Ben's stride on Speed Trap book cover?

Expert Discussion Biomechanics and Physiology
1

On the cover of Speed Trap the photo of the '88 games when Ben was 5 meters ahead of the field. I was looking at the shot and I notice Ben’s foot is landing ahead of his COM at ground contact. Is he decelerating w/ each foot contact?

I’m asking because if you look at the other guys like Dennis Mitchell in lane 8 he doesn’t have as much breaking as Ben form this shot anyway.

Maybe because Ben is so much stronger than his counterparts he can have more breaking because he’s applying more forces… I’m guessin ???

:smiley:

Dennis landed flat footed on this shot… Who’s breaking more Ben or Dennis?

It’s funny how Carl, Linford and Calvin are all in the same swing phase.

Looks like Carl will land first & cover more ground…

Any thoughts?

Kenny Mac~~~

2

Look at the cover shot more closely. DM’s heel has contacted while Ben’s hasn’t. DM also has much more knee flexion. They are in different phases of their stride. I’d say Ben has the better mechanics. It looks like DM is straining and pushing more.

3

This was also the point in the race where Ben shut it down (80 meters)!

4

Why did Ben want to shut it down as early as 80m in an Olympic final? I know he raised his arm in the last 10m, but not at 80m. He looks to be still going flat out at 80m!

5

He shut down long before his hand went up. Check the splits for reference. Maurice was 8.09 at 80m when he ran 9.79. Ben was at 8.02, even though his 30m time was slower! This means he could have gone 9.72 if he’d finished up. Much more than the time loss of raising the hand at 94 meters.

6

Very impressive, but why did Ben shut it down at 80m? Was it to avoid injury?

7

i think i heard someone say it was about money.ben got x amount for running .79 and he was capable in running faster so faster time=another WR=money.charlie am i correct?

8

There’s always the concept of “slicing the Baloney thin” but I think he just was dominating the field and had no idea he was going that fast.

9

Originally posted by Charlie Francis
He shut down long before his hand went up. Check the splits for reference. Maurice was 8.09 at 80m when he ran 9.79. Ben was at 8.02, even though his 30m time was slower! This means he could have gone 9.72 if he’d finished up. Much more than the time loss of raising the hand at 94 meters.

charlie, the trend of the last meters at seoul, about ben, shows he could run 9.75- 9.76 not 9.72.
Mo’s speed endurance is better than ben’s
here the last 10 split of ben at seoul and mo at sevilla:
seoul
60-70: 0"84
70-80: 0"85
80-90: 0"87
90-100: 0"90
i can imaginate a trend that could drive at:
80-90: 0"86
90-100: 0"87-0"88

You also can imaginate the stress of ben’s cns in that race after 3 heats and a tremendous acceleretion/speed phase (6"33 at 60 m…)

Here mo at sevilla (i think as well as athens)
60- 70: 0"85
70-80: 0"85
80-90: 0"85
90- 100: 0"86

Charlie, do you know edmonton’s split times?
coud mo bit his wr?

valerio

10

Look at the film again and then get back to me. Also please review the Rome splits, where the effect of his breathing pattern is shown clearly, as Ben picked up speed again after the inspiration phase from 70 to 80 (.90) then 80 to 90 (.87) and 90 to 100 (.85). Please note that Ben picked up .09 between 30 and 80m on the Rome time.

11

To Kenny Mac. re Ben’s foot landing. You may have been brain-washed by the misleading concept, promoted by such people as Professors Bresnahan & Tuttle, Prof. J.G.Hay, George Gandy from Lougbourough, and numerous coaching manuals, that the foot lands immediately under the centre of mass. Half an hour with a ruler, protractor and calculator and the IAAF publication “Athletes in Action” (Ed Howard Payne) is sufficient to establish that athletes such as Alan Wells, Don Quarrie, Carl Lewis, Sebastian Coe and Steve ovett ( all Olympic or World Champions, and/or World record Holders) typically land with the foot about 20% of height in front of the centre of mass. Alternatively an elementary knowledge of mechanics and muscle action, and a “back of the envelope” calculation will establish the basis for this.
To Vabo &4: Mo’s apparent superiority in speed endurance is because he was almost certainly running hard all the way, unlike Ben. The estimate of 9.72 is perhaps optimistic, I might have gone for 9.73 to 9.74, however Ben would have been under no pressure to attempt a dip finish, and suffer the consequent loss in pace in the preceding 10m, so 9.72 might have been on.

12

Originally posted by Charlie Francis
Look at the film again and then get back to me. Also please review the Rome splits, where the effect of his breathing pattern is shown clearly, as Ben picked up speed again after the inspiration phase from 70 to 80 (.90) then 80 to 90 (.87) and 90 to 100 (.85). Please note that Ben picked up .09 between 30 and 80m on the Rome time.

the problem is the crediblty of split time.
For example in the last 10 m in rome, lewis accordly to the official split time gained only 0"01 but in the tape seemed a bit more
in tokyo, lewis reached is max speed at 80 m (0"83) with poor 20 last meters
today, split time are timed by laser
only god can kwow…

do anyone know split time in edmonton?
valerio

13

The split times were taken electronically by the IAAF science group at Charles Univ in Prague and by Quickfacts in Cologne. If these people are inaccurate, why do you want their splits from Edmonton and why do you accept them from Tokyo?

14

Originally posted by Charlie Francis
The split times were taken electronically by the IAAF science group at Charles Univ in Prague and by Quickfacts in Cologne. If these people are inaccurate, why do you want their splits from Edmonton and why do you accept them from Tokyo?

