JS did not change Mo’s mechanics to keep him going through at the end - he emphasized absolute max less in favor of staying power.
It’s not like JS walked up and said, “I’m going to force you to run completely different now,” but both the amount of emphasis on MaxV and the race modeling is different, and what we can see in splits falls out from both.
Yes you are correct, faster overall segments. Back in 1998 Matt Shirvington ran 10.03 using very old style adidas spikes( flexible plate) and the track wasn’t mondo. Obviously he is not in the same shape these days, but changes in foot technology or surfaces haven’t helped him run any faster. Also Tim and Asafa have run 9.79 & 9.77 on older style tracks.
I am not sure using the term sitters is accurate. Gay & Powell have their knee more flexed during the support phase however throughout the flight phase their well and truly up off the track.
here is some more of the report
Recovery leg movements
Leg movements during the recovery phase when the support leg leaves the ground and
then the leg is moved forward were analyzed in terms of maximum thigh angle (maximum angle
formed by the thigh and the vertical line), minimum knee angle, and maximum leg angle (maximum
angle formed by the vertical line and the line connecting the hip joint and the lateral malleolus)
(Figure 2). According to Ito et al. (1998), sprint running velocity is not related to maximum thigh
angle and maximum leg angle, but the faster the sprint running velocity, the greater the minimum
knee angle. The maximum thigh angle for Gay and Powell was comparable at 65° and 70°, and
these numbers were similar to the data obtained by Ito et al. (1998). The minimum knee angle for
Gay and Powell was 41° and 38°, respectively, and these numbers were comparable to past data.
The maximum leg angle for both sprinters was 34°, and this number was similar to the data
obtained by Ito et al. (1998).
Although the technique of the two sprinters appeared different to the naked eye, there
were no marked differences in the parameters measured in the present study. In other words, both
sprinters moved their legs forward without excessively raising the thigh, thus resulting in relatively
low knee height. The horizontal distance from the toe at the point of landing to the center of gravity
(this relates to the maximum leg angle) for the two sprinters was 0.31 m, and this number is
comparable to that for sprinters who run 100 meters in 11 seconds (Fukuda and Ito, 2004).
Therefore, it is not necessarily good to land immediately underneath the center of gravity when
landing.
Support leg movements
In the present study, the driving movements of the support leg were analyzed in terms of
the maximum extension velocity of the hip, knee and ankle joints of the support leg during landing
(Figure 3). Ito et al. (1998) reported that while fast sprinters exhibited fast hip extension and slow
knee extension, the maximum ankle extension velocity did not correlate to sprint running velocity.
However, an interesting finding was seen with maximum knee extension velocity for Gay and
Powell. During landing, the knee joint of both sprinters always remained bent, and when
acceleration force was expressed during the later half of the support phase, the extension velocity
had a negative value: -50 degrees/s for Gay and -68 degrees/s for Powell. According to our
unpublished data, Maurice Greene, the previous world record holder, exhibited the similar
movement. The knee extension velocity for Lewis was almost zero (Ito et al., 1998), and the results
of the present study suggest that sprint running technology has entered a new era.
With regard to knee extension velocity, if the knee joint is fixed like Lewis, then 100% of hip
extension can be transferred to drive the leg in the posterior direction, but if the knee joint is bent
like Gay and Powell, hip extension velocity is added to the leg, causing the drive velocity of the leg
in the posterior direction to exceed 100%. Furthermore, with a driving movement where the knee
joint is extended, hip extension velocity is absorbed by knee extension velocity, thus reducing the
drive velocity of the leg in the posterior direction.
The maximum hip extension velocity for Gay and Powell was 774 and 693 degrees/s, and
the maximum ankle extension velocity 664 and 743 degrees/s, respectively, and these values were
mostly comparable to the data obtained by Ito et al. (1998).
4. Guidance recommendations
The results of the present study show that Gay and Powell are world-class sprinters with
different characteristics in terms of step length and step frequency, and suggest that caution must
be exercised when strongly correcting step frequency and length.
Past studies have shown that the maximum ankle extension velocity is constant and is not
related to sprint running velocity, and this suggests that so-called “snapping” movements are due to
the spring-like properties of the muscle-tendon complex involving the triceps muscle of the calf and
the Achilles tendon. In other words, athletes do not consciously extend the ankle, and guidance
should take into account this point.
Training guidance that attempts to increase sprint running velocity by reducing the
deceleration associated with landing must be reexamined because the landing distance for Gay
and Powell is comparable to that of sprinters who run 100 m in 11 seconds.
What is important here is that Gay and Powell continue to bend the knee of the support leg
during the support phase, and training guidance that instructs sprinters to actively extend the knee
and ankle joints of the support leg must be reevaluated.
Abstract
The running speed of men’s and women’s 100-m sprintes, including Tyson Gay (USA), Asafa Powell
(JAM) and Veronica Campbell (JAM), at the 11th IAAF Athletic Championships in OSAKA were
measued by using laser beam apparatus (LAVEG Sport, JENOPTIK, Germany). The purpose of this
brief report was to investigate changes in running speed during the 100-m races and to provide
information a sprint training. The highest speed of Gay (USA), who won the men’s 100-m, and Powell
(JAM) was 11.83 m/s and 11.79 m/s, respectively, and the rate of decrease in speed was 2.2% for Gay
and 8.1% for Powell. However, their top speed was slower than that of Carl Lewis at the 3rd IAAF
World Championships in Tokyo (12.05m/s, 9.86s of previous WR). In women, the highest speed
attained by Campbell (JAM) was 10.56m/s and the rate of decrease in speed was 9.6%. The
correlational coefficient between the top speed and goal time was -0.933 for men (p < 0.0001) and -
0.962 for women (p < 0.0001). The rate of decrease in speed ranging from 2% to 13% has a small
effect on the goal time. However, it may influence the ranking of the races of both the men’s and
women’s.
here are the related figures 1 & 2
not sure why the link isnt working right but click on the link to see the images.
