Instinctive reaction?

I noticed the other day when I was out riding my bike through rugged terrain that when I rode in the standing up position, my legs and arms absorbed all the bumps that occured while I was riding. This allowed my head to remain steady. What I was wondering is, how do I do this? How are my legs and arms absorbing these bumps without thinking about it?

I’ve noticed something similar. If I’m holding a drink of some sort while I’m driving, I try not to let my arm or hand rest on anything in the car when I’m going over a bumpy road. If I hold it with my arm away from my body, my arm absorbs the shocks of the road and the drink doesn’t slosh or spill.

I think inertia causes the the object being supported (your torso, my Mountain Dew) to continue in a smooth motion. The limbs then reflexively catch up to the motion and catch the weight before it can follow the bouncing of the vehicle.

How’s your neck? I would assume your head and body stay pretty much the same distance apart while biking, and most of your weight, and hence momentum ((weight/G)*velocity), is in your body. . .most likely? Inertia (weight/G) has long antedated brains, and once a body gets kicked into motion, the resultant momentum will keep it in a certain trajectory (read, ‘rut’ – as bikers are often wont :wink: ) – until it/you hit(s) a brick wall).

Ray (a hiker)

Well, MrKnowItAll seems to have gotten in there while I was putting frills on my answer.

I think the drink case requires more than the biker’s head case. It seems to me it must additionally involve reflexes or part of the cerebellum, in sensing the momentum of the cup, which is definitely much less than that of the holder’s body, which is definitely taking a path of irregular mostion in the inertial field that the cup is not. I might reluctantly allow a little of such bodily control also to the biker out there tearing up the trail. :wink:

Ray

I think that’s probably a fair assumption considering the fact most bikers are equipped with a neck.