Stairmaster, Incline Treadmill, or Rowing Machine: Which Cardio Machine Is Best for Lifters?

Why "Which Machine Is Best" Is the Wrong Question

Ask which cardio machine burns the most calories and you get an answer that turns out to be almost useless. At a matched hard effort, the spread across seven common machines in a 2024 measurement study was 15.18 kcal per minute on the treadmill down to 11.07 on a recumbent bike. Over a thirty-minute session that is a gap of about 123 calories, roughly a slice of bread. Over a week of four sessions it is 490 calories, which is a seventh of a pound of fat. Machine choice is not where fat loss is won.

What machine choice does decide is what your legs feel like tomorrow. A lifter is not a general population exerciser with an open recovery budget. The cardio session is competing for the same tissue, the same connective structures, and the same central fatigue as the training that is the actual point. So the question worth answering is not which machine burns the most. It is which machine leaves the next lifting session intact.

This article answers that with numbers rather than vibes: published MET values from the Compendium of Physical Activities, the ACSM metabolic equation run out at real settings, measured EMG from grade-controlled treadmill work, in vivo joint contact forces from instrumented implants, and the surprisingly poor track record of the calorie readouts on the machines themselves.

If you are still deciding how much cardio to do at all, or how to fit Zone 2 around a lifting week, start with our guide to building a cardio base without losing muscle. This piece assumes you have already decided to do cardio and are standing in front of three machines trying to pick one.

What the Three Machines Actually Do

Before the data, a mechanical description, because the three are less similar than the "cardio machine" label suggests.

The stair machine

A stair-treadmill ergometer, the type with revolving actual steps rather than the pedal-and-piston stepper, is a repeated single-leg step-up carrying your own body weight. Each step is a concentric quadriceps and gluteal contraction lifting your whole mass through the step height, followed by a controlled transfer to the other leg. There is very little eccentric loading if you are stepping cleanly, because the machine takes the step away underneath you rather than making you lower yourself onto it. That is a meaningful difference from actual stairs, and it works in the machine's favor.

The incline treadmill

Uphill walking is close to concentric-only work as well. At grade, the leg does positive work lifting the center of mass and does progressively less negative work absorbing impact, because you are stepping up into the slope rather than dropping onto a flat surface. The cost is that the hip and ankle have to produce noticeably more torque, and the postural muscles have to hold the trunk upright against a slope. Both show up clearly in the EMG data below.

The rowing ergometer

The erg is the only one of the three that is not weight-bearing. You are seated, your body weight is supported, and the resistance comes from a flywheel that only ever pushes back. There is no eccentric phase in a rowing stroke in the way there is in running, because the recovery phase is unloaded. What the erg does have that the others do not is a repeated hip hinge under load, performed hundreds of times per session, with a lumbar spine that flexes further as you get tired.

Those three descriptions already contain most of the answer. Everything that follows is the quantification. Two other options worth knowing about sit outside this comparison because they are not machines: rucking covers loaded walking outdoors, and jump rope covers the high-density, low-footprint end.

Energy Cost: The Published Numbers

The Compendium of Physical Activities is the standard reference for the metabolic cost of activities, compiled from measured oxygen consumption across the literature. The 2011 edition assigns each activity a code and a MET value, where one MET is resting metabolism, conventionally 3.5 mL of oxygen per kilogram per minute.

Three things jump out of that table. The stair machine at its generic listing is the most expensive of the three by a small margin. Rowing spans the widest range of any machine here, from 7.0 to 12.0 METs, because it is the only one where the user sets the power output directly rather than the machine setting it. And incline walking at a steep grade is metabolically indistinguishable from running a 12-minute mile.

The rowing range is the important one, because it exposes the flaw in every "rowing burns the most calories" article. It can. It does not, for most people, because most people do not row at 200 W. That output corresponds to a 2:00 per 500 meter pace held continuously, which is a serious effort for a trained rower and out of reach for most lifters using the erg as conditioning. The Concept2 relationship between power and pace is fixed and published, so you can read your own MET bracket straight off the monitor.

Pace and watts on a Concept2 are related by watts equal to 2.80 divided by the cube of the pace in seconds per meter. That is a fixed formula on the monitor, not an estimate, which makes the erg the only one of the three machines that gives you a genuinely honest workload number. Whatever else is wrong with erg consoles, the watts figure is real.

