Article #54 of 50: I have made it a goal of mine to share at least 50 research articles with you to review in 2012. These articles will be shared with no opinion of mine, just purely the information provided in the research and where to go to read more about the topic. This weekly challenge will feature many different aspects of the field: strength, conditioning, nutrition, psychology, etc. If you would like to submit research articles to be included in this segment, please email me a PDF version of the peer reviewed journal article.
J Strength Cond Res 26(9): 2426–2431, 2012.
Abstract: The purpose of this study was to determine if wearing rocker-bottom shoes with compliant midsoles (RB) influences muscle activity and metabolic cost of walking. Furthermore, we sought to determine if weight differences between shod conditions accounted for any potential change. Twenty-eight subjects (17 women, 11 men, age 22.8 +/- 6.6 years; weight 72 +/- 20 kg; height 170 +/- 6.7 cm; percent body fat 23.0 +/- 11.7) walked on a treadmill (0% grade) for 10 minutes at a self-selected speed plus 10% (1.3 +/- 0.2 m.s-1) in each of the following laboratory-provided shoes: flat-bottomed shoe (W), flat-bottomed shoe weight-matched to RB (WM), and RB. Muscle activity of the right side biceps femoris (BF), rectus femoris (RF), gastrocnemius (GA), and tibalis anterior (TA) was recorded for 30 seconds at the beginning, middle, and ending of the 10-minute walk using an electromyography (EMG) system. The average (AVG) and root mean square (RMS) were calculated from full-wave rectified EMG data at each interval. The rate of oxygen consumption (VO2) was measured for 10 minutes during each condition. A 3 (shoe) x 3 (time) repeated-measures analysis of variance (ANOVA) was used to compare each EMG-dependent variable (AVG and RMS EMG of each muscle), and repeated measures ANOVA was used to test VO2. Muscle activity (for any muscle) was not influenced by the interaction of shoe and time (p . 0.05). The AVG and RMS for RF, BF, and GA, including VO2, were not different among shod conditions (W: 9.7 +/- 0.6 ml.kg-1.min-1; WM: 10.0 +/- 0.5 ml.kg-1.min-1; RB: 10.1 +/- 0.5 ml.kg-1.min-1), whereas TA AVG and RMS were lower during RB (p < 0.05). It seems that there is no increase in muscle activity or metabolic cost while wearing RB beyond the flat-bottomed shoe despite there being the rocker-profile design and mass differences.