Misconceptions about Exercise - mental_floss on YouTube (Ep. 9)

Hi, I'm Elliot, and this is Mental Floss on YouTube

Today I'm going to talk about some misconceptions about exercise. Misconception number one, running on a treadmill will result in less knee injury

It's true that treadmills are designed to include padding, which softens impact. Running outside can be harder on the knees in that sense

but researchers have found that runners actually use a slightly modified stride when they're running on a treadmill

as opposed to running outside. They tend to have a bouncier run on the treadmill

They also might overstride. These two differences in form actually do affect the knees

So if you start having knee pain, take the day off from running and see a doctor who can recommend how to proceed

Watch some reruns of like Parks and Rec or something. Misconception number two, replace running shoes every six months

How often you should replace your running shoes depends on your size, running style, and running habits and preferred running shoe

Because of that, there's no way to pick a maximum number of months or miles that shoes should be worn for

Many experts believe that the best time to replace your shoes is when the ethylene vinyl acetate

or the shoe lining starts to wear down An 18 study that started in 1991 found that Europeans tended to wear their running shoes for around 600 miles but the researchers determined that the shoes could still

safely be worn even after that point. So, for this one, you pretty much just have to decide for

yourself how your shoes feel. Misconception number three, stretching prevents injury. Studies have

actually found that static stretching before exercise does not lower the likelihood of injury. In fact

sprinters who participate in this kind of stretching before running might even have slower speeds

Plus, according to a 2013 study published in the Journal of Strength and Conditioning

Research, people who stretched before weightlifting actually felt weaker. That stinks. According to Dr. Markovic, a professor of kinesiology at the University of Zagreb

after static stretching, muscle power lowers by around 2%. You should still warm up, but static stretching might not be the way to go

Misconception number four, you have to be sweating or you're not working hard

According to Jessica Matthews, a spokesperson for the American Council on Exercise

Sweat is a biological response that cools your skin and regulates internal body temperature

So, sweat is a sign that your body is working to cool itself, but you can burn calories

and plenty of ways that don't end with you dripping in sweat. Misconception number five you sweat out toxins Since I just gave you the definition of sweat this one should be common sense You only losing around 1 of your toxins via sweat gland Your gastrointestinal tract does most of the detoxing work in your body Misconception number six calorie counters on exercise machines are accurate

I don't want to shock you or anything, but fitness machines don't know anything about you

Okay? They don't know your sex, weight, or fitness level, and all of those factors affect how many

calories you're burning during exercise. So don't take calorie counters on machines too seriously

Some are more accurate than others, though. Like, according to one study, treadmills are pretty accurate

accurate, especially if you can punch in your weight, whereas many elliptical machines overestimate calorie count by 42%. Bummer

Misconception number seven, if you do enough sit-ups, you'll get a six-pack

According to experts, you can't spot reduce fat. Doing strength training and toning exercises will help, but in order to see the muscle definition

that you want, you'll probably have to incorporate cardio and a good diet into your routine

Misconception number eight, cardio burns more calories than weight training. Obviously, this completely depends on you and what workout you've chosen

Some studies have found that typically more calories are burned during cardio workouts, but

strength training allows calories to be burned for longer after the workout is over

This is known as excess post-exercise oxygen consumption, or epoch. After exercise is over the body metabolism continues to work hard resulting in calorie burn which happens more after weight training Misconception number nine maximum heart rate equals 220 minus age

Many people think that there's like an ideal fat burning zone for their heart rate, which is between 60 to 75 percent of maximum heart rate

So if they stay in that zone while working out, their workout would be the most efficient. But according to the American Council on exercise, the problem is that there's no perfect

formula to determine your maximum heart rate and therefore your fat burning zone

This formula is wrong because it overestimates the heart rates of young people and does the opposite for older people

But if you're obsessed with the zone system, talk to a doctor or trainer to get a more accurate number

Misconception number 10. No pain, no gain. Actually, most exercise experts agree that you should not be in pain while exercising

Discomfort and muscle soreness are fairly normal, but if you're in real pain, you might be risking

injury or already injured. I know I sound like a nag, but talk to your doctor if that's the case. Okay

Stop trying to lift cars all the time. Mom. Thank you for watching misconceptions on mental flow

loss on YouTube, which is made with the help of all of these wonderful people. If you have a topic for an upcoming misconceptions episode that you would like to see

please leave it in the comments and check it out. And I'll see you next week. Bye