THE EFFECT OF FOOT ORTHOSES ON ENERGETICS AND LOWER EXTREMITY CYCLING MECHANICS IN HEALTHY RECREATIONAL ADULTS By Jake O. Campbell A Thesis Presented to The Faculty of Humboldt State University In Partial Fulfillment of the Requirements for the Degree Master of Science in Kinesiology Committee Membership Dr. Justus Ortega, Committee Chair, Graduate Coordinator Dr. Young Sub Kwon, Committee Member Dr. Sheila Alicea, Committee Member May 2016 ABSTRACT THE EFFECT OF FOOT ORTHOSES ON ENERGETICS AND LOWER EXTREMITY CYCLING MECHANICS IN HEALTHY RECREATIONAL ADULTS Jake O. Campbell The use of custom foot orthotics and wedging techniques has been recognized in the literature as an accepted method to mechanically alter or improve joint function at the hip and knee. This study investigated the effect of foot orthoses on energetics and lower extremity cycling mechanics in healthy recreational adults during. Specifically, the effect of two commercial insoles and one lateral heel wedge on net metabolic power and lower extremity mechanics was quantified. It was hypothesized that alterations to medial foot support would affect lower extremity mechanics as well as net metabolic power. Participants (n = 10) included young (26 ± 4 years) male (n=6) and female (n=4) recreational cyclists (8 ± 4 hours/week cycling). The cyclists completed an individualized protocol that involved cycling in four foot orthoses conditions (Control, Insole 1, Insole 2, Wedge) at three power intensities (50%, 65%, 80%) derived from initial max watt test. A one-way repeated measures analyses of variance (ANOVA) was employed to detect influences of condition and sub-maximal workload on net metabolic power. Furthermore, a multivariate analysis of variance (MANOVA) was chosen to detect differences between condition and sub-maximal workload on cycling kinematics. Contrary to our proposed hypothesis, there was no significant effect of foot orthoses on net metabolic power or lower extremity mechanics during cycling. While the findings ii from this study did not show significant differences in net metabolic power or lower extremity cycling mechanics between shoe conditions, there were observed trends that warrant the need for more comprehensive research. iii ACKNOWLEDGEMENTS Dr. Ortega – When I began the next step of my education at Humboldt State, I was unaware of the influence the world of biomechanics would have on me. Your constant positive energy, and creative mindset to troubleshoot any problem will motivate me for years to come. Thank you for your ability to be tough on me when needed and always supportive with the best of intentions. Dr. Kwon –Your knowledge and expertise in exercise physiology required me to defend my testing protocol, which resulted in a significantly better understanding for my overall study design. Thank you for working with me through this process. Dr. Alicea – Thank you for your support and feedback to help me achieve this final product. Jack Thorpe - I wouldn't be where I am today if it wasn't for your constant support. You always have an energetic and positive attitude and I am grateful for your help along the way. Superfeet provided the insoles used for this study. No sources of funding were used to conduct this study. iv TABLE OF CONTENTS ABSTRACT ........................................................................................................................ ii ACKNOWLEDGEMENTS ............................................................................................... iv LIST OF TABLES ............................................................................................................. vi LIST OF FIGURES .......................................................................................................... vii LIST OF APPENDICES .................................................................................................. viii INTRODUCTION ...............................................................................................................1 Pedal Cycle ....................................................................................................................2 Foot-Shoe-Pedal Interface .............................................................................................4 Corrective Orthotics/Cleat Wedges ...............................................................................5 Thesis Statement ............................................................................................................6 METHODS ..........................................................................................................................8 Design ............................................................................................................................8 Participants and Recruitment .........................................................................................8 Procedures ....................................................................................................................10 Measures ......................................................................................................................12 Data Analysis ...............................................................................................................15 Assumptions .................................................................................................................16 Limitations ...................................................................................................................16 Delimitations ................................................................................................................17 Operational Definitions ................................................................................................17 RESULTS ..........................................................................................................................18 DISCUSSION ....................................................................................................................23 Limitations ...................................................................................................................26 CONCLUSION ..................................................................................................................29 REFERENCES ..................................................................................................................30 v LIST OF TABLES Table 1. Individual Subject Characteristics ........................................................................ 9 Table 2. Net Metabolic Power .......................................................................................... 19 Table 3. Condition Values Across Submaximal Workloads (mean ± SEM). ................... 20 Table 4. Subject Shoes/Pedals Used. ................................................................................ 28 vi LIST OF FIGURES Figure 1. Phases of a Pedal Cycle. Material published by So, Ng, Ng, 2005. .................... 3 Figure 2. Plantar Pressures During Cycling. (a) with and (b) without in-shoe orthoses. Material published by Bousie et al., 2013. .................................................................. 4 Figure 3. Forefoot Varus. Uncorrected forefoot varus resulting in unwanted medial knee drift and loss of power transfer to the pedal (a), compared to corrected forefoot varus with improved knee and hip mechanics (b). Dinsdale & Williams, 2010. ................. 6 Figure 4. Average Medial-Lateral Knee Motion (cm) During the Power Phase. ............. 21 Figure 5. Average Max Ankle Internal Rotation (degrees). ............................................. 22 vii LIST OF APPENDICES Appendix A ....................................................................................................................... 32 Appendix B ....................................................................................................................... 33 viii EFFECT OF FOOT ORTHOSES ON HEALTHY RECREATIONAL ADULTS 1 INTRODUCTION With an ever-growing demand for transportation and an increase in technology, cycling is being harnessed more than ever. Ranging from a means of transportation to a full-time career as a competitive professional, cycling is available to a more diverse population than previously seen. As the number of cyclists within a community grows, so does the prevalence for reported discomfort. More often than not, this discomfort is reported in the cyclists’ lower extremity (LE). Literature suggests that a cyclist can reach up to 5000 pedal strokes or more within one hour of activity (Dinsdale & Williams, 2010), or up to 1.5 million pedal strokes in a 5000-mile year (Pruitt & Matheny, 2006). With such high repetitions it is no surprise that a majority of cycling related injuries reported involve the LE, with anterior knee pain being one of the most commonly reported (Wolchok, Hull, & Howell, 1998). Roughly, one-fourth to one-third of all cycling injuries occur at the knees (Clarsen, Krosshaug, & Bahr, 2010; Van Zyl, Schwellnus, & Noakes, 2001; Wilber, Holland, Madison, & Loy, 1995). LE injury can inhibit time on the bike and negatively affect performance. In order to minimize injury and maximize performance, understanding the interaction of the LE, and specifically the foot-shoe-pedal connection, is necessary. The use of corrective foot orthoses and wedging techniques has been recognized in literature as an accepted method to mechanically alter or improve joint function at the ankle, hip, and knee (Bousie, Blanch,