Archive for November, 2012

Slow and Fast Marathon Runners are the Same

November 26th, 2012

These runners are the Same at what. When taking steps, or running strides, they are the same. How come? By counting their steps!

Yup! In early February 1972, John ‘Jack’ Falkner, PhD, and I were counting steps at the Las Vegas Marathon. We like many others have found this to be the ‘facts.’

Jack was Keynote Speaker at the First Annual Meeting of the RMC, ACSM. I happened to be one of the three co-founders of this Regional Chapter. We chose to have the meeting on the two days before the Las Vegas Marathon.

More importantly, after the meeting, many of us gathered near the finish line with the spectators.

Jack said something like, “I wonder what we could learn from this marathon!?” After hemming and hawing, we decided to investigate stride length as a function of race speed.

METHOD: We noticed a series of telephones poles on the road across from us that the participants took just before they made a right turn and came straight at us for about 200 meters to the finish line. A pair of poles were selected that were the third and fourth from the turn.

Which of the marathoners should we pick? Our sample were 10 of the leaders, 10 at the beginning of the main pack, 10 near the end of the main pack, and 10 who were jogging to the finish near the last of the participants. Our null hypothesis was that the faster runners would have a faster stride frequency than the middle and end runners.

Data collection chores were split by having Jack get the time the runner took from the third to fourth pole and by having me counts the steps run between the poles.  Doing the calculations seemed  complicated until after the race. Jack and I went to the telephone poles and paced off the distance between them, something like 80 feet. First we divided number of steps by number of seconds, then multiplied by 60 s/min, giving steps per minute.

RESULTS: And all four group had about the SAME value of 182 steps per minute (STP). In each of the groups there were persons with faster and slower STP values; there was overlap.

Very, very interesting! Of course, each of the faster groups averaged longer strides.

CONCLUSION: Overall, with similar STP, a runner with longer running strides had increased leg power per stride, and this runner had faster speed.

NEXT WEEK: Is there a relationship between running speed and brain power?

Perceived Effort: along a hallway vs. up a stairway

November 20th, 2012

One day last week, I put Perceived Effort to another test.

As I walked along a hallway, and since I am “an anticipation machine,” (Freyd, 1987, cited by Siegel, 1999), I noticed a stairway at its end. Aha. What if I just kept up this momentum and start up the stairs two steps at a time. “But I might fall on my nose,” I thought. “So I will not change my speed.”

Sure enough, as my right leg made the first double-step, I noticed that I was falling. Well, I also noticed my body sagging as I stepped. And then I felt a definite shift, as my body went to the left leg for the second double-step. Without thinking I pushed harder and arched my back to sorta leap over those next two steps. And a seemingly unconscious leap also happened for the third double-step using my right leg again.  This time I did not arch my back. Whoa! What happened? How did this just happen!?

My body seemed to ignore my request to “keep on keeping on”. It leaped. It was not into teleoanticipation; it did a face saving maneuver. How? (Rather than “How come?” or “Why?”)

Let me hazard a guess: if it was not seemingly conscious, then it was done subconsciously. Okay, then how? Perhaps “not falling on my face” mainly by using vestibulomotor and leg motor reflexes as like a musical score. Maybe the musical managing council was the subcortical locomotor control network comprised of the basal ganglia, the medullary and subthalamic locomotor regions, and the cerebellar locomotor regions. And the musical section leaders were the thoracic and lumbar locomotor regions making sure my arms were coordinated with my legs. Finally, my leg muscles compensated for the muscles in my overly bent right leg via were mediated by musical players in the hemi-spinal  central pattern generators and their contralateral interneurons. Wow, what a modern neurobiological summary gifted by the works of Grillner et al. (2008) and la Fougère et al. (2010).

And where is the word: “Effort”? Well, it is hidden in the phrase, “change my speed”.

So, how do I know how fast I am going?

Please tune in next week…..

References:

Freyd JJ (1987) Dynamic mental representations. Psychological Reviews 94: 427-438.

Grillner S, Wallén P, Saitoh K, Kozlov A, Robertson B (2008)Neural bases of goal-directed locomotion in vertebrates—An overview. Brain Research Reviews 57: 2-12l.

la Fougère C, Zwergal A, Rominger A, Förster F, Fesl G, Dieterich M, Brandt T, Strupp M, Bartenstein P, Jahn K (2010) Real versus imagined locomotion: A [18F]-FDG PET-fMRI comparison, NeuroImage 50: 1589-1598.

Siegel DJ (1999) “The Developing Mind” New York: Guilford Press. p 30.