Hip Flexors role in Vmax!!!

I am just reading huge letter sent to me by Alexander Michalow, who wrote Analysis of sprint models (posted at supertrainng, 2002)! We are arguing about Harvard study, swing time in Fast and Slow runners, and hip flexor importance. He putted an interesting concept that strength of hip flexors (yes, flexors) are very important in running high speed!
So I decided to put this concept into thread, but for putting his whole huge letter (25 pages in word, font 12) I must ask his approval (not till next weekend). Actually, I am still reading his letter, so I maybe misundertanded some concepts, but I hope I cathed the meaning…
Here is the part of the letter:

So this is just one part of the letter… in the following parts Michalow explained me his concepts of improving hip flexor strength, very thouroughly and with pictures (he put a great effort to explain me his point of view – great guy I must say!
I created one graph to depict what is happening during stance phase, and why contra-lateral hip flexors are important (according to Michalow explanation)

This is very similar to Tidow and Wiemanns paper on hip extension flexion in sprinting. They advocate training the flexors using leg weight as the starting point to determine loading.


You can only be as strong as your weakest link…what a great tidbit.

Tnx for the link martn… I will read it as soon as I finish reading DaVinchy’s code :slight_smile:

yeah, me too…

Great book I must say…
… actualy I am having a break from reading (page 110 of 400), and just to see what is happening at CF.com :slight_smile:

This article notes a large activity in the adductors near full hip extension. It says the adductor and glutes are like “reins”. Glute rotates the leg outward at full extension and the adductor couteracts this by supplying an inward rotational force.

Do we need to worry about specific training for the adductors (to prevent excessive outward rotation)?

And what routines can be performed to strengthen and/or improve the work of the adductors?

Is there any real need to load the hip flexors??

I didnt have time yet to read that article so I dont know… and actually adductors dont produce invard rotations, but rather frontal parts of gluteus minimus et medius…

The sprinting and hills itself are good, and you dont need any more HI load… but you can do general LI work with sumo lifts, side lunges, hip work on the side etc. just thoughts…

Michalow recomended some exercises, but as Charlie stated, hip flexors are enough worked with hills, sprinting, ab work, med balls, A & B drills etc!
Flexors tend to become shortened and stiff, so the best idea is to stretch them, nut to overload them!
Look at the picture, when you extensors works, you hip flexors must work too during a stance phase to provide torso stab!

I note that the article also addresses the topic of fibre conversion which according to who you believe seems either important or of no practical significance.

The authors appear to favour the former and state that “…very few type IIB fibres can be seen in strength trained muscles. This leads to a considerable reduction in contractile velocity…However the former disadvantage is at least to some extent counteracted by an increase in contractile strength.”

Later in support of the notion of detraining to encourage re conversion of fibres they state “Comparatively great volumes and short rest intervals within a training session or between training sessions cause especially fast muscles to be in an energetic “emergency”. These muscles adapt to such loads by changing their energy provison…There is a reduction of the contractability of the fastest fibres and there is an increase in endurance capability because of increased mitichondrial volume and capillarisation”.

Accordingly they assert that “it seems essential with the approach of a seasons highlights to reduce significantly the amount of strength and conditioning training to use longer rest intervals and to place the emphasis on quality”.

I am still not entirely sure how you manipulate rest and training to get the greatest amount of fibre reconversion without detraining but overall a pretty useful explanation of the processes involved I thought.

This is a isolation/integration problem!
So, knowing that bench press performance is limited by strength of pecs, delts and triceps, is there a need to strengthen those mucles in isolation/separately with HI training emphasis?
Same question regarding sprinting! The whole body is involved in sprinting action, so do you need to isolate muscles and work them to prosper?
As Zatsiorsky stated we need not to train muscles but rather movements! So, we need to develop a muscle action in kinematic chain, or in other words, to teach them (muscles - motor controler truly) to act as a WHOLE! So, isolation is misleading on my opinion! But it can be done as a part of structural, LI training with low volume! Thought?

