This gal came to see us with right-sided hamstring insertional pain. During gait analysis we noted that she has a crossover gait as seen in the first two sections of this video. In addition to making other changes both biomechanically (manipulation, gluteus medius exercises) and in her running style (“Rounding out her gait” and making her gait more “circular”, running with less impact on foot strike, extending her toes slightly in her shoes) she was told to run with her arms at her sides rather than across her body. You can see the results and the third part of this.
Because of her bilateral gluteus medius weakness that is seen with the dipping and lateral shift of the pelvis on the footstrike side, she moves her arms across her body to move her center of gravity over her feet.
Yes, there is much more work that needs to be done. This is one simple step in the entire process.
Did you know using a sauna can (in some areas) produce better results than exercise?
I didn’t believe it either. What are we listening to this week? For 1, one of Dr Ivo’s new favs: Dr Rhonda Patrick
This is an absolutely great, referenced short on some of the benefits of hyperthermic conditioning (ie sauna use). One of the most surprising effects was benefits which exceeded exercising!
Here is one small excerpt: Being heat acclimated enhances endurance by the following mechanisms:
It increases plasma volume and blood flow to the heart (stroke volume). This results in reduced cardiovascular strain and lowers the heart rate for the same given workload. These cardiovascular improvements have been shown to enhance endurance in highly trained as well as untrained athletes.
It increases blood flow to the skeletal muscles, keeping them fueled with glucose, esterified fatty acids, and oxygen. The increased delivery of nutrients to muscles reduces their dependence on glycogen stores. Endurance athletes often hit a “wall” when they have depleted their muscle glycogen stores. Hyperthermic conditioning has been shown to reduce muscle glycogen use by 40%-50% compared to before heat acclimation. This is presumably due to the increased blood flow to the muscles. In addition, lactate accumulation in blood and muscle during exercise is reduced after heat acclimation.
It improves thermoregulatory control, which operates by activating the sympathetic nervous system and increasing the blood flow to the skin and, thus the sweat rate. This dissipates some of the core body heat. After acclimation, sweating occurs at a lower core temperature and the sweat rate is maintained for a longer period.
waaaayyyyy more in her video. Check it out here. I had to listen to it several times to catch all the details.
Usain… Again!!! How good are your powers of observation?
Take a look at this video again. Yes, we have shown it many times before. It is from a 2001 race in Monaco.
These are all incredible athletes. What can we note about the fastest of the fast?
Most of them have excellent hip extension (ok, the gent immediately to Usain’s right does not appear to be optimal)
the fastest of the pack have a upright head posture with the neck neutral or in slight extension (gents in lanes 1, 3 and 6; notice the head forward posture of the others)
minimal heel rebound (see our last post on this here)
minimal torso motion (note the increased torso motion with arm swing of the gents in lanes 1, 3, 4 and 5)
symmetrical hip flexion, with the thigh parallel or nearly parallel to the ground in float phase
Watch it a few more times. It took us a while too…
Really, go watch it again…
Did you see it?
Watch the vertical oscillation of the runners. At this level (or any level for that matter), outside of improving biomechanics and neuromechanics, there are really only a few things you can do to run faster. One is to have a faster cadence and another is to have a longer stride length. You can control both, but if not done concurrently, one gets better at the expense of the other.
If your cadence is slower and you try and increase stride length, you increase your vertical oscillation (ie: how much you bounce up and down). Note the handrail at the far side of the track. It makes a convenient marker for vertical oscillation. Watch this bar and watch the video again. Usain and the gent in lane 6 (Nesta Carter) have little vertical oscillation compared to the rest of the pack. Note also the close finish. difficult to say if Usain’s knee or Carters foot crossed 1st. Usiain’s time was 9.88 and Nesta’s 9.90.
On the topic of endurance training (which we discussed on this weeks PODcast, forthcoming in the next day or so; we have both been extraordinarily busy in our clinics); if you are a well trained athlete (ie endurance junkie), how might this effect your running gait?
So, you run 103 miles with an elevation change of over 31,000 feet, how do you think you would fare? These folks were tested pre and 3 hours post race on a 22 foot long pressure walkway at about 7.5 miles per hour. Here’s how this group of 18 folks did:
increased step frequency
decreased “aerial” time
no change in contact time
decrease in downward displacement of the center of mass
decrease in peak vertical ground reactive force
increased vertical oscillation
leg stiffness remained unchanged
So what does this tell us?
wow, that is a lot of vertical
holy smokes, that is really far
don’t know how I would do with a race like that
they are fatigued (1, 2, 6)
they are trying to attenuate impact forces (2, 3, 4, 5, 7)
The system is trying to adapt the best it can. If you were to do a standard hip screen test (like we spoke about here) you would probably see increased horizontal drift due to proprioceptive fatigue. Remember that proprioception (our bodies ability to sense its position in space) makes the world go round. Proprioception is dependent on an intact visual system (see our post yesterday) , an intact vestibular system and muscle and joint mechanoreceptors functioning appropriately). We would add here that central nervous system fatigue (ie central processing both at the cord and in the cortex) would probably play a role as well.
The take home message? The human machine is a neuro mechanical marvel and much more complex than having the right shoe or the right running technique. Training often makes us more competent and efficient, but everything has it limits.
The Gait Guys. Making it real with each and every post.
all material copyright 2013 The Gait Guys/ The Homunculus Group
Université de Lyon, F-42023 Saint-Etienne, France. firstname.lastname@example.org
Changes in running mechanics and spring-mass behavior due to fatigue induced by a mountain ultra-marathon race (MUM, 166km, total positive and negative elevation of 9500m) were studied in 18 ultra-marathon runners. Mechanical measurements were undertaken pre- and 3h post-MUM at 12km h(-1) on a 7m long pressure walkway: contact (t(c)), aerial (t(a)) times, step frequency (f), and running velocity (v) were sampled and averaged over 5-8 steps. From these variables, spring-mass parameters of peak vertical ground reaction force (F(max)), vertical downward displacement of the center of mass (Δz), leg length change (ΔL), vertical (k(vert)) and leg (k(leg)) stiffness were computed. After the MUM, there was a significant increase in f (5.9±5.5%; P<0.001) associated with reduced t(a) (-18.5±17.4%; P<0.001) with no change in t(c), and a significant decrease in both Δz and F(max) (-11.6±10.5 and -6.3±7.3%, respectively; P<0.001). k(vert) increased by 5.6±11.7% (P=0.053), and k(leg) remained unchanged. These results show that 3h post-MUM, subjects ran with a reduced verticaloscillation of their spring-mass system. This is consistent with (i) previous studies concerning muscular structure/function impairment in running and (ii) the hypothesis that these changes in the running pattern could be associated with lower overall impact (especially during the braking phase) supported by the locomotor system at each step, potentially leading to reduced pain during running.