THE EFFECT OF HANDLE BAR HEIGHT ON LOW BACK PAIN IN CYCLISTS DURING SPINNING. Kim Modlin

Transcription

1 THE EFFECT OF HANDLE BAR HEIGHT ON LOW BACK PAIN IN CYCLISTS DURING SPINNING Kim Modlin A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Physiotherapy Johannesburg, 2004

2 Declaration I, Kim Modlin declare that this research report is my own work. It is being submitted for the degree of Master of Science in Physiotherapy, in the University of the Witwatersrand, Johannesburg. It has not been submitted before for any degree or examination at this or any other University...day of.., 2004 ii

3 In honour of my parents Denise and Martin Modlin iii

4 Abstract A study was conducted to determine the optimum position of the handlebar on the Johnny G. Spinning bicycle to reduce low back pain in cyclists participating in a Spinning class. A three period open label cross over design, involving thirty six subjects was conducted. Each subject participated in three Spinning classes with a different handlebar height at each session. The saddle angle, saddle post height and fore/aft position of the saddle remained fixed to eliminate variability. The cyclists pain perception was measured via the Visual Analogue Scale, Lickert Scale and the McGill Pain Questionnaire. The results were analysed with respect to the change in the mean and standard deviation of the Visual Analogue Scale, the Lickert scale and the McGill Pain Questionnaire. The significance of the study was set at the 0.05 level. A zero value was recorded with respect to pain experienced by the cyclists during a Spinning class on the VAS, Lickert scale and on the McGill Pain scale, when the handlebars were placed in the high handlebar height position on the Spinning bicycle; this is the most important outcome of the study conducted. In conclusion, there is a statistically meaningful difference (p<0.001) between the mean values of pain recorded by participants of the low handlebar height compared to the normal handlebar height, with the normal handlebar height being the better position. The standard deviation remains relatively constant. No pain was recorded on the VAS, Lickert scale and on the McGill Pain scale when the handlebars were placed in the high handlebar height position on the Spinning bicycle. The results of the study indicate that the high handlebar height position is the best position for participants in a Spinning class. iv

5 Acknowledgements Acknowledgements to Mrs L Jacobs supervisor Dr P Becker statistician Mr C Kaminski graphic designer Denise Modlin - Spinning instructor Cyclists from Core Health Fitness Centre v

6 TABLE OF CONTENTS DECLARATION DEDICATION ABSTRACT ACKNOWLEDGEMENTS TABLE OF CONTENTS LIST OF FIGURES LIST OF TABLES LIST OF APPENDICES LIST OF ABBREVIATIONS Page ii iii iv v vi ix x xi xii 1.0 INTRODUCTION Aim of the study Significance of the study Null hypotheses Alternative hypotheses LITERATURE REVIEW Introduction Definition of Spinning The causes of low back pain experienced by cyclists Definition of spinal stability and contributing factors resulting in 8 low back pain Definition of the neutral zone Definition of spinal instability The adverse effect of an altered neutral zone 11 vi

7 2.3.5 Loading of the lumbar spine with alterations in spinal positions Bicycle configuration Spinal angle related to crossbar Spinal angle related to saddle angle LBP and pedal unit positions The alteration in bicycle configuration to compensate for 21 anatomical variations of the cyclist 2.6 Associated injuries seen in cyclists with low back pain Measuring instruments MATERIALS AND METHODS Study Design Sample size Subjects Inclusion criteria Exclusion criteria Withdrawal criteria Procedures Pilot study Flow Chart Instrumentation Equipment Variables Special ethical issues Data analysis RESULTS 39 vii

8 4.1 Introduction Justification for the alteration of the study design DISCUSSION Suggestions for further research CONCLUSION 52 REFERENCES 53 viii

9 LIST OF FIGURES Figure Page 2.1 A cyclist on a road bicycle / A cyclist on a Spinning bicycle The three subsystems of spinal stability The alteration in lumbar lordosis due to a handlebar 14 height adjustment- high, normal and low handlebar height 2.4 Forces occurring around the lumbar spine during cycling Spinal angle related to saddle angle The optimal saddle angle on a bicycle Optimal bicycle configuration Possible alterations in bicycle configuration due to an 22 alteration in a cyclist s biomechanics Comparison between groups with respect to the change in mean 42 of the VAS pain scores for low, normal and high handlebar heights on completion of the Spinning class Comparison between groups with respect to the change in mean 43 of the Lickert scale for low, normal and high handlebar heights on completion of the Spinning class Comparison between groups with respect to the change in mean 44 of McGill pain scores for low, normal and high handlebar heights on completion of the Spinning class ix

10 LIST OF TABLES Page Table 4.1 The mean VAS at the start and end of the Spinning class 41 Table 4.2 The mean Lickert scale at the start and end of the Spinning class 42 Table 4.3 The mean McGill Pain score at the start and end of the 43 Spinning class Table 4.4 Analysis of groups 1 and 2 45 Table 4.5 Analysis of groups 1 and 3 46 Table 4.6 Analysis of groups 1 and 2/3 47 x

11 LIST OF APPENDICES Page Appendix A The origin of Spinning 57 Appendix B Subject information sheet 60 Appendix C Consent form for research 62 Appendix D Subject Details Questionnaire 63 Appendix E McGill Pain Questionnaire 68 Appendix F Visual Analogue Scale and Lickert scale 68 Appendix G Ethical Clearance 69 Appendix H Statistical Analysis 74 xi

12 LIST OF ABBREVIATIONS Page 1. Low Back Pain (LBP) 1 2. Visual Analogue Scale (VAS) Non steroidal anti-inflammatory drugs (NSAIDS) Analysis of variance (ANOVA) Generalized Least Squares (GLS) 38 xii