Archive for June, 2012

Mary Keitany, a muscle named Lady Dorothy, and the future of the women’s marathon

June 3, 2012

The past decade has seen an astounding increase in the standard of marathon running, at least in the men’s event.  Not only has the world record continued to tumble but the event has become a race from start to finish.  This was clearly evident in Wanjiru’s victory in Beijing, but was also made manifest in the London marathon a few weeks ago by Wilson Kipsang’s devastating surge beginning as he approached Tower Bridge, around the half-way mark, and continuing for more than 5 Km at 2:50 per Km (sub 2 hour marathon pace).  Abel Kirui hung on until 35 Km but the damage inflicted by Kipsang’s self-assured mid-race surge became apparent as Kirui’s pace slowed to about 4 min/Km and he dropped back from 2nd to 6th place over the final few Km.  Just as significant as the shift towards the mental toughness exemplified by Wanjiru in Beijing and Kipsang in London, is the manner in which the winner in most male events nowadays maintains a graceful but powerfully efficient stride similar to that we are used to seeing in a track 10,000m, all the way to the finish.   The era in which gruelling training and gritty determination took Emil Zatopek to victory in 5000m, 10000m and marathon in Helsinki is a distant memory.  The marathon is no longer merely a test of endurance, but an event that calls for tactical finesse coupled with the ability to sustain a powerful efficient gait for 42.2 Km.

How does the women’s marathon compare?  

In contrast, advance in the women’s event has been much more patchy.  Although Paula Radcliffe’s record of 2:15:25 set in London in 2003 with the assistance of two male pacers is widely regarded as phenomenal, it is not clear that it is especially outstanding when compared with the men’s record.  One might expect that in the marathon that efficiency should count for more than strength, and that women would be less disadvantaged relative to men, than in shorter events.  The evidence is ambiguous.  Across the range of distances from 100m to marathon, the female world record is slower than the male record by a margin of 9-12%.  FloJo’s time for 100m is 9.5% slower than Usain Bolt’s, though controversy lingers over FloJo’s performance.  Similarly, a cloud unfortunately hangs over Marita Koch’s 400m time, which is 10% slower than Michael Johnson’s.  Paula’s marathon record is 9.5% slower than Patrick Makau’s record of 2:03:38.  Furthermore, whereas no other woman has approached Paula’s time, at least 3 other men have demonstrated the potential to demolish Makau’s record.  Kipsang missed that mark by only a few seconds in Frankfurt last year, while both Geoffrey Mutai (2:03:02) and Moses Mosop (2:03:06) have actually recorded times faster than Makau’s record on the demanding down-hill Boston course, which unfortunately does not satisfy world record requirements.  Unlike the performances of Flo-Jo and Marita Koch, no clouds hang over Paula’s performance in London in 2003, and it is truly an outstanding performance.  But if we acknowledge that strength is less of an issue in the marathon compared with sprints, it is not clear that Paula’s female marathon record is any faster than might reasonably be expected.

More grit than grace 

When it comes to style, Paula’s head bobbing is legendary.  But it is not merely a matter of head bobbing.  She carries her shoulders high and her torso lurches.  Her victory in Chicago in 2002 when she broke Katherine Ndereba’s world record, was a triumph of gritty determination, but it was as painful as it was awe- inspiring to watch her straining virtually every muscle in the final few Km.  In London, 8 months later, as she turned into the Mall on her way to smashing her own world record, the strain in her upper body was only slightly less apparent.  Perhaps Paula Radcliffe is the Emil Zatopek of the woman’s marathon.  Katherine Ndereba is markedly different.  She is always graceful.  To my eye she swings her arm too far back and leaves her trailing foot on the ground for a little too long, resulting is a slightly delayed swing.  However the issue of how quickly the trailing foot should lift-off stance remains a controversial topic which I will return to again in a future post.    While there can be no denying that Ndereba is graceful, I think her race tactics have cost her dearly on a number of occasions, most notably in Beijing in 2008.  On previous occasions she had been prepared to let the leaders get ahead by a minute or two, only to subsequently nibble away the margin and take command in the final few Km.  In Beijing she allowed Constantina Tomescu-Dita to get away, and then she could not catch her.