For incline walking there is a second, independent way to get the number, which is the ACSM metabolic equation. For treadmill speeds below 5 mph it estimates oxygen uptake as 0.1 times speed in meters per minute, plus 1.8 times speed times fractional grade, plus 3.5 for resting metabolism. Running it at 3 mph across grades gives a clean ladder.

The equation and the Compendium agree with each other, which is reassuring. The Compendium's bracket for 2.9 to 3.5 mph at 6 to 15 percent grade is 8.0 METs, and the ACSM equation puts the middle of that bracket at 8.3. Two independent methods landing within four percent is about as much confidence as you get in exercise physiology.

What Thirty Minutes Actually Costs, by Body Weight

MET values are per kilogram, so the calorie figure depends entirely on how much of you there is. The conversion is METs times 3.5 times body mass in kilograms, divided by 200, which gives kcal per minute. Here is thirty minutes on each option across four body weights, expressed as gross energy expenditure.

Two honest notes on that table. These are gross figures, meaning they include the calories you would have burned lying on the couch for the same thirty minutes. Net expenditure, which is what actually adds to your deficit, is lower by about one MET's worth. For a 170-pound lifter on the incline treadmill, that is 334 gross against 294 net, a difference of 40 calories that most calculators quietly ignore.

The second note is the more useful one. Excluding the 200 W erg effort, which almost nobody sustains, the entire realistic range for a 170-pound lifter across three machines is 283 to 364 calories in half an hour. That is an 81-calorie spread. You will make bigger errors than that estimating a tablespoon of peanut butter. If you are picking a machine to maximize calorie burn, you are optimizing the wrong variable, and our calorie counting guide covers where the real errors live.

Your Console Is Wrong, and Not Always in the Same Direction

Every one of those calculations is more trustworthy than the number on the machine's screen, and the errors are not consistent between machine types.

Glave and colleagues compared an elliptical console against indirect calorimetry in 34 adults in 2018. The machine overstated energy expenditure by an average of 128 kcal across a thirty-minute session, and the error grew with duration, from 19 kcal at the five-minute mark to 120 kcal by twenty-five minutes. Their regression suggested that true expenditure was roughly 0.36 times the machine's number at that intensity, which is close to the machine reading nearly three times high. That was in "quick start" mode with no user data entered, which is the worst case and also how most people use the machine.

Stair machines err in the opposite direction. Butts and colleagues measured 28 adults on a StairMaster 4000PT and found actual METs significantly higher than the manufacturer's estimate at every stepping rate except the lowest. More recently, von Schaumburg and colleagues tested a Matrix stepmill in 16 participants and found measured METs higher than the machine's estimate at all stages, with the console's VO2max prediction coming in at 28.06 mL per kg per minute against a measured 39.18. That console was low by roughly a quarter.

The practical takeaway is that the console is a repeatability instrument, not a measurement instrument. Comparing today's 300 to last week's 280 on the same machine tells you something real. Putting 300 into a food tracking app does not. If you want a defensible number, use the MET table above and your own body weight, and be aware that even that carries individual variation of perhaps ten to fifteen percent.

Muscle Engagement: The Incline Treadmill

This is the best-quantified of the three, because grade is easy to control in a lab and treadmill EMG studies are common.

Franz and Kram put ten young adults on a motorized treadmill at seven grades from 9 degrees downhill to 9 degrees uphill and three speeds from 1.7 to 3.9 mph, recording stance-phase EMG from six leg muscles. Nine degrees is a 15.8 percent grade, which is close to the top of what commercial treadmills offer. Their uphill results, averaged across the three speeds and expressed as the increase over level walking, are the numbers worth knowing.

Read that carefully, because it is easy to over-interpret. These are percentage increases relative to level walking, and level walking is a low bar. A 345 percent increase in gluteus maximus activity over walking is not the same as a set of hip thrusts. EMG measures electrical activation, not force or mechanical work, and the authors flag that the biarticular muscles in particular cannot be read as a direct index of what the muscle is doing mechanically.

What the pattern does tell you is where the load goes. Steep incline walking is a posterior chain and calf activity. The hamstring and glute numbers dominate, the calf numbers are real, and the quadriceps involvement is present but secondary. That is exactly the profile you do not want stacked on top of a heavy deadlift or Romanian deadlift day, and exactly the profile that is harmless before a bench press session.

