I read a study a few years back, that suggested muscle stiffness, increases and decreases to the leval of ground surface hardness. That when people ran on the gras, their muscle stiffness increased straight away. It also implied that the tension responded to external environment quickly, and therefor implied that there would be a quick loss in that tension after leaving that ground surface onto a differant surface.
Are you suggesting that repeated grass runs, can have a longer term result on muscle stiffness than no grass runs? (By long term, I mean, would they have more muscle stiffness every day, becuase of the inclusion of grass field runs?)
Do we have to then mention all the football, rugby, and soccer players who do more grass running than anyone, but ofcourse they are not as fast as track sprinters.
The program appears to be 2-3 days of weights and sprints in most cases. These are done on the same day. I do believe he has mentioned the training can be more frequent, but I believe he stated earlier in this thread that it is most often 2-3 days a week. This should also answer Davan.
I have known 100/200 guys 10.03 & 20.1 whose coaches followed a similar program. They did get immediate results, however neither one of them ran well after the age of 25. It does raise questions of longevity, maybe not from overtraining, but from continual loading that does not vary a great degree throughout the training year. It’s much harder to periodise training systems based on protocols that have been outlined.
At first thought, I’d think that the grass would require less stiffness…that’s what’s confusing me. I also don’t get how in the above link they say they used their research to design the Harvard and Yale indoor tracks. Then they say humans can sprint faster on compliant surfaces than a hard surface like concrete.
So if stiffness is desirable, why not train on grass at all times? Maybe this is why Peter Pratt trains his jumpers in sand and on pole vault mats a la the guys you saw at York training on HJ mats for explosive jumping power. None of this makes much sense to me.
I’m pretty sure it all depends on the contact times- longer contact times favour softer surfaces but softer surfaces limit the ability to generate shorter contact times.
See: “Training principles for jumpers: implications for special strength development,” Nelio Moura and Tania Fernandes de Paula Moura, IAAF New Studies in Athletics 4.01.
When heavy strength lasts for more than 8 weeks, it has been shown to cause negative effects on special strength (Bosco 1985) and microfiber structure (Tidow 1995). This also leads to hypertrophy of Type I fiber and lower performance.
So doing this sort of stuff for more than 7 weeks at a time (with significant breaks) is not necessarily positive in the long run.
That’s one reason to use the 3-1-3 approach to max strength but I think you could say that about any specific quality that is being advanced (not just maintained) in a training block. Think of speed work. L-to-S, SE is advanced then maintained while Sp is advanced, while S-to-L is Vice Verse. It’s not likely that any specific quality would “run out the 7 week clock” if double or triple phases are used.
When I initially read your post I thought you where wrong. Based on the fact grass is a much more compliant surface; it will change more for the given amount of force. A logical extrapolation is that leg angles would flex more under these conditions. However after reviewing the research on leg stiffness across different surfaces, support mechanics do not change across varying surfaces. Leg stiffness does become greater on softer surfaces but it’s mostly from increased stiffness at the ankle joint, hip & knee mechanics remain unaltered.
A stiffer leg increased stride frequency & stride length decreased.
Energetics and mechanics of human running on surfaces of different stiffnesses
Amy E. Kerdok1,2, Andrew A. Biewener3, Thomas A. McMahon1,2, Peter G. Weyand3,4, and Hugh M. Herr1,5,6
1 Harvard Division of Health Sciences and Technology, and 5 Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge 02138; 3 Concord Field Station, Museum of Comparative Zoology, Harvard University, Bedford 01730; 2 Division of Engineering and Applied Sciences, Harvard University, Cambridge 02138; 4 United States Army Research Institute for Environmental Medicine, Natick 01760; and 6 Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, Massachusetts 02114
Mammals use the elastic components in their legs (principally tendons, ligaments, and muscles) to run economically, while maintaining consistent support mechanics across various surfaces. To examine how leg stiffness and metabolic cost are affected by changes in substrate stiffness, we built experimental platforms with adjustable stiffness to fit on a force-plate-fitted treadmill. Eight male subjects [mean body mass: 74.4 ± 7.1 (SD) kg; leg length: 0.96 ± 0.05 m] ran at 3.7 m/s over five different surface stiffnesses (75.4, 97.5, 216.8, 454.2, and 945.7 kN/m). Metabolic, ground-reaction force, and kinematic data were collected. The 12.5-fold decrease in surface stiffness resulted in a 12% decrease in the runner’s metabolic rate and a 29% increase in their leg stiffness. The runner’s support mechanics remained essentially unchanged. These results indicate that surface stiffness affects running economy without affecting running support mechanics. We postulate that an increased energy rebound from the compliant surfaces studied contributes to the enhanced running economy.
Mechanism of leg stiffness adjustment for hopping on surfaces of different stiffnesses
Claire T. Farley1, Han H. P. Houdijk2, Ciska Van Strien2, and Micky Louie1
1 Locomotion Laboratory, Department of Integrative Biology, University of California, Berkeley, California 94720-3140; and 2 Department of Human Movement Sciences, Vrije Universiteit, 1081 BT Amsterdam, The Netherlands
When humans hop in place or run forward, leg stiffness is increased to offset reductions in surface stiffness, allowing the global kinematics and mechanics to remain the same on all surfaces. The purpose of the present study was to determine the mechanism for adjusting leg stiffness. Seven subjects hopped in place on surfaces of different stiffnesses (23-35,000 kN/m) while force platform, kinematic, and electromyographic data were collected. Leg stiffness approximately doubled between the most stiff surface and the least stiff surface. Over the same range of surfaces, ankle torsional stiffness increased 1.75-fold, and the knee became more extended at the time of touchdown (2.81 vs. 2.65 rad). We used a computer simulation to examine the sensitivity of leg stiffness to the observed changes in ankle stiffness and touchdown knee angle. Our model consisted of four segments (foot, shank, thigh, head-arms-trunk) interconnected by three torsional springs (ankle, knee, hip). In the model, an increase in ankle stiffness 1.75-fold caused leg stiffness to increase 1.7-fold. A change in touchdown knee angle as observed in the subjects caused leg stiffness to increase 1.3-fold. Thus both joint stiffness and limb geometry adjustments are important in adjusting leg stiffness to allow similar hopping on different surfaces.
A soft surface permits (rather than require) a “stiffer” leg. Isn’t that obvious? At impact the body has a certain amount of kinetic energy that will act to deform the surface and the leg. If the surface is very hard, it will not be deformed but the leg will. If the surface is very soft, the surface will be deformed but the leg won’t.
Partly true. But it does actually requirea stiffer leg. Since all other variables (such as mass and gravity) the amount of force required to overcome them remains the same, deforming the surface requires the leg to be stiffer at a given speed to make up the balance. It’s simple mathematics.
Has any one noticed how sprinting on a softer surface effects where you fatigue in different ways? An endurance session on a soft track or grass will leave you fatigued in the glute med, calves and vastus muscles whilst the same session on a hard track will hit the glute max and hammies alot more whilst allowing for greater speeds.
A soft surface permits less deformation of the leg. If a certain criterion is to be met, you could of course also say that the soft surface requires less deformation of the leg. For example, to keep the contact time short, the soft surface requires less deformation of the lag.
Or if, as in you example, the leg muscle tension is constant, the soft surface will result in less deformation of the leg.
Before a month I run with one triathlon guy on concrete. I said that I adapted running on the grass, mostly barefoot and that my knees are killing me on the concrete (I have 100kg/183cm). He said that a runner must adapt running to concrete and thus it is smart to run on concrete if you plan to race on concrete. I guess leg stiffnes alternations explained here may explain this issue.
