This is a common practice among road runners, yes.
If this is the case, then why there are so much injuries with runners on concrete? If the legs are able to adapt (no matter if it is permited or required) to the stiffnes of the surface?
Even if skeletal muscles adapt, the JOINTS don’t adapt. Harder surfaces=greater energy return which transmits greater rebound forces up the leg. I doubt that many here would want to train on mondo every day for that very reason.
Energy return from the ground depends on how much elastic rebound can occur. Concrete is much harder then mondo yet it gives less elastic return, it doesn’t deform at all, its too hard. At the extreme end of the scale, harder surfaces don’t elicit a greater energy return. Elastance requires some change in length for a given force. Clearly concrete doesn’t deform on ground contacts therefore energy return is lower. Mondo by contrast is more elastic surface, as it deforms and has a recoil effect.
Such comments come from not knowing the researchers and hazarding a guess that 1) they have never run or competed themselves and 2) they have never coached.
Here is part of Dr. Weyand’s bio from our '02 seminar: "As part of his extensive background on speed, Weyand has been involved in ambulatory monitoring of Michael Johnson’s running mechanics through his relationship with NBC.Olympics.com, Quokka Sorts, and FitSense.com. He has provided live commentary for the Boston Marathon, in addition to offering scientific and technical education for fellow commentators Frank Shorter, Kathrine Switzer, Uta Pippig, and Bob Lobel.
His interviews, research features, and writing have appeared in Time Magazine, the London Times, NBC Discovery News, Discovery Online News, the New Scientist, Harvard Magazine, Men’s Journal, Runner’s World, the Harvard Gazette, and Self Magazine.
As a former Head Track Coach, at Duxbury High in Duxbury, Massachusetts, he developed several high-caliber individual performers, including an All New England and nationally ranked 800 meter runner, as well as an All Massachusetts runner-up in the 110 meter high hurdles
Weyand was trained under former University of Massachusetts, Boston and Boston State coach Bill Squires known internationally for his expertise in middle and long distances, and former coach of Bill Rodgers and Alberto Salazar.
As a competitor, he earned 10 varsity letters in four different sports (basketball, cross-country, indoor track, outdoor track) during undergraduate career at Bates College. He ran the 800 in 1:54.56, the 1500 in 3:51.71, and the 5000 in 14:41. He has extensive experience conducting physiological and laboratory testing on national and international caliber athletes.
Will a golf ball dropped on a Mondo surface rebound as high as one dropped onto concrete from the same height?
Am I on to something here???
Ever tried bending concrete?
Impact forces are higher on concrete then mondo. Elastance on the other hand is a separate issue, it tells you how much of the deformation on impact is elastic or how much is inelastic.
Do a hammer test, try hitting a mondo track with a hammer and watch the bounce, compare it with concrete. Clearly is will be evident Mondo is much more elastic then concrete.
You don’t get it. EVERY material has some elastic properties (stretching under force, and the people who build buildings and highways DO measure this) and energy return is the portion of the impulse energy not absorbed by the substrate.
By the law of conervation of mass and energy the energy applied by a footstrike is either returned (reflected back up the leg by a substrate that does not deform [much]) or absorbed (actually converted to heat through friction in the material). You cannot say the energy simply disappears because a material has minimal elastic properties (Newton’s Laws).
In fact, a compliant, elastic material will provide LESS energy return because some of the energy applied is converted to friction in the elastic material as it stretches. A mondo surface is a thin layer of compliant material on top of a firmer material (usually asphalt), and is selected to optimize the energy return form maximum performance.
A high occurrence of injuries occurs from running on concrete precisely because of the high energy return:
This sounds right. I assume this is why sprinters like a hard track for racing, but a softer one for training.
The spring and stiffness issues are conceptually difficult, especially in the
absence of understanding that the body loads the limbs and the limbs get set up to absorb the load.
