Load Magnitude and Locomotion Pattern Alter Locomotor System Function in Healthy Young Adult Women

Frontiers in Bioengineering and Biotechnology

William J. Anderst¹  Camille C. Johnson¹  Richard J. Simpson²  Gavin L. Moir³  Chris Connaboy⁴  Dennis E. Dever⁴  Qi Mi⁴  Kellen T. Krajewski⁴  Shawn D. Flanagan⁴  Nizam U. Ahamed⁴  Scott M. Graham⁵ 

[1] Biodynamics Laboratory, Department of Orthopedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States;Department of Nutritional Sciences, University of Arizona, Tucson, AZ, United States;Exercise Science Department, East Stroudsburg University, East Stroudsburg, PA, United States;Neuromuscular Research Laboratory and Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, United States;School of Applied Sciences, Edinburgh Napier University, Edinburgh, United Kingdom;

关键词: complexity;    motor variability;    load carriage;    motor control;    regulation;    biomechanics;   

DOI  :  10.3389/fbioe.2020.582219

来源: DOAJ

【 摘 要 】

IntroductionDuring cyclical steady state ambulation, such as walking, variability in stride intervals can indicate the state of the system. In order to define locomotor system function, observed variability in motor patterns, stride regulation and gait complexity must be assessed in the presence of a perturbation. Common perturbations, especially for military populations, are load carriage and an imposed locomotion pattern known as forced marching (FM). We examined the interactive effects of load magnitude and locomotion pattern on motor variability, stride regulation and gait complexity during bipedal ambulation in recruit-aged females.MethodsEleven healthy physically active females (18–30 years) completed 1-min trials of running and FM at three load conditions: no additional weight/bodyweight (BW), an additional 25% of BW (BW + 25%), and an additional 45% of BW (BW + 45%). A goal equivalent manifold (GEM) approach was used to assess motor variability yielding relative variability (RV; ratio of “good” to “bad” variability) and detrended fluctuation analysis (DFA) to determine gait complexity on stride length (SL) and stride time (ST) parameters. DFA was also used on GEM outcomes to calculate stride regulation.ResultsThere was a main effect of load (p = 0.01) on RV; as load increased, RV decreased. There was a main effect of locomotion (p = 0.01), with FM exhibiting greater RV than running. Strides were regulated more tightly and corrected quicker at BW + 45% compared (p < 0.05) to BW. Stride regulation was greater for FM compared to running. There was a main effect of load for gait complexity (p = 0.002); as load increased gait complexity decreased, likewise FM had less (p = 0.02) gait complexity than running.DiscussionThis study is the first to employ a GEM approach and a complexity analysis to gait tasks under load carriage. Reduction in “good” variability as load increases potentially exposes anatomical structures to repetitive site-specific loading. Furthermore, load carriage magnitudes of BW + 45% potentially destabilize the system making individuals less adaptable to additional perturbations. This is further evidenced by the decrease in gait complexity, which all participants demonstrated values similarly observed in neurologically impaired populations during the BW + 45% load condition.

【 授权许可】

Unknown