The American College of Sports Medicine annual meeting in Boston has just come to a close and as I bemoaned about a year ago, I did not get to it, yet again. One day I will go. I do, however devour the abstract books each year as there are always some gems. Here is my selection this year:
Mercer et al looked at the effect of wearing extreme cushioning shoes on running economy at different speeds and inclines (Addidas Prene vs Hoka Bondi 4).Using VO2 max, they found no differences based on the cushioning of the shoe, concluding that “It seems that the cushioning of the shoe (extreme vs. regular) play no role in the influence of running economy“.
Zhang and Li to compared peak forces and the variability of forces in horizontal directions among maximum, regular, and minimum running shoes. They found that maximum shoe provides greater horizontal instability, specifically greater medial-lateral peak force and greater variability at the AP direction.
Cheung et al reported that a transition to minimalist footwear running was associated greater extrinsic and intrinsic foot muscle volume. Also Johnson et al reported walking in minimalist shoes appears to increase the size of some leg muscles (though my reading of the abstract leave me confused on what they actually did).
Coughlin and Rider reported that minimalist footwear improved running economy (2.33-2.75%), based on VO2 values at a self-selected pace. However, Zacharogiannis et al reported that there were no differences of using minimalist footwear in habitually shod runners on peak VO2 and 5 km performance time. These two studies are pretty consistent with what has been widely reported previously; ie the results are all over the place, indicated that the running economy issue and minimalist footwear is probably subject specific.
The study reported by Beltz et al was interesting. Pretty much every study that has looked at this (and a whole lot of studies that did not specifically look at that) have reported (and I have blogged about several) that the main risk factor for an injury is a history of a previous injury. Their study was on basketball players, but a history of a previous injury did not increase the risk for a subsequent injury in that cohort.
Brilliant et al reported that female runners with a history of anterior compartment syndrome had a “propensity of landing with their foot further in front of their knee and with their foot more dorsiflexed at initial contact phase of running compared with healthy female runners“. No surprise there, but good to have it confirmed. That ‘touch down’ angle seem to be a crucial factors in anterior compartment syndrome (I blogged about that here).
Firminger and Edwards found that “unning in minimalist footwear was beneficial for knee joint loading, however increased loads were observed at the MTP and ankle joints” (yep; been there done that many times).
This cool study by Morgan et looked at stride frequency and injury rates (important in the context of the hype surrounding the 180-cadence). This was a prospective study (good), but only on 28 runners (however, the effect size of the results look healthy, so that is good). They found that “prior to beginning training, 42.9% of participants had stride freuecny below 163 spm, and this group had injury rates of 66.7%. Comparatively, 32.1% of participants had SF above 168 spm, and their injury rates were 22.2%. This suggests SF _169 spm may have been protective.” 169 is certainly less than that “magical” 180.
Futrell et al looked at the relationship between natural running cadence and vertical load rates in both healthy and injured runners. They found that cadence was not significantly correlated with either ground reaction forces in both groups. They did report that the ground reaction forces were significantly higher in the injured group.
Morin et al looked at forefoot loading and step rate manipulation and found “with a larger 10% step rate modification compared to 5% change, support previous work indicating reduced medial and central forefoot loading“.
Gould et al measured intrinsic foot strength (yet the method used would have also included extrinsic muscles!) and divided the 15 runners into high and low groups. The lower strength group had high total force under the foot.
Bridges et al investigated a 8-wk foot strengthening program on the vertical deformation of the arch during the mid-stance in running. From the abstract they reported no differences in the between group analysis (which is the correct way to analyse this type of study design), but also reported a within groups increase in the intervention group (which is the wrong way to analyse this types of study design).
Fuller et al round that it is harder for heavier runners to transition to minimalist footwear with those with a higher BMI getting more injuries.
Tenforde et al reported that symmetry was generally improved during typical barefoot running compared to shod. They attributed this to Improved sensory input.
It is hard to provide too much more information on a lot of these studies, let alone a detailed analysis as I just do not have enough information to go on (I did comment on a few). Unfortunately reviewing previous abstracts from this conference, a lot do not make it into full peer reviewed publication, either from the authors not getting around to it (my excuse) or some flaws in the study meaning that they do not pass peer review. I will certainly look forward to seeing all of the above in print and see what I can do about making next years meeting!
As always, I go where the evidence takes me until convinced otherwise and there is always a lot of good evidence presented at the ACSM meeting (though I have no empirical evidence to support that statement)