Wednesday, September 29, 2010

ACLs, knees, and genes

a provocative article in the NY Times projects the possibility that genetics predisposes some - esp women - to NON-CONTACT anterior cruciate ligament (ACL) tears. http://well.blogs.nytimes.com/2010/09/29/phys-ed-are-bad-knees-in-our-genes/?ref=health

tim hewett, of cincinnati children's hospital, a prominent researcher on ACL injury and prevention, reports that one set of twin girls tore their knees up within a year. their older sister also tore her ACL. another set of twin sisters had incurred torn ACLs in high school, as did their dad...and his two triplet brothers!!!! scary huh? suggesting that you can look at your family's knees and see your risk profile in scar tissue.

studies in south africa have found a gene sequence that alters the customary elasticity of ligamentous collagen. interestingly, more women had this aberration whereas males who had had ACL injuries did not have this variant and women who had not torn their ACLs also did not have it.

so, we can now add to the list of predisposing factors - weak, easily-fatiguing, and late-firing hamstrings; weak and delayed-firing gluteus medii; possible femoral notch anatomical variations; and poor training/jumping/cutting technique - genetics. like many things genetics, this does not mean you WILL have an ACL tear if other family members have had one. but it does mean you might want to train properly with more closed chain- squats and lunges - and plyometric - jumping/hopping - and agility - cutting, changing direction - exercises. see a pro who's studied this syndrome, not just one who knows how to build bigger muscles. you need better ones, not bigger ones.

Thursday, September 23, 2010

sugar, hi fructose corn syrup

the corn growers of america want you to not be afraid of hi fructose corn syrup, so they're changing the name: corn sugar!!! that should allay any fears of consuming too many wasted calories now that its name has changed, right?

wrong.

there are unwarranted fears about the correlational link of hi fructose corn syrup (HFCS) to the burgeoning girths of americans, and people all around the world. (see: http://economix.blogs.nytimes.com/2010/09/23/the-world-is-fat/?ref=business) but the science of sugar suggests there are no substantial differences bw table sugar and HFCS. many health foodies still hold onto their faith-based prejudice against HFCS but the evidence is pretty clear on at least one thing: those who consume hi sugar foods/drinks tend toward obesity more than those who get their sugars in the foods from which they come naturally - fruits, veggies, and complex carbs.

in another blog on the NY Times website today, the issue of HFCS vs sugar is well analyzed so that even the non-scientist can understand it. both sides of the argument are presented but the one thing that stands out clearly is the commentary of the main researcher whose 2004 study showed the correlation of obesity to the ever-increasing amount of HFCS in our diet. he contends that it's the sugar, not the type of sugar, that matters. and that alone should cause you to pause as you shop, for HFCS, and now the soon-to-be-renamed "corn sugar" that's in the processed foods you buy are not making you any healthier. in fact, sugar, being sugar, is, if consumed to too large a degree in your diet, you put yourself at risk not just for cavities but for diabetes, heart disease, overweight/obesity, and nothing positive unless consumed right before a hard workout. in other words, cut the sugar, eat the fruit: http://well.blogs.nytimes.com/2010/09/20/in-worries-about-sweeteners-think-of-all-sugars/?ref=health

Tuesday, September 21, 2010

stability balls at work

much has been done by exercise pros over the past 20 yrs to elevate the formerly known "swiss ball" (SB) to near-olympian levels of wonder results. what was originally a ball used in neurological therapy for newborns with developmental issues, once the ball hit america, like many other things that had intrinsic value and utility unto their own, the SB took on a mind of its own, with claims that only now are being fully investigated for veracity. but let me give some history here....

about 18 yrs ago, my colleague, who had received treatment for chronic low back issues, came to the gym with a new-fangled exercise toy - the SB. she knew two exercises, as prescribed by her PT: the crunch and the bridge (feet on ball, lying supine on floor, raising hips.) both were good enough for most people's needs but the story doesn't end there. within a few years, every gym and trainer had a SB and new exercises were being created a mile a minute. within a few years, some jokers - you know them, and they know who they are - were even promoting the SB for doing squats - no, not against a wall or with a partner; doing squats ON the ball. like the dogs in the circus, or even the elephants. only stupider - because presumably these were bright human beings doing stupid human tricks...of absolutely no legitimate value whatsoever.

