Remember the bodybuilders of yesteryear who would often shift their workouts to high reps for cuts? Oh, brother [roll eyes]. I guess back in the dark ages they didn’t know that you can’t etch in cuts with higher reps—or can you? Before we go any further I want to point out that bodybuilders have been leading the way as far as exercise and nutrition for decades. Don’t skip this because it can help you with your goals, even if it is just being lean and fit.
If you’ve ever done a set of longer-tension-time leg extensions, you’d swear you were searing in lines of definition and blasting off fat with every rep—especially near the end of the set, when the burn was so fierce you almost punched your training partner in the neck to stop him from telling you to get another rep. But science tells us that you can’t “burn in” detail—ah, but you can affect fat-burning hormones with higher reps—or, more accurately, longer tension times….
Studies show that growth hormone, a potent fat burner, significantly increases due to muscle burn. Lactic acid and other fatigue products have been shown to boost GH as well as testosterone. T is another power-packed fat burners, and both help you pack on muscle mass too. Canadian researchers discovered the muscle burn-GH connection back in 1997. (Can J Appl Physio. 22:244-255; 1997)
More recently IRON MAN‘s resident Ph.D.s, Gabriel and Jacob Wilson, discovered that fatigue also triggers testosterone increases:
“Researchers found large changes in testosterone following a moderate-intensity protocol [70% 1RM, multiple subfailure sets], and no significant increases were found after numerous sets performed at 100 percent intensity [1RM]. This suggests that bodybuilders may benefit from lifting in a moderate repetition range of eight to 12.
“It appears the greater rise in testosterone may be the result of greater metabolic stress, such as increases in lactic acid following moderate-intensity, rather than maximal-intensity, training. Moderate intensity, high-volume exercise—eight to 12 reps and more than four sets—leads to greater increases in testosterone than low-volume, maximal-intensity exercise.” (Med Sci Sports Exerc. 36(9):1499-1506. 2004.; J Appl Physiol. 74(2):882-887. 1993.)
So the better testosterone boost was caused by volume—more sets—with most sets being subfailure. Interesting. That is very similar to the F4X method I’ve adopted (and am always barking about).
For those unfamiliar with F4X, you take a weight with which you can get 15 reps, but you only do 10; rest 35 seconds, and then do it again—and so on for four sets. On the fourth set you go all out. If you get 10 or more, you add weight at your next workout. The short rests cause cumulative fatigue pooling and a searing burn by the end, which is when you crash through the growth threshold.
Remember, it’s all about tension time, not necessarily rep count. For example, f you do 10 reps, lifting in one second and lowering in three, you will get 40 seconds of tension time on every set (10 reps times 4 seconds). Whereas if you do 15 rapid-fire reps, you may only get 20 seconds of tension time. The 10-rep set will do a better torching job.
So tension time is the more accurate fat-to-muscle trigger here. And it’s why I recommend four-second reps on almost every set of a F4X sequence. (Note: There are exceptions, which I will cover in a future blog; for example, X-celeration sets, 1.5 seconds per rep, can activate more and dormant fibers.)
So maybe the bodybuilders of yesteryear weren’t wrong after all. Longer tension times for more muscle burn would increase growth hormone and testosterone, which in turn would get them leaner faster for more muscle and rippedness. If you’re trying to build muscle and get leaner at the same time, you may want to try 4X, at least on an exercise or two for each bodypart.
I’ve been using it exclusively for almost two years straight—no superheavy training, only moderate weights—and I’m amazed at how my lean muscularity has stayed intact through the winter months, even with my looser diet (plus, I’m 52 years old!). Plus, my joints no longer wake me up at night.
Another reason F4X works so well at burning fat and building muscle is less cortisol release. Extreme weights traumatize joints and connective tissue, which means more stress hormones, which tend to eat muscle tissue and impair proper recovery. Excess cortisol also derails growth hormone output, so in that respect it may hamper your fat-loss efforts. Interesting.
That may be one reason Danny Padilla, one of the greatest short bodybuilders of all time back in the late ’70s and early ’80s often went to 5×12 with about 45 seconds between sets on every exercise for months before a contest. He did about four exercises for each muscle, and his workouts were quick.
His 5X did not overstress his joints, so he was keeping cortisol down, jacking up GH and testosterone and blasting through the growth threshold for maximum muscle development without overtraining. And he got built-in cardio too. No wonder he was renowned for getting big and ripped quick!
So F4X is not new. It’s actually an old-school ripping tool that packs on plenty of muscle too.
Stay tuned, train smart and be Built for Life.
Co-Creator of Old School New Body
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