Day to Day Consistency and Inter-subject Variability of Neuromuscular Responses and Performance Fatigability as the Result of Maximal,Bilateral,Dynamic Leg Extensions  

作　　者：Joshua L.Keller Terry J.Housh John Paul V.Anders Cory M.Smith Ethan C.Hill Richard J.Schmidt Glen O.Johnson 

机构地区：[1]Exercise Physiology Laboratory,University of Nebraska-Lincoln,1740 Vine Street,Lincoln,NE 68508,USA [2]Department of Kinesiology,Human and Environmental Physiology Laboratory,University of Texas At El Paso,El Paso,TX 79968,USA [3]School of Kinesiology and Physical Therapy,Division of Kinesiology,University of Central Florida,Orlando,FL 32816,USA

出　　处：《Journal of Science in Sport and Exercise》2021年第2期195-204,共10页体育运动科学（英文）

摘　　要：Purpose The purpose of the present study was to examine the day-to-day consistency and inter-subject variability of com-posite and individual,neuromuscular and torque patterns of responses as a result of a fatiguing bout of maximal,bilateral,isokinetic leg extension muscle actions.Methods Ten men (Mean ± SD =21.6 ± 2.5 years) completed two testing visits consisting of pretest and posttest maximal voluntary isometric contractions (MVIC) as well as 25 maximal,bilateral,isokinetic (180°/s),leg extension muscle actions.Electromyographic (EMG) and mechanomyographic (MMG) signals were collected from the vastus lateralis and normalized to the MVIC.Performance fatigability was defined as the percent decline in torque between the average of repetitions 1,2,and 3 and repetitions 23,24,and 25.Polynomial regression was used to examine the individual and composite relation-ships between EMG amplitude (AMP),EMG mean power frequency (MPF),MMG AMP,MMG MPF,and torque versus repetitions.Results There was no significant difference (d =0.80;P =0.17) in the performance fatigability between Day 1 (19.3% ± 7.1%)and Day 2 (26.9% ± 11.3%).Polynomial regression indicated substantial inter-subject variability,but high day-to-day consistency.Conclusion The composite EMG AMP,MMG AMP,and MMG MPF patterns of responses demonstrated consistency across days.The composite EMG MPF patterns of responses,however,were not consistent between Day 1 and Day 2.In addition,based on the high inter-subject variability,future studies should present both composite patterns of neuromuscular responses and the patterns of responses on a subject-by-subject basis to make inferences regarding fatigue-induced changes in motor unit activation strategies.

关 键 词：Performance fatigability Electromyography MECHANOMYOGRAPHY BILATERAL DYNAMIC 

分 类 号：G804[文化科学—运动人体科学]