So. You may have heard about the 1% treadmill rule:
In order for the effort of a treadmill run to equal the effort of an outside run, you must run on the treadmill at a 1% incline.
The reasoning behind this rule is that when running inside there is no wind resistance. When you run outside there is always some degree of wind pushing against you, causing you to work the slightest bit harder than if it weren’t there (unless it’s a windy day and then you work a lot harder when running into the wind!) So the thinking is that on the treadmill it’s exactly like running outside, except there’s no wind.
But it’s not. I’ve run a lot outside and inside. I’ve run on all kinds of different treadmills and in different gyms. Running on a treadmill is not identical to running outside, except for the wind.
I do not believe in the 1% incline rule. And here’s why:
First, I want to say that if the 1% rule works for you and feels right, than go ahead and stick with it. However, I do not think this is a “rule” in the true sense of the word. Calling this a rule says that it’s always true for everyone that a 1% incline on the treadmill is necessary for the effort it takes to run a pace on the treadmill to equal running that same pace outside. That is definitely not true. It might be true in some situations for some people, but it is most definitely not a universal truth! I picture the person who declared this a hard and fast rule as one of those people who thinks running on a treadmill isn’t “real” running (whatever that means)!
It’s time to respect the ‘mill, people!
Let’s start with the objective experts, the scientists: namely, exercise scientists who have studied the effect of wind speeds on running effort. While I do not know who Jim2 is, his synopsis of Martin and Coe and Noakes (all highly regarded sports scientists) is great. I’ll leave it to him to lay it all out. Basically, unless you’re running really fast there is no benefit to decreases wind resistance, meaning that it’s not easier to run on a treadmill than running outside. For most easy runs, the 1% incline likely makes it more difficult to run on the treadmill than outside. It’s a bit grayer when discussing paces between say 7:30 and 5:30/mile. However we can surmise that, the slower you are in that range, the less you have to worry about it.
Wait. What Does “Easier” Even Mean Here?
Ok. Let’s take a step back. If you are generally an outdoor runner and you hop on the ‘mill do you think to yourself, “Oooo this feels sooooo easy?” Seriously? I don’t think I have ever in all my life heard someone tell me that running on the treadmill actually feels easier than running outside. Most people get on the treadmill and feel like they’re working way too hard to be running so slow (am I right? Please feel free to tell me you disagree!)
When the scientists study the effect of wind resistance on running, they are testing things like heart rate and lactic acid clearance rates. That’s great, but those are just a small fraction of the variables that impact running effort. How about a run outside on a not windy day in 45 degrees versus stuck in a smelly humid basement gym at 68 degrees? You need a 1% incline for those conditions to equal out? What about the mental challenges of staying focused while running in place for 40 straight minutes at tempo pace? What about not being able to naturally adjust your pace and needing to meta-analyze it so your brain and fingers can set the pace? That takes a lot more energy than just pushing a button, believe me.
Lastly on this point, some workouts might max out the muscular power of your legs. So by upping the incline to get the cardiovascular effort right, you’re overtaxing your biomechanics. I definitely am the type of runner who is limited more by my biomechanics than my cardiovascular fitness, so upping the incline doesn’t help me achieve the purpose of many of my workouts. Besides it making sense here on “paper” I can actually feel this, when upping the incline 1% makes things hurt in ways they’re not supposed to, in ways they certainly don’t hurt at the same pace or faster outside. I’ve been training both outside and inside long enough to know my body and I can assure you I do not need 1% incline to get the effort right.
Why Does It Even Matter? Who Cares?
Now we’re getting to the heart of this matter. If you have 6 at 6:30 pace on the schedule, then you want to make sure you do the work of 6 miles at 6:30 pace. There are physiological benefits you seek to gain from this workout that can only be achieved if you do it at the right effort. This is always true no matter where we run and important to know.
However, there are so many things that can effect how a pace feels to you on any given run. We already talked a little about wind speed, air temperatures and boring scenery. Sometimes we just feel off for a workout. Maybe we aren’t quite recovered from our last hard run. Maybe we aren’t recovered from some big life event. Maybe the full moon is on a Tuesday this month or we’re in a progesterone slump, or hung over or just haven’t stretched enough lately. So many things can impact the way a run feels and there are no universal rules about that. Some of us handle the heat better than others. Some of us thrive on hills. Some of us don’t blink in the face of menstrual cramps. And hey, good for you if you’re really good at handling some level of running adversity better than others! But to say every single person must adjust their pace, etc. because of this or that variable is silly.
In fact, the self-aware runner knows the right effort level her workouts requires and know how to adjust to get it right. I have not always been good about this; lord knows I have had my share of doing almost race-effort tempos trying to hit some or another pace that I had no business hitting that day. But when it comes to my treadmill workouts, I know with 100% certainty that I do not generally need to adjust the incline to get it right.
Running on a treadmill is harder than running outside in some ways and not in others. If you’re like me and running on the treadmill always feels more difficult than outside running, then it’s not necessary to round up when setting your pace or incline. And no, that’s not being a wuss or cheating, that’s trusting your sense of effort.
Do you believe in the 1% rule? Have you followed it, and if so, do you think it has yielded more positive results than you would have otherwise achieved?