One more finding from the same study is worth carrying. The increases got larger with faster walking for every muscle except rectus femoris. Grade and speed compound. Bumping from 3 mph to 3.5 mph at the same incline is not a small change in local muscular demand, even though the calorie difference looks minor.

Muscle Engagement: The Rowing Machine, Minus the Marketing

The rowing machine is sold on a claim that does not survive checking. You will see it stated that rowing uses 85 percent of your muscles, or 86 percent, or "over 80 percent of your muscle mass." No study has measured that. The chain of citations runs back to a 1993 review by Steinacker in the International Journal of Sports Medicine, whose abstract observes that the muscles of successful rowers show 70 to 85 percent slow-twitch fibers. That is a fiber type composition, not a share of body muscle mass, and at some point in the retelling somebody swapped one for the other. There is no standard way to operationalize "percentage of muscles used" in the first place, which is a decent hint that a precise-sounding number for it is not measured.

What has been measured is the power split. Kleshnev instrumented 88 elite rowers, recording force at the footstretcher and the handle alongside seat, trunk, and handle velocities, and computed the mechanical power contributed by each segment.

The often-repeated 60 / 30 / 10 split appears in coaching materials and not in the peer-reviewed literature. The measured figures are closer to 45 / 32 / 23, and they shift with stroke rate, with the leg share rising and the arm share falling as rate goes up. Two caveats belong with them: the measurement was on-water rather than on an erg, and it was elite rowers, whose sequencing is better than yours.

The honest summary is that rowing is a genuine whole-body movement in which the legs still do the largest single share and the arms do more than most people expect. For a lifter, the practical consequence is that the erg is not a lower-body-free option. It is a lower body exercise with a substantial trunk and upper back component bolted on.

Muscle Engagement: The Stair Machine

There is less direct EMG work on stair machines than on treadmills, so the honest position is that the muscle engagement picture here rests more on mechanics than on measurement.

What has been measured is the intensity ceiling. Halder and colleagues put 25 participants with a mean VO2max of 46.7 mL per kg per minute on a stair machine at three climbing speeds. At the step rate corresponding to 90 percent of VO2max, oxygen uptake reached 43.9 mL per kg per minute and heart rate hit 185 beats per minute, and participants could only tolerate it for 4.32 minutes. The limiting factor was a combination of local muscle fatigue and cardiorespiratory strain, not one or the other alone.

That 4.32-minute tolerance is the most useful single fact about the stair machine. It is a machine that reaches genuinely high intensities and then stops you with quadriceps fatigue. For interval work that is a feature. For steady Zone 2 work it means you have to keep the step rate substantially lower than instinct suggests, and it means that the local leg cost of a hard stair session is real in a way that a bike session's is not. Our HIIT and LISS comparison covers where each intensity actually pays off.

Joint Stress Profiles

This is where the three machines genuinely separate, and it is the section most machine comparisons skip because the data is harder to find than a calorie chart.

The knee on the stair machine

Reilly and Martens measured quadriceps and patellofemoral forces across activities in 1972, in a small study of three healthy men, using a quasi-static analysis that the authors themselves described as yielding a lower bound. Their figures are the ones everyone still cites: patellofemoral joint reaction force at about 0.5 times body weight in level walking, 3.3 times body weight on stairs, and 7.6 times body weight in a deep knee bend.

The comparison that matters for a lifter is the last one. The stair machine loads the kneecap roughly six and a half times harder than walking does, and a deep squat loads it more than twice as hard again as the stairs. So the stair machine is not, in absolute terms, a brutal knee exercise for someone who squats. It is a moderate one, added on top of a heavy one.

The tibiofemoral picture comes from a better study design. Kutzner and colleagues measured contact forces directly inside instrumented knee replacements in five subjects going about ordinary activities. Peak resultant contact force came in at 261 percent of body weight for level walking, 316 percent ascending stairs, and 346 percent descending. Two things there are worth noting. The stair-versus-walking difference is real but modest, about a 21 percent increase for ascent. And descent loads the knee more than ascent does, which cuts against the usual assumption. A stair machine only makes you ascend, which is a point in its favor over actual stairs.

Impact on the incline treadmill

Peak vertical ground reaction force in walking runs about 1.0 to 1.5 times body weight across the normal speed range, while running spans roughly 2.0 to 2.9 times body weight. At 3 mph you are at the bottom of the walking range, near 1.1 times body weight. That is the lowest impact loading of the three machines and one of the lowest of any weight-bearing activity.

