THE CURRENT (AUGUST 2007) EDITION OF THE IAF’S NEW STUDIES IN ATHLETICS INCLUDES THE FOLLOWING TWO FINDINGS:
IF ANYONE HAS MORE INFO FROM THE STUDIES, IT WOULD BE INTERESTING TO READ…
400m
Changes in the accumulated oxygen deficit and energy cost of running 400 metres
Thursday 2 August 2007
By Victor Machado Reis, Paulo Paixão Miguel
The aim of this study was to compare the accumulated oxygen deficit (AOD), the energy cost of running and the anaerobic fraction of energy elicited during all-out 400m track runs in the off-season and summer preparation phases of a season. Five trained 400m runners with an average best time of 47.72 took part in the tests. The authors found that the subjects’ performance improved significantly between the two tests but this improvement was not matched by significant changes in the AOD. They did find that the performance improvement was matched by significant decreases in the energy cost of running and oxygen uptake during the run and a significant increase in the anaerobic fraction of energy used. These results suggest that improving high-speed running economy is a key to better performance in the 400m.
100m
Optimisation of performance through kinematic analysis of the different phases of the 100 metres
Thursday 2 August 2007
By Krzysztof Mackala
The aim of this study was to investigate the variability of stride length and stride frequency between athletes of different performance levels in the 100m and then verify the influence of these kinematic parameters on the phases of the race and technical efficiency. Data from a group of 8 average male sprinters (mean performance 11.18) and the men’s 100m finalists in 1991 IAAF World Championships in Athletics were compared. Based on statistical analysis of the kinematic parameters, the author identifies different phase structures for the races of the two groups. The results suggest that stride length contributes much more to the course of the 100m than stride frequency, which cannot anymore be considered the most important performance-determining factor in either average- or high- level performers. It is therefore necessary to find an optimal balance between stride length and stride frequency, especially during the initial acceleration phase, in order to optimise the performance.
Interesting. My undergraduate dissertation looked at performermance indicators in the 100m and I found that stride length was a better predictor of performance than stride frequency. Obviously my study was not as in depth as this. Interestingly I seem to remember the subject with the highest frequency had a best flying 30m of 3.43! Other subjects included in my study were Darren Campbell, Jason Gardener, Craig Pickering and Tim Abeyie.
TO Maris
im very interested to hear some finding u found on those great sprinters, also any important info’ about practice weights or anything would really interest me. and besides i was wondering 3.43 for 30 flys? how did they run it?
Haha. The flying 30s were done off a 30m roll on if I remember correctly. I’ll have a hunt around for my diss and see if I can upload it onto here or something. It’s fairly lengthy, 10,000 words or so. Regarding the weights, the study didn’t look into the training, but J, you know me, I can tell you a fair bit about what all those guys did in the weights room
The researchers may have interpreted the data incorrectly. It is true that stride length is an important variable. However this is usually the case at max velocity. Studies show that at max velocity elite sprinters have longer stride lengths. During acceleration stride rating is more important, especially for the first 30m.
Maybe the researchers looked at the data at max velocity and tried to impose it onto all phases of the race. Data on kinematic variables can be open to interpretation. Especially when the variables are velocity or distance. GRF data is more useful, however the IAAF don’t have tracks with forces plates along the entire 100m.
The devil is in the detail of how they interpret their data.
As a (once active) coach, I still think the best we can work toward is improving the quality of contact, the quality of impulse.
I have always been entertained by the fact that when Ben Johnson ran 10.2sec he took 48 strides and when he ran 9.79sec he took 48 strides.
Charlie will correct me. Perhaps my figures are slightly out, but I remember CF highlighting the fact that Ben took the same number of strides when he was world recordbreaker as when he was outside 10sec.
Now apparently the stride pattern and length changed somewhere, but it would seem that stride rate was still the overriding determinent of a significantly faster 100m.
I know there are various factors determining length of stride, but at max velocity or close to it I think the value of the impulse and quality of ground contact will ultimately be the major influences on stride length (and indeed stride frequency). Hence my initial comment: as coaches (and not necessarily academics) we should keep working on improving the quality of contact and that entails improving the quality of the impulse.
ok, all you academics can shoot me down now …arghhh
No Kitkak i think your right on, it would seem that the issue is the value of the contact. So its seen as at max volocity the stride length and frequency are greatest (obviously) there for the quality is at its finest.? If this be true as i suspect then for greater speed it’s better to over-stride than to under-stride, although the quality would go down, the length of the stride would make up for the let down in quality. Unless you were talking 'bout a 15m shuttle such as in skilled sports.
Stride length is greatest at max velocity however rating peaks at late acceleration (30m). If length and rating peaked at the same time, max speeds would be; (2.40x5.2) = 12.48ms or 0.80 splits.
I think the runners average time is too low. Looking from 10.50 (where stride length is prob near to maximal) to 9.80 (where rate makes the diff) would show as you suggest.
It’s saying my dissertation is an invalid file type. It is a word document and from what I can see, the valid file types are all images-I’m not that good with computers. Any ideas how I can do it??
How large is it (kbytes)? You should be able to do select all on your word document (from within word), then paste it into Charlie’s text box, just like any other quote. I am able to do this with David Woodhouse’s entire training theory document (which is a word document and actually more than 10,000 words).
