There is an increasing number of individuals participating in organised races every year. Running involves repetitive movements and cyclical activation of lower extremity muscles, with foot-strike pattern and fatigue proposed to be contributing factors to running-related injuries. A variety of measures can be used to assess neuromuscular performance and gait of runners. The aims of this thesis were to: (1) systematically review and quality appraise articles addressing the reliability of plantar pressure (PP) distribution and centre of pressure (COP) measures in static stance, 2D video-based assessments of foot-strike pattern (FSP), and plantar-flexion isometric strength-endurance (PFisom) measures (Chapter One); (2) assess the test-retest reliability of these measures in a cohort of recreationally competitive runners (Chapter Two); (3) determine the intra-rater and inter-rater reliability of 2D analyses of overground running in an outdoor environment (Chapter Three); and (4) investigate the effects of running a 12-km race on these measures (Chapter Four).
As part of the systematic review in Chapter One, forty-three articles were assessed for their methodological quality, with only 21% obtaining a high quality score (≥ 75%) based on the Consensus-based Standards for the selection of health Measurement Instruments. From the reviewed studies, the most reliable measures were: PP mean pressure, % body weight, and contact area; COP sway area and path length; FSP when using a two level classification system; and PFisom peak torque and peak force.
In Chapter Two, twenty-one (10 males, 11 females) recreational runners completed tests of PP distribution in a bilateral stance, a 30 second eyes-closed postural balance test, a self-selected running over task 15-m with video assessment, and a test to determine PFisom on two force plates in order to assess test-retest reliability. Measures of PP surface area, COP path length, FSP classification, foot-strike angle, and running speed were found to be the most reliable across intra-session and inter-session testing occasions. The reliability of PFisom measures could not be determined due to technical difficulties with the software and loss of data.
In Chapter Three, the intra-rater and inter-rater reliability of 2D video analyses of overground running in an outdoor environment were assessed from 155 high-speed videos (240 Hz). These 2D video analyses were reliable for quantifying FSP, foot-strike angle, and running speed, although foot-strike angle errors of 2.5° were typical. The associated large CV (17.6%) is likely a reflection of the limited foot-strike angle range (42°) in our population.
In Chapter Four, twenty-four (15 males, 9 males) recreationally competitive runners completed PP distribution, postural balance, FSP, and PFisom tests before and after a 12-km organised race. Running a 12-km race influenced several neuromuscular measures, notably postural control (92.1% and 22.7% increase for area 95 ellipse and path length, respectively) and PFisom (10.8% decrease), confirming racing-induced fatigue. However, these alterations did not lead to observable changes in FSP, indicating that this measure might not be appropriate for quantifying fatigue in recreationally competitive runners.
Results from the systematic review highlight the need for higher quality methodological reliability studies to be undertaken to make stronger inferences about the reliability of measures of PP, COP, FSP and PFisom. The two reliability studies demonstrated measures of PP surface area, COP path length, FSP, foot-strike angle, and running speed to be the most reliable. Furthermore, quantifiable declines in COP and PFisom were observed post a 12-km race, confirming racing-induce fatigue.