I’d recommend Tom McMahon’s book, Muscles, Reflexes, and Locomotion (Princeton University Press, 1984)
McMahon discusses how athletes utilize elastic rebound, and presents the evolution of the Harvard “tuned track.” What McMahon points out is that it has generally been assumed by coaches and athletes that the hardest surface is the fastest. In fact, this is not quite true.
“…there exists a particular set of mechanical properties for a running track which both lowers the potential for injury and slightly enhances speed.”
His section on the design of the Harvard track is interesting without being too technical. He explains why step length should change with the track stiffness. The math is all there for those who like that approach, but his conclusion is pretty straightforward. It should be possible to build a running track in the appropriate range of stiffness that will 1) decrease foot contact time, 2) increase step length and 3) reduce running injuries.
At the conclusion of that section, McMahon says the following:
“No outdoor track of the optimium mechanical design has been built as of the time of writing. If such a track were to be built, the results of our research and experience with the Harvard and Madison Square Garden prototypes suggest that the world record for the mile could be bettered by 5 to 7 seconds by the best miler of that day.”
Should I buy specially formulated rubber insoles then, so i can SPRING BACK
or should i get http://www.con-cret.com/CON-CRET/index.asp
I am so confused???
5 to 7 seconds??!! That seems preposterous. Does he project proportionate improvements in sprint times?
When all else fails (or, preferably, before all fails so you can save the PT fee), listen to Charlie and do that tempo on grass.
The well-known Michael Warburton paper on barefoot running has some references concerning the effectiveness of cushioning in running shoes. What apparently happens is that the cushioning doesn’t actually cushion (absorb most of the energy), but instead it merely attenuates certain frequencies that the body is attuned to. So, while it feels softer, most of the energy from running on a too-hard surface is still running up your leg, stressing your joints and shins, and trying to injure you. The solution, really, is to avoid as much of that energy as possible in the first place, by running on a softer surface. And if the shoes really did absorb all that energy being returned, there might be so much heat generated through friction that you couldn’t even run in them.
You can’t run OR hide from Sir Isaac Newton.
“Will a golf ball dropped on a Mondo surface rebound as high as one dropped onto concrete from the same height?”
Stiffness in this example is perhaps misapplied?
Now say a beach ball vs. a golf ball, dropped on to cement would speak to stiffness of contractiles & connective tissues, footwear, etc.
“In fact, a compliant, elastic material will provide LESS energy return because some of the energy applied is converted to friction in the elastic material as it stretches. A mondo surface is a thin layer of compliant material on top of a firmer material (usually asphalt), and is selected to optimize the energy return form maximum performance.” speaks to the elastic properties of the surface while getting to the root of the question which is: What is the optimal surface condition?
Extend that out to:
What is the optimal surface for __________ activity?
And further out to:
What is the optimal surface for __________ activity when used by performers of ________ conditioning level?
I would suggest that the relative stiffness or elasticity of the Track in Osaka is not optimal for the World Masters Championship 100m dash for 85 to 90 year olds…
Conversely you could make the point that the top 100m runners any given year are a some what more homogonous group when view against the competition surface’s role in energy return?
There doesn’t seem to be any general agreement in the research/rehabilitation world regarding this issue of CNS fatigue, and those on the forum who have pointed out that the concept is often misused may indeed be accurate.
Over a year ago I wrote to Dr. T. George Hornby of the Sensory Motor Performance Program at the Rehabilitation Institute of Chicago. Dr. Hornby is also a research assistant professor at Northwestern University’s Department of Physical Medicine and Rehabilitation. He has an extensive background in the neurobiology of muscle fatigue, biophysical properties of active spinal neurons, neuromodulation of motor neural activity, and segmental motor mechanisms.
Below is my letter to Dr. Hornby, and his response:
“No issue comes up in performance training as much as this issue of CNS fatigue, yet I’m not sure if we in the sports training community fully understand what is really going on.
