Archive for the ‘Exercise’ Category

The Physiology of Fat Loss

by: Len Kravitz, PhD , Christine Mermier, PhD and Mike Deyhle

From the fat cell to the fat furnace, find out exactly what causes the body to burn fat.

Fat may seem like the enemy of civilized people—especially sedentary ones. Yet we cannot live without it.Fat plays a key role in the structure and flexibility of cell membranes, and it helps regulate the movement of substances through those membranes. Special types of fat, known as eicosanoids, send hormone-like signals that exert intricate control over many bodily systems, mostly those affecting inflammation or immune function.

Of course, the best-known function of fat is as an energy reserve. Fat has more than twice the energy-storage capacity of carbohydrate (9 calories per gram vs. 4 calories per gram). It has been estimated that lean adult men store about 131,000 calories in fat (Horowitz & Klein 2000), enough energy to keep the average person alive for about 65 days.

For fitness professionals, the prime concern arises when the body’s fat-storage function works too well, hoarding unwanted fat that makes people unhealthy and self-conscious about their appearance. Understanding how fat travels through the body can help personal trainers work with clients to reduce excess body fat and improve athletic performance.

The Journey of a Fatty Acid to Muscle

THE ADIPOCYTE

p38 ImageFat resides primarily in designated fat-storage cells called adipocytes. Most adipocytes are just under the skin (subcutaneous fat) and in regions surrounding (and protecting) vital organs (visceral fat). Nearly all fat in adipocytes exists in the form of triacylglycerols (TAGs or triglycerides). Each TAG consists of a backbone (glycerol) with three fatty-acid tails (see Figure 1).

Depending on energy supply and demand, adipocytes can either store fat from the blood or release fat back to the blood. After we eat, when the energy supply is high, the hormone insulin keeps fatty acids inside the adipocytes (Duncan et al. 2007). After a few hours of fasting or (especially) during exercise, insulin levels tend to drop (see Figure 2), while levels of other hormones—such as epinephrine (adrenaline)—increase.

When epinephrine binds to adipocytes, TAG stores go through a process called lipolysis (Duncan et al. 2007), which separates fatty acids from their glycerol backbone. After lipolysis, fatty acids and glycerol can leave the adipocytes and enter the blood.

p39 ImageFatty Acids in the Blood

Because fat does not easily dissolve in water, it needs a carrier protein to keep it evenly suspended in the water-based environment of the blood. The primary protein carrier for fat in the blood is albumin (Holloway et. al. 2008). One albumin protein can carry multiple fatty acids through the blood to muscle cells (Horowitz & Klein 2000). In the very small blood vessels (capillaries) surrounding the muscle, fatty acids can be removed from albumin and taken into the muscle (Holloway et al. 2008).

Fatty Acids Going From the Blood Into Muscle

Fatty acids must cross two barriers to get from the blood into the muscle. The first is the cell lining of the capillary (called the endothelium), and the second is the muscle-cell membrane (known as the sarcolemma). Fatty-acid movement across these barriers was once thought to be extremely rapid and unregulated (Holloway et al. 2008). More recent research has shown that this process is not nearly as fast as once thought and that the presence of special binding proteins is required at the endothelium and sarcolemma for fatty acids to pass through (Holloway et al. 2008). Two proteins that are important for fatty-acid transport into the muscle cells are FAT/CD36 and FABPpm.

Two Fates of Fat Inside Muscle

Once fat is inside the muscle, a molecule called coenzyme A (CoA) is added to the fatty acids (Holloway et al. 2008). CoA is a transport protein that maintains the inward flow of fatty acids entering the muscle and prepares the fatty acid for one of two fates:

  • oxidation (in which electrons are removed from a molecule) to produce energy or
  • storage within the muscle (Holloway et al. 2008; Shaw, Clark & Wagenmakers 2010)

The majority (80%) of fatty acids entering the muscle during exercise are oxidized for energy, while most fatty acids entering the muscle after a meal are repackaged into TAGs and stored in the muscle in lipid droplets (Shaw, Clark & Wagenmakers, 2010). Fatty acids stored in muscle are called intramyocellular triacylglycerols (IMTAGs) or intramuscular fat.

There are two to three times more IMTAGs stored in slow twitch muscle fibers (the slow oxidative fibers) than there are in fast-twitch muscle fibers (Shaw, Clark & Wagenmakers 2010). Shaw and colleagues note that even though this IMTAG supply makes up only a fraction (1%–2%) of the total fat stores within the body, it is of great interest to exercise physiologists because it is a metabolically active fatty-acid substrate especially used during periods of increased energy expenditure, such as endurance exercise.

