Myth: Sweating on a treadmill is just as good as sweating outside.Mythbuster: Alwyn Cosgrove
In the past people moved more and their exercise programs were well rounded, but recently more people have switched to doing treadmill-only workouts for their cardio. Whether they think it's better for their joints or because they're closet vampires who can't...stand...the light! and never want to venture outside, I'm not sure.
What I am sure of is that steady-state cardio on the treadmill is just fucking stupid. And, no, I'm not going to rehash the old argument about how intervals burn more calories. You already know that.
Instead I'm going to do some math.
Walking a mile is about two thousand reps in the sagittal plane at about one and a half to two times your bodyweight. Jogging would be around fifteen hundred total reps at about two to three times your bodyweight.
And since the treadmill switches your hamstring and glutes off — your foot hits the belt and the belt pulls you through — it's mainly a quad exercise.
So let's say a client does three miles three times per week for one year (and I'm being conservative).
That's 6000 reps x 3 days per week x 52 weeks, which equals 936,000 reps of knee extension work. Or 468,000 reps per leg.
Let's say the load going through with the knee was a measly 100 pounds. That's 4.6 millionpounds of work for the quad with absolutely no hamstring work.
Think of it this way: if you did 400,000 reps of triceps extensions with 100 pounds you'd get four million pounds of volume. If you didn't balance that out with biceps curls you'd expect the elbow joint to hurt, right? You're damn straight it would!
So long term walking or running on the treadmill is almost guaranteeing knee pain. And that's not even the worst part. Since the hamstring is switched off you're actually burning even less calories than you would if you were to walk on the ground!
This study showed that hip flexion angle increases on the treadmill as opposed to the ground and that stance time was reduced. Basically, the whole hip extensor mechanism is affected; hip and knee flexion angles have to increase to bring the hip through on the stride. So hip flexor fatigue plus substitution patterns equals severe knee pain.
Ten or twenty years ago we'd get away with this because our clients ran outside and did other activities. The contribution of treadmill time to total exercise time was much lower. It's hardly the case today.
One of the problems with low intensity steady-state aerobics for fat loss in the deconditioned population is the sheer amount of reps needed. I can do a bodyweight circuit and spread the "reps" over the whole body and get a similar metabolic effect.
At my gym we've always done interval training as we felt the results were superior, but over time we've moved to a "metabolic resistance training" model.
For example, one mile on the treadmill would be 1500 reps and burn around 100 calories. If you did a circuit of kettlebell swings, undulating ropes, inverted rows, sled pushes, and burpees for four rounds with 10 to 15 reps each, you'd burn 100 calories in less time with less load, and the reps would be spread over the entire body instead of on the ankles, knees, and hips. It's just a superior model.
Alwyn Cosgrove is owner of Results Fitness in California, and coauthor of "The New Rules of Lifting and The New Rules of Lifting for Women."
And I was reminded of my own dislike of the treadmill for a variety of reasons - 1) proprioceptively disturbing - our brain expects us to cover ground and have stuff pass by - being stuck in one place eliminates that and can confuse the body. 2) Inside will never trump outside! Fresh air (depending on where you live) and being outdoors wins every time. 3) Because Alwyn and Jeff said so!
So from now on I will be hitting the hill/alley in the back of house.