 5 km walk at 5.5 km/h wearing a 23 kg torso-borne vest. The results were good: squat jump maximal force rose from 1,660.7 N to 1,757.3 N, push-ups in two minutes went from 35 to 48 repetitions in the women and 51 to 57 in the men, and both rating of perceived exertion and heart rate during the loaded walk fell significantly.

The catch is in the design. The programme contained a resistance-training block, so none of the strength improvement can be attributed to the rucking on its own. And the aerobic result split by sex in a way that is worth naming rather than smoothing over: estimated VO2max rose 5.4 percent in the men, from 42.9 to 45.2 mL/kg/min, and did not move in the women, going from 39.9 to 39.7. The authors' own conclusion is that sex-specific programming should be considered. We read that as a caution against assuming any one protocol transfers evenly.

A 2025 review in the International Journal of Environmental Research and Public Health by Orr, Knapik and colleagues frames the relationship in the direction most rucking content gets backwards. It reports that "a combination of both aerobic fitness and strength training is needed to improve load carriage performance," and that "relative, as opposed to absolute, strength is more strongly associated with load carriage capability." Strength is an input to rucking. It is not reliably an output.

Our position: rucking is an endurance stimulus with a strength-endurance flavour. If you want bigger or stronger legs, the pack is a poor tool and a barbell is a good one. If you want your legs to stop complaining on the third hour of a hike, the pack is exactly right.

Is rucking a full body workout? The trunk data is genuinely surprising

Here we part company with almost every article on this topic. The claim that carrying a pack "engages your core" is close to universal in rucking marketing, and the most direct measurement we could find points the other way.

A 2025 study in Medical and Biological Engineering and Computing by Matur, Alnamroush and Büyüksaraç recorded muscle activity and spinal motion in 20 adults, average age 24.2, walking with a backpack at 12 percent of bodyweight. On flat ground, erector spinae activation fell 34.9 percent on the left and 33.4 percent on the right compared with walking unloaded. Multifidus activity fell too — 42.3 percent on the left, 16.8 percent on the right. Spinal range of motion collapsed alongside it: axial bending at L5-S1 dropped 68.3 percent, lateral bending 35.2 percent.

The usual biomechanical explanation runs like this. A back-mounted load shifts the combined centre of mass of trunk-plus-pack backwards, and the torso leans forward to bring it back over the feet — a compensation the load-carriage literature describes consistently. On that account the spinal extensors have less to resist at moderate loads rather than more, and the trunk under a ruck becomes a stiffer, quieter, less mobile segment. That mechanism is an interpretation, not something this study set out to test.

Is that harmful? Nothing in the study says so, and we are not going to imply it. It is a 20-person laboratory measurement at a single load, and the authors themselves note the adaptations were asymmetric between sides. The paper is also inconsistent with itself here: its results section reports the back-muscle reductions as significant and then states that the change in the erector spinae was not statistically significant, so we would not treat those two figures as settled. But it is direct evidence pointing against a specific claim, which is more than the claim itself has behind it. Whether that stiffening matters over years is exactly the question we take up in our look at rucking, knees and backs.

What does work under a pack: the legs, the hips, and the shoulder girdle holding the straps. That is a real training effect, and it is not nothing. It is just not "full body."

Bone density: the claim running furthest ahead of the data

Bone is the benefit rucking content has leaned on hardest in the last two years, and it rests on an inference rather than a trial.

The starting point is what walking alone does. A 2013 systematic review and meta-analysis in Menopause by Ma, Wu and He pooled 10 trials in perimenopausal and postmenopausal women and concluded that "walking as a singular exercise therapy has no significant effects on BMD at the lumbar spine," while "significant and positive effects on femoral neck BMD in this population are evident with interventions more than 6 months in duration." So: something at the hip, given enough months. Nothing at the spine.

The rucking argument is that adding external load raises ground reaction forces and therefore the osteogenic stimulus. That is mechanically reasonable, and it is why we grade it plausible rather than marketing. But it is an extrapolation. We could not find a trial that put a rucksack on people and measured their bone density, and the closest weighted-vest work has been done in weight-loss populations where several other things are changing at once. Research may eventually support the claim. Today it does not test it.

Our practical read: if bone health is your primary reason for training, rucking is a reasonable addition to a plan and a poor substitute for one built around resistance training and impact.

What rucking is not good for

A short list, because knowing the boundaries of a tool is most of using it well.

• Hypertrophy. No credible mechanism at recreational loads and no supporting trial. Rucking is not a leg day.
• Maximal strength. The load is too light and the contraction pattern too repetitive. See the load-carriage literature above, which treats strength as the prerequisite.
• Top-end aerobic power. Rucking is capped by walking speed. It will not do what intervals do to your VO2max ceiling.
• Rehabilitation. Load carriage is a load. If something hurts, this is not the tool, and the decision is not one to make from an article.
• A shortcut around calorie arithmetic. The extra burn is real and modest.

None of that is a criticism. It is a description of a moderate-intensity, high-adherence endurance modality that happens to be marketed as a panacea.

The benefit nobody bothers to grade: you will actually do it

This is the one we would defend hardest, and it is the one with the least rucking-specific evidence behind it. Rucking requires no facility, no skill acquisition, no scheduling around a class, and it converts time you were going to spend walking anyway into training. It can be done while talking to someone, which is more than can be said for most conditioning.

The reason that matters is the dose-response curve underneath it. A 2023 meta-analysis in the European Journal of Preventive Cardiology by Banach and colleagues pooled 17 cohort studies covering 226,889 participants with a median follow-up of 7.1 years, and found that each 1,000-step daily increment was associated with a 15 percent lower risk of all-cause mortality (hazard ratio 0.85, 95 percent confidence interval 0.81 to 0.91), and each 500-step increment with a 7 percent lower risk of cardiovascular mortality (hazard ratio 0.93, 0.91 to 0.95). Those are observational associations, not proof of cause, and the cohorts skewed older, with a mean age of 64.4 years. But the base activity that rucking modifies has one of the cleanest dose-response relationships in preventive medicine.

Worth pairing that with a dose caution from the military side. The 2025 International Journal of Environmental Research and Public Health review suggests an optimal frequency of "one session every 7-14 days" for progressive load-carriage conditioning in soldiers. Those are far heavier packs than a recreational rucker carries, so the interval is not a rule for you. It is a reminder that in the populations where load carriage has been studied most, the loaded sessions are a small fraction of the total walking.

The rucking benefits scorecard

If you want the summary in one line: rucking is a well-evidenced way to make walking harder, a plausible way to build carrying endurance, and a poorly evidenced way to build muscle or bone.

The numbers we would keep. Roughly 60 percent more metabolic demand at the same walking speed under a genuinely heavy vest, with the cost curve accelerating as load rises. Erector spinae activation down about a third under a 12 percent bodyweight pack, not up. Strength as the input to load carriage rather than its output. And a walking dose-response curve underneath all of it that rewards frequency more than it rewards intensity.

None of that argues against rucking. It argues for rucking for the right reasons — conditioning, adherence, time outside, and the specific ability to carry something heavy for a long way — and for getting muscle, maximal strength and bone from the tools that are actually built for them.

If you are starting from zero, our full rucking beginner's guide covers the pack, the load and the first month. Then pick a route, put something modest in the bag, and do it often enough for the walking literature to apply to you.