Whether they're debunking long-held myths by citing specific research, drawing from personal experience, or just making an educated guess, our rotating panel of experts likes to put the smack down on some of the most pervasive gym myths that cloud our consciousness and keep us from building lean, muscular, powerful bodies.

But as any self-respecting GI Joe fan understands, knowing is half the battle. The other half? Well, it's putting advice into practice. That's up to you.

This is Mythbusters Volume 6 with Dr. Clay Hyght, Alwyn Cosgrove, Chase Karnes, Mike Robertson, and Nia Shanks.

Myth: To gain muscle you must select exercises that enable you to use the maximum amount of weight.

Mythbuster: Dr. Clay Hyght

If you've been in the iron game for any length of time, I'm sure you've heard this. It's been passed around so much and is spoken with such certainty and authority that you would assume it's part of the Holy Gospel.

The problem is this "fact" is built upon faulty logic. First, an analogy.

Let's say you have a choice between a job that pays $50,000 per year and one that pays $55,000 per year. I bet you'd go for the one that pays $55,000 right? But what if that job is selling Kirby vacuums and you have to use your own car and pay for your own gas to travel around the Midwest? And what if the other job is in an office within walking distance from you house, saving you precious gas money and hellish trips to Akron to sell vacuum cleaners?

It may be time to reevaluate your job situation and pick the job that pays less. As the saying goes, "It's not how much money you make, it's how much you keep."

We train with weights in order to stimulate our muscles. This, obviously, can be done with a number of different methods. However, there's one thing that everyone agrees on: in order to maximize size and strength gains you must maximize the stimulation to the target muscle.

However, maximizing the stimulation to a muscle is not accomplished by simply moving more weight. Pesky little things like gravity, rotary force, leverage, and momentum come into play.

For an easy illustration let's look at the leg press. If getting big and strong was as simple as using more weight, then the leg press would be the single best leg exercise on the planet. But it's not.

Let's say you can leg press 500 pounds. But are you really doing 500 pounds?

To find the actual force (or resistance) of a leg press (a standard, angled sled), use the equation F = W x sin 45 degrees. "F" is the Force (what we call resistance), "W" is the weight, and 45 degrees is the angle of the machine. So if you leg press 500 pounds, then F = 500lbs x 0.707. Thus F = 353.5 pounds. Kind of disappointing isn't it?

And this is assuming that your leg press is actually 45 degrees and not 30 degrees like many are these days. If the machine is angled at 30 degrees, then the resistance is a measly 250 pounds!

Now I'm certainly not bashing the leg press. It's a great exercise for some people. The point is that selecting exercises simply based upon the amount of weight that can be used is erroneous and does not pass a logic test.

The most fundamental principle of weight training, whether for size or strength, is Gradual Progressive Overload (GPO). So go ahead and focus on using progressively heavier weight and more reps, but do not ignore physics and base your exercise selection simply upon the amount of weight you'll be able to use.

Dr. Clay Hyght, DC, CSCS, CISSN has been a competitive bodybuilder for 17 years. He works with some of the top competitors in bodybuilding and figure. You can visit his website here.

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 million pounds 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.

Myth: You're not putting on muscle because you're too active outside the gym.

Mythbuster: Chase Karnes

The big guys at my local gym used to tell me I couldn't gain weight because I was too active. I played football, worked a manual labor job, raced motocross, and lifted three days per week. They'd always tell me if I wanted to gain weight I'd have to cut back on all the activity and sit on my ass all day. Luckily for me they had it all wrong.

I've heard many recreational athletes or guys who work manual labor jobs blame their failure in gaining weight on their high activity levels. On the surface it may seem like they have a valid point. I mean, if too much cardio causes catabolism then recreational sports and manual labor would do the same, wouldn't they? Not exactly.

You won't burn so many calories that they can't be replaced with proper nutrition and eating big. Take some freakin' protein bars to work with you. Try packing a lunch. If gaining muscle is important to you, you'll sure as hell find a way to sneak in some hard-boiled eggs and tuna packets.

And anyone who's familiar with the "G-Flux" concept may argue that this increased physical activity should cause you to have an even better chance at gaining muscle and losing fat.

And what about the training thing? Most guys think they'll have no energy to train after they work at the construction site. The simple fact is the human body has a very remarkable ability to adapt. So while the first few weeks of adding in a training program may seem difficult, the body will eventually adapt to the increased activity and it won't seem as hard.