claims such as improving balance, stability, and core strength overwhelmed the media and trade mags. but there was still no research to back it up until the late 90s. at first, the reports looked good - SB crunches engaged the ab muscles better than regular ones tho not as well as other - in particular, the bicycle - exercises. still, it had value now. and the new concepts of spinal stability especially of the smaller interspinous muscles - rotatores and multifidi - were supportive of unstable surfaces for performing exercises to benefit these mini muscles that normally atrophy post injury. from there, tho, it was a stretch to make other claims such as get stronger, get better core stability for athletics, and get better posture. thus far, none of these claims have been verified.

having been an instructor for Exercise ETC, Inc, out of Ft lauderdale, i had to confront these issues head on with participants who bought into such claims. many a time i sat on a SB with lousy posture mimicking that which they themselves were sitting to demonstrate that it's feasible to sit on a ball and get no inherent benefit to posture. likewise, many studies have been done demonstrating that more strength is gained by doing exercises on stable surfaces than on unstable ones. furthermore, once basic stability of the spine is intact, further challenges via the SB probably don't offer any functional benefits. after all, how many life activities take place on a 65 cm spherical surface? no great athlete in pre-modern or modern history has gotten there with such a tool and all great athletes who use them were great before they used them; the SB may simply be another of many tools in their training arsenals, one likely to be more a waste of time than anything else.

so here comes an article in the Times discussing claims that sitting on a ball at work increases calorie burn and posture. and one study did indeed show an increase of 4 - read: FOUR - extra calories per hour of sitting. let's put that in perspective: get up and get a drink of water, talk with a co-worker for a few minutes - and you'll burn more calories, hydrate yourself, and derive social benefits far beyond sitting those extra few minutes on a ball. besides, for a full 32 extra calories/day, why not take a 1/3 mile walk and get cardiovascular benefits that far exceed those of sitting anywhere let alone a ball.

btw the studies do not support improved posture. in fact, not only can people slouch on a ball; not only might you sit straighter whether on a ball or in a chair; but posture is nearly impossible to train without conscious decisions made throughout the day to exert oneself into a proper posture. so it ain't the ball, per se. in fact, if anything, the new science of sedentary behavior suggests that sitting on anything is less valuable to health and body composition than standing, so SB sitting is actually bad for you, and no better than sitting on a good chair.

read on: http://www.nytimes.com/2010/09/21/health/21really.html?ref=health

Wednesday, September 1, 2010

stretching

another article sums up the latest professional spin on stretching. done on runners, many many runners, of all ages, some of whom were assigned a 5 mins stretching routine, others who were asked not to - it took two years to find enough who would not stretch - the study found that 16% of stretchers and 16% of non-stretchers got injured over the course of the study. thus, stretching's a wash.

but is it? they also found that 23% of former stretchers who stopped stretching for the study got injured. the researchers concluded that the change of training habits likely contributed to their injuries and warned that “sudden changes are probably not a good idea.” i hate to say 'duh' but there's more to this than meets the eye.

i've written before on the lack of benefits of stretching and the value of dynamic warm ups instead. and i stand by the research both professionally and personally, from experience. but i do want to clarify something here: stretching passively may indeed be necessary for those who have conditions or muscle imbalances that do contribute to injury, such as ITB syndromeor patellofemoral pain. i would also add that for many, static stretching is essential even compared to dynamic stretching. older adults, those with known pathologies, and those for whom balance may be an issue benefit from slow, long-held stretches. of course, a dynamic warm up of even light walking loosens up the intended muscles and gets blood flowing deeper into the tissue to be stretched, so don't forget that part PRIOR to your stretches. nonetheless, there is still merit here.

what makes this study interesting was the data on previous stretchers' injuries. what we did not hear, tho, is a breakdown of the nature of the injuries incurred. it is very possible that the non-stretchers suffered injuries that would indeed have been mitigated if not prevented had they stretched. it's also possible that the stretchers, feeling like they'd warmed up enough, went out too fast and furious and thus injured themselves for reasons totally different than those related to stretching. as such, we still do not know whether or not stretching is beneficial or possibly hurtful. though large-subject pool studies have shown no benefits, like this study, it's not unreasonable to think that stretchers get injured as much as non-stretchers, just with different types of injuries. therefore, stretchers may not need to stretch and non-stretchers need to stretch but we'll never know til a study looks at the nature of the injuries within each group. til then:

http://well.blogs.nytimes.com/2010/09/01/phys-ed-does-stretching-before-running-prevent-injuries/?ref=health