This is not new. Doesn’t mean cycling or swimming are not good for you, just that we need other types of activities that are load (and bone) bearing too.

This.

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http://www.jt10000.com/

Did they also measure the bone density of life-long sedentary couch-dwellers? I was going to put that in pink until I actually read the article and realized that they didn't test a control group.

Notwithstanding that, I did find the article interesting. I am a former HS/College swimmer (competitively from age 7-22) and ran almost ZERO until I reached my late 20's, and didn't start running consistently until my early 30's when I started tris. I have broken 3 bones in my lower extremities from running, and 1 stress fracture. One of those was a freak tibial spiral fracture in 2011 that occurred at mile 3.0 of a 5k (cause unknown, bone just broke mid-stride), which sidelined me for the better part of a year. I have had bone scans and my density came back normal.

Just an N=1 experience but interesting (at least to me) nonetheless.

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Strava

Agreed. Not new information AT ALL. At 30 years old (20 years ago), I was a pure cyclist and reports were coming out THEN about reduced bone density in cyclists---I think I read an article in Bicycling mag. My Dad is an MD, I talked about it with him...and decided to add running into the mix. Did a marathon, the next year....and figured I might as well learn to swim...and do this stupid sport.

Pretty well known amoung racing cyclists. I started running in the offseason to offset this- enjoyed the run, eventually did a duathlon as a lark, did well so did a few seriously, did well so did a triathlon as a lark, did well and, well here I am. So, careful of the side effects of running. . . .

lower bone density improves your W/kg....what's the problem?

Bone density generally max's out between the age of 25 and 30, so picking up lifting and running wouldn't do so much in regard to improving density after you're 30 for the most part (maybe prevent early loss though).

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Matt Leu, M.S. Kinesiology
San Pedro Fit Works, Los Angeles, CA
Endurance Athlete and Coach
Consistency/time=results

Wouldn’t flipturns in swimming count as a weight bearing activity? Just in a different plane?

I swam in college then got into extreme sports where I broke a few bones. Based on that my doc sent me for a bone density test to double check. The results came back that my bones were significantly denser than average for my stats. I would think all of those high speed flip turns contributed.

I find it difficult to believe that cycling and swimming pits one at risk. Isn’t bone loss a metabolic state? While weight bearing exercise may help mitigate it, shouldn’t the cause of increased osteoclastic activity be addressed primarily? I don’t think weightlifting and running will fix metabolic dysfunction.

Wouldn’t flipturns in swimming count as a weight bearing activity? Just in a different plane?
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Geez- how hard are you hitting the wall?

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Take a short break from ST and read my blog:
http://tri-banter.blogspot.com/

I said I swam in college- I don’t hit the walls- I just push off them :-)

Seriously- isn’t it like a squat against the resistance of the water instead of a weight every time you flip though?

10,000 yards is up to 399 flipturns a session depending on how your workout is broken out.

That’s a lot of squats.

Here’s some research but I don’t know how the forces compare to a regular squat- which is why I asked.
https://www.researchgate.net/...e_Flip_Turn_Push-Off

Good question:

Flip turning does provide very mild eccentric loading, but technically not weight bearing because we "weigh" very little in the water; All things considered I'd say not really. Think about it a little more: Water is nearly 800 times denser than air. Also, astronauts use water to to mimic conditions in space (to which they lose massive amounts of bone in space). Between initiating a turn, at best while moving at 4 mph, changing direction, and hitting the wall, the water and direction change would cushion/decelerate any potential for significant eccentric loading to make a huge contribution to bone density. On land gravity accelerates our motions more that air can slow us down, plus what ever external force you provide has much greater potential for gains in bone. You probably get more whole body impact and eccentric loading jumping up and down on mattress or a trampoline, not to mention you can get a lot more of it in in the less time compared to swimming 4-5k short course everyday. You'd need to do more flip turns than our stomachs can handle to equate to the same amount of forces experienced from a 5k jog or a solid leg day in the gym.

That doesn't mean that your genetics, swimming, diet, not smoking and other activities in your life didn't lead to a higher bone density. It certainly could have contributed, but it's less likely that swimming is as much of a contributor to your bone density than other factors may have been.

I would like to point out that, to me, "extreme" sports = greater chance for broken bones, no matter how dense they are. My bone density is in the 99th percentile (via dexa scan), and I have still broken a few bones over the years, not doing extreme sports (In fact the stories are pretty boring unfortunately).

This is all ignoring the fact that the upper body need eccentric/high loading forces just as much as the lower body, and swimming flip turning or not again will not contribute even close to other activities.

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Matt Leu, M.S. Kinesiology
San Pedro Fit Works, Los Angeles, CA
Endurance Athlete and Coach
Consistency/time=results

Thank you!