vet kan je niet plaatselijk verbranden, je moet je vetpercentage in het algemeen doen zakken;)

Zijn de meningen toch wel verdeeld over. Bekkende coaches zoals Fred Koch geloven er wel in (onder bepaalde voorwarde) en er is ook vrij recent onderzoek dat aantoont dat het wel kan.

ONDERZOEK

Are blood flow and lipolysis in subcutaneous adipose tissue influenced by contractions in adjacent muscles in humans?

Bente Stallknecht1*, Flemming Dela1, and Jorn Wulff Helge2
1 Department of Medical Physiology, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
2 Medical Physiological Department, Panum Institute, Blegdamsvej 3, Copenhagen, Denmark; Department of Medical Physiology, The Panum Institute, University of Copenhagen, Copenhagen, Denmark

* To whom correspondence should be addressed. E-mail:

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Aerobic exercise increases whole-body adipose tissue lipolysis, but is lipolysis higher in subcutaneous adipose tissue (SCAT) adjacent to contracting muscles than in SCAT adjacent to resting muscles?

Ten healthy, overnight-fasted males performed one-legged knee extension exercise at 25% of maximal workload (Wmax) for 30 minutes followed by exercise at 55% Wmax for 120 minutes with the other leg and finally exercised at 85% Wmax for 30 minutes with the first leg. Subjects rested for 30 minutes between exercise periods.

Femoral SCAT blood flow was estimated from washout of 133Xe and lipolysis was calculated from femoral SCAT interstitial and arterial glycerol concentrations and blood flow.

In general, blood flow as well as lipolysis was higher in femoral SCAT adjacent to contracting than adjacent to resting muscle (time 15-30 min: blood flow: 25% Wmax: 6.6 ± 1.0 vs. 3.9 ± 0.8 ml 100 g-1 min-1, P < 0.05; 55% Wmax: 7.3 ± 0.6 vs. 5.0 ± 0.6, P < 0.05; 85% Wmax: 6.6 ± 1.3 vs. 5.9 ± 0.7, P > 0.05; lipolysis: 25% Wmax: 102 ± 19 vs. 55 ± 14 nmol 100 g-1 min-1, P = 0.06; 55% Wmax: 86 ± 11 vs. 50 ± 20, P > 0.05; 85% Wmax: 88 ± 31 vs. -9 ± 25, P < 0.05).

In conclusion, blood flow and lipolysis are generally higher in SCAT adjacent to contracting than adjacent to resting muscle irrespective of exercise intensity. Thus, specific exercises can induce "spot lipolysis" in adipose tissue.
Are blood flow and lipolysis in subcutaneous adipose tissue influenced by contractions in adjacent muscles in humans? -- Stallknecht et al., 10.1152/ajpendo.00215.2006 -- AJP - Endocrinology and Metabolism
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ARTIKEL ADHV FRED KOCH

Spot Training: New Insights by Fred Koch

It's probably the most common question not only in bodybuilding but in all of fitness: Is it possible to spot train? Is it possible to burn localized fat with high-repetition weight training? No matter who you ask, you1ll get an unequivocal answer: no. There1s no such thing as spot training.

Bodybuilders and fitness enthusiasts alike take that no as gospelÐexcept, of course, that we're always secretly hoping it isn1t true. Why else would so many of us do hundreds of reps for the midsection when we don't train any other bodypart that way?

Maybe it's just instinctive. Bodybuilders have traditionally used this kind of high-rep training on their abdominals, despite the general belief that spot training doesn't work. When all the scientific evidence is finally in, however, it may turn out that the bodybuilders1 instincts were right.

The common belief about high reps and spot reduction is based on a study performed at the University of Massachusetts. The results of the study, titled "Effects of Situp Exercise Training on Adipose Cell Size and Adiposity," were published in a 1984 issue of Research Quarterly for Exercise and Sport (Vol. 55., No. 3). At the time of the study the scientists used the latest data they had on localized fat reduction. I suggest that we1ve learned a few things since thenÐand that the premises and circumstances of the study may no longer apply.

The funny thing is, while people in the fitness industry all seem to know that there was some experiment that proved that spot reduction doesn1t work, almost no one is familiar with the research. During a recent seminar for personal trainers I conducted, I asked the crowd if anyone knew about this study or the criteria under which it was performed. To my amazement I discovered that not one of the highly trained individuals knew anything about it. Whether they knew it or not, however, their opinion on spot reducing was based on this study.

The experiment1s premise was to see if it was possible to burn fat in the stomach area by performing situps. The subjects used the standard bent-legs, elbow-to-knee situps we all did back in high school gym class. Thirteen male subjects took part in the 27-day experiment. On day 1 they did situps for 10 rounds of 10 seconds each, getting roughly seven reps per set, with 10 seconds1 rest between sets; and by the 27th day they worked up to 14 rounds of 30 seconds each, getting roughly 24 reps, with 10 seconds1 rest. Choice of Exercise

The problems with this experiment begin with the exercise used. I'm sure that almost everyone in the fitness industry today would agree that situps as they were performed in 1984 are not the exercise of choice for the abdominals. We1ve known for years that the situp performed on a flat floor is more of a hip flexor exercise and that the work done by the abs is mostly an isometric contraction. That in itself should be enough to set off buzzers about this study.

