11/15/06

Positive Running by Frans Bosch

When I was in Holland Frans Bosch introduced the concept of Positive Running to me. I thought it was thought provoking and should be put on the table for discussion. Frans was kind enough to translate some of his remarks on his idea into English. Much of the background for this is the Book and the DVD available at www.gambetta.com

Positive Running - Maintaining top speed in running - Basic ideas

By Frans Bosch

In top speed running there are limiting factors. One could be the amount of power muscles can generate. There is good reason to assume this not a very important factor. An important factor is the ability to maintain elastic energy in the system by converting it to kinetic energy and back to elastic energy again. This means a lot of elastic energy is transported from one leg to the other each step. In sprinting this occurs 4-5 times per second.

How is elastic energy transported from one leg to the other?

In top speed running hamstrings play a crucial role. In the swing phase, at the moment of the fast knee extension, the hamstring is stretched elastic by the pendulum motion of the lower leg. To load the hamstrings elastic pelvic rotation backward has to be avoided, since backward rotation unloads the hamstrings. Therefore it is necessary to have the pelvic not in a forward tilted position immediately before the hamstring-loading phase. This means that at the end of the stance phase forward pelvic rotation has to be avoided. Abdominal muscles play a crucial role in this.

When there is no or limited forward tilt at the moment of toe-off. m. iliopsoas activity of the behind leg can help with loading the hamstring together with the knee extension. (See BK book)

Around the moment of toe off (in the leg that was the stance leg) there is an important transition in muscle activity from one set of muscles (hamstring gluteus erector spinae) to an other set of muscles (abd. Iliopsoas rectus). This big change in muscle activity means transferring elastic energy from one group of muscles to the next is under pressure. It becomes even more difficult when there is forward tilt of the pelvis, because abdominals only have a narrow range in witch they can generate big forces.

Is avoiding of forward rotation of the pelvis difficult and is it a limiting factor in high speed running?

Avoiding too much forward tilt of the pelvis together with keeping the pelvis in a forward position (like M Johnson etc. >> making it possible to load the abd, iliops rectus -set with lots of elastic energy) facilitates the energy transfer from one leg to the other. Losing control of the hip position under fatigue can be observed in many runners (being unable to bring the swing leg forward fast enough).

How is this stabilizing of the pelvis done?

In positive running a large retroflecive motion of the stance leg is avoided, because that will always result in pelvis tilt forward. The knee of the stance leg does not travel far behind the hip. In Asafa Powell's technique this is done to an extreme, the knee hardly travels until behind the hip. Many sprinters that are excellent in the last stage of a 100m show this pattern and they show it even more in their best races (Carl Lewis in his world record race).

Why is it called positive Running?

Take the moment of toe off and draw lines trough the upper legs (yellow dotted line). Divide the angle in two equal parts (a) and draw a new line (blue). In sprinters with the mentioned speed maintaining technique this blue line points forward (positive) in runners with less suited technique the blue line points more downward (more in a negative direction). This positive resultant is seen in the whole running cycle, also for instance at the when the stance leg is vertical, the swing leg has passed it already a lot in positive running.


Maintaining elastic energy in the system by keeping the pelvis in the right position is difficult at high speed and could be the limiting factor in running. This can be improved with;

Technique training

Conditioning the muscles in the front of the body to a much higher level than done before. (from my experience this easily can be achieved) Muscles in the front are often neglected.

11 Comments:

At 11/16/06, 9:01 AM, Blogger Joe Przytula said...

Here the whole issue of proper muscle "stiffness" comes up again, especially as it pertains to the abs. I still think good old 3D jumping jacks is a great way to achieve this. Having the arms driving in one direction, with the feet moving in another, leaves the abs to deal with this statically, yet in an integrated manor. You get a great ab burn doing them.

 
At 11/16/06, 10:12 AM, Anonymous Anonymous said...

Joe,
Do you have a video clip of this?

 
At 11/16/06, 1:51 PM, Anonymous Anonymous said...

Check out some of Gary Gray's video's. I just can't remember the name of which one.

Mark Day D.C., CSCS, DACBSP

 
At 11/16/06, 3:30 PM, Anonymous Anonymous said...

How is this method modified for a longer (5K) distance runner?

 
At 11/16/06, 4:03 PM, Blogger Joe Przytula said...

You would scissor the feet forward & back. Hands together, arms straight at shoulder height. As the R foot is coming forward, the arms are driven to the right. Repeat to the opposite side. Start slow and go for reps until you get the hang of it. Later try to see how many reps you can squeeze into 15 seconds. In the BK DVD, they do a similar movement as a skip.

To answer the other question, in the BK book they emphasise there is not much difference between sprinting and distance running, other than the tempo.

 
At 11/17/06, 1:53 AM, Anonymous Anonymous said...

This Positive running is about difficult technique. Can you reduce it to one exercise (jumping jacks). I don't think so. It takes years of coordination training to get it done. This is what I understand from the BK concept.