The 2025 isocaloric comparison makes the point directly. Krieger and colleagues matched high-incline walking at a 20 percent grade against level-grade jogging at identical energy cost in nineteen inactive adults, ten minutes each. Jogging produced significantly higher peak resultant acceleration at the foot, 22.14 meters per second squared, and at the sacrum, 27.21. Peak EMG was significantly higher in jogging for tibialis anterior and vastus lateralis. Same metabolic cost, measurably more mechanical stress. Their conclusion was that high-incline walking is a lower-impact but equally demanding alternative to jogging, which is about as clean a validation of the incline treadmill for lifters as the literature offers.

The lumbar spine on the rowing erg

This is the one lifters underrate. Morris and colleagues modeled lumbar loading in 14 female rowers during a six-minute simulated race on a Concept II and calculated peak compressive force at L4 and L5 of 2,694 newtons, which worked out to 4.6 times body weight, with peak shear at 660 newtons. The study's framing was actually positive, since the authors were explaining why rowers carry higher lumbar spine bone mineral density than matched controls. The load is osteogenic. It is also a load, and it lands on the same structure your deadlift lands on.

The epidemiology backs up the concern. Newlands and colleagues followed 76 international-level rowers with monthly questionnaires for a year and found 53 percent reporting at least one episode of low back pain, with 72 episodes total. In a prospective cohort of 20 Irish international rowers, the lumbar spine accounted for 31.8 percent of all injuries. A 2025 systematic review and meta-analysis of 10 studies covering 2,082 rowers found cohort-study prevalence between 52.6 and 57 percent, and identified previous low back pain as the only statistically significant risk factor, at an odds ratio of 2.65. Notably, that meta-analysis did not find training volume significant, which contradicts the older literature, and it rated the overall evidence quality as low to very low.

The mechanism is the part you can act on. Nugent and colleagues systematically reviewed 22 biomechanics studies and found that rowers without back pain hold a neutral or anteriorly rotated pelvis at the catch and a flatter lumbar position at the finish, while rowers with pain show more posterior pelvic rotation at the catch. Fatigue increases lumbar flexion at the catch in both groups, and it does so more on the ergometer than in a boat.

What Each Machine Costs the Next Lifting Session

The interference effect is the reason lifters care about any of this. The standard reference is Wilson and colleagues' 2012 meta-analysis of 21 concurrent training studies with 422 effect sizes. Averaged across studies, hypertrophy effect sizes were 1.23 for strength training alone against 0.85 for concurrent training, strength was 1.76 against 1.44, and power was 0.91 against 0.55. Endurance frequency and duration both correlated negatively with all three outcomes, with duration showing the stronger relationship. That is a dose finding as much as a modality finding, and it interacts with how much lifting volume you are already carrying, which our training volume guide covers.

The finding relevant here is the modality one. Resistance training concurrent with running produced significant decrements in both hypertrophy and strength. Resistance training concurrent with cycling did not. The usual explanation is eccentric loading: running involves repeated high-force eccentric contractions in the quadriceps and calves that overlap directly with the muscle damage from squatting, while cycling is close to concentric-only.

Now the honest caveat, which most articles citing this study omit. The meta-analysis compared running against cycling. It did not include stair machines, incline treadmills, or rowing ergometers as separate modalities. Extending the finding to those three is a mechanistic inference, not a research result. What we can say is that all three of our machines sit closer to the cycling end of the eccentric spectrum than to the running end, because none of them requires you to absorb landing forces.

That is genuinely good news for the machine question. It means the interference cost of all three is probably low relative to running, and it means the differentiator between them is not systemic interference but local, specific fatigue. Which brings us back to the scheduling framing. Our deeper look at the interference effect covers the dose side of this.

The Machine Comparison Table

Everything above, condensed into the form you would actually use standing in the gym.

Notice that the METs row, the one everybody argues about, is the row with the least variation. Between 7.0 and 9.0 METs is a spread of about 25 percent, and you can erase it by adjusting one setting on any of the machines. Every other row differs qualitatively.

12-3-30, Evaluated on the Arithmetic

The 12-3-30 protocol, meaning a 12 percent incline at 3 mph for 30 minutes, went viral several years ago and is still the single most common thing people are doing on an incline treadmill. It deserves an honest evaluation rather than either dismissal or enthusiasm, and it happens to be unusually easy to evaluate because every variable is specified.

