During exercise, the body will typically utilize either carbohydrate or fat for energy but as exercise intensity increases to near-maximal levels, the body shifts to using carbohydrates such as glucose and glycogen as the predominant source of energy.
Understanding the underlying principles as to why the body prefers carbohydrates during high-intensity training would be tremendously important for those interested in maximizing their performance, as this insight may lead to optimized energy levels throughout your entire workout— achieving greater gains in muscle and strength.
FAST-TWITCH MUSCLE FIBERS PREFER CARBS FOR ENERGY
As exercise intensity increases, the muscle cells’ energy preference shifts from fat to carbohydrate.1 This is primarily because heavy weightlifting or intense exercise principally activates fast-twitch muscle fibers. Fast-twitch fibers, as the name suggests, contract much more quickly— producing more power than the alternate slow-twitch muscle fiber type found in the human body. Therefore, fast-twitch muscle fibers are preferentially activated during intense exercise such as heavy weightlifting because more power is needed to move the heavier weight. Since fast-twitch fibers are preferentially activated during maximum-effort exercise that typically depletes oxygen levels, and carbohydrates are the only macronutrient that anaerobically provides energy, fast-twitch fibers are loaded with enzymes that can anaerobically convert carbohydrate into energy.2 Additionally, fast-twitch muscle fibers have fewer enzymes that turn fat into energy because utilizing fat for energy requires oxygen— and fast-twitch muscle fibers are primarily activated under anaerobic conditions. Consequently, fast-twitch muscle fibers are best acclimated to burn carbohydrates for energy under anaerobic conditions— demonstrating the body’s inclination for carbohydrates while under severe physical stress.
HIGHER EPINEPHRINE LEVELS
This story is from the October 2018 edition of Muscular Development.
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This story is from the October 2018 edition of Muscular Development.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
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Best Cardio for Fat Loss - High Intensity vs. Low Intensity
Low-intensity cardiovascular exercise is the most common way to reduce body fat, despite mounting scientific evidence showing this form of cardiovascular training may not burn body fat as effectively as high-intensity cardio. In addition, low-intensity cardio has also been shown to inhibit muscle growth¹2, making the use of this approach to enhance your physique even more questionable.
Are Unilateral Exercises More Effective Than Bilateral Exercises?
Bilateral exercises simultaneously use both limbs to lift the weight, so that the resistance is being shared between each limb.
THE AMAZING POWER OF JULIA DI POMPEO
Pro Figure Champ and Pro Powerlifter!
BRYAN JONES: THE LORD OF CLASSIC RETURNS!
It seems like a decade has passed since the pandemic began in 2020. That was a chaotic year for all of us. MD sent me to Atlanta to cover the Chicago Pro, because restrictions in Illinois made it impossible to hold Tim Gardner's annual extravaganza there. The athletes still showed up in force to compete, and the Classic Physique division alone featured 30 men. When they came out to be adjudicated, one man stood out in a flash as the one to beat. I had never heard of Bryan Jones until that point aside from a vague recollection that he'd won the USA a couple of years before. With his braided and colored hair piled on top of his head in a gathered bun with the ends appearing to be some type of bizarre plant, I dubbed him \"The Kai Greene of Classic.\" That didn't stick, thankfully, because Bryan \"Lord\" Jones is a unique athlete in his own right. I knew I was looking at a man who was going to make waves in that division. A few months later he did just that, placing fifth in his first Olympia appearance. But we only saw him twice more after that, at the Arnold Classic and once again at the Olympia at the end of 2021. Since then, Jones has been working hard to build the additional size needed to successfully transition to the Open category. I spoke with him about his brief but notable time in Classic, and how he plans to make a big splash in Open.
Andrew vs. Hunter: THE BATTLE FOR TEXAS!
A BATTLE IS BREWING
GET A CLASSIC SUMMER PHYSIQUE WITH LOGAN FRANKLIN
Summer is in full swing, and for the vast majority of bodybuilders that don't compete, this is our showtime! All the many months of toiling away covered up while the sky was dark and gray and icy temperatures had you shivering have led to this. Last month we provided you with eight excellent tips to get ripped and ready, but let's take it a step further. This month, we enlisted the help of Classic Physique superstar and GAT Sport athlete Logan Franklin to come up with his best advice on how to make sure you have the most Classic-looking physique possible to show off on the beaches or at the pool. Here's what he has to say about the Classic look, areas of the physique to emphasize and how, and his best nutrition tips to make sure you turn plenty of heads this summer!
SUCCESS STORY: YANIV ZUR
BALANCING BUSINESS, FAMILY, AND ELITE FITNESS
HOW MUCH REST IS BEST?
Getting enough rest after weight training is essential for optimal muscle growth and performance. Unfortunately, many get insufficient rest because they simply disregard the fact that weightlifting breaks down muscle tissue, creating the requirement for adequate rest to fully recuperate.
Get Peeled With Extra Virgin Olive Oil
As you know, pathologic fat accretion results in obesity. The medical community and pharmaceutical industry have been struggling to address this burgeoning condition in the Western culture - particularly in the United States. Obviously, individuals have also been struggling in their attempts to avoid or correct unsightly or unhealthy fat gain. Imagine the shame these professionals and people must feel when they realize they may have been ignoring a risk-free, health-promoting, inexpensive dietary ingredient that can enhance fat loss. Bodybuilders seek potent drugs or supplements to force the metabolism to strip body fat to low single-digit percentages, but failing to acknowledge the foundation of diet can sabotage even their extreme measures.
CREATINE: THE BEST FORMS
New products and formulations are introduced to the supplement market every day. However, it is very rare for a product or especially an ingredient to create noteworthy evolution in supplement performance. Arguably, the greatest leap up this axiomatic evolutionary ladder occurred with the advent of creatine supplements in the 1990s. Creatine has proven over and over to be \"the real deal\" in clinical research and broscience. It's a muscle-building, performance-enhancing supplement that nearly all athletes should use.
