Biomechanical variations in gait of active and sedentary individuals upon perceived exertion

Abstract

Aim: The aim of this research was to investigate whether there are comparable differences in the gait kinematic, kinetic and spatio-temporal parameters which can be observed within the gait of both active and sedentary young adults upon exertion up to the point of maximal fatigue. Method: The current study is a quantitative, correlational, experimental study. The entire research protocol was performed in a clinical gait and motion analysis laboratory in the Podiatry Department, within the Faculty of Health Sciences (University of Malta, Mater Dei Hospital). An 18-camera Vicon Motion Capture System was utilised to collect all gait parameters. Retroreflective markers were placed upon various anatomical locations on the participants’ lower limbs as dictated by the Plugin-Gait model (Vicon). This system provided a digital map of the participants’ walking pattern in space whilst also providing quantifiable data which was then used to measure pattern differences. All participants were asked the same questions and the same readings were taken throughout the entire research process. After the initial motion capture, participants were asked to run/jog on a treadmill at a self-selected, comfortable pace whilst having their relevant recordings of Rate of Perceived Exertion (RPE), speed, distance, time, peripheral oxygen saturation (SPO2), and Heart Rate (HR) recorded. Once fatigue was achieved (when the participants stated that they scored their fatigue as 20 on the RPE scale), the participants were required to perform one final motion capture with the same instructions as the earlier gait analysis procedure. Subsequently, the six best pre- and post- trials (three for pre- and three for post-) with the most representative gait patterns were selected from each session and used for data processing. In data processing, the captures were tabulated and an average was calculated. This entire process was conducted for all participants and spanned over a period of 6 months. Results: A total of forty healthy participants successfully participated in this study, (Active participants: 31; Sedentary participants: 9; Male Participants: 20; Female Participants: 20; Age average: 26; SD ± 2.05). Significant (p <0.05) fatigue-induced changes in ankle dorsi/plantarflexion and GRFZ occurred in all the five phases of gait (Heel Strike, Mid-Stance, Weight-Transference, Toe-off, and Mid-Swing). This study found that these kinematic and kinetic variations altered various spatio-temporal parameters. These variations were evident in all the participants’ reduction in cadence (p = 0.002), step times (p <0.001) and stride times (p = 0.012). Furthermore, this study observed that fatigue alters gait significantly regardless of whether participants are active or sedentary. Conclusion: Considering the nature of the fatiguing task, subjects experienced maximal exhaustion, but they may not have progressed through to maximal fatigue. Nevertheless, the readings obtained within this study, which could be described as a “fatigued/exhaustive state”, still satisfy the requirements of the aim. Furthermore, this research observed significant effect of fatigue on ankle kinematic and kinetic mechanisms. Ankle dorsi/plantarflexion, GRFZ, along with other (less-significant) biomechanical alterations led to significant reduction in cadence, step times and stride times. It was also discussed how these kinematic and kinetic paradigms have substantial implications for the gait pattern of athletes, the elderly, and the general population. Addressing these may decrease the risk of falls and injuries.