Run the ACSM walking equation at exactly those settings. Three miles per hour is 80.4 meters per minute. Oxygen uptake comes out at 8.04 for the horizontal component, plus 17.37 for the vertical, plus 3.5 resting, for 28.9 mL per kilogram per minute. Divide by 3.5 and you get 8.26 METs.

The Compendium lists running at 5 mph, a 12-minute mile, at 8.3 METs. Those are the same number. A protocol that a lot of people file under "easy walking cardio" costs the same oxygen per minute as jogging a 12-minute mile, and the Compendium's own bracket for uphill walking at 6 to 15 percent grade, at 8.0 METs, agrees.

In calories, for a 170-pound person, that is 334 gross or 294 net over thirty minutes. For a 200-pound lifter it is 393 gross and 346 net. The commonly quoted "300 to 400 calories" is defensible as a gross figure across ordinary body weights, and it becomes optimistic if you meant net.

So what does 12-3-30 actually buy you over jogging? The Krieger study answers that. Matched isocalorically, jogging produced significantly higher peak accelerations at both the foot and the sacrum and higher peak activation in tibialis anterior and vastus lateralis. You pay the same metabolic bill and take less mechanical stress. For a lifter with a squat session two days out, that trade is straightforwardly good.

Our walking for fat loss guide covers the NEAT case for walking generally, which is a different and arguably more important argument than the one about any specific incline protocol.

The Decision Rule: Pick by the Lift Day It Lands Next To

Here is the entire article compressed into something you can use. Look at what you are lifting tomorrow, and what you lifted today. Then pick the machine whose local fatigue does not collide with either.

The pattern to internalize is that these three machines are not interchangeable substitutes but complementary tools, and that the constraint driving the choice is almost always a lifting session rather than a cardiovascular goal. That is the right way round. The cardio is in service of the training, not the other way around.

Programming Each Machine

Concrete starting points for each, assuming you already know your weekly cardio volume target. If you do not, the cardio base guide works that out first.

Incline treadmill

For steady work, set the grade first and the speed second. Start at 6 percent and 3 mph, which is about 5.8 METs, and progress the grade by 1 to 2 percentage points every week or two until you reach a grade you can hold for the full session without touching the rails. Most lifters top out usefully somewhere between 10 and 15 percent. Twenty to forty minutes is the productive range. Because the impact cost is so low, this is the machine that tolerates the most weekly volume without eating into recovery.

For intervals, keep the speed constant and alternate grade. Three minutes at 12 percent and two minutes at 4 percent, repeated five or six times, is a clean structure that does not require you to change your gait mid-session.

Stair machine

Two facts should shape your programming here: the intensity ceiling is high, and local quadriceps fatigue arrives before cardiovascular limits do. That makes this a better interval machine than a steady-state machine for most lifters.

For steady work, keep the step rate low enough that you can hold a conversation, and expect that to be slower than feels dignified. The case for keeping most of your aerobic work genuinely easy is made in full in our piece on slow steady-state cardio. Fifteen to twenty-five minutes is enough. For intervals, the Halder data suggests that near-maximal step rates are tolerable for about four minutes, so structure around that: 90 seconds hard and 90 seconds easy, six to eight rounds. Never hold the rails for the same reason as the treadmill, and never do a hard stair session within 48 hours of a heavy squat day.

Rowing ergometer

Set the damper between 3 and 5, which for most people corresponds to a drag factor in the low 100s. High damper settings make the stroke feel like a leg press and increase lumbar load without improving the cardiovascular stimulus.

Use watts rather than distance or calories as your target, since the watts figure on a Concept2 is computed from a fixed formula and is directly comparable across sessions and machines. A lifter doing Zone 2 work should expect to sit somewhere between 90 and 130 W, which is a 2:20 to 2:35 pace, and should treat any session where the catch position starts to round as finished regardless of the clock.

Keep sessions shorter than you would on the other two machines. The technique degradation with fatigue is the specific risk, and it is measurable rather than theoretical. Twenty minutes of clean rowing beats thirty-five minutes where the last fifteen are performed with a rounded lower back.

