The effects of spinal manipulation at L3/ L4 level on active electromyographic activity of the ipsilateral Vastus medialis Obliques (VMO)

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Acknowledgement

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible.

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I, [type your full first names and surname here], declare that the contents of this dissertation/thesis represent my own unaided work, and that the dissertation/thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University.

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Abstract

The repeatability of initial values and rate of change of EMG signal mean spectral frequency (MNF), average rectified values (ARV), Maximal Force, Maximal torque, muscle fiber conduction velocity (CV) and muscle activation signal(MAC) was investigated in the vastus medialis obliquus (VMO) and vastus lateralis (VL) muscles of both legs of nine healthy male subjects during voluntary, isometric contractions sustained for 50 s at 50% MVC. The values of MVC were recorded for both legs three times on each day and for three subsequent days, while the EMG signals have been recorded twice a day for three subsequent days. The degree of repeatability was investigated using the Fisher test based upon the ANalysis Of VAriance (ANOVA), the Standard Error of the Mean (SEM) and the Intraclass Correlation Coefficient (ICC). Data collected showed a high level of repeatability of MVC measurement (normalized SEM from 1.1% to 6.4% of the mean). MNF and ARV initial values also showed a high level of repeatability (ICC70% for all muscles and legs except right VMO). At 50% MVC level no relevant pattern of fatigue was observed for the VMO and VL muscles, suggesting that other portions of the quadriceps might have contributed to the generated effort. These observations seem to suggest that in the investigation of muscles belonging to a multi-muscular group at submaximal level, the more selective electrically elicited contractions should be preferred to voluntary contractions.

Table of Contents

CHAPTER 1: INTRODUCTION1

Background3

Aims and Objectives5

CHAPTER 2: LITERATURE REVIEW6

Comparison vastus medialis and vastus laterals6

Related Research7

Vastus lateralis muscle and portions8

Why is VMO so Important?8

The effects of SM L/S on the corticospinal and spinal reflex9

Anatomy of the knee12

Electromyography (EMG)13

Isokinetic Dynamometer14

Gravitational Effect on Isokinetic Movements15

Hip and Vasti Activation in the Management of Pfps16

Effect of tibia rotation on the electromyographical activity of the vastus medialis oblique17

CHAPTER 3: MATERIALS AND METHODS21

Methods21

Procedures22

Experimental protocol23

Experimental setup24

Surface EMG detection24

Signal processing25

Statistical processing26

Osteoarthritis of the knee29

CHAPTER 4: RESULT AND DISCUSSION31

Data Analysis31

VMO to VL Ratios31

Asymptomatic Vs. symptomatic31

CHAPTER 5: DISCUSSION AND CONCLUSION34

EMG variable repeatability34

Myoelectrical manifestations of muscle fatigue39

About dominant and non-dominant legs41

CHAPTER 6: CONCLUSIONS42

REFERENCES43

CHAPTER 1: INTRODUCTION

The quadriceps is comprised of four muscles; each with different responsibilities to assist in the function of the knee. The four muscles are the vastus medalis oblique (VMO), vastus intermedius, vastus lateralis, and rectus femoris. The vastus medialis is made up of two parts: the distal portion is the VMO and the proximal portion is the vastus medialis oblique longus (VML). The primary movement of the quadriceps is extension of the ...