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ROLE OF LENGTH SPECIFICITY, VELOCITY SPECIFICITY AND NEURAL

ADAPTATIONS IN STRENGTH TRAINING

By

AHMAD NAIM ISMAIL

Thesis submitted to the School of Graduate Studies, Universiti Putra Malaysia, in

Fulfilment of the Requirements for the Degree of Doctor of Philosophy

March 2012

ii

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of

the requirements for the degree of Doctor of Philosophy

ROLE OF LENGTH SPECIFICITY, VELOCITY SPECIFICITY AND NEURAL

ADAPTATIONS IN STRENGTH TRAINING

By

AHMAD NAIM ISMAIL

March 2012

Chair: Tengku Fadilah Tengku Kamalden, PhD

Faculty: Faculty of Educational Studies

A very common finding among many training studies is that the increase in weight-

lifting strength is greater than the increase seen in isometric strength. Most are in view

that this is the result of training and testing specificity. However the exact underlying

mechanism that is responsible for the discrepancy has yet to be explained. The three

studies of this thesis examine the explanation behind the discrepancy between the

increases seen in weight-lifting strength compared to isometric strength after resistance

training.

The first study was to look into the role of learning. Thirty two students completed the

training. The subjects underwent four weeks of unilateral leg extension training, three

times per week,three sets of eight lifts. One leg was chosen arbitrarily for the training.

The contralateral leg, which was not trained, acted as a control. Subjects performed at a

steady pace. The result showed that the lesser experienced subjects showed a significant

iii

improvement in training weights lifted which illustrated that weight-lifting is very much

a skill based task.

The second study was to look into length specificity and velocity specificity. Eighteen

subjects completed the study. Subjects completed eight weeks of leg extension training,

three times per week,four sets of six to eight lifts. One leg was arbitrarily assigned to

perform the dynamic training. Isometric strength measured in the strength-testing chair.

Measurements of isometric strength at 15° intervals from 60° to 105° of knee flexion

using isokinetic dynamometer. Isokinetic strength testing was also measured at

velocities of 45° s-1

, 180° s-1

and 300° s-1

. A non-significant 6% increase of isometric

maximum voluntary contraction (MVC) at 90° was found and between 13% and 19%

.Increases of isometric torque were found at all angles measured. The training resulted

in increases in the isokinetic torque at all velocities for the trained leg. The result has

shown no evidence to any length or velocity specific adaptations.

The third study was to look into whether there is any increase in neural activity during

dynamic contractions in explaining the discrepancy between the increase in training

weights and MVC. Seven male subjects participated in this study. Subjects were trained

three times per week for four weeks, 80 - 85% of 1RM for three sets. One leg was

chosen randomly. Subjects performed dynamic leg extension on a leg extension

machine. The electromyogram (EMG) activity of vastus lateralis and biceps femoris

was recorded for the training and control leg during all testing. There were no

significant differences in terms of MVC force produced between the training chair and

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the strength testing chair. The EMG data showed there was no significant change in the

EMG activity of the vastus lateralis of the trained leg after training. There was a

reduction in EMG activity of the hamstring during the 1 RM post training but was not

significant. The results of the study have shown that there is no increase in neural

activity which would explain the difference between the increase in training weights

and MVC. Nor were there any significant changes in co-activation of the hamstring.

The discrepancy seen in the large increase in the weight lifting strength as compared to

isometric strength cannot be accounted for by the angle specificity and velocity

specificity factors. There is also no increase in neural activity which would explain the

difference between the increase in training weights and MVC. Nor were there any

significant changes in co-activation of the hamstring, consequently the discrepancy

remains unexplained.

v

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai

memenuhi keperluan untuk ijazah Doktor Falsafah.

PERANAN SPESIFISITI PANJANG, SPESIFISITI HALAJU DAN ADAPTASI

NEURAL DALAM LATIHAN KEKUATAN

Oleh

AHMAD NAIM ISMAIL

Mac 2012

Pengerusi: Tengku Fadilah Tengku Kamalden, PhD

Fakulti: Fakulti Pengajian Pendidikan

Kebanyakan dapatan daripada kajian mengenai latihan kekuatan mendapati bahawa

peningkatan kekuatan (selepas latihan kekuatan) untuk mengangkat bebanan adalah

melebihi kekuatan isometrik. Di antara alasan yang dikemukakan ialah kerana spesifisiti

latihan dan ujian. Tetapi, dari segi mekanisme yang sebenarnya terlibat masih belum

diketahui dengan jelas. Tiga kajian dalam tesis ini meneliti penjelasan di sebalik

percanggahan di antara peningkatan yang dilihat dalam kekuatan mengangkat bebanan

berbanding kekuatan isometrik selepas latihan kekuatan.

