A.M. Ran with Jeff. Lots of snow, but runnable. Decent traction. Ran 15.2 in 1:57:12. Just for kicks we did a hard quarter on snow. 80 seconds with about a 70 second effort.
Had a discussion on muscle spindles, and the effect of hypersensitive spindles in hip flexors on running economy. My suspicion is that a hip flexor is the worst place for a runner to have a hypersensitive spindle because it will make the hip flexor contract to resist the stretch during the later phases of the ground contact as the body moves forward and the hip is extended. Such an inopportune hip flexor contraction will then having a braking effect on the forward motion. There is really no other joint I can think of where excessive stretch reflex is so undesirable when running.
The reason we got so technical in the discussion is that I've read some research showing that a trigger point is a bundle of hypersensitive spindle tissue, I do have some nasty trigger point in my right hip flexors, and my range of motion in the right hip extension when running is noticeably worse than on the left side. To make things more interesting, stretching the hip flexors has never done anything for my running speed. I can improve the static range of motion, but the stretch reflex resistance is still there.
So I have a thought on the importance of flexibility for a runner. A number of studies demonstrated that faster runners are not that flexible. Yet it is fairly obvious that if you have zero flexibility you will not run at all. So what's up? I've wondered about it for a while and never had anything meaningful to say except the obvious "you just have to have a balance". Now I think I finally have something worth sharing.
The flexibility in and of itself is not important. What is important is to have low antagonist muscle resistance in the critical range of motion in critical motions in critical joints. The only critical joint/motion I can think of the is the hip joint and the motion of extension. You do need to have a reasonable range of motion, enough to run, but that is good enough. You do not need a gymnast's range of motion or anywhere close. In some joints/motions the high antagonist resistance may actually be good. E.g. knee flexion and dorsi-flexion. Not so high that you get injured, but as high as you can get away with. So that means it is good for the quads and the calves to be a little tight.
But when it comes to the hip joint, things are a little different because resistance to hip extension is a braking agent. Normal running range of motion is not too difficult to achieve. But we do not want just the range of motion. Improving the range of motion does us zero good if we did not reduce the stretch reflex of the hip flexors in the normal running range of motion. And stretching in some cases (maybe more often than in "some cases") can make it worse by irritating the spindle tissue and thus increasing the stretch reflex. The fix in this case would be to work on the trigger points in the hip flexors to eliminate them and restore the muscles to their normal state.
The above, of course, is all just theory now. I'll have a chance to test it this year.
P.M. 2 with Benjamin and Jenny in 17:19. Julia ran 1.5 with us in 13:26. 0.5 with Joseph in 4:38. 0.25 with Jacob in 2:25.