The running economy issue again: been there, done that: here, here, here, here, here, here, here and here. Short and sweat post today as on the road and have to be somewhat careful what I say about this one as I do not yet have access to the full publication, so posting it more as an FYI than a detailed appraisal:
Metabolic comparison of running shod and barefoot in mid-forefoot runners
Vincent H. K., Montero C. , Conrad B. P. , Seay A. , Edenfield K. , Vincent K. R.
The Journal of Sports Medicine and Physical Fitness 2014 Apr 29
AIMS: The purposes of this study were to compare the oxygen cost, metabolic parameters and temporalspatial variables between barefoot and shod running in trained mid-forefoot runners.
METHODS: Experienced runners (N=21; 30.0±10.9 years; 16 men) performed two separate 20 minute treadmill running bouts at ~77% of estimated maximal heart rate. Rate of oxygen consumption (VO2), energy cost, fuel use and heart rate (HR) were collected continuously using a portable gas analyzer. Three-dimensional motion capture was used to measure temporalspatial parameters.
RESULTS: Participants ran at a mean self-selected speed of 3.1±0.3 m/s for both conditions, at intensities corresponding to mean HR values of 146 bpm (shod) and 144 bpm (barefoot). Steady State VO2 was not different between the shod and barefoot conditions (39.4 ± 4.7 ml/kg*min vs 40.0 ± 5.2 ml/kg*min, respectively). The total energy expended in the shod and barefoot conditions was 974 ± 134 kJ and 979 ±142 kJ. The average non-protein respiratory exchange ratios, proportions and amount of fat and carbohydrate used were not different between conditions. Cadence was 2.5% higher and center of gravity vertical displacement was 0.5 cm less for the barefoot condition (p<0.05).
CONCLUSION: In trained mid-forefoot runners experienced with barefoot running, there are not significant metabolic differences between shod and barefoot running conditions. Barefoot running increases cadence and decreases foot contact time and vertical displacement. Experienced participants were likely able to titrate kinematics to standardize energy output and fuel use for a given running distance and speed irrespective of shoe wear.
Even though I do not have access to the full paper, there is nothing in the abstract that jumps out at me as being an issue and the results seem pretty clear and consistent with most of the recent research:
there are not significant metabolic differences between shod and barefoot running conditions
As always, I go where the evidence takes me until convinced otherwise, and the preponderance of evidence on this topic is all heading in one direction.
Vincent HK, Montero C, Conrad B, Seay A, Edenfield K, & Vincent K (2014). Metabolic comparison of running shod and barefoot in mid-forefoot runners. The Journal of sports medicine and physical fitness PMID: 24777114