Weyand v. Pose: it’s the push that counts

A few weeks ago, I presented an overview of my plan to get fit enough to run a ‘good’ marathon again in 3 years time. Each 3-4 month period will have a specific goal in addition to the continuing basic objective of improving my aerobic capacity. The specific goal for the first 4 month period is recovering some of my lost muscle strength, largely by resistance exercises and drills, together with a small amount of sprinting and uphill running.

Although I have now completed the first three weeks of the program, I have not fully settled the question of what leg strength exercises and drills are likely to be most beneficial. At present the exercises that I am doing are mainly body-weight exercises performed standing on one leg (such as one leg squats , hip swings, calf raises etc) since the major muscle actions of running are executed while standing on one leg. I am also doing a very small amount of plyometric exercise to increase my capacity to deal with eccentric contractions but in view of the risk of long term damage, I am being quite sparing with these exercises. I plan to test for gains in leg muscle strength (assessed by a hopping test, and by measuring my sprinting speed) after 6 weeks and if there has not evidence of substantial gain, I will modify the types of exercises and drills in my program.

In preparation for this, I have been once again reviewing the question of running technique in order to identify what exercises and drills are likely to be most beneficial. Two apparently coincidental happenings in the past two weeks have also served to re-focus my attention on running style.

 Gravitational torque

One has been a series of comments by Simbil on a post entitled ‘if gravitational torque is a red herring, how to do we run fast?, which I had posted in February. Simbil is a runner and thinker based in Sheffield, who contributes thought-provoking comments to the Efficient Running thread on the Fetch website. He is an advocate for Pose technique, though he is prepared to re-examine the tenets of Pose in a thoughtful manner. Gravitational torque plays a crucial role in the theory of Pose. Simbil has been challenging my assertion that the gravitational torque that generates head-forwards and downwards angular momentum in the second half of the stance phase is balanced by an oppositely directed torque acting in the first half of stance. We have been lobbing arguments back and forth for some time. We have not yet reached any definitive conclusion, though we are in agreement that the gravitational torque must be counteracted by an oppositely directed torque acting a some point in the gait cycle, and furthermore, that whatever the mechanism, the forces involved in generating gravitational torque and compensating for it are far less important that the forces required to get airborne. I will return to this issue a little later.

Pose Tech

The other coincidental happening came to my attention when I noted a little upwards blip in the number of hits on this site a little over a week ago. At present this site gets about 2000 hits per month (far below the league of the Huffington Post or Belle de Jour, or, I suspect, Younger Legs for Older Runners, but nonetheless, satisfying). Most of the hits come from Google searches seeking information about various aspects of running technique and training, though the flurry of increased activity in the few days after each posting indicates that there are also some faithful followers. It always gives me a little thrill to see these flurries of activity and I hope that those of you who read the posts find them interesting. In addition there are occasional flurries of increased activity at other times indicating that some other website has drawn attention to something on my site. One such flurry occurred last week, and inspection of the stats provided by WordPress revealed that the hits were referred from one of the forums on the Pose Tech website. Those forums are protected by password, but as runner interested in Pose, I have been registered with the site for several years. So I was tempted to have a look.

When I logged on I was intrigued to find that there was a quite active thread discussing my blog. Those of you familiar with the Pose Tech site will probably be aware that many of the people who post on the forums are strong believers in Pose. Therefore, I was more amused than surprised to see comments such as ‘burn the heretic’. However a gratifyingly number of the postings were in agreement with my views, especially my view that landing on the ball of the foot, in combination with a short time on stance places large forces on the foot, and is associated with risk of injury to metatarsals and connective tissues of the foot and ankle.

I was a little saddened by a passionate posting from Lana, the wife of Nicholas Romanov [correction: Lana is his daughter, see comments below], lamenting the fact that I and others did not give due credit to the amount of work and expertise that her husband has devoted to the Pose technique. However, while I am happy to acknowledge the work and expertise of Dr Romanov, I think there is a serious issue arising from the fact that the 2002 edition of Pose Method of Running reproduces the diagrams and photos from the first edition showing the heel held high off the ground at mid stance. In the early years, it was quite common for Pose novices to report Achilles or calf muscle problems, which I think are largely due to holding the heel off the ground. The importance of these problems was reinforced by the findings of the Capetown study (Arendse et al, Medicine & Science in Sports & Exercise: Vol 36 pp 272-277, 2004) demonstrating that Pose is associated with increased stress around the ankle, together with the reports by Ross Tucker (who assisted Dr Romanov in coaching the Pose technique in that study) that the runners in the Pose group suffered a high rate of injuries to connective tissue around the ankle (http://www.sportsscientists.com/2007/09/running-technique-part-ii-scientific.html).

When I expressed disappointment that these figures had been reproduced without anything in either text or illustrations (as far as I have been able to ascertain) describing how the risk of these injuries might be minimized by relaxing the ankle to allow the heel to touch the ground, Lana suggested that ‘you need to “zoom out” a bit – because you are not doing yourself any favours by using a magnifying glass all the time’. In an email, a good friend has suggested that it is unlikely that I will be on Lana’s Christmas card list this year.

