Power Leaks: Asafa Powell

We all know Asafa: the Jamacian sprinter who specializes in the 100 meter. World record holder in ‘05 and '08 with times under 10 seconds. Lets take a closer look at some French slow motion footage we found. Remember, these are not criticisms; they are observations. What we see may also not be what is wrong, rather a compensation strategy.  We are just looking for some potential power leaks.

We begin at :16

Nice supinated Right hand posture and pronated Left hand, neither of which cross the mid-line of the body, which is an important fact.

(This goes back to our blog posts from last week on arm and leg swing and how they are tandem paired, and when this normal pairing is lost there is likely a problem in one of the limbs. It is a pretty consistent finding, the difficulty is having the detailed muscle assessment skills to accurately find the problem).

The fingers are extended as well (the more extensors the better; remember the function of the cerebellum?) But what about the Left shoulder drop at :19? Remember he is bearing weight on his left leg at this point (at footstance). Did you catch the slight body lean to the right? What could be causing this left shoulder drop ? A possible Forefoot deformity? Short leg? Weak left gluteus medius ? We see this again at :22, but this time on the right side. Could there be something in his foot strike ? We will never know because we cannot examine him.

Look at his nice shoulder extension in the 0:16+ opening seconds.  First you have to have sufficient length in the biceps and chest wall musculature to get this kind of extension, and his is awesome. Secondly, you have to have sufficient thoracic spine extension to achieve this, once again Asafa’s is likely pristine. But our point in bringing this up was that generous shoulder extension brought on by posterior deltoids, scapular retractors, latissimus dorsi and triceps and a few others is critical in order to get to optimal hip extension and full gluteus maximus contraction. Limitations in the upper limb will play into limitations in the lower limbs. To hit our point home, look at 1:16, look at the freakishly generous right shoulder extension, from what we talked about here do you think the load into the left gluteus maximus has any power leak ? Not likely ! Amazing !

Now look at his right foot position in the blocks at :59, it is abducted and everted (meaning the foot is pronated and non-rigid); it is even more pronounced from 1:00-1:04. We see extreme valgus at the rear foot, that is a lot of load on the achilles mechanism. This is not what you want to see exploding out of the blocks, even if he is loading posteriorly into that foot to explode off of it. It would be more efficient if it remained supinated or neutral and force the posterior load into flexing at the ankle, knee and hips via plyometric type preload.

At 1:08 notice 2 things; the subtle left lateral bend of the torso and prominence of the left lumbar erectors. Nice linear sagittal load !

At 1:13 he laterally bends to the left as he explodes off his left foot. Could his extensors be overpowering the Gluteus medius? Or is he just keeping his body mass over the power foot ? Did you catch that right knee adducting as it came off the blocks? If you have watched enough sprinters you will recognize this as a likely product of the extreme lateral side-to-side foot positioning of sprinters in the early 10-20 meters to help drive harder and gain speed. It is the same motor pattern used in skaters, it can be a product of increased use of external hip rotation to get to more gluteus maximus and spinal extensors, to gain more power.

Look at the torso flexion at 1:25 and how far forward his head is flexed. It is going to be tough to fire those spinal extensors that way but he is likely just leaning to drive that forward momentum, kind of playing the game of “lets make my legs catch up with the risk of falling over forward”. This seems to prove true at 1:25, 1:29, 1:33 and 1:37.  But our point here is that flexion inhibits extension and that is where the power is, so a happy medium must be met to reduce wasted time and power.  Additionally, did you see that his thigh doesn’t really extend past zero (hint: look at the torso and angle the thigh makes; you can see this at 1:41 and 1:46. Nice forefoot landing here as well. No lateral to medial load, no cross-over gait in Asafa.

He seems to hit his stride at 2:36.  At this point there is a nice, circular gait pattern and he extends his neck more at 2:50, which just keeps getting better.

At 1:17 if you had a keen eye, you will notice something that we have been watching in Asafa for years, there is a kind of skip after exploding off of that left foot in the blocks.  Most runners will put the right foot down first but not Asafa, he literally explodes out of the blocks and drags the left toe while he begins to load the right gluteus. We have been thinking about this for a long time. Coach Chris Korfist (whom we work with alot on our elite sprinters) and The Gait Guys have studied this strange left foot phenomenon for a many hours watching Asafa’s starts. We believe it may be serving to to stop any drop of the left side of the body, kind of posting up that left side while the right glute takes its turn to power up.

Finally, lets go back to arms swing observations once more. Compare his “casting open” of the elbow angle. Meaning, the angle at the elbows is never held at a fixed angle such as 90 degrees, the angle is always increased as he enters into the posterior arm swing phase. Sprinters use the weight of the forearm as a weighted pendulum to maximize the triceps and posterior arm drive, which in turn gives more contralateral glute contraction (try it at home, get out of your chair right now and cast the arm swing backwards with more force through the triceps, you will feel the power in the glute push off on the opposite side). In distance runners, this high octane maneuver is a bolus of power that is not in the MO of the athlete. Energy conservation is however, so the elbow is held tight in its angle and the pendulum swings far less.

Potential power leaks? You decide. He is an incredibly gifted athlete either way.  Just helping you to increase your powers of observation.  Remember, we did not give any strong suggestions as to what is possibly wrong here, mainly because without examination it is all speculation.  What is seen on video is rarely ever what is wrong, you are seeing the compensations they are using to get around what is not working correctly.  If we could see what was wrong on video this would be an easier game and no one would ever need folks like us to fix things, they would all be fixed by changing what is seen on the video gait analysis.  We will go into this theory once again this week when we look at another dimension of the “turned out foot” in someones gait.  It is too bad it wasn’t as simple as, “hey dude, your right foot is turning out. Stop doing that !”

We remain…The Gait Guys

Analyzing gait, looking for clues and ways to make people move better ….