Kajian pertama adalah untuk mengkaji peranan pembelajaran. Seramai 32 subjek

menamatkan latihan setelah menjalani 4 minggu latihan ekstensi kaki unilateral, tiga

kali seminggu, tiga set lapan ulangan. Sebelah kaki telah dipilih secara rawak untuk

latihan. Kaki kontralateral, yang tidak terlatih, bertindak sebagai kawalan. Hasil kajian

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menunjukkan bahawa subjek yang kurang berpengalaman mempamerkan peningkatan

yang signifikan dalam mengangkat bebanan. Ini menunjukkan bahawa latihan kekuatan

(angkat bebanan) adalah satu kemahiran yang tersendiri.

Kajian kedua adalah untuk melihat spesifisiti sudut-panjang dan spesifisiti halaju.

Seramai 18 subjek terlibat dalam kajian ini. Subjek menyelesaikan lapan minggu latihan

ekstensi kaki, tiga kali seminggu, empat set 6-8 ulangan. Satu kaki secara rawak

ditugaskan untuk melaksanakan latihan. Kekuatan isometrik diukur di kerusi ujian

kekuatan isometrik. Pengukuran kekuatan isometrik pada 15° 60° hingga 105° fleksi

lutut juga diukur menggunakan dinamometer isokinetik. Ujian kekuatan isokinetik juga

diukur pada halaju 45° s-1

, 180° s-1

dan 300° s-1

. Satu peningkatan kekuatan isometrik

didapati sebanyak 6% tetapi tidak signifikan pada 90° dan peningkatan di antara 13%

dan 19% didapati pada semua sudut yang diukur menggunakan dinamometer isokinetik.

Latihan menyebabkan peningkatan tork isokinetik pada semua halaju untuk kaki

terlatih. Hasil kajian menunjukkan tiada bukti adaptasi spesifisiti sudut-panjang atau

spesifisiti halaju berlaku.

Kajian terakhir meninjau sama ada terdapat sebarang peningkatan dalam aktiviti neural

semasa kontraksi dinamik dalam menjelaskan percanggahan di antara peningkatan

dalam berat latihan dan peningkatan kekuatan isometrik. Tujuh subjek lelaki mengambil

bahagian dalam kajian ini. Subjek telah dilatih tiga kali seminggu selama empat

minggu, 80 - 85% daripada 1RM sebanyak tiga set. Subjek melakukan ekstensi kaki

dinamik menggunakan mesin extensi kaki. Aktiviti electromyogram (EMG) vastus

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lateralis dan biseps femoris dicatatkan bagi kaki latihan dan kawalan dalam semua

ujian. Terdapat tiada perbezaan yang signifikan dihasilkan antara kerusi latihan dan

kerusi ujian kekuatan. Data EMG menunjukkan tiada perubahan signifikan dalam

aktiviti EMG bagi vastus lateralis selepas latihan. Terdapat pengurangan dalam aktiviti

EMG biseps femoris selepas latihan tetapi tidak signifikan. Kajian terakhir tesis ini

menunjukkan dengan jelas bahawa tiada sebarang peningkatan aktiviti neural yang

boleh menjelaskan perbezaan di antara peningkatan mengangkat bebanan dengan

peningkatan kekuatan isometrik selepas sesuatu latihan dijalankan. Didapati juga

bahawa tidak terdapat perubahan yang signifikan bagi koaktivasi otot hamstring.

Dengan itu penjelasan tentang mengapa terdapat perbezaan yang ketara itu masih tidak

dapat dijelaskan oleh kajian dalam tesis ini.

viii

ACKNOWLEDGEMENTS

I would like to thank all of my friends and my family for the support and

encouragement over these years. I am also indebted to all the volunteers that were

involved in this work.

A special acknowledgement to my supervisor for the motivation and guidance.

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I certify that a Thesis Examination Committee has met on March 30, 2012 to conduct

the final examination of Ahmad Naim Ismail on his thesis entitled “ROLE OF

LENGTH SPECIFICITY, VELOCITY SPECIFICITY AND NEURAL

ADAPTATIONS IN STRENGTH TRAINING” in accordance with the Universities

and University Colleges Act 1971 and the Constitution of the Universiti Putra Malaysia

[P.U.(A) 106] 15 March 1998. The Committee recommends that the student can be

awarded the degree of Doctor of Philosophy.

