I would think so yes.
I used to walk with an old friend for years. We would do a 3 mile loop in the hills and we also had horses and were horse nuts.
She was 5’10 in her bare feet and I am 5’3.

I had to take about 3 strides for her every one. We nicknamed each other after the horse characters in the novel “Black Beauty.”
I was “Merrylegs” the little pony and she was “Ginger” the big red thoroughbred. lol
I kept up a fast trot to her walk.

Man whatta workout but my little legs looked great. haha

They are likely to take more strides, but the taller person is also typically proportionately heavier (if both are at recommended BMI), so moving more weight also requires more energy.

Of course there are great ranges of variability for leg length and body mass. My proportions are such that my torso is long relative to my limbs, while my fiancé‘s limbs are long relative to his torso. He’s about 5” taller than I when we’re standing, but when we’re sitting, I’m at least an inch higher than he is. I also weigh more than he does; so yes, I work much more when we walk together – but at least he is patient about it.

The “Square Cube” law says no. Take two people, one twice as tall as the other. Assuming the same proportions (or pretty close), the larger person will have four times the strength (2^2) moving 8 times the mass (2^3). My buddy and I have the same build and proportions, but I’m 6’, 170 lbs while he’s just shy of 7’ and considerably heavier. He works harder just standing up than I do jogging. Conversely, cats and small children never run out of energy moving their tiny legs.

Seems to me like the answer to your question (based on the other answers here) is: whichever one of you is in the poorest shape. If your bodies resemble x and X, it’s the same. If you’re k and R, R is working harder.

What I want to know is what’s the point of walking together if you are always way ahead? If you walked the opposite directions, you might at least get to great/smile at each other once in a while.

No. It is all relative. The short step takes less energy while the long stride takes more. Over distance, the energy used is the same.

I know that Jerv and Kritiper are probably right but I am 5 feet and I once went on a walk with my cousin who is 10 inches taller. Like @Coloma I had to go at a quicker pace for every one of her steps. She is not the kind to work out either, where as I was use to jogging at least 3 miles a day at that time. She barely broke a sweat at a leisurely gait and I felt like her puppy running to catch up

I would argue it’s all relative. A person with a longer stride most likely weights more and has to accommodate that way…

Try visualizing this way. Take Running Back Darren Sproles. He is 5’6” and about 175 (with a ton of muscle mind you) vs a 340 pound linemen with a longer stride who is 6’4”

Well, I seem to recall from my school days (a long time ago) that work is measured in foot-pounds, that is, how much weight is carried over how much distance. That’s why the treadmill machine at the gym asks you to enter your weight if you want a more accurate estimate of calories burned.

If you’re both walking the same distance, then the one who weighs more does more work. So, it’s the weight that counts, not length of stride.

Thanks for all the great answers. It brings me to another question. So, if we’re trying to do equal amounts of exercise, should I encourage her to keep up with me?

@ibstubro Well, I usually walk zig-zag when I get too far ahead so she can catch up. I didn’t include that because it would definitely mean I’m doing more work. It’s also good to be around incase something bad happens.

The shorter person will be working harder by repeatedly calling ahead, “Hey, wait for me!!”

The taller person could wear ankle weights, or carry a bag of cement, or have a watermelon in their backpack to even things out.
As in horse-racing where you would keep adding weight to the faster horse until the horses come in dead even. (handicapping)

I think the shorter person is working harder assuming both people are an average weight for their height. Although, @jerv‘s analysis does look very scientific and maybe he is right. I would think just take the pulse of both people. My guess is the shorter person rushing to keep up has a faster beating heart and is actually getting more of an aerobic workout.

@simone54; You could walk backwards also from time to time.

My guess would be the difference would be negligible.

But I think the real deciding factor here is not stride length, but pace. Her trying to keep up with your faster pace is giving her a higher heart rate and that’s goiing to be more important than the actual stride.

Maybe this will help: You have a car with a manual transmission and you always drive the same route between fill-ups. One tank of gas you drive with the transmission in the highest gear possible to keep the engine total revs at a minimum. The next tank of gas you drive with the transmission in the lowest gear possible for the most (highest) total engine revs. Which tank of gas will show the highest MPG?
(I did this once when I was in Denver. The car I had was a 1956 Pontiac with a three-speed manual transmission.)