Here is my take:
In the PNS, there is a decrease in neural drive to the muscles (probably due to a depletion in neural transmitter) which may explain why force production may not be maintained during heavy intensity training. However, it is my understanding that the reuptake of neurotransmitter occurs after the activity ends. Many believe that the consequence of training (inability to maintain high force output) results from muscle fatigue, and so recovery from training is required for the muscle to ”heal."
But where does neural recovery come in? Does research support a necessity to recover due to the CNS/PNS being ”overtaxed?" I may not be seeing why the nervous system would need time to recover. But I am interested in knowing if there is a mechanism by which the CNS/PNS would require time off from strenuous activity."
Dr. Hornby’s response:
"Basically, I’m not sure there’s a neurotransmitter depletion that’s substantial enough to decrease force generation in the proportion that is observed. I’ve e-mailed some about this and the consensus is lactic acid and potassium at high intensity workouts (lifting weights).
For low intensity workouts, taking glycogen/glucose depletion out of the equation, the neural mechanisms for 'fatigue" could be spinal or supraspinal adaptation of motoneuronal output. Meaning . … the action potential simply cannot fire as rapidly.
What did the Enoka text say about this (R. M. Enoka, Neuromechanical Kinesiology - I don’t think it’s called exactly that, but he is the expert.)
Serotonin may play a role, but I’m not clear how (no one is).
However, to try to answer the question, the "wait period’ for recovery is probably small for “neural recovery”, but again, I don’t know that answer.
I’m assigned to teach a course on Plasticity of tissue and organ systems next spring and will dig into this.
Basically, there is no definitive answer that I can dig up."
I felt the same way when I first read the book. However, the math is quite elegant, the testing thorough, and the research sound.
McMahon does not comment on sprint times. He does note the following:
“The first several years of service have shown that the new track has been responsilble for an abrupt reduction in the rate of running injuries–that rate is now less than half what it was on the previous training surface (cinders). Furthermore, Harvard runners and runners from other schools are able to better their times by about 2%, or about five seconds in the mile, by comparison with their times on other tracks of the same length and top surface (polyurethane).”
Forum members might with to check out the wavespring technology in Spira Running Shoes. I had dinner with CEO Andy Krafsur back in August. Spira has provided us with shoes for our cross country team this fall. The concept itself is as fascinating as the IAAF and USATF ban on shoes with springs.
Check out the Spira website at:
Pardon my ignorance. This is truly astonishing to me. If mile times can be improved 2% on this track, why in hell aren’t all the top milers in the world clamoring for competitions on this track? I would think that instead of demanding payment to run, they would pay to run!
Okay, so there is no extrapolation to sprints, but apparently no evidence to the contrary yet either. Why isn’t every top sprinter in the world at Harvard in the summer? When I was a mediocre 400 runner I would have about killed to cut 2%. Imagine what it would mean to Wariner, Powell, Felix, Richards, etc.!
Hi Sharmer! Thanks for noting that old article!
When I wrote the “Sultans of Swing” on sprint mechanics, I thought I knew what I was talking about. Turns out I really didn’t.
It took an epiphany moment in coaching for me to begin to re-consider what I held as gospel throughout the first 23 years of my high school career.
That epiphany came in 1997 when I had paralympians Tony Volpentest and Marlon Shirley competing on my track here in Lisle, Illinois. I assembled one of the best master’s fields in the state–including former Big Ten spring champion and Olympic relay alternate Tim Graf–to compete against Volpentest in the 100 and 200.
Volpentest was not all that impressive in the 100 (11.63), but he destroyed the field in the 200, clocking a 22.94, which at that time was the fastest paralympic 200 in the world. I spent two days with these guys, and watching them compete raised all kinds of questions which my conventional background in speed training couldn’t answer. Volpentest had no lower arms. In fact, to start he had to rest his stumps on padded paint cans. So much for the significance of arm swing mechanics. He had no feet or ankles. So much for dorsiflexion and push-off. Despite these apparently significant disadvantages, he had run faster than 97% of every able bodied high school athlete I had coached since 1975.