Tomescu-Dita entered the stadium with arms flailing in a manner that could scarcely be described as graceful, though it was heart-warming to see a 38 year old achieve such a spirited Olympic victory.  Ndereba and Zhou entered the stadium several minutes later, and when Zhou challenged for the silver medal with less than 100 metres to go, Ndereba sprinted away elegantly.  Whether or not a more spirited performance at an earlier stage would have given her Olympic gold is unknowable.   She has indeed many memorable marathon honours to her credit, including gold medals in the world championships in the pre-Olympic years, 2003 and 2007, but on each occasion she achieved only silver in the Olympics the following year.  In their different ways the two women who dominated the marathon in the past decade might look back ruefully on the Olympics of 2004 and 2008.   Paula still has a slender chance in 2012 following a creditable 2:23:46  in Berlin last year, but Katherine now hands over the mantle of Kenya’s queen of the marathon to be shared by a handful of promising younger women, including this year’s London winner, Mary Keitany.  Might this new generation of Kenyan women do for the women’s marathon what their male compatriots have done or the men’s event?

A new era?

In contrast to the men’s event in London in April 2012, the elite women started cautiously, reaching the halfway mark in 70:53, but shortly after a new pattern emerged. It was not the male-type self-assurance of Kipsang, but rather a quiet, unassuming yet determined increase in pressure by  Keitany.  Her pace for that middle 5Km provided only a hint of her gathering speed, but she continued to accelerate, covering the 5 Km from 35 to 40km in 15:45.  Ross Tucker in Science of Sport reports that this is the fastest 5Km split ever recorded by a woman in a major marathon, faster even than Radcliffe’s 15:47 for the first 5Km in London in 2005.   In the final 2Km Keitany increased her pace even further to a pace only slightly slower than 3 min/Km.

I believe that a major factor that transformed Radcliffe from fourth placed 10,000m runner in Sydney in 2000, to a sub-2:16 marathoner in 2003 was an increase in her leg strength resulting from a program of plyometrics introduced by Gerry Hartman after the Sydney Olympics.  Maybe Paula’s 2:15:25 will only be seriously challenged when women marathoners develop the type of strength that took middle distance runner Kelly Holmes to a gold medal double in Athens, but I am inclined to think that for a marathoner efficient muscle recruitment is even more important than sheer strength.  Observing the video of Mary Keitany in VLM 2012 suggests that her efficient gait was a major factor in her ability to increase speed steadily despite accumulating exhaustion in the late stages.

Controlling rotation of the torso

Keitany swings her arms in a neatly controlled manner that sets the tone for her trunk and legs. As her arm swings down and back close to her body, the hip of her swinging leg rotates forward and the contralateral hip rotates back.  By virtue of allowing her pelvis to rotate she minimises wasteful angular rotation of the whole body around the vertical axis.  In general, her foot usually lands fairly near the midline of the body when viewed from the front (eg at 1:55:13).  In contrast, Edna Kiplagat, who vied with Keitany for the lead until around 35 Km, and Priscah Jeptoo, who eventually finished in third place to put three Kenyan women on the podium, both land more often with the foot more to the side of midline, due to lack of rotation of the pelvis. If the foot is grounded to the side of the midline, the body must rotate around the vertical axis, on account of the momentum of the torso.  The tendency for the torso to swing around can be minimised by a counter rotation of the arm.  Because a less compact body has a greater moment of inertia, if the arm displaced outwards, the angular displacement of the torso itself is reduced but the angular momentum of the torso plus arms is not.  This angular momentum must be cancelled in the next step, which wastes energy.

Lady Dorothy

The crucial link that coordinates the action of arm and opposite leg is provided not only by the motor programmes the evolved in the brains of our distant quadripedal ancestors, but also by a direct connection via the most extensive muscle of the human body: Latissimus dorsi.  The Latin name means ‘widest back muscle’.  Body builders refers to this muscle when they talk about  developing their ‘lats’, while medical students call it ‘Lady Dorothy’ to help them remember the arrangement of its attachment to the humerus in the upper arm.   The mildly bawdy mnemonic  ‘Lady Dorothy lies in a ditch between two majors’ reminds them that its tendon runs in a groove between the attachments of Pec Major and Teres Major.   However this mnemonic serves to reinforce the role of Latissimus dorsi in pulling the arm inwards and back, while distracting attention from its attachment to the thoraco-lumbar fascia (TLF).

Figure 1: Latissimus dorsi (in red) and its attachment to the iliac crest and lumbar spine via the thoraco lumber fascia (From Grays Anantomy)

When the left foot is grounded and the hip extends back, the glutes on the left side stabilise the pelvis, providing a firm anchor point for the TLF along its line of attachment to the iliac crest.  The simultaneous contraction of latissimus on the right side, pulls the arm back while rotating the lumbar spine so that the left side of the pelvis rotates forwards while the more lateral, vertically oriented muscle fibres tend to prevent it dropping as the swing leg moves forwards.  Thus the coordinated action of glutes with the latissimus stabilises the pelvis in a horizontal position as seen from the front, while allowing it to rotate about the vertical axis that facilitates the efficient passage of the swinging leg.

