2 New Messages
Digest #4605
Messages
Wed Aug 8, 2012 11:23 am (PDT) . Posted by:
"CoachJ1@aol.com" coachj12002
Hi Linda!
>Considering the spikes on his blades - could they be the wrong ones 1
day, the right ones another? Is slipping much more a hazard than it is for the
average runner even on the world class surface?
Good questions!
The track surface in London is Mondo. It is sheet material that is
rolled and glued. Mondo is often considered the "Cadillac" of the industry for
big meets like the Olympic Games. Other tracks of high caliber are poured
polyurethane with small rubber granules that are "broadcast" (shoveled)
over the second layer of polyurethane. Still others (like mine here in
Lisle) have the polyurethane and EPDM rubber mixed and then sprayed over
surface.
Many athletes feel that Mondo is the fastest surface in the world. (It
also has a very distinct smell that you either love or hate)
Regarding spikes: Mondo will recommend either a "Pyramid" or
"Christmas tree" type spike that is not longer than 6mm. Anything longer, or if
the spike itself is either a pin or needle type , has the potential to
damage the surface.
Ken Jakalski
Lisle HS
Lisle, Illinois USA
[Non-text portions of this message have been removed]
>Considering the spikes on his blades - could they be the wrong ones 1
day, the right ones another? Is slipping much more a hazard than it is for the
average runner even on the world class surface?
Good questions!
The track surface in London is Mondo. It is sheet material that is
rolled and glued. Mondo is often considered the "Cadillac" of the industry for
big meets like the Olympic Games. Other tracks of high caliber are poured
polyurethane with small rubber granules that are "broadcast" (shoveled)
over the second layer of polyurethane. Still others (like mine here in
Lisle) have the polyurethane and EPDM rubber mixed and then sprayed over
surface.
Many athletes feel that Mondo is the fastest surface in the world. (It
also has a very distinct smell that you either love or hate)
Regarding spikes: Mondo will recommend either a "Pyramid" or
"Christmas tree" type spike that is not longer than 6mm. Anything longer, or if
the spike itself is either a pin or needle type , has the potential to
damage the surface.
Ken Jakalski
Lisle HS
Lisle, Illinois USA
[Non-text portions of this message have been removed]
Wed Aug 8, 2012 11:23 am (PDT) . Posted by:
"CoachJ1@aol.com" coachj12002
Hi John!
>Why? My reasoning was that the calves were as far away from my heart as
possible which meant longer circulatory routing. As well the blood vessels
in the calves are smaller, and the distance back to the heart was all
vertical and again the longest in the body
I'd recommend going Dr. Weyand's lab site:
_http://smu.edu/education/apw/LocomotorNews.asp_ (http://smu.edu/education/apw/LocomotorNews.asp )
Look to your left and scroll down to the lab videos.
There is a clip of Pistorius there, but note the other views as well and
watch where force is peaking at these higher speeds. By the time the
athletes appear to be "pushing off," (later phase of stance) force is at its
lowest. For many, this is not intuitive.
As noted in the Weyand/Bundle JAP paper: (Artificial Limbs Do Make
Artificially Fast Running Speeds Possible):
"The classical literature on terrestrial locomotion established that level
running is mechanically analogous to a ball bouncing forward along the
ground. Like a bouncing ball, a runner's mechanical energy and forward momentum
are conserved via recurring exchanges of kinetic and potential energy
during travel. Runners accomplish this by using their legs in a springlike
manner to bounce off the ground with each step. On landing, strain energy is
stored as the body's weight and forward speed compress the stance limb and
forcibly lengthen muscles and tendons. The strain energy stored on landing is
subsequently released via elastic recoil as the limb extends to lift and
accelerate the body back into the air prior to take off. The conservation of
mechanical energy and forward momentum minimizes the need for propulsive
force and the input of additional mechanical energy once a runner is up to
speed."
Ken Jakalski
Lisle HS
Lisle, Illinois USA
[Non-text portions of this message have been removed]
>Why? My reasoning was that the calves were as far away from my heart as
possible which meant longer circulatory routing. As well the blood vessels
in the calves are smaller, and the distance back to the heart was all
vertical and again the longest in the body
I'd recommend going Dr. Weyand's lab site:
_http://smu.edu/
Look to your left and scroll down to the lab videos.
There is a clip of Pistorius there, but note the other views as well and
watch where force is peaking at these higher speeds. By the time the
athletes appear to be "pushing off," (later phase of stance) force is at its
lowest. For many, this is not intuitive.
As noted in the Weyand/Bundle JAP paper: (Artificial Limbs Do Make
Artificially Fast Running Speeds Possible):
"The classical literature on terrestrial locomotion established that level
running is mechanically analogous to a ball bouncing forward along the
ground. Like a bouncing ball, a runner's mechanical energy and forward momentum
are conserved via recurring exchanges of kinetic and potential energy
during travel. Runners accomplish this by using their legs in a springlike
manner to bounce off the ground with each step. On landing, strain energy is
stored as the body's weight and forward speed compress the stance limb and
forcibly lengthen muscles and tendons. The strain energy stored on landing is
subsequently released via elastic recoil as the limb extends to lift and
accelerate the body back into the air prior to take off. The conservation of
mechanical energy and forward momentum minimizes the need for propulsive
force and the input of additional mechanical energy once a runner is up to
speed."
Ken Jakalski
Lisle HS
Lisle, Illinois USA
[Non-text portions of this message have been removed]
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