Common Mistakes

1. Holding the handrails. On a treadmill or a stair machine, supporting even a fraction of your body weight through your arms changes the exercise and invalidates every metabolic estimate. If you need the rails, the setting is too aggressive.
2. Logging the console calorie number. The elliptical over-reports by around 128 kcal in thirty minutes in one measured comparison, the stair machine under-reports intensity in two, and no console knows your actual efficiency. Use METs and your body weight instead.
3. Believing the rowing machine is a full-body cardio miracle. The measured power split is 45 percent legs, 32 percent trunk, 23 percent arms. It is a very good machine. It is not an 85 percent of your muscles machine, because nobody has measured such a thing.
4. Rowing the day before deadlifts. Peak lumbar compression on an erg was measured at 4.6 times body weight in one cohort, and lumbar flexion at the catch worsens with fatigue more on the ergometer than in a boat. Move it.
5. Stacking the stair machine on top of a squat day. Patellofemoral load on stairs is 3.3 times body weight against 0.5 for walking, and the local quadriceps fatigue arrives before the cardiovascular limit does. That is exactly the wrong overlap.
6. Jumping to a 12 percent incline on day one. Stance-phase soleus and gastrocnemius activity rise sharply with grade, and unaccustomed calves stay sore for days. Ramp from 6 percent.
7. Chasing the machine that burns the most. The realistic spread across all three for a 170-pound lifter is about 80 calories in half an hour. That is not the variable to optimize.
8. Rowing with the damper at 10. It converts a cardiovascular session into a poorly loaded leg press with a rounded spine, and it does not make you fitter faster.
9. Never rotating. Using one machine exclusively concentrates the same tissue stress week after week. Rotating spreads it, which is the same logic that makes exercise variation useful in a lifting program.

Frequently Asked Questions

Which cardio machine burns the most calories?

At a matched hard effort, the treadmill does, and the rowing machine does worse than most people expect. Prieto-Gonzalez and Yagin measured seven machines in 30 recreationally active men in 2024 and found 15.18 kcal per minute on the treadmill, 13.35 on the stair climber, 12.82 on the elliptical, and 11.45 on the rowing ergometer, which placed second to last. The reason is not that rowing is easy. It is that most people cannot hold a high power output on an erg for long, because the technique is unfamiliar and the legs fatigue locally before the cardiovascular system is fully stressed. Machine choice moves calorie burn by a couple hundred calories per session at most, which is small next to how many sessions you actually do.

Is 12-3-30 as hard as running?

By oxygen cost, it is almost exactly as hard as a 12-minute mile. Running the ACSM walking equation at 3 mph and a 12 percent grade gives 28.9 mL per kg per minute, which is 8.26 METs. The Compendium lists running at 5 mph at 8.3 METs. Those two numbers are within a rounding error of each other, so anyone who tells you 12-3-30 is easy cardio has not run the arithmetic. What it is not is equally punishing. A 2025 study matched high-incline walking at a 20 percent grade against level-grade jogging at identical energy cost and found jogging produced significantly higher peak accelerations at the foot and sacrum and higher peak activation in tibialis anterior and vastus lateralis. Same metabolic bill, lower mechanical one.

Does the rowing machine really use 85 percent of your muscles?

No source supports that number. The claim traces back through a chain of citations to a 1993 review by Steinacker in the International Journal of Sports Medicine, whose abstract says that successful rowers show 70 to 85 percent slow-twitch fibers. That is a fiber type figure, not a share of body muscle mass, and somewhere in the retelling the two got swapped. What has actually been measured is the power split. Kleshnev instrumented 88 elite rowers and found the legs contributing 45.2 percent of stroke power, the trunk 32.2 percent, and the arms 22.6 percent. Rowing is a genuine whole-body movement. It is not whole-body in the proportion the marketing implies, and the legs are still doing most of the work.

Is the Stairmaster bad for your knees?

It loads the kneecap harder than walking and much less than a squat, which for most lifters puts it in a manageable middle. Reilly and Martens measured patellofemoral joint reaction force at roughly 0.5 times body weight during level walking, 3.3 times body weight on stairs, and 7.6 times body weight in a deep knee bend. So a stair machine asks the patellofemoral joint for about six and a half times what walking does, while a single set of squats asks for more than twice what the stairs do. Kutzner and colleagues, measuring inside instrumented knee replacements, found peak tibiofemoral contact force at 316 percent of body weight ascending stairs against 261 percent walking. If your knees are healthy, the stair machine is a tool. If you have anterior knee pain that flares in squats and lunges, it is the worst of the three choices.

Can I trust the calorie number on the machine display?