The key term here is ACTIVELY. You do not consciously try to do anything during the support phase- it MUST be automatic there or performance will suffer. The automatic response is determined by position going in (hip height, flexibility, etc) and level of strength, elasticity , and endurance.
Yes. Hip height is the key.
During landing, the knee joint of both sprinters always remained bent, and when
acceleration force was expressed during the later half of the support phase, the extension velocity had a negative value: -50 degrees/s for Gay and -68 degrees/s for Powell
Freakin scientists invariable you never understand what they mean without further investigation. I think their saying that during the later half on the support phase, when the knee extends. The rotatory velocity at Powell knee joint extends at a faster rate than Gays ( -50 deg/s v -68 deg/s).
The maximum hip extension velocity for Gay and Powell was 774 and 693 degrees/s, and
the maximum ankle extension velocity 664 and 743 degrees/s, respectively, and these values were
mostly comparable to the data obtained by Ito et al. (1998).
Powell hip Ext 774 deg/s Gay 693 deg/s
Powell ankle Ext 693 deg/s Gay 743 deg/s
Very interesting data, Asafa generate more torque and power than Gay at the hip joint during ext. However at the ankle joint , Gay max ankle extension velocity is 79 deg/s faster.
Conclusion/ Powell generate greater rotatory velocity than Gay at the hip and knee joints. However Gay generates significantly greater extension velocity at the ankle joint.
http://www.charliefrancis.com/community/showthread.php?t=17585
People talk about triple extension when sprinting. A straightening of the hip, knee and ankle joints concurrently in the full extension phase of the stride cycle. But Powell appears not to do that. His action is almost a fast shuffle, like that you see from sprint hurdlers between the barriers.
Francis explained: "One of the things that I observe is that every human action whether it is a swinging bat or racquet, a swimming action - crawl or butterfly - or sprinting action. They are unique to an individual.
"When you get very good it is not possible to take Michael Jordan’s jump shot - no matter if it is a little bit off what you think it should be - change it, and expect Michael Jordan to be the same as he was before.
"I look at coaching as trying to get the most good out of the plan that you have. There are some issues which if you managed to change them there would be a huge gain in performance. There are others you wouldn’t want to change, especially if the performances are already good.
[B[u]]"Asafa ‘sits’ a little bit [/u]as he runs in top flight. But that is characteristic to him. He manages to get all the benefits of triple extension without actually doing it which means he’s able to turn his feet over, his frequency will benefit. The person who has to fully extend to get the benefit that Asafa gets is obviously at a disadvantage.
"There are times, during most of last season for example, when he was overdoing it (pressing his stride frequency) . Between April last year (2007) and August he was overdoing it. In fact that was one of the big differences between what you saw up to Osaka and then after it (in Rieti and Brussels).
"I think what happened is he began to understand.”[/b]
Sitting during support phase is fine. His hips don’t stay low through out air time.
"Asafa ‘sits’ a little bit as he runs in top flight. But that is characteristic to him
Gay does the same according to the Osaka data.
Sharmer, we are talking about those capable of world record times who are in shape, . At the very top, new technologies make a difference. Alot of the top guys in the 80s ran faster than 10.03 so I don’t see your point here. What I am talking about is the real elite, those who benefit from small but useful improvements from new technologies.
I would 100% agree if we were talking about swimmers. But for track sprinters I don’t see the significant impact of technology, especially with footwear design.
I think we getting away from the topic, thats another thread( technology). Are you in favor of knee bend during the support phase ?
If thats the case then why not run in concrete boots?
I am in favour of what is optimal, like I said the study is inconclusive and less knee bend would be the best outcome IMO.
How can you say that the study is inconclusive, when it doesn’t test any hypothesis? It gives characteristics of the top guys. Both Powell and Gay have significant knee bend during support.
If the researchers hypothesis was greater knee bend results in faster max vel, than at this stage there is no proof, however they are not making such claims.
Its inclonclusive because it doesn’t prove that sitting is the definitive technique or that you can not run faster using triple extension. Hypothesis or no hypothesis, the conclusion made from the observations can be interpreted which ever way you want ESPECIALLY if you run transforms on data. You can prove anything conclusively. Can you prove from wihtout doubt that trple extension is not the way to go? No so my assertion is correct and yours is a moot point.
You are saying that we don’t have to worry about triple extension. How can you make such a claim from just one study?
I don’t need to answer that question because triple extension never actually happens. The hip, knee and ankle never fully extend, so the term triple extension is an oxymoron. It’s a physical impossibility. Maybe that’s a bit pedantic. When people say triple extension, they really mean sequential summation of forces from the hip, knee & ankle joint. So I agree with your reasoning (summation of forces) but I disagree with the term (triple extension).
In support leg
movements, an interesting finding was seen with maximum knee extension velocity for Gay and
Powell. During landing, the knee joint of both sprinters always remained bent, and when
acceleration force was expressed during the later half of the support phase, the extension velocity
had a negative value: -50 degrees/s for Gay and -68 degrees/s for Powell.
Could someone explain this…I’m a bit lost :o
the knee is collapsing slightly on ground contact after passing BDC.