Fatty Acids Burned for Energy

Fatty acids burned for energy (oxidized) in the muscle can come either directly from the blood or from IMTAG stores. For fatty acids to be oxidized, they must be transported into the cells’ mitochondria (see Figure 3). A mitochondrion is an organelle that functions like a cellular power plant; it processes fatty acids (and other fuels) to create a readily usable energy currency (ATP) in order to meet the energy needs of a muscle cell.

Most fatty acids are transported into the mitochondria via the carnitine shuttle (Holloway et al. 2008), which uses two enzymes and carnitine (an amino acid-like molecule) to do the transporting. One of these enzymes is called carnitine palmitoyltransferase I (CPT1). CPT1 may work with one of the same proteins (FAT/CD36) used to bring fatty acids into the muscle cells from the blood (Holloway et al. 2008). Once inside the mitochondria, fatty acids are broken down through several enzymatic pathways—including beta-oxidation, the tricarboxylic acid (TCA) cycle and the electron transport chain—to produce ATP.

Fatty-Acid Oxidation During a Single Bout of Exercise

At the start of exercise, more blood flows to adipose tissue and muscle (Horowitz & Klein 2000), releasing more fatty acids from adipose tissue and delivering more fatty acids to the muscle.

Exercise intensity has a great impact on fat oxidation.We burn the most fat when exercising at low to moderate intensity—that is, when oxygen consumption is between 25% and 60% of maximum (Horowitz & Klein 2000). At very low exercise intensities (25% VO2max), most of the fatty acids used during exercise come from the blood (Achten & Jeukendrup 2004). As exercise increases to moderate intensity (around 60% of VO2max), most of the fatty acids oxidized appear to come from IMTAG stores (Horowitz & Klein 2000).

p39 ImageAt higher exercise intensities (>70% VO2max), total fat oxidation falls below the levels observed at moderate intensity (Horowitz & Klein 2000). This reduction in fatty-acid oxidation is coupled with an increase in carbohydrate breakdown to meet the energy demands of the exercise (Horowitz & Klein 2000).

We often overemphasize the fatty-acid contribution to calories burned during a bout of exercise. It’s also important to consider recovery from a bout of exercise, as well as training adaptations to repeated bouts, if you’re helping clients meet their fat-loss goals.

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ACE – ProSource: October 2014 – Build Strong Glutes and a Pain-free Lower Back.

By Justin Price

There are two things many of our clients have in common: They want to have nice-looking buns and, at some point in their lives, they will experience lower-back pain. The good news is that developing strong, shapely glutes can contribute to a pain-free lower back. In this article, you’ll learn why deconditioned and/or dysfunctional gluteal muscles and lower-back pain often go hand-in-hand. You’ll also learn which exercises build strong glutes and can help keep lower-back pain at bay.

What Causes Back Pain

Many people mistakenly believe that lower-back pain is caused by a problem with their lower back. This is understandable given that movements of daily life, sports and most weight-bearing exercise modalities require the spine to move forward, backward, side to side and in rotation (McGill, 2002). When you lean forward, for example, the spine rounds/flexes. When walking and running, it moves from side to side as you transfer weight from one foot to the other. When performing sporting movements like golf, tennis and baseball, the spine must rotate to achieve the desired motion (Chasan, 2002).

However, all these movements of the spine require other parts of the body to work as well. When bending forward to pick a weight up from the ground, for example, the ankles, knees and hips should also bend to help lower the torso. Similarly, as the spine moves from side to side during walking, the legs and hips should also move from side to side (i.e., adduct and abduct) to help provide a good base of support for the spine as it moves. Rotational movements of the spine should be accompanied by rotational movements in the legs and hips so the tremendous force created by swinging a tennis racket or golf club, for example, is dissipated throughout the entire body. When actions of the spine are not accompanied by correct movement in the rest of the body, the spine and its surrounding muscles (e.g., the lower back) have to take up the slack and may become overworked and injured.

How Strong Glutes Can Help Prevent Back Pain

The gluteal complex of muscles (i.e., gluteus maximus, medius and minimus) plays a key role in helping take stress off the spine during multiplanar movements. That’s because these muscles help control movements of the torso, pelvis, hips and legs. When you bend forward or squat, for example, your hips should bend backward to counterbalance the forward motion of your upper body to help you stay upright (Figure 1). The gluteus maximus works to decelerate flexion of your hips to help counteract the downward pull of gravity and prevent your lumbar spine from over-rounding forward (Price and Bratcher, 2010). If your glutes are not strong enough to fully engage when your hips bend backward, your spine must round forward excessively to lower your arms to the ground (Figure 2).

