Originally posted by dcw23
I would really like to have the data at 1m intervals. To really see what happens in more detail, as 10m segments really only show a trend between two points.
The velocity curve for Maurice Greene in 1997 World Championships for 9.86 may help you there.
“The speed-time curves of the male 100m World Champion […] were obtained from laser measurement. In brief, laser apparatus (LAVEG Sport, Jenoptik, Jena, Germany) were placed 15m behind the start line at a height of approximately 1.7m. The laser beams were directed to the lower part of the runner’s back in the upright position. Consequently, measurements were not possible during the first instants of the race when the runners were crouched in the starting blocks. Speed values were obtained from that instant when the athletes began to raise the thrunk until he had crossed the finish line. Any error due to the difference in height of the system in relation to the height of the lower back is considered insignificant.
The system operated at 50Hz and measured the distance covered by the runner every 0.2s. The system was scaled using the exact metric distance between laser apparatus and start line (15m) and finish line (115m). Video cameras operating at 50Hz were placed perpendicular to the running direction on the upper stands at the 30m, 50m and 60m line which allowed the distance-time results at regular 10-m intervals over 100m to be measured. Laser and video measurement were compared and there was a 0.10m+/-0.06 (n=10) average difference between video and laser measurements for male World Champion.”
Source “Modeling the energetics of 100-m running
using speed-curves of World Champions” (L.Arsac, E.Locatelli)
Wouldn’t you know it, this is covered in the video series. I have been going through them this rainy long weekend but hadn’t got far enough for this exact topic. Its great food for thought though.
So, the more developed the athlete, the closer the “dotted line” is to the 100m mark, therefore, a lesser percentage of the race is in the lactic system.
Conversely, the less developed the athlete, the greater percentage of the 100m is in the lactic system.
Some random thoughts…
Do women need to train the lactic system more than men because it will always contribute a greater portion of the race.
Do top level men need to train the lactic system with a higher intensity but a shorter duration?
Originally posted by dcw23
No, the data is very reliable. Keep in mind the speeds are very different here. Look at Greene’s velocity v Inger’s. Comparing his numbers don’t make as much sense because he is travelling so much more quickly.
I don’t know. Looking at the other graphs including those of Gardner, and the first graph with two other athletes compared to Inger, I note that Inger’s graph is the only one that does not show a dropping off in acceleration at the 25m mark. Everybody else, from the faster males to the slower females, has a drop off at 25m. Inger’s curve is anomalous compared with the others, and I suspect that’s more due to the data than due to a physical difference.
[quote]and I suspect that’s more due to the data than due to a physical difference.
The figures for Greene, Gardner and Miller all come from the High Performance & Research Sport Centre Laboratory of Biomechanics in Madrid, prepared by a research team of seven scientists. I feel pretty confident that they are accurate.
Thinking about it more, its probably the steeper initial curve that we should be looking at, which is a function of the greater power of the males. It simply takes longer for the female to reach the higher speeds. The male just reaches them earlier but then other limitations slow their rate of acceleration, e.g., gravity etc.
Originally posted by snelkracht
Inger’s data may be suspect; published 10m splits for elite athletes sometimes show anomalies that leave me scratching my head. Such as, for instance, Flo-Jo’s 10.49 run: 20-30m in 0.99, 30-40m in 0.92, 40m-50m in 0.98 ---- ???
No, the data is very reliable. Keep in mind the speeds are very different here. Look at Greene’s velocity v Inger’s. Comparing his numbers don’t make as much sense because he is travelling so much more quickly.
I also find it hard to believe that elite female sprinters are more efficient in the lactic energy zone than males,
At the elite level, clearly they aren’t. Contrast Greene and Inger.
Elite females are better trained and probably mechanically more efficient in a race than 10.54 male athletes, which would explain most of the discrepancy in the last 30m.
Originally posted by dcw23
Then from 30-50m we see how strength/power is less of a factor and Inger’s better developed elastic/reactive strength allows her to out accelerate the guy for a 10m segment until they even out.
Yes, but Inger out-accelerates Maurice Greene in the same segment also for 10m. In fact, the curve of Greene and the French sprinter match each other fairly well for 70m.
Inger’s data may be suspect; published 10m splits for elite athletes sometimes show anomalies that leave me scratching my head. Such as, for instance, Flo-Jo’s 10.49 run: 20-30m in 0.99, 30-40m in 0.92, 40m-50m in 0.98 ---- ???
I also find it hard to believe that elite female sprinters are more efficient in the lactic energy zone than males, given their almost universally poor 200m times compared to males of the same speed.
Elite females are better trained and probably mechanically more efficient in a race than 10.54 male athletes, which would explain most of the discrepancy in the last 30m. Remember, Inger is a professional athlete; a 10.5 guy is holding a day job - probably fulltime, because sponsors aren’t fighting each other to get at him.
OK, lets look at segmental analysis of this comparison with reference to the primary quality utilised in each segment.
The greater strength/power of the male shows over the first 30m.
