Quote: " …a raft of unexpected findings, some showing that competitive swimmers had lower-than-anticipated bone density, others that, as an earlier Phys Ed column pointed out, competitive cyclists sometimes had fragile bones and, finally, some studies suggesting, to the surprise of many researchers, that weight lifting did not necessarily strengthen bones much."
Quote 2: “Too much endurance exercise, it appears, may reduce bone density.”
Sounds like one of those ‘on the one hand’ type arguments but maybe I should get back in the gym for hoops just in case.
They did not mention bone remodeling, osteoblasts, and osteoclasts at all. ??? she’s missing a criticlal part there.
They may have hit on this with the endocrine comments, but another problem with endurance exercise is hormone levels - cortisol and estrogen - getting to abnormal levels; both can play role in bone. Specifically more cortisol and less estrogen from endurance exercise → more bone problems.
Building bone through lifting - you need to axially load them - hard to strengthen spine bones for instance, and that’s one of the sites bone density is measured at. (They extrapolate from a couple vertebrae and the greater trochanter of the femur what your bone density is). Why jumping is good. Like they said plyometrics are great if your bones can take it in the first place, and I like the comment that “fragile bones aren’t a problem if you don’t fall in the first place.” Well I would add to it that running stresses bone so fragile bones if you want to run lots = problem. Cool comment though and when I started having problems with my bone structure, my doctor said “start doing yoga: balance will be helpful for you when you get old.”
Well, N=a couple, but you can get greater bone density through lifting.
I am/was part of this study.
As a part of the study they did DEXA scans before and after to measure body fat
and bone density. Bone density was measured of the spine and the femur in
addition to the overall.
A PURELY NONSCIENTIFIC LOOK AT THE INITIAL DATA FROM A SLIGHTLY INFORMED
SOURCE said that for runners the density at the femur didn’t really change
and for the lifters the spine density didn’t change, but there were differences
between them and lifting tended to even them out. (This is for about N=12).
In my N=1 case my bone densities were already good, but there were changes:
BMD (g/cm^2):
Pretest: 1.317
Post: 1.341 (1.8% increase)
Femur was fundamentally unchanged (sBMD (mg/CM^2)), going from 1,096 to
1097.
FWIW, N=1, for Total and Spine the 8 weight intensive weight training for
total and spine increases were 1.8% and 3.8% respectively. No difference
in right femur.
(i.e. weight training for runners helps spine, and as a result total, but has
no bearing on femur, in my layperson interpretation)
I’ll leave the overall results for the N~= 20 (I don’t know how many people
were in the second group) to the research specialists.
People in this field have tried to figure out for decades what exercises are most effective in building bone and which ones are not. Unfortunately, you can look at any exercise mode in the literature and you will find positive and negative results. Many studies were poorly designed and relied on cross-sectional data in which self-selection bias is inherent. Overall, weight lifting is one of the better exercises if you are osteopenic or try to prevent bone loss. Not great …
Building bone through lifting - you need to axially load them - hard to strengthen spine bones for instance, and that’s one of the sites bone density is measured at.
Well … there is quite a bit of evidence from animal studies that you don’t want to load your bones axially if building bone is your objective. Most long bones are subjected primarily to bending moments during functional activities … and ideally … you want to load your bones in an off-axis direction (to produce an “unusual” loading event) for increasing bone formation.
People in this field have tried to figure out for decades what exercises are most effective in building bone and which ones are not. Unfortunately, you can look at any exercise mode in the literature and you will find positive and negative results. Many studies were poorly designed and relied on cross-sectional data in which self-selection bias is inherent. Overall, weight lifting is one of the better exercises if you are osteopenic or try to prevent bone loss. Not great …
I’ve come to the realization that bias is just as prevalent in scientific fields as religion.
The difference is in religion they say “You’re an infidel.” In science they say: “The study was poorly designed.”
Also, to be perfectly clear: The study I was in was specifically selected for men between the ages of 20 and 40.
I suspect it has applicability outside of that, but I’m just a rational computer engineer, not a kinesiology expert.
Some of this is actually old news. Swimming and cycling are non weight bearing, so the calcium loss is not surprising and has been studied before AFAIK. I was always told/read that weight bearing activities such as weight lifting, etc did build bones, so this is surprising news to me.
Also, to be perfectly clear: The study I was in was specifically selected for men between the ages of 20 and 40.
I suspect it has applicability outside of that, but I’m just a rational computer engineer, not a kinesiology expert.
What you can generalize from one study to put into practice is another big question. If this study was done with all men, you may not be able to generalize the results to females… or people out of that age bracket… etc. In education research (what I’m doing right now) there’s implied generality, claimed generality, warranted generality, and potential generality. (I’ll spare you the boring definitions
Once you’ve had a chance to ‘internalize’ the whole thing I’d love to hear about it.
Some consideration should be done regarding low bone mass in cyclists: **1. ****Most trials use the term Osteopenia or Osteoporosis in young cyclist, but this is not correct. The WHO classification of bone loss applies only to Caucasian postmenopausal women and not to young population. Recent position paper by the ISCD (International Society of Clinical Densitometry) states that the term osteopenia or osteoporosis should not be use in young subjects and “Low Bone Mass” in comparison to same age and sex must be used whenever low BMD is found. All studies in cyclists include young subjects and most of the times the peak bone mass has not yet being achieved. 2. There are no studies that correlate bone mass loss in cycling and risk of fracture, therefore the meaning of the small decrease in bone mass reported in many trials has no clear significance at this time, in terms of real risk of fractures3. More specific techniques of estimation of bone strength like pQCT does not seem to support the fact of bone loss in cyclist4. **** It seems like calcium supplementation does not prevent bone loss, but this statement is far from clear at the present time. ****5. **The final answers to the questions we ask early in this review can’t be found at the present time. Measuring Bone Mineral Density to elite cyclists looks prudent according to many published reports of low bone mass in such athletes. However, there are no approved treatment guidelines by any medical organization or association to use in this disorder, specifically related to cycling. Calcium supplementation in the order of 1500 mg day seems reasonably due to excessive calcium losses by sweat