Similarly, much of the rotational movement stress experienced by the spine during sporting activities is moderated by the gluteus maximus muscle. When the spine rotates over the leg on one side of the body (e.g., when taking a backswing or follow through in golf, tennis or baseball), the hip and leg should also rotate to take stress off the lower back (Figure 3). Because the gluteus maximus muscle attaches to the structures of spine and pelvis and to the leg, rotation of the hip and leg should engage and lengthen this muscle, thus helping to decelerate rotation of the torso (Golding and Golding, 2003). If the gluteus maximus muscle is not working properly, stress from rotational movements is instead transferred to the lumbar spine and may manifest as pain in the lower back.

Side-to-side movement stress to the spine is moderated by the smaller muscles of the gluteal complex—the gluteus medius and minimus (Dimon and Qualter, 2008). As the spine moves from left to right as a person takes alternating steps when walking and running, the pelvis should also move from side to side (Figure 4). This shifting motion of the pelvis with the torso is decelerated by the gluteus medius and minimus because of their attachments from the pelvis to the side of the hip and leg. When they are healthy and functional they act as a brake for the lumbar spine, protecting it from excessive movement and stress. If they are not working correctly, pain may manifest in the hips and lower back.

How to Build Strong Glutes and a Pain-free Lower Back

As you have seen, correct functioning of the gluteal complex of muscles can help protect the structures of the lumbar spine as it moves during multiple planes of motion. However, before you begin overloading these muscles in an attempt to build strong glutes and a pain-free back, it is extremely important to adequately prepare them so as not to injure your lower back (Price and Bratcher, 2010). The following “warm up and wake up” series of self-myofascial release exercises and neuromuscular activation techniques will help ensure your gluteal muscles are working correctly and can protect your lower back as you move through various ranges of motion in the glute-strengthening program that follows.

Warm-up Exercises

For gluteal muscles to be flexible enough to lengthen effectively and decelerate movements of the pelvis, hips and spine, have your clients perform some self-myofascial release techniques on the muscles of the glutes and lower back prior to exercising. This will ensure the tissues are warm and mobile and can move in all three planes of motion.

Tennis Ball on the Butt

Massaging the gluteal complex of muscles before working out can help promote better movement of the pelvis, hips and legs, and ensure you get the most out of the strengthening exercises that follow.

Have your client to lie on his or her back with the knees bent. Place a tennis ball under the right side of the butt and scoot the body up and down and from side to side to move the ball to any sore spots, from the base of the spine all the way out to the side of the leg. You can progress this exercise by coaching your client to place the right ankle on the left knee. Place a rolled-up towel under the left hip to help keep the pelvis level. Roll out each buttock for one to two minutes. While a tennis ball is the easiest piece of equipment to purchase and use, a foam roller can also be used to massage the gluteal complex.

Tennis Ball on Lower Back

The gluteus maximus muscle ties into the fascia of the lower back (i.e., thoracolumbar fascia). Therefore, massaging the muscles on either side of the lumbar spine is important before performing glute-strengthening exercises.

Instruct your client to lie on his or her back with the knees bent. Place a tennis ball under the right side of the lower back (away from the spine itself) and scoot the body to move the ball to any sore spots between the bottom of the rib cage and the top of the hip. (Note: Do not place the tennis ball directly under the bottom two ribs. These are “floating ribs,” which do not attach to the sternum at the front of the rib cage.) Massage the area on each side of the spine for one to two minutes.

Foam Roller on Side of Thigh

The iliotibial band on the side of the thigh attaches the gluteus maximus muscle to the lower leg. Increasing blood supply to this structure will encourage correct movement of the hip and leg.

Instruct your client to place a foam roller beneath and perpendicular to the right leg, which is extended, and to balance the body on the right elbow and the left foot. Roll the leg up and down over the roller and pause on any sore spots. If your client has shoulder problems, or finds it difficult to balance, instruct him or her to lie on the ground with the head supported by a pillow, and place a tennis ball under the outside of the thigh. Perform this exercise for one to two minutes on each side.

Wake-up Exercises

People with lower-back problems typically have difficulty activating their glutes correctly. The following isometric and/or single-joint neuromuscular-activation exercises for the gluteus maximus, minimus and medius ensure these muscles are receiving correct input from the nervous system before you load them up with dynamic, multiplanar strengthening exercises.

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ING NYC Marathon

Reposted from: http://dailyburn.com/life/fitness/running-marathon-training-tips/

In high school, I could barely run the timed mile test, walking most of it.

Three years ago, I ran my first marathon after losing 50 pounds. I finished in 4:59, and I was happy just to have finished. But I knew I had more in me.