Not without knowing which direction the specific machine errs, and the errors run both ways. Glave and colleagues compared an elliptical console against indirect calorimetry in 34 adults and found the machine overstating expenditure by an average of 128 kcal across a thirty-minute session, with the gap widening the longer people exercised. Stair machine consoles do the opposite. Butts and colleagues found actual METs on a StairMaster significantly higher than the manufacturer estimate at every stepping rate above the lowest, and a 2022 study on a Matrix stepmill found measured METs higher than the machine's estimate at all stages. Treat the console as a consistency check against your own previous sessions on the same machine, not as a calorie figure you can put in a food log.

Which machine should I use the day before squats?

None of these three at any real volume. The stair machine is a repeated single-leg step-up under body weight and competes directly with the quadriceps work you are about to do. The incline treadmill at a steep grade raises gluteus maximus stance-phase activation by around 345 percent and biceps femoris by around 635 percent compared with level walking, which is a real posterior chain demand the day before a heavy hinge or squat. The rowing erg loaded the lumbar spine at roughly 4.6 times body weight at the L4 and L5 level in a maximal effort in one measured cohort, and lumbar flexion at the catch gets worse as you fatigue. The day before squats, use a stationary bike or flat walking. Save these three for the day after leg work or for upper body days.

Do I have to pick one machine, or can I rotate?

Rotate, and rotate on purpose rather than by mood. Each of the three has a different local fatigue signature, so alternating them spreads the tissue cost the way alternating exercises spreads it in a lifting program. A practical week for a lifter running an upper and lower split is rowing after an upper body day, when a tired lat and a warm lumbar spine cost you nothing tomorrow, the incline treadmill on a rest day or after lower body work, and the stair machine on the day furthest from your next squat session. The one thing worth avoiding is stacking the same machine three days in a row while also training the same muscle group, since that is how calf strains and anterior knee pain start.

The Bottom Line

The three machines sit between 7.0 and 9.0 METs at ordinary settings, which for a 170-pound lifter is a thirty-minute range of 283 to 364 calories. That 81-calorie spread is not worth an argument, and it is smaller than the error in your food tracking. Calorie burn is the wrong axis to choose on.

The right axis is where the load lands. The stair machine puts it in the quadriceps and the patellofemoral joint at 3.3 times body weight. The incline treadmill puts it in the glutes, hamstrings, and calves, with stance-phase hamstring activation running over six times level walking at a steep grade, while keeping impact at the lowest of the three. The rowing erg puts it in the lumbar spine at a measured peak of 4.6 times body weight and in the pulling musculature, with the specific hazard that your technique degrades exactly when you are most tired.

Two claims should not survive this article. Rowing does not use 85 percent of your muscles; the measured power split is 45 percent legs, 32 percent trunk, 23 percent arms, and the 85 figure is a garbled restatement of a fiber type observation. And your console's calorie number is not a measurement; the errors run in both directions and reach 128 kcal in half an hour in the one carefully controlled comparison available.

One claim survives intact. 12-3-30 costs 8.26 METs, which is the same as jogging a 12-minute mile, and it delivers that at significantly lower peak accelerations and lower peak quadriceps activation. It is a genuinely good tool that happens to have a catchy name, which is rarer than it should be.

Do this: look at your training week, find the two or three slots where cardio fits, and assign a machine to each slot based on what you lift the following day rather than on what the machine promises. Rotate across the week. Keep the rails untouched, keep the erg damper under 5, and ramp the incline from 6 percent rather than starting at 12. That is the whole decision, and it takes about two minutes to make once and then never again.

