Access Type

Open Access Thesis

Date of Award

January 2016

Degree Type

Thesis

Degree Name

M.Ed.

Department

Health Education

First Advisor

Dr. Qin Lai

Abstract

ABSTRACT

EFFECTS OF LOCAL MUSCLE FATIGUE ON PROPRIOCEPTION

AND MOTOR LEARNING

by

GOWTAMI DATLA

May 2016

Advisor: Dr. Qin Lai

Major: Kinesiology and Exercise Science

Degree: Masters of Education

Background: Muscle fatigue is an exercise induced decline in the ability of muscles to produce force or power. Recent studies showed that decline in proprioception due to fatigue lead to an increasing risk of falls and injury. However, it was unknown whether fatigue-induced proprioception decrease affects skill acquisition and memory consolidation. Purpose: The aim of the study was to investigate the effects of local muscle fatigue on perceptual motor learning in arm positioning task and to compare surface EMG activities in the fatigue and non-fatigue muscle conditions. Two experiments were used to investigate the purpose. In Experiment 1, Methods: 24 healthy young adults (Age: 20-40) were randomly and equally assigned into either control or experiment group. An informed consent was signed prior to the study. Both the groups performed the same task but the experiment group underwent a fatigue protocol (biceps curls with weight of 80% voluntary contraction until fatigue) during the acquisition phase. The task was to place the left forearm on a kinestheiometer and moved the handle to 30, 45, 60 degrees by flexion. All the participants performed 1 block of pre-test, 5 blocks of acquisition phase, 1 block of post-immediate test during the first visit. A delayed retention and bilateral transfer tests were administered 48 hrs after the first visit. Each block had 12 trials. Throughout the task participants were blind folded and were given verbal feedback during the acquisition only. Results: A 2 X 5 (Group vs. Block) ANOVA with repeated measure on Block for acquisition demonstrated both groups decreased total movement error (E) with practice, F (4, 88) = 10.46, p<.01. A main effect of group was detected, F (1, 22) = 4.91, p<.05. Duncan’s MRT indicated fatigue group (M=5.73) produced more E relative to the controlled (M=4.93). A separated ANOVA for retention, and transfer tests also detected a main effect of group, F (1, 22) = 10.19, p<.01 for total error. DMRT revealed that fatigue group (M=8.08) produced more variable error than control group (M=5.41). The analysis did not detect difference between retention and transfer [F (1, 22) = 0.26, P> 0.05] or interaction [F (1, 22) = 0.00, P> 0.05]. In Experiment 2, Methods: 12 healthy individuals (age 20-40) participated in the experiment that consisted of 6 blocks with 12 trials each. All the participants performed 6 blocks of task and fatigue protocol before every other block. After fatigue protocol participants were made to perform the task immediately without rest but were given 2 minutes rest after each block. Results: One way ANOVA with repeated measure on condition showed a main effect of fatigue for the EMG frequency, F (1, 22) = 7, P<.05. Where fatigue condition was greater than non-fatigue. The main effect was also detected for the integral EMG (amplitude), F (1, 12) = 6.14, P< .05, where non fatigue was greater than fatigue. Conclusion: Both the control and experiment group exhibited perceptual motor learning with practice. The fatigue group showed a greater error than the control group in acquisition, retention and transfer. The surface EMG showed increased frequency and decreased integral (amplitude) in the fatigued muscle when compared to non-fatigue condition. In summary, local muscle fatigue had negative effects on perceptual motor acquisition and memory consolidation by degrading proprioception and efficiency on the muscles.

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