Try planning your workouts when you feel most rested. If you work construction Monday through Friday, hit the gym hard with an upper-body workout on Saturday, a lower-body workout on Sunday, and a full-body workout on Wednesday. If you don't go to work until 9 A.M., try training at 7:30. Careful periodization of your program with planned back-off weeks is a must, but just because you work or play hard doesn't mean you still can't train hard.

You're just not that special. Look at college, pro, and Olympic level athletes. Some of these guys practice and train hours everyday, yet they're still jacked. You don't see their physical activity affecting their abilities to gain or maintain muscle do you?

I know you've heard this a million times, but it's calories in versus calories out. If you work or play hard, then you're going to have to eat that much more. Another thing I recommend is using BCAAs before and during any prolonged physical activity.

Chase Karnes is a NSCA certified personal trainer and strength coach and an accomplished bodybuilder (Two NPC 1st place finishes) and powerlifter (SLP National Raw Powerlifting record-holder) who trains strength and physique athletes from around the country.

Myth: You should never wear a weight belt.

Mythbuster: Mike Robertson

This is a classic case of people swinging too far to one side. The answer is always going to be "it depends."

Are you a competitive powerlifter? Then, yes, I think using a belt on sets above 90 percent of your one rep max is a good idea. But you've also got to understand that the stronger you are raw, the stronger you'll be once you get in your gear.

Are you a guy who trains hard in the gym and is concerned mostly about building huge muscles? Then, no, I don't think you need a belt. Well, at least not all the time.

First, let's talk about what a weight belt does. It gives you a psychological advantage when you start to move out of your comfort zone and also provides some extra stability to your lumbar area.

The problem is you should already have an "inner weight belt" which consists of your abdominals, lower back, and diaphragm before you even consider using an external weight belt to compensate for your lack of muscular balance. Most guys with weak cores are the same guys who think squats and deadlifts are enough to work their torso. Sure, they help, but if you're truly interested in building muscle and strength, you need to target your core directly and get it as strong as possible.

The whole point to building the core is to effectively transfer energy from your legs, through your "inner weight belt," and into the bar. As Dave Tate says, "Would you rather have a pillow or a rock for a stomach?"

If you've got a doughboy core, you won't be moving heavy weight.

So let me go ahead and throw out a general rule about belts. If you're a powerlifter or just someone who wants to work on max strength, then I think a belt is a good thing to have in your gym bag.

But if you're not pulling max singles or heavy triples, I think you can safely get by without one if you really work on your core strength and stability.

Mike Robertson, M.S., C.S.C.S., U.S.A.W and received his Masters Degree in Sports Biomechanics from the world-renowned Human Performance Lab at Ball State University.

Myth: Intervals are the best training method for fat loss for everybody.

Mythbuster: Nia Shanks

I've done my fair share of running full speed up a hill and nearly losing my breakfast doing barbell complexes. There's no argument that interval training is effective for fat loss.

But if you're serious about building muscle and increasing your strength, sitting on the bike and pedaling furiously till your legs look like the Roadrunner's will negatively impact your progress. So interval training is not always the best method.

From personal experience, and from the results of my clients, I've noticed that interval training can be so overwhelming that performance in weight training sessions start to decline. Weights that once felt easy barely move and you start to lose motivation. This sub-par performance in the weight room will lead to a decrease in fat loss.

The way I've always trained has been ovaries-to-the-wall. (I'm a woman, so deal with the analogy). It doesn't matter if I'm deadlifting 250 pounds for reps or jumping rope, I go all out every time, and so do my clients.

If you train with that intensity multiple times a week it'll catch up with you quickly, causing you to lose focus, burn out, or not recover properly. That's why if your main goals include building muscle and strength, you should lay off intervals for a while and make sure you kick your ass every time you're in the gym.

But if you still want to lose a little fat and need to huff and puff like an overweight Wal-Mart whale to feel productive, I suggest going on brisk walks outside after your weight training session. Find a hill or put on a weight vest to make it harder. But keep these walks limited to twenty to thirty minutes and don't do it more than four times per week. This will help you retain your muscle mass and burn fat at the same time without sacrificing any of your precious energy. And if you really need to shed a lot of fat and want to do intervals, at least be smart enough to tune down the frequency and intensity of your weight training sessions.

Nia graduated from the University of Louisville with a degree in Exercise Science with high honors. Nia is also the SPF push/pull national record holder for her division with a bench press of 145 pounds and a deadlift of 300 pounds at the bodyweight of 122.

Your Turn

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