Despite this little storm in a tea-cup on Pose Tech, I have a fairly positive view of how Pose works in practice, based not only on looking at the evidence through a magnifying glass; but also by talking to runners who have applied it; and by experimenting with it myself. I am less impressed with the theory underlying Pose, but the evidence that the technique can be beneficial makes me want to understand more clearly why it works

A subjective overview of Pose

Many of the principles of Pose such as high cadence, short time of stance; avoiding reaching out with the leading foot, and keeping the pelvis forward, make mechanical sense. I discuss these features in my own account of technique (‘Running: a dance with the devil’ – listed on the side panel). Many elite athletes exhibit these features despite never having been trained in Pose, though I think Nicholas Romanov deserves credit for publicizing these principles among amateur runners.

Other features such as landing on the ball of the foot (BOF) also make sense, but are attended by risk. As I had mentioned in my comments on Pose Tech that provoked the anguished response from Lana, BOF landing places substantial stress on the bones and connective tissue of the foot and lower leg, and creates a risk of repetitive strain injury to metatarsal, planate fascia, Achilles tendon and peroneal tendons. At least when running long distances, I consider it is best to relax the ankle so that the heel brushes the ground in mid-stance

I also consider that Dr Romanov’s claim that gravitational torque provides the motive force for running is misleading. According to the law of conservation of energy, it is impossible for gravity to provide net energy when running on a level surface. I accept that the unbalancing due to gravitational torque during the second half of stance does help promote the muscular actions necessary to swing the leg forwards in time to support the body at subsequent footfall. However I am not convinced that this is plays a major role, and I therefore consider that gravitational torque is probably a red herring. Nonetheless, I am quite happy to continue debating this issue with Simbil.

However in my opinion the most interesting issue for debate is the concept of pulling from stance rather than pushing. The Pose mantra is ‘Pose, Fall, Pull’ implying that the crucial actions are:

1) adopting the classic pose with the point of support (BOF), hips, and shoulders aligned, in mid-stance;

2) falling under the influence of gravitational torque as the centre of mass moves in front of the point of support;

3) pulling the leg from stance by means of a contraction of the hamstrings.

In practice, I think that getting airborne is impossible without a push. Pulling from stance would amount to lifting oneself by one’s own boot straps. Of course pulling the leg forwards by hip flexor contraction once airborne is essential, but is largely automatic. While I think that pulling from stance is largely an illusion, I think it might be a useful illusion to cultivate because it encourages a short time of stance, high cadence and relatively short strides – possibly not the best style for record breaking performances, but nonetheless fairly safe. For most of us, avoiding injury is more important than maximizing mechanical efficiency.

So, while I think that the Pose concept of pull is not mechanically correct, I think that it is a useful mental image to cultivate, in the same way that some of the principles of Alexander technique are based on creating helpful illusions. Therefore, Pose drills such as Change of Stance that encourage the illusion of pulling are probably useful. But if one want to increase one’s speed of running, are Pose drills more important that developing the muscles responsible for the push?

Weyand: it’s the push that counts

Perhaps the most important evidence about the muscular action required for running fast comes from a study by Peter Weyand and colleagues from Harvard (J Appl Physiol Vol 89: pp 1991–1999, 2000). In a study of runners with various different maximum running speeds, using a force plate to assess ground reaction forces during treadmill running, they demonstrated that ‘human runners reach faster top speeds not by repositioning their limbs more rapidly in the air, but by applying greater support forces to the ground.’ The force plate data showed clearly that a larger vertical ground reaction force achieved by the foot pushing against the ground was the main factor distinguishing fast runners from slower runners.

The extensor paradox

However, Weyand’s findings present a problem: the extensor paradox. Studies employing electromyography to measure the electrical activity in muscles demonstrate the major muscle groups that would be expected to execute a push off the ground, especially the quadriceps which are responsible for knee extension, are almost silent in late stance (Elliot et al. Medicine & Science in Sports vol 11, pp 322-327, 1979). So where does the push come from? Much of it almost certainly comes from elastic recoil of quadriceps, acting in conjunction with the hamstrings, and soleus, all of which have been stretched on impact at foot fall. Thus the crucial strength that is required for running fast is the ability to sustain a strong eccentric contraction of the quads, hams and calf muscles.

Conclusions

In a program to rebuild the strength necessary to run fast, it is crucial to recover the capacity for strong eccentric contraction of quads, hams and calf muscles. Of course other muscles also play a role – especially the gluteals which help hold the pelvis in a horizontal position during swing, and the hip flexors, which drive the swinging leg forwards – but Weyand’s study indicates that it is the ability to push strongly that distinguishes fast runners from slow runners. Clearly any strengthening program should involve a reasonable balance between all relevant muscle groups as muscles do not work in isolation, but nonetheless, much of the focus should be on eccentric strengthening of quads, hams and calf muscles.

However there is a problem: as I have discussed several times previously on this blog, eccentric contraction damages muscle, possibly permanently, especially in older runners. So a program of plyometrics designed to increase the ability to withstand eccentric contraction must be undertaken cautiously. I am inclined to think that the first priority is to recover strength of the major muscle groups, especially quads and hams with a program of resistance training with free weights, including a gradual build up of eccentric loading, before moving on to a modest amount of plyometrics. Meanwhile, I will also continue with regular uphill running, as this invokes the required muscular actions in a way that is ‘natural’ for a runner.

As for drills, any drill that promotes a short time on stance is likely to be beneficial. I am still exploring the options, but despite my opinion that the pull is less important than the push in getting airborne, I think that the Pose ‘Change of Stance’ drill is beneficial, even if it is largely cultivating a beneficial illusion of pulling from stance.