Muscle Activation of Chest, Core, Delts & Rotator Cuff When You Bench on Unstable Ground, Calcium Supplementation & Vascular Disease. BMI, BAI , Body Fat & CVD Risk

This week's SuppVersity figure(s) of the week deal with the leading cause of death in the USA (see paper attached to the guy's big toe ;-).

After reading yesterday's installment of the Science Round-Up Seconds, you already know that it is unlikely that you are going to die from prostate cancer.... but let's face it - we all are going to die one day, so if your death is not natural and not due to prostate cancer? What's going to the reason? Well, according to the latest CDC data you, my American friends are going to die from heart disease - ok, not you, a devoted follower of physical culturist, but the average American a devoted follower of Dr. Oz and the sedentary way of living, has an 0.2‰ chance of dying from heart disease and following one of the 597,689 victims the Western way of life claimed in 2010 (CDC. 2011)

Chest presses on an unstable surface - A new staple exercise? Or bogus?

(McHardy. 2013) -- I am not quite sure about the States, but over here in Germany much of the funky news sh*t like squatting on unstable surfaces, benching with your bag on a bogus... ah, pardon bozo ball etc. have literally disappeared from both, the mainstream fitness magazines and the gyms. Heavy iron, machine based circle training and classic, as well as HIIT cardio are what people do, so that the  twenty-seven healthy male subjects from the McHardy study would probably have attracted much attention, when they performed their isometric chest presses at maximal voluntary contraction (MVC), 75% MVC, and 50% MVC on a stability ball.

Figure 1: Exercise specific rel. activation patterns for DB chest presses; data expressed relative to to mean (McHard. 2013)

As it was to be expected the additional task of having to stabilize their trunk and body, lead to a significant reduction in MVC force output of the main, as well as the agonistic muscle groups. The core, on the other hand was trained pretty effectively, especially in the low(er) intensity conditions.

What's somewhat surprising, yet maybe highly relevant and an important argument that would speak against doing your chest presses on a stability ball, though, is the highly significant activation of the infraspinatus, the "small" muscle, most people tend to forget about until they suffer from their first rotator cuff injury.

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Bottom line: Due to an increased risk of injury and non-specificity of the exercise doing shoulder presses on a stability ball is probably useful only as a low weight additional movement used either to warm up or after a primary move like the classic or decline bench presses (learn more about the best chest exercises, here).

Calcium supplementation and vascular disease + Tip: Use Super Tracker

(Dpwning. 2013) --  It is one of those never-ending research stories, the quest for the answer to the (important?) question, whether calcium supplementation increases, decreases or does not influence the risk of cardiovascular disease at all.

As a student of the SuppVersity, you know that casein can build 3.2kg muscle literally overnight (learn more). But did you know that a single serving of one of the best selling casein proteins will satisfy 50% of your daily calcium needs? No? Well, in that case you probably don't know that that both lactose and certain caseinophosphopeptides greatly improve the bioavailability of calcium in dairy products over that of most other natural ans certainly supplemental sources (Cámara-Martos. 2002).

The latest and certainly not last chapter in this never-ending story has just been published in the medical journal Obesity. It is a meta-analysis conducted on 13 observational studies and 9 clinical trials pertaining to calcium supplement use and the risk of adverse outcomes such as cardiovascular disease (CVD), myocardial infarction (MI) that concludes:

"Overall, the benefits of calcium supplementation, including the positive effects on bone health, appear to outweigh the theoretical risk of increased cardiovascular events." (Downing. 2013)

Considering the fact that at least those of you who consume significant amounts (not "one serving") of preferably green vegetables and dairy on a regular basis are not in need of calcium supplements, I'd suggest you leave worrying about questions like this to people who should better look into the overall quality of their diet instead of resorting to supplements to maintain bone and heart health (yeah, low calcium is bad for the heart).