A few weeks ago, I ran my fourth marathon in 3:56. I took more than an hour off my time in three years, without devoting my entire life to running. I work a full-time job, volunteer and have an active social life, but I never felt like I was giving anything up for running. If anything, it added to the quality of my life.

I trained hard to get there, but there are also a few important tweaks I made that helped. Of course, the marathon is a special beast, and anything can happen on race day. But most coaches agree that training smarter physically and mentally can get you to the starting line stronger and ready to tackle 26.2. Here are five strategies that can be effective across the board, along with insights from Bart Yasso, Chief Running Officer of Runner’s World.

1. Add Speedwork

When I started training for my first marathon, I was still pretty new to running. I’d been at it for about a year, and the thought of intentionally running faster sounded terrifying. I just wanted to finish. During subsequent training cycles, I learned that speedwork (pushing harder in the middle of a workout at a specific speed for a specific amount of time) would change everything. That’s right, running faster… helps you get faster. Crazy, right? Speedwork works best when you’re running hard at a distance relative to your race distance, so tempo runs or mile repeats are best for marathoners. “I always felt like I was getting a little bit of speed but lots of endurance from mile repeats,” says Yasso.

2. Log Race Pace Miles

How are you going to run your goal pace for hours on end if you don’t know what it feels like to run at that pace? Speedwork paces and goal race paces should be fairly different. Your speedwork pace is typically your pace for a 10K or a half-marathon, or, a pace you can hold for roughly one to two hours. Your race pace is something that you’re trying to hold for 3-plus hours, unless you’re an elite athlete.

I practiced at my goal pace for mid-distance runs and at the end of long runs, so that I knew what it felt like to hold it for a sustained amount of time, and what it felt like to hold it on tired legs. On race day, while I checked my watch obsessively, I easily could have told you if I were running faster or slower than my goal pace by how I felt the cadence in my legs. By running race pace miles, says Yasso, “I always felt that innate sense of rhythm that I can carry this pace on race day.”

3. Up Your Days and Your Mileage

The first time around, I ran between two and three times per week, supplementing that with other forms of cardio at the gym and lifting with a trainer. I finished that marathon at an 11:25 pace, hitting the wall colossally at mile 18. I knew if I wanted to get faster, though, that I would need to run more. I used to be terrified of running two days in a row, but this year I typically ran five days per week, and I maxed out my mileage at 47 miles one week. I got to run on tired legs quite often, which was a huge mental boost at mile 22 of the marathon, when my legs felt like someone had strapped massive sandbags to them.

Though there are many variables to determining weekly mileage, says Yasso, the key is to listen to your body and not overtrain. Experts generally recommend not increasing your weekly mileage more than 10 percent each week.

4. Get Comfortable Being Uncomfortable

Running is hard. Running fast(er) is even harder. Miles 21 to 24 of the New York City Marathon were incredibly uncomfortable. Of course they were. I’d just run 20 miles! I reminded myself it was supposed to be uncomfortable and not to walk.

“The only way to advance in our sport,” says Yasso, “is to go to the uncomfortable zone. Embrace the pain, and you will be rewarded at the finish line.”

5. Never Set Limits

I took off 40 minutes between marathons 1 and 2. If I had believed that was impossible, I wouldn’t have had the guts to go for that time and make gutsier goals from there. But I thought about what I could do and shot high. I missed the mark last year, but if I hadn’t set such an audacious goal, it wouldn’t have lit the fire in my belly to chase the 3:56 this year.

Burpee Equivalents:  Understanding Junk Food in terms of Your Favorite Exercise

by Dr. Jeff Godin, Ph.D., CSCS, & Spartan Coach

Occasionally we slip up with our diets and sneak in some junk calories. When we do, we have to pay the price…In Burpees!  At Spartan Coaching HQ we have been conducting research to quantify energy expenditure during the Burpee exercise.  Here is what we found:

Burpee

 

Calories (kcals)

burpees for 130lb individual

burpees for 180lb individual

1 large French Fries

500

524

349

1 IPA beer

195

204

136

1 Slice of Dominos Peperoni Pizza

260

272

182

1 8 ounce Ted’s Bison Cheesburger

730

765

510

1 scoop of Ben Jerry’s Cookie Dough ice cream

270

283

189

1 12” Roast beef sub from Subway

970

1016

677

1 Cola soft drink

200

210

140

1 Fried Calamari Appetizer

700

733

489

1 Plain Bagel

320

335

223

1 Slice of Cheescake

1000

1048

698

1 Egg McMuffin Sandwich

300

314

210

1 Cadbury Creme Egg

59

62

41

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