There has been a flurry of studies on the effects of foot strike pattern or shoe condition on running economy this year. They are all pretty much showing the same thing. I have blogged about them here, here, here, here, here and here, so there is no point litigating old ground again. Two more related studies recently appeared. I can’t say a lot about the two abstracts below as I know nothing more than what is in the abstracts and we will have to await full publication to get all the details. They were presented at the The American College of Sports Medicine Southeast Meeting in September.
NO INFLUENCE OF BAREFOOT RUNNING ON RUNNING ECONOMY
J.T. Repshas, M.M. Koehler, E.E. Hawkins, K.L. Hines and M.G. Flynn.
Barefoot running (BR) has been reported to change running gait and reduce the risk of injury, but few studies have been completed to examine these claims. Proponents of BR claim that running barefoot causes a shift from the heel to a forefoot strike—which improves running economy (RE). Most previous research on BR and RE has used high-level athletes. Therefore, the purpose of this study was to determine if RE differed in recreational runners when running barefoot (BR), running with shoes (SR), or weighted running (WR, foot weights added equal to shoe weight) . The subjects were active male (n=9) and female (n=9) college-aged runners who were training to run in a local 10 km race. Height, weight, body composition (skinfold), and resting blood pressure were recorded and a medical history was completed before testing. Subjects performed three consecutive, seven-minute, randomly assigned, sub-maximal running trials either BR, SR, or WR. Oxygen consumption was measured using a Parvomedics TrueMax 2400 (Sandy, Utah). RPE (Borg 6-20 scale) and heart rate (Polar Heart Rate Monitor) were measured at 5.5 and 6.5 min of each segment. There were no significant differences (p >0.05) in RE (ml/kg/min) among trials. Heart rate and RPE (BR, 12.6 +2.1; SR, 11.9 +2.9; WR, 13.4 +2.8) were not different among trials. Grouping subjects by sex also did not yield any significant differences. We conclude that RE, RPE, and heart rate were not significantly altered by BR in recreational runners who did not have a significant amount of previous experience with running barefoot.
Even though this was an acute intervention in novices, the results are pretty much consistent with what the preponderance of evidence is showing on the issue of running economy in barefoot vs shod.
THE EFFECT OF SHOD VERSUS BAREFOOT RUNNING ON LOWER LIMB MUSCLE ACTIVATION
L. Bauer and C. Inman,
Purpose: Little research has focused on the effect of footwear on lower limb muscle activation. While increased muscle activation may result in increased speed, higher levels of muscle activation during distance walking and running may result in greater muscle fatigue and injury. The purpose of this study is to determine the effects of being shod or barefoot on lower limb muscle activation when walking and running.
Methods: Six college-aged men (n=2) and women (n=4) participated in the protocol (21.4±1yrs, 178.3±8cm, 83.8±26 kg). Average electromyography (EMG) amplitude (mV) over a 15 second measurement period was recorded for the tibialis anterior (TA) , peroneus brevis (PB) , medial gastrocnemius (MG), lateral gastrocnemius (LG), soleus (SO) and peroneus longus (PL). All EMG activity was recorded, transformed, and reported as root mean square (RMS) activity. Recordings were taken during the last 15 seconds of a single bout of 3 minutes of walking (0.55 m/s) or running (3.6 m/s). Separate trials of barefoot or shod were completed for each speed; all trials were completed on the same day and counterbalanced with 2 minutes recovery between trials.
Results: As expected, running increased muscle activation for all lower limb muscles from walking to running, regardless of being barefoot or shod (p<0.05). When comparing barefoot to shod during walking, there was no significant difference in EMG activity of any muscle (p=0.16 – 0.87). However, EMG activity during barefoot running was reduced in the PL (11%, p=0.04) and tended to be lower in the soleus (23%, p=0.07) when compared to shod running.
Conclusions: Some lower limb muscles show reduced neural activation when running barefoot.
Only 6 subjects, so not going to jump too high about these results but its certainty not a fatal sample size. What was interesting was the reduced EMG activity in barefoot running. EMG is a measure of muscle activity and not strength, but if some muscles are less active during barefoot compared to shod, surely that goes against all the propaganda and rhetoric that barefoot makes the muscles stronger and running shoe weaken muscles? This study would suggest the opposite? Think about it.
As always, I go where the evidence takes me until convinced otherwise, and these studies support the contention that there is no one most economical way to run for everyone and that running shoes do not weaken muscles.