Then you have to consider how those situps were probably performed. Have you ever watched someone perform a high-rep set of situps? People never use perfect form on these. Instead, they use these jerky rock 1n1 roll-type movements that are not full contractions of the abdominals. Today we know that to work the abdominals effectively, the movement must be a perfect contraction of the abs through a full range of motion.

What's more, we also know that it takes a variety of resistance to work all the fibers in the target muscles to their maximum potential. You can't add resistance to situps, however; you1re limited to the weight of your body. Consequently, you may not be able to hit all the fibers in the target muscles with that movement. Definition of High Reps

This brings up several questions, not the least of which involves the energy systems used for the short bouts of exercise in the experiment. In 1984 the subjects worked up to 30 seconds of continuous energy. Today, we know that it takes at least two minutes of exercise for the fatty acids to kick in as fuel, with the ATP-PC cycle going to work for the first five to 10 seconds and glycolysis taking over at around 20 seconds.

In 1984 the term "high reps" was generally considered to mean 20 to 25. In 1996 the term has been redefined.

In traditional sports training athletes do high reps in the 70-to-100 range. Tudor Bompa, Ph.D. pointed this out to me once. As you may know, Tudor is one of the most respected sports-training experts in the world. He wasn1t very familiar with bodybuilders when I first met him though, so he saw things from a different perspective.

In the world of Olympic sports such as swimming and track and field, many athletes train on a periodization program that includes a muscle-endurance phase in which they work up to reps of 100 or more per set for a series of exercises. For example, they might do squats followed by crunches, bench presses and curl-grip, or underhand, lat pulldowns. That means performing up to 400 reps in a row.

Tudor was describing how the athletes got what he called a 3stringy look2 in their muscles during the endurance phase, and that set off a buzzer with me. He didn1t know bodybuilding terminology. Could what Tudor referred to as "stringy" be the exact condition that competitive bodybuilders seek to achieveÐthat is, cut?

I subsequently brought up this point with a top cellular-research scientist I know. Why is fat intertwined with muscle? Is it there just to protect the body? Fat has numerous jobs in the body, from protection, to creating heat to fueling energy needs. Since fat is a fuel, doesn1t it seem strange that we cannot burn this fat as fuel? What about the fatty acid in the blood, which we can even measure? There were no answers to my questions.

Adaptation Time

I also had questions about the length of the 1984 study. Twenty-seven days is not enough time to adapt to high-rep training. As you1ll recall, the subjects only worked up to 30 seconds. Based on the experiences of athletes using periodized training during a 12-week muscle-endurance phase, it can take eight weeks for the body to adapt to the high-rep training before it starts using fat as fuel during the final four weeks. At first you1re going to get the burn of your life due to lactic acid building up around the muscle and stopping it from contracting. Only after you build up your endurance can you make the shift and get the benefit.

What About the Diet?

The subjects in the study were college students, and the journal report made no mention of monitoring their diets. As I see it, this is a significant problem. How can you know why there is no significant change in fat levels if you don1t control what they eat? If those subjects were like the college students I know, I can only imagine what their diets were like. This is another reason why I think the researchers1 conclusions about spot reducing with high reps to be in error.

So What1s the Bottom Line on Spot Reduction?

Current research on circuit training with weights shows that an hour of that type of exercise burns more fat than an hour of aerobics. That helps explain why athletes who perform a series of high-rep exercises achieve natural muscular definition with low bodyfat. I believe that this holds true for specific areas of the body.

If you could do arm curls for three minutes without producing lactic acid, is it possible that you1d use up the ATP, begin using other systems and burn fatty acid as fuel in your biceps? Theoretically, it is, but three solid minutes of curling is a lot to ask of the typical musclehead.

The answer is to periodize your training. Your muscles will adapt to high-rep training if you take your time, including a phase like the muscle-endurance phase of a periodized sports program. You don1t have to use a lot of weight. Working your way up to 80 to 100 reps over a 12-week phase with a planned loading pattern will enable your body to adapt to this fat-burning process. The same holds true for abdominal exercise.

A focused program building up to ultrahigh reps of resistance-based exercises can1t help but have a positive effect on your midsection. If you1re lucky enough to be able to train on an Ab Bench, you get the extra benefit of a complete range of motion. (Unlike the partial contraction you get with crunch movements performed on the floor and all other ab machines, this device features a prestretch and complete contraction.)

I predict that science will prove my theory right. The accompanying statements by a number of experts indicate a whole new world of possibilities. While there will never be a miracle cure that enables someone with a big stomach to do hundreds of ab reps and get a washboard midsection, there is a way to strip off that last layer of fatÐsomething that should make a lot of bodybuilders very happy.

Frank Katch, Ph.D., of the University of Massachusetts is the co-author of Exercise Physiology (Lea & Febiger, fourth edition) and the author of what is probably the most quoted study in fitness history, "The Effects of Situp Exercise Training on Adipose Cell Size and Adiposity." When this study was first published in 1984, it was considered the most professional of its kind ever performed. Based on this study, most people in the fitness industry believe that it's impossible to burn fat with localized high-repetition weight training. When interviewed for this article, Katch made it clear that until there is a definite measuring tool, such a study done with magnetic resonance imaging, to determine if fat does come out of fat cells, he stands by his study and believes that it is still valid. Although everyone still quotes his study, Katch said that, other than my call, he hasn1t been contacted for his opinion on the subject for the last five years

Tudor O. Bompa http://www.tudorbompa.net/

Goede boeken trouwens.

Dat lijkt mij ook. Goede opmerking.