Award Date

5-1-2020

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Kinesiology and Nutrition Sciences

First Committee Member

John Mercer

Second Committee Member

Julia Freedman Silvernail

Third Committee Member

James Navalta

Fourth Committee Member

David Lee

Number of Pages

100

Abstract

New and innovative technology is consistently being introduced to help runners gain an edge over their competition. One of the more popular ergogenic aids in running today is compression garments. It is estimated that the compression garment market will surpass $5 billion by the year 2022. Despite the popularity, there is no clear consensus as to if or why compression is effective as an ergogenic aid. Although there has been a large variety of variables tested, there is little agreement on any of them as to the effect compression has. It appears as if the rate at which compression is used and the research to support performance improvement disagree. More research is needed to expand the knowledge base on individual variables until it becomes clearer if compression garments have an effect or not.

Therefore, the purpose of the first study was to compare muscle activity, heart rate, and rating of perceived exertion while wearing graduated compression socks (CS), regular socks (RS), and a placebo sock (PS) during running. Methods: Recreational runners (n=9; 1.65 ± .08 m; 69.90 ± 9.33 kg; 22.78 ± 3.33yr) completed three 10 minute running conditions either wearing CS, RS, and PS. CS were knee-high socks that had graduated compression moving proximally up the leg. RS were determined by the type of sock each subject was wearing on the day of testing. PS were regular XL soccer socks with no claims to compressive effect. Muscle activity of the rectus femoris, biceps femoris, gastrocnemius, and tibialis anterior were measured through electromyography (EMG; Delsys, Natick, MA). Heart rate (HR) and rating of perceived exertion (RPE) were recorded at 3 minute intervals. EMG data were processed by removing any zero offset, rectifying, and averaging over 30 seconds of minutes 3, 6, and 9 of each 10-min condition. Dependent variables (EMG, HR, RPE) were each compared between conditions using repeated measure ANOVAs (α=0.05). Results. HR, RPE, nor muscle activity for any muscle tested were not different between conditions (p>.05). Conclusion. Neither the compression sock nor placebo sock influenced muscle activity, HR, or RPE when running speed was controlled.

The first study demonstrated that there was no influence, positively or negatively, of CS, PS, or RS on muscle activity, HR, or RPE. However, all trials were performed and data collected while participants were running on a treadmill. There have been well-documented differences between treadmill and overground running and as the majority of competitive running occurs overground more research is needed in that regard.

The purpose of this study was to compare muscle activity while running overground between wearing compression socks, placebo socks, and regular socks. Methods: Recreational runners (n=11, 1.70 ± 0.11 m, 71.45 ± 15.13 kg, 27.09 ± 4.39 yrs) completed three 10 minute running conditions: wearing graduated compression socks (CS), regular socks (RS), and placebo socks (PS). Participants were instructed to run at a pace comparable to that of a typical 30-minute recreational run. CS were knee-high socks that had graduated compression moving proximally up the leg. RS were determined by the type of sock each subject was wearing on the day of testing as long as they were not compression socks. PS were cotton knee-high socks with no claims of a compressive effect. Muscle activity of the rectus femoris, biceps femoris, gastrocnemius, and tibialis anterior were measured through electromyography (EMG; Delsys, Natick, MA) of one limb. Heart rate (HR) and rating of perceived exertion (RPE) were recorded at 3 minute intervals. EMG data were processed by removing any zero offset, rectifying, and averaging over 5 strides at minutes 3, 6, and 9 of each 10-min condition. Dependent variables (EMG, HR, RPE) were each compared between conditions using 3(sock) X 3(time) repeated measure ANOVAs (α=0.05). Results: No variables were influenced by sock-time interaction. Muscle activity for any muscle tested nor HR were not different between socks (p>.05). RPE significantly increased between time points (p

The second study demonstrated that again compression socks and placebo socks had no positive nor negative influence on muscle activity, HR or RPE while running overground. These data suggest that even with a stiffer less pliable running surface sock condition does not help nor hinder performance via alterations to muscle activity. This is useful information to athletes and coaches in knowing that the use of compression socks does not induce drawbacks through altered muscle activity. The first two studies evaluated the use of compression socks stopping below the knee in lieu of full lower-limb compression. It is possible that additional compression above the knee is necessary to observe significant differences in measured outcomes.

The purpose of the third study was to compare muscle oscillation, muscle activation time, and oxygen consumption while wearing compression pants vs. a control garment during running. Secondary purpose: To determine the relationship between participant’s belief in compression efficacy and percent change in measured outcomes Methods. Participants (n=11; 1.74±0.05m; 74.30±12.58kg; 26.73±12.74yr; 5 female, 6 male) ran in compression pants (COMP; ankle-hip, 68.5% nylon/31.5% elastane, 20-25 mmHg) and a loose-fitting control garment (CON). For each condition, participants ran 6 minutes at three speeds: preferred speed (PS), preferred speed minus 10% (PS-10%), and preferred speed plus 10% (PS+10%).Garment condition order was counterbalanced; speed order was randomly assigned. Muscle activity of the rectus femoris, biceps femoris, gastrocnemius, and tibialis anterior was measured through electromyography (EMG). Muscle Oscillation (MO) was measured with accelerometers attached to the thigh and shank. EMG, MO, stride frequency (SF), and rating of perceived exertion (RPE) were measured during the last minute of each condition. Rate of oxygen consumption (V̇O2) and heart rate (HR) were recorded and averaged over the final 3 minutes of for each condition. MO was assessed over the 0-60 Hz range in 10 Hz bins. Power was averaged across 10Hz bins resulting in six dependent (0-10Hz, 10-20Hz, etc.) variables per leg segment. EMG data were processed by removing any zero offset, rectifying, and averaging activation time over 5 strides. A muscle was determined to be active if it had a greater amplitude than 10% of peak activation amplitude. After completing all conditions, ‘belief was assessed by having participants place a mark on a continuous scale ranging from ‘no belief’ to ‘belief.’ Dependent variables (Muscle activation time, MO, V̇O2, HR, RPE, SF) were each compared between conditions using 2 (garment) X 3 (speed) repeated measure ANOVAs (α=0.05). The relationship between belief score and percent change in each dependent variable (compression-control) was analyzed using Pearson’s product-moment correlation (α=0.05) Results. Muscle oscillation or activation time were not influenced by the interaction of garment and speed for any frequency bin assessed (p>0.05). Muscle oscillation up to 40 Hz was lower during compression pants vs. control garment (p0.05). There was no significant correlation between changes in dependent variables and belief. Conclusion. Wearing compression pants resulted in a reduction in muscle oscillation and activation time; however, these changes did not translate into a reduction of oxygen consumption.

In conclusion, compression pants induced changes in physiological and biomechanical mechanisms that can be potentially beneficial to overall performance. Wearing compression pants resulted in a reduction of muscle oscillation of the lower limb up to 40hz. Subsequently, a reduction in muscle activation time was observed while wearing compression pants. Although these factors did not influence running economy, more research is needed to evaluate potential benefits while running for a longer duration.

Keywords

Compression; EMG; Exercise; Muscle Oscillation; Oxygen Consumption; VO2

Disciplines

Biomechanics

File Format

pdf

File Size

5.3 MB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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