 
At 11/17/06, 7:16 AM, Anonymous Anonymous said...

If Frans Bosch is correct, it should make a difference in speed, and (in my opionion) ground reaction force profile (2 or 3D). Unfortunately, neither in his book nor in his presentations I visited data on ground reaction forces are given. There are a lot of experts claiming stuff based on kinematical and EMG data, but is this valid if ground reaction forces are not taken into account>

I question whether movements in the air really have an impact on what happens when the foot is on the ground.

The first third of the ground reaction force profile clearly shows a horizontal braking component (note in runing it is always a vector, so you cannot separate horizontal an vertical forces really). If you do a pawback motion as he proposes, I would suspect braking force would be higher (foot is moving backward relative to the ground ==> the ground reacts with pulling the foot forward ==> slowing the leg). Kinematical data also suggest that the foot is near the same speed as the ground in fast sprinting (0 m/s), see www.bearpowered.com/resources.

Fast forward knee movement can also be accomplished by quickly lifting the foot with the hamstring only, as the POSE people suggest (www.posetech.com).

Where it comes down to is the following, what is the limiting factor for top speed. The people at www.bearpowered.com, think that it is rate of force development to offset the forces of gravity (in vertical direction, based on the study by Weyand et al, which can be found at www.elitetrack.com:
http://www.elitetrack.com/main/index.php?option=com_directory&page=viewcat&catid=280&Itemid=37
[article "faster top running speeds"]

Of interest is also the ideas by Wiemann. Do they also point in the direction of Frans Bosch.

http://www.elitetrack.com/main/index.php?option=com_directory&page=viewcat&catid=283&Itemid=37

Last comment (I am a bit sceptical about the trainig concepts of Frans): In the Netherlands his ideas are supported, but did this really influenced the performance level in the Netherlands???

Regards
Stefan IJmker
the Netherlands

 
At 11/17/06, 10:27 AM, Anonymous Anonymous said...

Looked at the Weinand article, but i do not uderstand why it is controverial to Positive running. Forces in stance are limiting, but where do they come from. From muscle I would say. What muscles are strong. The muscles round the hip. So transfering their power from the hip to the ground is the trick. That is what Positive running aims at from what I understand.
Last comment is a bit silly. Succes is not that easy and don'y the have a polevault worldchamp and a 800 europe champ there? Looks like a tiny country on my map.

 
At 11/17/06, 10:46 AM, Anonymous Anonymous said...

I think it is good to recognize that good running mechanics tend to be similar, the methods of teaching them are different. That to me is where the individual variations seen in the above methods come in. It is just different folks views on running and how to teach it. You see the same thing with swimming, and other sports.

In coaching, seeing all these ideas and breaking out the aspects that can help you teach people to perform more effectively is the key. You can draw information from several pools of knowledge and help an individual better than by saying "this method is good" or "this method is bad".

Positive running is a good concept. It is one that can help coaches assist there athletes develop. It is not the holy grail - nor is any "method".

BUT

It is a good addition to our pool of knowledge and provides different ideas to help teach.

Will

 
At 11/17/06, 11:55 AM, Anonymous Anonymous said...

@anonymous: I did not want to say it is useless, I would like to state my concerns regarding putting time in an idea that is based on kinematical data only (i.e. not referring to ground reaction forces)

With other words: can form interventions actually have an beneficial effect on top speeds? Or is this just belief? Doesn't it all come down do ground reaction forces? Support time on the ground is very short, there does not seem to betime for volitional efforts.

As you state the results of weyand do not directly contradict the positive running idea. However, how can we know that positive running is good?


Could you explain more what you mean by transferring the power from the hip to the foot? Where does it occure during ground contact, what is the function etc.?

In what direction do you want to increase force? Do you want to increase horizontal, vertical or vector force? What is exact the limiting factor. Frans argues that elastic energy should be reserved in the system. My question is where should we use it for: a stronger pawback is questionable, but only in my opinion. We need some proof of the pudding: ground force measurement in my opinion.

At least I would like to know whether such an idea has a real basis (can you chance and will it result in greater rate of force development)

I did not mention succes I mentioned performance level (so more general than succes), you could measure it for example by averaging the best time on 100m for the then fastest guys in a country. It is in a way a silly argument, I agree. But can't we be critical about what we do? And especially look for things we do without the effect (instead of adding extra things to training all the thime)

Train as much as necessary, not as much as possible. (Kraayenhof)

regards
Stefan

 
At 8/11/07, 5:49 PM, Blogger Scott said...

Hey. I think Frans' Running is fantastic. A Google search for more from him brought me to this site.

I have a few questions:

At the end of the 4th paragraph above, it says "(see BK book)". What is the BK book, anyone?

Lastly, does Hans allow email questions, does anyone know?

Thanks for any help in advance!

Cheers!

Scott

 

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