Not only is it a highly effective exercise for working both the front and back of the thighs, it’s also great for the glutes (perfect for ladies wanting a firmer backside).

WARNING: If you've never done it before, then approach with caution. This exercise is almost unrivalled in its ability to generate extreme muscle soreness. If you push it too hard you’ll be limping around for days!

But be warned... it’s not for the faint hearted!

Today, I’ve got another short (69 seconds) clip from the documentary Bigger, Stronger, Faster that will "pull back the curtains" and reveal another supplement industry "secret"...

It's taken from a documentary called Bigger, Stronger, Faster, which is worth watching if you haven't seen it already.

Even though it's old news to anyone who's seen what goes on "behind the scenes" in the supplement industry, a lot of people are surprised when they realize that this kind of thing goes on.

Is it true or false that once you hit the age of 35, your chances of building a decent body are all but over?

At least once a week, I get an e-mail that goes something like this:

"I'm 37 and wondered to what extent is my age an obstacle to muscle growth? What are my chances of ever having the kind of muscles that would be worthy of appearing on the cover of Men’s Health?

Here's my answer…

"I read in a fitness magazine that if you continue with a workout for longer than six weeks you’ll actually become less fit and less muscular," wrote KB.

"Do I need to shock my muscles by changing exercises every six weeks? How long should the 4-day routine in the Maximum Muscle Plan be followed before changing the exercises so my muscles don't adapt to them and become less effective?"

"I've just started working with a new trainer," he wrote. "Some of the exercises we do, such as the overhead dumbbell press, are done sitting on a Swiss ball."

"My trainer says that doing them on a ball makes them more functional for my core. And the exercise does feel harder, even though I'm using a lot less weight. My goal is to build some more muscle before I go on holiday later in the year. Should I be doing more exercises on a Swiss ball to strengthen my core?"

To cut a long story short, no. You don't need to do anything on a Swiss ball to strengthen your "core" muscles. If your main goal is to build muscle, doing more exercises on a Swiss ball isn't just unnecessary, it may actually slow your rate of muscle growth...

In fact, as you'll see in these videos, you can get a great upper body workout with just a towel, a rucksack, a tow rope and a bag of sand...