Then from 30-50m we see how strength/power is less of a factor and Inger’s better developed elastic/reactive strength allows her to out accelerate the guy for a 10m segment until they even out.
From 50-70, we now again see male biological dominance. I would hazard a guess that one factor would be the level of eccentric strength required to continue acceleration.
From 70-100 we see that Inger is a more fully developed athlete in the lactic energy zone.
With many thanks to PJ, here is where it gets interesting.
I have now included the French national level B guy (who runs 10.52) v Green and Inger. Look what happens.
This is one of the things I was hinting at with a previous post re comparing an 11s male and 11s female. It is easy to see that Inger’s total race is far more highly developed than Mr. 10.52.
He can accelerate better than her in 20-30m, but then she out accelerates him in 30-40m.
They then have an almost identical rate at 40-50m. But he then continues to accelerate from 50-60m, where Inger has now reached max speed and cannot accelerate further.
He then plateaus between 60-70m and then dies at almost exactly the point that the energy system switches over.
Inger on the other hand, manages a far less dramatic loss of speed, probably because she is more highly developed in this section of the race.
At the 100m mark, the speeds of Inger and Mr. 10.52 are heading towards intersection.
You’ve used sufficient illustrations to show the trend first seen by the East Germans in 1982. The drop increases as performance decreases. The trick is to take an established phenominon and explain it and its implication on training choices.
Originally posted by pierrejeandcw23, how do you determine the point where you draw that drop line?
Energy system changes over at roughly 7.5 seconds, though it is believed that this can be enhanced towards 8 seconds for elite athletes with appropriate training.
Originally posted by Charlie Francis
Is the alactic threshold fixed or can it be favourably influenced by training, and, if so, by what sort of training?
Some guy with a bald avatar suggested that they could in a video series. Possibly via working in this zone for acceleration and speed training in order to expand the envelope. He also mentioned this sort of training means that the athlete will spend less time in the alactic zone as they have travelled more distance.
I would really like to have the data at 1m intervals. To really see what happens in more detail, as 10m segments really only show a trend between two points.
But, we can see that in all but one of the examples, the speed tails off around the time the alactic threshhold is hit. This seems to be less evident with the men.
I would also really like to get some accurate date of national level and junior national level men and see what the tail off is like with them.
A great topic, but, like all such analyses, it opens up new cans of worms every time you move into more detail. Some examples of questions that arise:
1: What is the effect of technique on the velocity curve. If you look at the East Germans (and Mo Green for that matter) You’ll see that the position they maintain and the reduced hip movement that results may limit top speed in favour of an extended speed curve. How do you account for that in an analysis of the shift in the alactic threshold?
2: Might there be a velocity “crest” where the sprinter “floats” over the peak before decelerating? (This could be addressed in theory by splitting the fastest race segment in half. as speed is not constant and is either rising or falling, then, logically, it would be rising over the first half of the fastest segment and falling over the second half)
3: What is the effect of technical emphasis on the location of the point of maximum speed? This factor alone will be massive, regardless of the limits of alactic capacity.
These hurdles should not deter us from investigating this subject, they just need to be considered along the way.
Originally posted by Charlie Francis
A great topic, but, like all such analyses, it opens up new cans of worms every time you move into more detail. Some examples of questions that arise:
1: What is the effect of technique on the velocity curve. If you look at the East Germans (and Mo Green for that matter) You’ll see that the position they maintain and the reduced hip movement that results may limit top speed in favour of an extended speed curve. How do you account for that in an analysis of the shift in the alactic threshold?
From the high-speed films i have, i’m trying to search some basic kinematics variables at 10m, 30m, 50-60m and 80m points (not the 100m point due to obvious technical changes because of final rush).
I no longer search 10m split times for 100m races (unless major performances) because of the lack of accuracy. Many publications give split times from sharp apparatus, but i still doubt some results.
East Germans used 0-30m, 30-60m, 60-80m and 80-100m splits as it was enough to see the speed curve and the changes in strid elenght and frequency. Each sprinter had a model to follow, based on their best split time in competition (each race in GDR was analysed), and compared with split times at practice, expressed in % of their model. USSR copied this methods as they were unable to reach same success.
IMO it’s the best opinion to evaluate sprinter’s progressions, short comings and improvements in competition.
pierrejean
I’m not sure that race modelling was as important to East German success as was the meticuluous attention to the physical preparation. Take, for example, the start model for Heike Dreschler. Placing a six foot tall, slim girl in a start position with her shoulders lower than anything that Ben could handle made no sense.
Drechsler is the example that don’t follow the GDR way of running. She was the exception. She wasn’t coached by Hille nor Meier, and there was jaleousy from other GDR sprinters about her participation in the 4x100 relay squad.
But all the other GDR sprinters since Stecher ran on the same model.
Drechsler’s sprint success was nearly an “accident” as she was seen as beeing part of the Long-Jump group (too tall for the sprints for GDR talent selectors according models).
Her bad position prevented her to get fast starts in 1986-87, little changes get things much better in 1988 though.