[QUOTE=sonicboom]
From the start to the finish of the 100m, what is the average stride increase over distances. For example, I realize the stride during the accel phase is shorter and slower in frequency, but by what distances will it increase over the first 10m, 20m, 30m, etc. You can be more specific than that if it is possible. [Quote]
I just thought I’d insert a reply I made to a similar question in T-Mag a few years ago.- Read on:
I have always gone against the mainstream in believing that stride frequency is trainable.
The prevalent theory is rooted in an extrapolation of the basic, unalterable fact that sprinters are separated from everyone else by the hereditary wiring of their brains that allows them to alternate muscle actions more rapidly, primarily due to their ability to shut down the antagonist muscles faster and more completely (though their contractile velocities are also faster, the difference is marginal). They therefore believe that talent is defined by frequency and, since talent is unalterable, so must be frequency.
Clearly, though, every sprinter is capable of cycling his legs at least 5 times per second in the air. The problem only comes in when the sprinter hits the ground and decelerative contact forces work against him. Improvements in strength and elasticity will certainly allow the sprinter to better resist these contact forces and maintain a higher turnover rate.
A cursory analysis of Ben’s 100meter running shows that, though he improved from 10.32 to 9.79 over the 100meters, his number of strides remained constant at 46.5 steps, leading to the conclusion that all of his improvement was based on frequency. Subtracting Ben’s reaction time (the time between the gun and first motion) of .132 from the overall time gives the true running time for each race. So 10.32 becomes 10.188 and 9.79 becomes 9.658. Divide each net number into 46.5 and you get a stride frequency of 4.564sps for 10.32 and 4.815sps for 9.79.
Most coaches have maintained that stride length will increase as strength improves- and they’re right too! Wait a second- how can they be right if Ben’s stride count remained constant over the years?
This is where it gets a little more complicated because it isn’t just the number of steps taken, but how those steps are distributed. Most 100meter runners reach their peak stride frequency at about 25 to 30 meters with a very gradual decline in frequency until about 70 meters where there is a marked drop in rate as the sprinter runs out of gas and begins to “freewheel” to the finish line.
The stride length increases from the start with the optimal combination of length and rate yielding top speed somewhere between 45 and 60 meters. The final few strides are usually very long but with a frequency so low that speed drops off significantly.
Now lets look at how Ben’s stride distribution changed over time. As Ben’s strength improved, he was able to drive out of the blocks harder and lower, driving his center of mass out farther ahead of his feet. The increased angle forced Ben’s feet to the ground sooner to keep him from falling, actually shortening his first few strides. Once underway, however, the additional power caused his stride length to improve all the way to the 70meter mark.
At this point, additional strength and efficiency allowed him to keep on driving to the finish and these “power strides” were shorter than the “freewheeling” strides at the final stages of his earlier races. Thus the total number of strides remained constant even though both frequency and stride length had improved.
Since the enhancement of all training elements improves both stride frequency and stride length, there is no need to worry about training one part at the expense of the other. But, before getting into specifics, the number one secret to greater speed is RELAXATION!
It allows a faster and more complete shutdown of antagonists, quickening alternation cycles and permitting more force to be delivered in the desired direction with less energy consumption. Relaxation must become second nature in every drill you do and every run you take.
You may feel that you are not generating enough force while relaxed- a perception that gets a lot of sprinters into trouble in big races- but, remember, only the NET force counts! The net force is the amount of force delivered in the desired direction MINUS the force generated by the antagonist muscle at the same moment. For example, if, by maximum effort you generate 100pounds of force in the desired direction while putting out 30pounds of force with the antagonists, you are left with 70pounds of net force. If you completely relax and put out an easy 80pounds of force in the desired direction and NO pounds with the antagonists, you are left with 14% more net power with 62% less effort (80 vs 130lb total output)!
This simplistic example shows a colossal energy savings and it understates the case since, in reality, increases in energy expenditure are exponential- not linear.
The shutting down of unwanted muscular activity also cuts down on the “background noise” that interferes with the hind brain’s ability to rapidly process input (this is also why it is critical to work on skills one at a time). Strangely, even though most coaches think that only stride length can be improved, they attempt to work on both stride length and frequency simultaneously with towing or “over speed” devices. These devices are bad news! They force the athlete to land farther ahead of his center of gravity than normal, increasing the risk of injury and INCREASING the ground contact time even though the key to greater frequency is REDUCED ground contact time. Drills are available to train frequency and stride length independently.
“Quick leg drills”, with very short steps done as fast as possible over a very short distance, enhance frequency. The emphasis must be on complete relaxation and rythem. A typical workout might be 4 sets of 6 drills over 10 to 15 meters with 1 to 2 min recovery between reps and 3 to 4 min recovery between sets. These drills would be done only on pure speed training days, not with speed endurance. Bounding and hopping drills allow for the development of maximum stride length. Workouts of this type usually consist of between 100 and 200foot contacts in a single session.
Remember that your drills must always be improving in quality, so you must make sure that you are recovered for each new workout and if your workout deteriorates, STOP!
A holistic approach was always used in our training cycles but we always ordered our programs to develop acceleration first (to coincide with our maximum weight phase), then maximum speed, and then speed endurance (first you need the speed, then you can worry about maintaining it).
Assuming you are already fit, you should assess your personal strengths as a sprinter and work primarily on them.
Spending too much time dealing with your weaknesses may well come under the heading of flogging a dead horse!