These experiences led to a clinic with Bryan Hoddle, Tony’s and Marlon’s coach at the time. We held that clinic here in Lisle. I called it: Ground Zero: The Role of the Foot and Ankle in Sprinting.
The key to that clinic was the focus on the role that the carbon fiber keel bars (crude by today’s Cheetah standards), played in delivering support forces. I was really in the dark, though, since conventional approaches to the speed puzzle just didn’t provide answers to the questions I had relative to how Volpentest was able to run that fast in the absence of a musculature that I had believed was essential to achieve and sustain higher end speeds.
These unanswered questions eventually led me to Dr. Weyand and the Concord Field Station Locomotion Lab at Harvard University. For me, Weyand was the first research/scientist to give freely of his time and talent, and I was just a high school coach who simply e-mailed him out of the blue with some questions about his ’02 study after Mel Siff had brought the study to the attention of Supertraining members.
At the time, I felt the research was way off base, and in no way did it reflect what I and the majority of my colleagues clearly understood to be the key components to high speed running. No lab guy was going to prove to me that my intuitive grasp of the mechanics of high speed running was mistaken. During my visit, I was able to study the evolution of human locomotion research going back to the legendary Dick Taylor, and the more I listened, the more I realized what little I actually understood about the mechanics of high speed running. And these guys weren’t’ just lab geeks. Dick Taylor and Tom McMahon were competitive runners in high school. Matt Bundle was a very good collegiate 800 runner, and Hugh Herr was a world class rock climber. They clearly had a passion for their work.
It didn’t take long for me to realize the models for speed that I had followed religiously since the early eighties were based on the mistaken assumption that the faster a person or animal runs the more rapidly their muscles contract. This is not true. Because support forces are all important regardless of speed, and since muscle force production is maximized by isometric contractions, both from a design and function standpoint, the optimal shortening velocity for muscle during level running is zero: the left hand side of the force-velocity curve.
Dick Taylor argued this point over twenty-five years ago, and in the past ten years researchers had the technology and data to show this directly (Roberts et al, Science, 275: 113-1115, 1997). Muscles shorten minimally regardless of speed in order to maximize force production.
In the case of swing mechanics, if active power were indeed the mechanism of limb repositioning rather than a largely passive process involving energy transfers and tendon springs, the researchers would have found that sprinters with faster muscle fibers and more power would reposition their limbs more rapidly – with no other complicating factors. In this scenario, differences in fiber speed would correspond one to one with minimum swing times. Clearly, this is not the reality. But it was hard at first for me to accept that minimum swing times could be similar (JAP 2000) or that the repositioning process could be largely passive and therefore independent of fiber speed. That sure contradicts a whole lot of what I believed in when I wrote the “Sultans of Swing”
But that’s OK. The more I listened, the more I grasped the ‘big picture’ regarding the mechanical variables influencing an athlete’s ability to run fast. As a result, my goal as I near the twilight of my prep coaching career is to keep an open mind so that, before I die, retire, or get fired, I’ll come to a better understanding of these issues.
In the process, I’ve found that I continue to learn a great deal from colleagues on forums like this one, colleagues who generally seem open to the fact that good science may actually affirm the protocols they’ve been using for years.
And the researchers I’ve had the good fortune to learn from acknowledge that the coaches are the ones in the best position to design and execute appropriate training protocols and strategies. They see themselves as simply providing a road map so that we have a somewhat better grasp of how best to undertake the journey toward higher speed running.
Remember that the Harvard facility was an indoor track featuring a substructure of wood and synthetic materials designed to achieve a near uniform vertical compliance. In other words, there were no hard or soft spots, which can be a feature of wood tracks unless they are designed carefully. Recall the problems with the track in Toronto for the Bailey/Johnson million dollar “Dash for Cash.”
It would seem problematic to construct such a facility outdoors. But you bring up a great point. If the data is indeed accurate, the numbers would be quite impressive for the elite athletes.