Is treadmill running good or bad?

It’s fine. It’s a treadmill. You won’t race on it but you’ll get what needs done done on it if you want.

Guy at my running club who has never run under 19:40. He's attempted that 15-20 times. Yet on the treadmill he "runs" 18:00 (and posts it to strava of course). Treadmill running is significantly easier he will never run that time on the road even with all the drugs in the world.

As a flatlander I use it for hill workouts and if it's a blizzard outside. Other than that I'd rather not run on one.

I’m way faster on actual roads than I am on the treadmill for some reason. Probably the fresh air and change in elevation helps keeps the legs fresh. I run in the treadmill because I refuse to run outside in snow in the dark. Way easier to run at the gym a block from my house.

At my gym all the treadmills are at least a minute slower. So the mill will tell you you're running at an 8:32 pace, but you're actually running at 9:32.

I've also had similar results. Easy runs feel different but it's when I increase the pace to ~5:45-5:50 on 1 incline (apparently this is the great equalizer on the treadmill for elevation, wind resistance etc) it feels exceptionally harder than when outside.

In fact, I ran 9 miles yesterday at a 6:21/ with 700ft of climbing and my HR (117avg.) was almost 10bpm lower than the mill... anecdotal, but interesting

I think it’s good when you need it. I prefer doing a day or two on the treadmill weekly when in a mileage building phase because it’s not as hard on your legs. The downside is you definitely do want running to be hard on your legs sometimes, if you develop the software but not the hardware you’ll find your body giving up on you even if you feel fine during an actual race.

I did run a 4:17 mile on a well calibrated treadmill when I was only in 4:30ish shape, so I like to mentally compensate by adding 10-15 seconds a mile. If my normal road 25 minute tempo is 5:30 pace I probably ought to keep it sub 5:20 on the treadmill for the same stimulus. Heart rate and cadence data tells me that’s probably an accurate figure for me.

What I find interesting, and I’ve read a couple studies on it, is that perceived effort seems to be higher on a treadmill but measurable data points tend to show that effort is lower.

I personally feel like I’m sprinting at sub 5:00 pace on a treadmill, but my heart rate will stay pretty low. I did 12x400m shooting for 70s on the treadmill over Christmas break, came back and did the same workout on the track and felt like I was jogging, but my HR averaged about 10 bpm higher by the end of each rep.

True but there's also treadmills at gyms where there aren't fans & it's super hot & you're getting a threshold heart rate running your easy pace.

Treadmill running is fine. It's easier on the body & has its place. 1 easy session/week sounds perfect.

when it is cold and wet, the treadmill is great. But I, in my older age, prefer grass and treadmill second best option. Avoid hard surfaces beyond a synthetic running track.

stuff like indoor tracks and treadmills are going to get talked down on because not everyone has access to them.

that also comes with overrating the mental toughness gained from doing workouts in hurricane wind or 20F temp or whatever

some pros basically live on those multi thousand dollar anti gravity treadmills

Running at tempo feels like a sprint (5:10). Running a steady at 5:25 feels like I’m jogging

Yeah, all my cooldowns are done on anti-gravity treadmills.

Because you experience lateral motion on a treadmill, running at “faster” speeds is more difficult. This is probably a balance issue.

It's not effect for your running if you do it too often.

The ground is moving forward - you don't have to do much other than your legs. There's no air resistance. You don't burn as much calories as outdoor running.

Most people that run regularly on a treadmill are not competitive runners or even have running as a priority in their fitness priorities. Most treadmill runners want a controlled, comfortable environment where they're not faced with the challenges of outdoor running.

You get your biggest bang for your buck with outdoor running.

Man was designed to run outdoors not on a treadmill.

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Your legs at doing the exact same type of work on a treadmill as they do outside. The ground is spinning at 1,000 mph and moving through space at nearly 70,000 mph when you run outside. The only thing that matters is the running surface movement relative to your body.

Treadmills are great tools for training. But they're just tools. The speed you can run on a treadmill is different from what you can run outside. Who cares...just run based on effort.

I actually find it harder to run outside at a slow pace. On treadmill, however, I quickly get into a zone.

^This. I can build up tremendous aerobic fitness off of a winter training block on the treadmill. The problem is when I shift to running outside, I can absolutely rip my first run, but only the first one. I then have debilitating soreness that I can’t overcome because the treadmill did not help develop my stabilizing muscles.

I always think of it like this: treadmills are a great aerobic workout that are a good approximation of running. There is no substitute for actual running.

You guys realize that most pros do some treadmill running routinely, right? I find that when used as a supplement and not a replacement it's a good tool. I do a couple of runs a week on the mill and save the longer and harder efforts for outside. When I only run outside I get more wear and tear and don't run any faster.