I have been aware of this article and the its implications for almost a decade. If you think about the implications of de-training or a reduction in volume with elite athletes as an example you will notice that it holds true. Example Jon Edwards was knocked out for near on 3-4 months suffering from Epstien-Barr syndrome, comes back and smashes the WR. We can postulate that this was due in part to fiber conversion. I know CF may not agree but even Ben’s 9.79 was precluded by a phase of reduced training in comparison to other years, who knows what the fiber conversion that MAY have taken place contributed to the performance? Take away the injury period that he had and just consider the genius of the tapering phase alone, and you could see that maybe even the early phases of slower to faster fiber conversion could be beneficial to performance improvement. Another phenomenon that may also be attributed to the fiber conversion that occurs after high volume strength or concentrated training proceeded by marked volume decrease is the delayed training effect identified by Prof Verkoshansky and his team. He identifies a minimum period of 3 weeks where rest and a massive decrease in volume is followed by an overshoot in performance.


Yes you are quite right. It is not new stuff but
it just caught my eye in reading the above article and I thought that it gave a persuasive and easily understandable explanation of why fibre conversion takes place and why it is important.

Looking back over past posts I see that you have written quite extensively regarding this matter and it was PowermanDL who appears to have been arguing that conversion is not significant. His view in summary was that the shift in MHC expression does not correlate to performance, either positively or negatively. Neural activity is and always will be the defining factor.

As a separate matter I came across your interesting post about hamstring hypertrophy which I think derived from the same author. Were there any developments on this?

The quality of the CNS is important, but certain types of training make different demands on the CNS for exmple Wilson et al have shown that IT IS not just the intention to move weights fast that will improve power but also the load selected as well. If that is the case then you could have an athlete with a high quality CNS that is well rested and innervates muscle at high frequency but because of the training done, his muscles are not able to react to the demands asked of it by the CNS becuse they cannot twitch at the frequency needed. Yet, the premise that the a sprinter should have a high percentage of FT fibers is dubious. ST fibers are also suited to elastic, plyometric work. This can be validated in the fact that ST fibers have stronger Z-discs in comparison to FT fibers and can absorb larger external forces. Also becuase they do not turn on but also turn off more slowly, ST fibers are able to maintain muscle stiffness which is important to sprinters. The soleus for example is full of ST fibers and contrary to common belief are very very reactive. The pennate structure of the soleus keeps it stiff and aids the elastic action of the achilles tendon. So plyometry or reactive strength training and ability is as important as the quality of muscle. So… u could in theory have an athlete with predominantly slow fibres but is incredibly reactive (high muscle stiffness).

Yes, it seems that muscle hypertrophy training IS NOT as detrimental to fast sprinting as may have been insinuated or expected. The research carried out by the author and co-author suggests that for the hamstrings atleast, max strength retards or even removes gains made by hypertrophy training. Before we throw the max st baby out with the bath water, it must be mentioned that the author and his collaborators used a specially constructed type of sprint training machine that had its loads set according to bodyweight for the hip extensors and leg weight for the hip flexors respectively. This may have had a different effect on the muscles involved. Obviously there must have been a muscle conversion from fast to slow with the hypertrophy training. I recently tried to get more info on this exact topic from the co-author and am still waiting. I speak no German and unusually the co-author does not speak v good english (Germans generally speak another language due to their good education unlike the UK…). I am still waiting and will post any useful info but I am not promising anything.

Thanks for the reply. I am afraid that with an incomplete understanding I find the science completely bewildering and obviously there is a danger in people like myself drawing practical
conclusions based on superficial knowledge.

Not at all, the more you question think and draw conclusions the more likely yoy are to understand and become more objective about what is likely to be the most effective methods of training.

First off, it is true that a reduction in training volume must eventually occur at the top level after years of training if intensification is to continue. It is also true that a rebound in performance occurs after a drop in volume (taper). Also, Ben routinely had brief training breaks (active rest) following Comp periods etc but these didn’t extend beyond a week.
That said, Ben’s injury period was not idle and his peak in performance was not accidental. He replaced those aspects that he couldn’t do with other training tasks.

While running you simply can’t apply force to the ground with one leg without bringing up the other leg working the hip flexor.
Do single legged hops and see what the other legs flexor is “trying” to do - it needs to move up every time the other leg apllies force to the ground…
The greater the force is working down one side - the greater the force has to be pulling up the other - hm almost sounds like Star Wars…