References

1. Ainsworth, B.E., Haskell, W.L., Herrmann, S.D., Meckes, N., Bassett, D.R., Tudor-Locke, C., Greer, J.L., Vezina, J., Whitt-Glover, M.C., & Leon, A.S. (2011). 2011 Compendium of Physical Activities: a second update of codes and MET values. Medicine and Science in Sports and Exercise, 43(8), 1575-1581.
2. American College of Sports Medicine. ACSM's Guidelines for Exercise Testing and Prescription. Metabolic equation for walking: VO2 (mL/kg/min) = (0.1 x speed in m/min) + (1.8 x speed x fractional grade) + 3.5, valid for treadmill speeds below 5.0 mph.
3. Prieto-Gonzalez, P., & Yagin, F.H. (2024). Energy expenditure, oxygen consumption, and heart rate while exercising on seven different indoor cardio machines at maximum and self-selected submaximal intensity. Frontiers in Sports and Active Living, 6, 1313886.
4. Zeni, A.I., Hoffman, M.D., & Clifford, P.S. (1996). Energy expenditure with indoor exercise machines. JAMA, 275(18), 1424-1427.
5. Rippe, J.M. (1996). Energy expenditure with indoor exercise machines [letter]. JAMA, 276(8), 605.
6. Glave, A.P., Didier, J.J., Oden, G.L., & Wagner, M.C. (2018). Caloric expenditure estimation differences between an elliptical machine and indirect calorimetry. Exercise Medicine, 2, 8.
7. Butts, N.K., Dodge, C., & McAlpine, M. (1993). Effect of stepping rate on energy costs during StairMaster exercise. Medicine and Science in Sports and Exercise, 25(3), 378-382.
8. von Schaumburg, L., Laurson, K.R., Thomas, D.Q., & Lagally, K.M. (2022). Submaximal testing to estimate aerobic capacity using a Matrix C5x Stepmill. Journal of Human Kinetics, 83, 121-129.
9. Halder, A., Gao, C., Miller, M., & Kuklane, K. (2018). Oxygen uptake and muscle activity limitations during stepping on a stair machine at three different climbing speeds. Ergonomics, 61(10), 1382-1394.
10. Franz, J.R., & Kram, R. (2012). The effects of grade and speed on leg muscle activations during walking. Gait & Posture, 35(1), 143-147.
11. Krieger, T., Sato, M., Gidley, L., Ortega, J., & Lankford, D.E. (2025). Accelerations and EMG differences between isocaloric high-incline walking and level-grade jogging. International Journal of Exercise Science, 18(1).
12. Reilly, D.T., & Martens, M. (1972). Experimental analysis of the quadriceps muscle force and patello-femoral joint reaction force for various activities. Acta Orthopaedica Scandinavica, 43(2), 126-137.
13. Kutzner, I., Heinlein, B., Graichen, F., Bender, A., Rohlmann, A., Halder, A., Beier, A., & Bergmann, G. (2010). Loading of the knee joint during activities of daily living measured in vivo in five subjects. Journal of Biomechanics, 43(11), 2164-2173.
14. Nilsson, J., & Thorstensson, A. (1989). Ground reaction forces at different speeds of human walking and running. Acta Physiologica Scandinavica, 136(2), 217-227.
15. Morris, F.L., Smith, R.M., Payne, W.R., Galloway, M.A., & Wark, J.D. (2000). Compressive and shear force generated in the lumbar spine of female rowers. International Journal of Sports Medicine, 21(7), 518-523.
16. Kleshnev, V. (2000). Power in rowing. In Proceedings of the 18th International Symposium on Biomechanics in Sports, Hong Kong. Reported segment power contributions of 45.2 percent legs, 32.2 percent trunk, and 22.6 percent arms in 88 elite rowers.
17. Steinacker, J.M. (1993). Physiological aspects of training in rowing. International Journal of Sports Medicine, 14(Suppl 1), S3-S10. Source of the 70 to 85 percent slow-twitch fiber observation frequently misquoted as a share of muscle mass.
18. Nugent, F.J., Vinther, A., McGregor, A., Thornton, J.S., Wilkie, K., & Wilson, F. (2021). The relationship between rowing-related low back pain and rowing biomechanics: a systematic review. British Journal of Sports Medicine, 55(11), 616-630.
19. Newlands, C., Reid, D., & Parmar, P. (2015). The prevalence, incidence and severity of low back pain among international-level rowers. British Journal of Sports Medicine, 49(14), 951-956.
20. Wilson, F., Gissane, C., Gormley, J., & Simms, C. (2010). A 12-month prospective cohort study of injury in international rowers. British Journal of Sports Medicine, 44(3), 207-214.
21. Ze, X., Zhang, S., Long, X., & Zhou, P. (2025). Risk factors associated with low back pain in rowers: a systematic review and meta-analysis. BMC Sports Science, Medicine and Rehabilitation, 17, 157.
22. Wilson, J.M., Marin, P.J., Rhea, M.R., Wilson, S.M.C., Loenneke, J.P., & Anderson, J.C. (2012). Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises. Journal of Strength and Conditioning Research, 26(8), 2293-2307.
23. Concept2. Watts calculator. Published relationship between power and pace: watts = 2.80 / (pace in seconds per meter) cubed.