John Duffield wrote:In 2005, I was Mountain Biking in the Pyrenees with a group of Brits. Out of nine of us, 3 broke collarbones.

Sierra Ledge Rat wrote:

John Duffield wrote:...But I don't know what percentage of bone density I'm increasing...

At your age, you are not increasing your bone density. There is no way to increase your bone density at your age, you're several decades too late to be thinking about increasing your bone density. All you can do now is slow the rate of loss of bone density.

They key is to maximally increase bone density when you're young - 2nd and 3rd decades of life. After that, it's just a game of slowing the loss of calcium. Diet and weight-bearing exercises are the key.

Sierra Ledge Rat wrote:

John Duffield wrote:...But I don't know what percentage of bone density I'm increasing...

At your age, you are not increasing your bone density. There is no way to increase your bone density at your age, you're several decades too late to be thinking about increasing your bone density. All you can do now is slow the rate of loss of bone density.

They key is to maximally increase bone density when you're young - 2nd and 3rd decades of life. After that, it's just a game of slowing the loss of calcium. Diet and weight-bearing exercises are the key.

knoback wrote: I like your first advice: lift heavy shit. Work your heart and lungs. Hone your balance and technique. Realize that if you go hard, no matter what you do , you may get hurt. If you decide it's worth it, then go.

knoback wrote:

NancyHands wrote:Absolutely true. It's a very important aspect of weight training in football as a means to prevent injury. Not only do muscles and tendons increase their load bearing capacity, but bones respond this way too and not just the load bearing ones. My old trainer used to say that there was no better way to make your forearms bigger than doing squats. Generally speaking the larger the muscle or bone being worked the more systemic the effect will be. Smaller muscles and bone will have little to no effect on a whole. Still, the last I read about this there were some conflicting opinions.

It is important that significant weight be applied, for instance, circuit training with light weights will have a minimum impact on bone density, but running or prolonged exposure to high impact sports (like football) will have a significant effect on bone density and strength.

Orthopedists have been using resistance training to assist the elderly with bone mass issues for some time as well.

Evidence please. I'd love to be wrong about this, but I have not seen anything in the literature to suggest a significant systemic effect. As a jack of all trades, master of none it is quite possible I've just missed it. But the proposed mechanism for forearm fracture reduction in the elderly with lower extremity exercise is improvement in muscle strength and balance precisely because there isn't a global improvement in bone density that would account for it. Your forearms are getting bigger because they are working to hold the bar across your shoulders, not because your quads are getting bigger and bringing them along for the ride.