Members of the Thesis Examination Committee were as follows:

Roselan Baki, PhD

Faculty of Educational Studies

Universiti Putra Malaysia

(Chairman)

Kok Lian Yee, PhD



(Internal Examiner)

Saidon Amri, PhD



(Internal Examiner)

Alun Williams, PhD

Department of Exercise & Sport Science

Manchester Metropolitan University

United Kingdom

(External Examiner)

________________________

SEOW HENG FONG, PhD

Professor and Deputy Dean

School of Graduate Studies


Date:

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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been

accepted as fulfillment of the requirement for the degree of Doctor of Philosophy. The

members of the Supervisory Committee were as follows:

Tengku Fadilah Tengku Kamalden, PhD

Senior Lecturer



(Chairman)

Aminuddin Yusof, PhD

Associate Professor

Faculty of Educational studies


(Member)

Mohd Roslan Sulaiman, PhD

Professor

Faculty of Medicine and Health Sciences

University Putra Malaysia

(Member)

__________________________________________

BUJANG BIN KIM HUAT, PhD

Professor and Dean

School of Graduate Studies


Date:

xi

DECLARATION

I declare that the thesis is my original work except for quotations and citations which

have been duly acknowledged. I also declare that it has not been previously, and is not

concurrently, submitted for any other degree at Universiti Putra Malaysia or at any other

institution.

____________________________

AHMAD NAIM ISMAIL

Date:

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TABLE OF CONTENTS

Page

ABSTRACT ii

ABSTRAK v

ACKNOWLEDGEMENTS viii

APPROVAL ix

DECLARATION xi

LIST OF TABLES xiv

LIST OF FIGURES xvii

LIST OF ABBREVIATIONS xxi

CHAPTER

1 INTRODUCTION AND LITERATURE

REVIEW

Introduction 1

Factors Relating to Muscle Strength 5

Specificity of Strength Training 10

Neural Adaptations 13

Direction of This Work 25

2 GENERAL METHODS

Strength Measurements 26

Electrical Stimulation and Voluntary Activation 33

EMG Measurements 36

3 ROLE OF LEARNING IN CHANGES SEEN

IN WEIGHT TRAINING: A COMPARISON

OF BOYS WITH DIFFERING LEVELS OF

SPORTING EXPERIENCE

Introduction 39

Methods 41

Results 46

Discussion 50

4 ROLE OF LENGTH SPECIFICITY AND

VELOCITY SPECIFICITY IN STRENGTH

TRAINING

Introduction 55

Methods 58

Results 61

Discussion 75

xiii

5 RELIABILITY OF USING M-WAVE IN

NORMALIZING THE EMG SIGNALS

Introduction 81

Methods 83

Results 91

Discussion 100

6 ROLE OF NEURAL ADAPTATIONS IN

SHORT TERM DYNAMIC WEIGHT

TRAINING

Introduction 103

Methods 105

Results 109

Discussion 120

7

CONCLUSION 124

REFERENCES 130

APPENDICES 150

BIODATA OF STUDENT 151

xiv

LIST OF TABLES

Table Page

2.1 COV of 1RM 27

2.2 COV of MVC 28

2.3 COV at Various Angle of Knee Flexion 31

2.4 COV of Torque-velocity Relationship at

Various Speed

32

2.5 COV % of Activation 35

3.1 Age, Height, Weight and Maturity 46

3.2a Pre and Post 1RM for Sports School 47

3.2b Pre and Post 1RM for Non Sports School 47

3.3a Pre and Post MVC for Sports School (SS) 48

3.3b Pre and Post MVC for Non Sports School

(NSS)

