This is the 4th new study to be published in the last few days. The first one showed no injury differences between barefoot and shod runners; the next one showed no differences in injuries and performance between heel and midfoot/forefoot strikers; the third one found some muscles generate more force when barefoot running and other muscles generate more force when running in a shoe. This new one had a pretty emphatic conclusion:
Mechanical and physiological analysis of minimalist versus traditionally shod running
Kahle A., Brown G. A., Shaw I., Shaw B. S.
The Journal of Sports Medicine and Physical Fitness 2015 Jun 26 [EPUB ahead of print]
It has been purported that minimalist running shoes allow runners to be more biomechanically and metabolically economical, but evidence supporting these claims remains equivocal.
AIM: This study’s aim was to measure oxygen consumption (VO2), heart rate (HR), pulmonary ventilation (VE) and electromyography (EMG) of gastrocnemius and tibialis anterior in 12 recreationally-trained, college-aged males during minimalist and shod running.
METHODS: Participants ran at 70% VO2max on a treadmill in both minimalist and traditional shoes for six minutes each while VO2, HR, VE, EMG and steps taken were recorded.
RESULTS: Results indicated no significant differences in VO2 (2.39 ± 0.17 vs. 2.43 ± 0.15 L•min-1), HR (156.59 ± 2.99 vs. 157.13 ± 3.86 beats•min-1), VE (46.97 ± 3.19 vs. 47.00 ± 2.83 L•min-1), EMG in the tibialis anterior (2.02 ± 0.28 vs. 1.79 ± 0.20 mv), EMG in the gastrocnemius (1.97 ± 0.36 vs. 2.03 ± 0.37 mv) or steps taken (946.08 ± 13.50 vs. 962.42 ± 19.68 steps) between running in traditional and minimalist shoes, respectively.
CONCLUSION: This study shows that there is no mechanical and physiological benefit when running wearing minimalist shoes as opposed to traditional shoes and warrants a cautious approach to transitioning to minimalist shoe use.
I can’t say much about the methods in this study as I do not have access to the full publication for this one (can anyone send me a copy?). It was on a treadmill, so has to be interpreted in that context (which had to be used for most of the measurements that they did). We do not know from the abstract if the runners were habituated to the minimalist condition or not.
Based on the variables that they measured and found no differences in, their conclusion of “no mechanical and physiological benefit when running wearing minimalist shoes as opposed to traditional shoes” from this study is warranted. We know from the preponderance of running economy studies to date, that there does not appear to be any systematic benefits to barefoot running over shod running; but there does appear to subject specific advantages and disadvantages.
The most likely explanation for the variability seen in the studies is that shod running carries the weight of the running shoe (which affects economy) and some muscles work harder when running in minimalist shoes or barefoot (which affects economy), which would possibly explain why the preponderance of studies are finding no differences. It is going to be one of trade-offs and for each individual those trade-offs will vary, with my speculative reason for that variable response being the lever arms that tendons have to joint axes which affect how hard muscles have to work in different condition (discussed here). Those lever arms affect economy and loads in the structures and those lever arms vary substantially from person to person.
As always, I go where the evidence takes me until convinced otherwise …. and there is still no evidence for minimalist running having systematic benefits compared to traditional shod running.