Figure 2: Posterior hip muscles (from Wikipedia) When the left foot is on stance, G. maximus on the left anchors the left side of the pelvis, thereby proving a firm anchor via the thoraco-lumbar facscia for right sided Latissimus dorsi as it contracts to pull the right arm down and back. Simultaneously G. medius (on the left) minimises the downwards tilt of the pelvis from left to right.

Avoiding snagging of the ITB

However this action must be quite precisely controlled.   If the swing leg rotates too far, carrying the foot too far towards the midline at foot-fall, the ilio-tibial band (ITB), which is under tension as it provides the anchor for gluteus maximus, will be dragged across the bony protrusion of bone on the lower end of the femur.  This problem will be greatly exacerbated if the pelvis has been allowed to tilt down on the side of the swinging leg.  This makes the angle between pelvis and femur even more acute, dragging the ITB closer to the femur.  This problem will also be exacerbated if the foot is prevented from pronating as the stance leg tends to twist over the grounded foot.   Thus, if risk of injury is to be minimised there is quite limited tolerance in the allowed range of rotation of the pelvis and movement of the swinging foot towards midline.  Sideways drop of the pelvis must be limited and adequate pronation of the foot allowed.    It is likely to be counter-productive to focus consciously on controlling all of these movements while running.  I believe that conscious attention to a neatly controlled arm swing, in which the hand sweeps down close to the body from a point to the side of the midline and a little above mid-chest height, towards the hip, is the best way to trigger the non-conscious motor control program that coordinates all of this.  The extent of the swing should increase a little as speed increases, but the hand should never cross the midline.

The crucial role of a stable core

Precisely controlled rotation of the pelvis about the vertical axis and minimal tilt from side to side is crucial not only for maintaining an efficient gait for the duration of a marathon, but perhaps even more importantly, for avoiding injury during the high volume training that the marathon demands.   While I believe that the program of plyometrics which Gerald Hartman introduced in 2001 to develop leg strength played a key part in the transformation of Paula Radcliffe into the most outstanding female marathoner the world has yet seen, I suspect that greater attention to the coordination of the complex system of muscles extending from shoulder to foot via Latissimus dorsi, the glutes, ITB and the lower leg muscles, might have protected her from the injuries that confounded her Olympic dreams in 2004 and 2008.

 

The future of the women’s marathon

With her victory in London in a time of 2:18:37, Mary Keitany broke the Kenyan women’s marathon record established by Catherine Ndereba in the 2001 Chicago marathon.  Ndereba’s  time of 2:18:47 was not only the Kenyan record but also the world record in 2001.   However it is noteworthy that even a decade later, Keitany shaved only 10 seconds off that time to take the Kenyan record, whereas in Chicago in 2002, Paula Radcliffe had taken possession of the world record by slicing almost a minute and a half off Ndereba’s time.  Then, the following year in London, Radcliffe took a further minute and 53 seconds off her own record.   While Keitany’s run in London in March has made her the favourite for gold in London in August 2012, Radcliffe’s world record is not threatened.  Keitany is now 30 and slightly older than Radcliffe was when she reached her peak, so the likelihood that Keitany will ever challenge Radcliffe’s record is receding.

The fact that three Kenyan women were on the podium in the World Championship in 2011 and again London in March this year confirms that Kenyan women are beginning to emulate their male compatriots’ domination of the event.  It is wild speculation to try to identify who among the current leading Kenyan women might eventually challenge Radcliffe’s record.  Nonetheless, I think that Florence Kiplagat is the one to watch – though her marathon performances so far have been erratic.  She did not finish her debut in Boston last year, but then looked very powerful and well-coordinated as she picked up speed in the final Km on her way to winning the Berlin marathon 5 months later.  However, in London in April this year, her fourth place was not enough to secure her a place in the Kenyan 2012 Olympic team.  Perhaps the intense pressure that Kenyans, both women and men, faced to achieve Olympic selection this year had taken its toll.  But it is probable that at 25, Florence is still some way from her peak.  However, if the women’s marathon is the follow the path of the men’s event, the upcoming generation will need to combine the grit of Radcliffe with the grace of Ndereba and Keitany.

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