49

3.4 Pre and Post Training Differences of 1RM 49

4.1 Physical Characteristics of the Subjects 58

4.2 1RM (Newtons) Pre and Post Training for the

Trained Legs of the Male and Female after 8

Weeks of Training

61

4.3 1RM (Newtons) Pre and Post Training for the

Untrained Legs after 8 Weeks of Training

62

4.4 1RM (Newtons) Pre and Post Training for

Trained (T) and Untrained Leg (UT) for Male

and Female and Control Subjects After 8

Weeks of Training

62

4.5 Isometric MVC for the Pre and Post Training of

the Trained Leg

65

xv


the Untrained Leg

66


the Trained (T) and Untrained (UT) Leg of

Male and Female and Control Group

66

4.8 Changes Seen in the Angle-torque Relationship

in the Trained Leg after 8 Weeks of Training

68

4.9 Changes Seen in the Angle-torque Relationship

in the Untrained Leg after 8 Weeks of Training

69

4.10 Angle-torque Relationship for the Pre and Post

Training of the Trained and Untrained Leg of

Male and Female Subjects

70

4.11 Isokinetic Torque at 3 Angular Velocities of the

Trained Leg after 8 Weeks of Training

73

4.12 Isokinetic Torque at 3 Angular Velocities of the

Untrained Leg after 8 Weeks of Training

74

4.13 Isokinetic Torque at 3 Angular Velocities for

the Pre and Post Training of the Trained and

Untrained Leg of Male and Female Subjects

74

5.1 Height, Weight and the MVC of the Subjects 84

5.2 Variance of sEMG and Normalising the EMG

Data by using sEMG Divided by the Amplitude

of the M-Wave

96

5.3 Normalising the EMG Data by using sEMG

Divided by the sMWave

96

5.4 Variance of iEMG and iMWave and

Normalising the EMG Data by using iEMG

Divided by the iMWave

97

5.5 % COV of the EMG Parameters of the 4

Subjects (Day to Day Variations) on 3 different

Days

97

6.1 Physical Characteristics of the Subjects 106

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6.2 i. 1RM (Newtons) and ii. MVC (Newtons) Pre

and Post Training for Trained Legs. The

Isometric MVC was tested on the Strength

Testing Chair Condition

110

6.3 i. 1RM (Newtons) and ii. MVC (Newtons) Pre

and Post Training for Untrained Legs. The

Isometric MVC was Tested on the Strength

Testing Chair Condition

110

6.4 Summary of the 1RM (Newtons) and MVC

(Newtons) Pre and Post Training for Trained

(T) and Untrained (UT) Legs

111

6.5 MVC Forces Produced in the Cybex Training

Chair (Measured at 105° Knee Flexion) and in

the Strength-testing Chair (Measured at 90°

Knee Flexion). Units in Newton-meter (Nm)

113

6.6 Rectified, Smoothed EMG (rsEMG) for 1RM

and MVC for the Trained Leg

115

6.7 Rectified, Smoothed EMG (rsEMG) for 1RM

and MVC for the Untrained Leg

115

6.8 Amplitude of Rectified Smoothed EMG

(rsEMG) of 1RM and MVC of the Hamstring

(Trained Leg)

117

6.9 Amplitude of Rectified Smoothed EMG

(rsEMG) of 1RM and MVC of the Hamstring

(Untrained Leg)

117

xvii

LIST OF FIGURES

Figure Page

2.1 Cybex-VR2 Leg Extension Machine 27

2.2 Isometric Strength Testing Chair 28

2.3 Ankle Strap and Strain Gauge 29

2.4 Example of the Calibration 29

2.5 Cybex Norm Isokinetic Dynamometer 30

2.6 (i) Digitimer Stimulator Model DS7, UK 33

2.6 (ii) CED-1401, Cambridge Electronic Design Ltd.,

UK

33

2.7 The Twitch Interpolation Technique To

Estimate Level of Muscle Activation

34

2.8 Bipolar Surface Electrodes 36

2.9 EMG Activity of the Vastus Lateralis, Showing

Raw, Rectified and Smooth EMG

37

2.10 Schematic Representation of the Experimental

Set Up For Detecting EMG Signals, Force

Management and Stimulating the Muscle

37

3.1 Universal Powercircuit Leg Extension Machine 43

3.2 Percentage Increase of 1RM after Training of

the Trained Leg and Untrained Leg of SS and

NSS

48

4.1 Percentage Change in the Weight Lifted (1RM)

in Trained, Untrained Leg and Control Group

after 8 Weeks of Training

63

4.2 Percentage Change in the Weight Lifted (1RM)

in Trained Leg versus Weeks of Training

63

xviii

4.3 Voluntary Activation of the Trained (Shaded

Bar) and Untrained (Open Bar) Leg Pre and

Post Training

64

4.4 Percentage Change in Isometric MVC in the

Trained, Untrained Leg and the Control Group

after 8 weeks of Training

67

4.5 Changes in the Angle-torque Relationship for

the Trained Leg

71

4.6 Changes in the Angle-torque Relationship for

the Untrained Leg

71

4.7 Percentage Change in the Angle-torque

Relationship in the Trained (Clean Bar),

Untrained (Dark Bar) and Control (Grey Bar)

after 8 Weeks of Training

72

4.8 Percentage Change in Isokinetic Torque at 3

Angular Velocities in the Trained (Clean Bar),

Untrained (Dark Bar) and Control (Grey Bar)