Ok
but is it possible that carl lewis coul reach his max speed at 80 m (70- 80 m split in 0"83) and then drop dramatically (80- 90 m split in 0"87, - 2 km/h) and after that have the power to acelerate (90- 100 m split in 0"86)?
laser time are more accurated but it will better when he will shoot one signal/0"001 and not /0"01

valerio

15

There is a breathing pattern and also the effect of a lean or forward movement of the chest/shoulder at the finish. I think alot of people were surprised at some of the raw data and often it was “massaged” to remove the anomalies and make the curve more even (usually this resulted in the 60 to 70 segment getting “slower” and the 70 to 80 segment getting “faster”)

16

Just found this topic by chance and can talk about Tokyo splits: The results were presented in New Studies in Athletics 1992, volume 7, n°1, and presented by JAAF/IAF Biomechanical Project Team. Some extracts:
“Methods - The analysis of the men’s 100 metres was carried out on the basis of recordings obtained from 12 video cameras (60 fields/sec). All cameras were synchronized with the flash of the starter’s gun. Ten cameras were located at 10m intervals along the home straight of the stadium. From these elapsed time, interval times and average speed was determined. A further two cameras were located at each en of the straight, recording the athletes ‘head on’ and from behind. From these the touchdown time for each stride, and thus stride frequency, was determinded”.

On the table presenting findings, it is mentioned that error allowance is +/- 0.02 seconds.

That means that the last 60m intevals by lewis
0.84 0.85 0.84 0.83 0.87 0.86
can also be viewed as
0.85 0.84 0.84 0.84 0.86 0.86
or even
0.83 0.85 0.83 0.82 0.88 0.85

There is an other problem with Rome’87 analysis.
Preliminary report gives numbers as:
1.86
2.87 (1.01)
3.80 (0.93)
4.66 (0.86)
5.55 (0.89)
6.38 (0.83)
7.21 (0.83)
8.11 (0.90)
8.98 (0.87)
9.83 (0.85)

But the Scientific Report published by IAF in their first and second editions gives splits as:
1.84
2.86 (1.02)
3.80 (0.94)
4.67 (0.87)
5.53 (0.86)
6.38 (0.85)
7.23 (0.85)
8.10 (0.87)
8.96 (0.86)
9.83 (0.87)

Here again the difference between the 2 analysis which were published by Charles University is 0.02.

Explanation: in the report we can read:
“Informations and findings from the video recordings were published as FAST INFORMATION REPORTS and were available to the press and to the athletes and coaches in the Athlete Village in Rome. The recordings from each round were shown the following day as part of a video presentation given to the athletes in the Village.
[…]
The location of the high speed cameras enabled 3-D analysis of the athletes […] The films were also used for comparing with the material obtained from the video recordings in the preparation of this report”

So first data was given to press and athletes during the competition, and more precise analysis were published in the final report.

However, we must take in account that 0.01sec is important for us, but sometimes difficult to see on film recordings. 0.01sec at sprinter’s speeds is worth 10cm. And when people ask for 0.001 accuracy for intermediate times, they don’t understand that they ask for a 1cm accuracy, which depends a lot of athlete’s body position in his stride cycle, more exactly on the arm position, as arm movements lead to shoulder rotations, which makes 0.001 accuracy very … inaccurate.
Same problem with photofinishes, technology allow to search times even to 0.0001, but the question is when does the athletes crosses the line. The IAAF rule is so vague (torso without neck and arms) that there are often discussion on where the torso starts and the arm finish, and from which part of the shoulder the time is taken. I know plenty of cases of debates for chosing official time at 0.01 because the sprinter was leaning in a torsion movement, the arm pointing ahead parallel to the track, and shoulder passing before neck and torso himself.

17

Arguing about what part of the body should be taken first with splits seems odd. Surely the SAME part should be used from split to split to get the best idea of speeds travelled by segment. I spoke briefly to the Quickfacts people from Cologne in 1988 and they handed out the first numbers from the final there and were bitter that their numbers from Rome had been “Massaged” to smooth out the curve of running times- eliminating the dips that Quickfacts though were comming on inspiration.

18

Exactly, same body part. But when analysing people like Privalova who has big shoulder rotations (don’t know exactly how to describe it in English words), it can lead to some troubles in reading the films.

An other example to show how difficult is 0.01 to obtain is given by 1997 Athens World Champs:
"The speed curves of the male 100m World Champion and the female World Champion were obtained from laser measurement. Laser apparatus (LAVEG Sport, Jena) were placed 15m behind the start line at a height of aproximately 1.7m […] The system operated at 50Hz and measured the distance covered by the runner every 0.2sec […]
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 10m intervals over 100m to be measured.
Laser and video were compared and there was a 0.10m +/- 0.06 (n=10) average difference between video and laser measurements for male World Champion and 0.09m +/- 0.06 (n=10) for female World Champion. "

It shall be noted that the laser curve showed a lot of variations (between say 11m/s and 13m/s !!!) and that the curve had to be coupled with video recording to have decent data.

19

How did you implement the breathing pattern in training? When he inspired did he hold his breath?

How do you train an athlete to use such a race pattern?

20

He wasn’t holding his breath or doing anything deliberate- it’s just that you accelerate slightly on exhalation under pressure (the normal way of breathing in a race, creating the Valsalva effect) and decellerate slightly on inhalation (unavoidable)