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Bottom line: Supplementation should not be necessary of someone who has both green vegetables and dairy in his/her diet. I would recommend you register a free account over at the USDA's SuperTracker and simply plug in your food choices for a couple of days to see if you get enough calcium and what other nutrients you may or may not be deficient in. Don't be shy, the registration is free - you don't even have to enter an email address and the USDA data base is the best source for accurate information about the nutrient contents of food you will find... just ignore "your plate" and you are good to go ;-)

Surprising superiority of the BMI over BAI as a marker of cardiometabolic risk

Table 1: If you go by the p-values which indicate the statitical significance of the correlations the BMI is even better than DEXA measured body fat percentages; nd. signifies no difference in p-value detected, while BMI and %BF tell you that the respective value is the "better" predictor (Lichtash. 2013)

(Lichtash. 2013) -- Let's get the most important things straight, first. The study we are looking at, here, was conduced on 698 Mexican subjects from 193 families (299 male and 399 female) which represent a cross section through the population of immigrants and the children of immigrants with average body fat percentages of 38% and 25% for female and male participants respectively. We are thus not talking about the average physical culturist, here.

Nevertheless, I personally was quite astonished, to read contrary to the BMI which was associated with all but two measured traits (carotid intima-media thickness and fasting glucose in men) of cardiovascular disease risk the body adiposity index (BAI) which has a 85% correlation with DEXA measured body fat index (Bergman. 2011) "lacked association with several variables" (Lichash. 2013).
 
Now if you come to think about the way the BAI is calculated (formula from wikipedia.com)


It is yet not really so surprising, after all the fat that's stored on the hip and buttocks has long been shown to be ugly and aesthetically displeasing, but not a major concern, when it comes to its impact on your metabolic health. The BIA will thus overestimate the risk of people who carry a relatively high amount of benign body fat and underestimate the risk of abdominally obese men and women, who often have a very low hip circumference.

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Bottom line: The important message of the study at hand is thus not that the BMI was a better, let alone good measure of cardiovascular disease risk, but rather that the BIA, i.e. the raio of hip circumference to body height is an even worse indicator of cardiovascular disease risk for the average (pretty chubby) American with Mexican ancestors.

That's it for today...

... as far as the official short news are concerned. If you want some additional up-to-date information from the realms of health, exercise, nutrition and supplementation sciences, I suggest you visit any of the following SuppVersity Facebook News

• Are you inflamed enough to lose fat? "Inflammation Is a True Fat Burner: BSO-Induced Glutathione Depletion Wards off Fat Gains on Hypercaloric Diet" (read more)

  Chronically fatigued? Maybe you are just lacking the HDL to get the cholesterol into the adrenal gland!? | read more
• Who is to blame for the obesity epidemic? If you ask the public, the obese are primarily to blame | see more
• Meta-analysis shows: Neither high nor low fat diets have definite beneficial effects on blood lipids | learn more 
• Further evidence for the involvement of antioxidants in the proliferation of cancer. They are the ones that help the cancer cells to survive | freak out 
• Want to lose 15% chest & ab fat and 10% of the subcutaneous fat on your thighs? Do some ultra endurance cycling | believe it or not
  

and/or come back later to check for the latest updates on Facebook or Sunday's SuppVersity article. Have a nice weekend, everyone!

References:

• Bergman RN, Stefanovski D, Buchanan TA, Sumner AE, Reynolds JC, Sebring NG, Xiang AH, Watanabe RM. A better index of body adiposity. Obesity (Silver Spring). 2011 May;19(5):1083-9.  
• Cámara-Martos F, Amaro-López MA. Influence of dietary factors on calcium bioavailability: a brief review. Biol Trace Elem Res. 2002 Oct;89(1):43-52. 
• Downing L, Islam MA. Influence of calcium supplements on the occurrence of cardiovascular events. Am J Health Syst Pharm. 2013 Jul 1;70(13):1132-9.
• Lichtash CT, Cui J, Guo X, Chen YD, Hsueh WA, Rotter JI, Goodarzi MO. Body Adiposity Index versus Body Mass Index and Other Anthropometric Traits as Correlates of Cardiometabolic Risk Factors. PLoS One. 2013 Jun 11;8(6):e65954. 
• McHardy, RD. An Electromyographical Analysis Of Shoulder And Trunk Muscles During Chest Press On Stable And Unstable Platforms. Thesis submitted to the Texas State University-San Marcos. August. 2013.