Leg after 8 Weeks of Training

75

5.1 Femoral Nerve Which Runs Lateral to the

Femoral Artery

85

5.2 The Cathode Probe 86

5.3 The femoral nerve (c) lies parallel to the

femoral artery (b). (a) is the femoral crease

which is just below the inguinal ligament

86

5.4 M-Waves Recorded from the Three Muscles, V.

Lateralis, R. Femoris and V. Medialis

87

5.5 Smoothed, Rectified Raw EMG and the Force

Elicited

89

5.6 Integrated, Rectified and Raw EMG 89

5.7 The Raw, Rectified and Amplitude of

Smoothed M-Wave of Vastus Lateralis

90

5.8 The Raw, Rectified and Integrated M-Wave of

Vastus Lateralis

90

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5.9 (a) Low Amperage at 100 mA 92

5.9 (b) Medium Amperage at 200 mA 92

5.9 (c) High Amperage at 300 mA 92

5.9 (d) A Typical M-Wave of the Vastus Lateralis at

100 mA

92

5.10 The Timing of the Evoked M-Waves after

Being Stimulated by a Single Pulse. X, Y and Z

Represents the Timing of the Vastus Medialis,

Rectus Femoris and Vastus Lateralis

Respectively

93

5.11 M-Waves Signal of the Vastus Lateralis, Rectus

Femoris and Vastus Medialis Recorded at

Various Current. The Force Elicited by the

Stimulation is shown in Newtons (N) on the

Secondary Axis Above It

94

5.12 (a,b,c) Amplitude of the M-Waves of the Three

Muscle at Different Currents taken 3 Times

During the Day

95

5.12 (d,e,f) Amplitude of the M-Waves of the Three

Muscle at Different Currents taken on 3

Subsequent Days

95

5.13 Mean % COV of the EMG Parameters of the 4

Subjects (Day to Day Variations) on Three

Different Days

98

5.14 The Branching of the Nerves in Relation to the

Placing of the Electrodes. X,Y,Z is the

Placement of the Electrodes for Vastus

Lateralis, Rectus Femoris and Vastus Medialis

Respectively and a,b,c is the Place Where the

Femoral Nerves Enters the Vastus Lateralis,

Rectus Femoris and Vastus Medialis

Respectively

99

6.1 EMG of the Biceps Femoris vs Force during a

Flexion

108

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6.2 The Increase in Weight Lifted (1RM) for 4

Weeks of Training

109

6.3 Percentage Change in Weights Lifted (1RM)

and in Isometric MVC in Trained and

Untrained Legs after 4 Weeks of Training

111

6.4 Percentage Change in Weight Lifted (1RM) and

Isometric MVC of the Trained Leg

112

6.5 Percentage Change in Isometric MVC of the

Testing Chair at 105o of Knee Flexion and at

90o Knee Flexion. No significant difference

(p=0.51)

113

6.6 Voluntary Activation of the Trained and

Untrained Before (Shaded) and After (Clear)

Training

114

6.7 EMG Activity of the Vastus Lateralis during

1RM Leg Extension (Cybex VR-2) and MVC

(Strength Testing Chair) of the Trained Leg and

Untrained Leg Pre (Shaded) and Post (Clear)

Training

116

6.8 EMG Activity of the Hamstring during a 1RM

Leg Extension (Cyber VR-2) and MVC

(Strength Testing Chair) of the Trained Leg and

Untrained Leg Pre (Shaded) and Post (Clear)

Training

118

6.9 Relationship of Rectified, Smoothed EMG of

Biceps Femoris and Antagonist Force

119

6.10 Relationship of Rectified, Smoothed EMG of

Vastus Lateralis, Biceps Femoris and

Quadriceps Force

119

xxi

LIST OF ABBREVIATIONS

CSA - cross-sectional area

CNS - central nervous system

EMG - electromyography

iEMG - integrated electromyography

sEMG - smoothed electromyography

rsEMG - rectified smoothed electromyography

COV - coefficient of variation

1 RM - one repetition maximum

SD - standard deviation

MVC - maximal voluntary contraction

MAP - muscle action potential

ROLE OF LENGTH SPECIFICITY, VELOCITY SPECIFICITY AND ... · berbanding kekuatan isometrik selepas...

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