Kinetic Asymmetries During Submaximal and Maximal Speed Running

An important issue for sports scientists, coaches and athletes is an understanding of the factors within a running stride that can enhance or limit maximal running speed. Previous research has identified many sprint-related parameters as potential kinetic limiters of maximal Center of Mass velocity (Chapman and Caldwell, 1983b; Weyand et al., 2001). Bilateral asymmetry is present for many of these parameters during running; however the degree to which such asymmetries change as running speed increases is unknown. It was hypothesized that asymmetries in key sprinting parameters would be larger at maximal speed than all other tested speeds. Kinematics and kinetics were collected from nine female competitive speed and power athletes (age = 21 ±3 years, mass = 60.58 ±7.48 kg, height = 1.64 ±0.07 m) who completed maximal and submaximal sprinting trials on a force-instrumented treadmill. A repeated-measures ANOVA was completed for each parameter to examine the asymmetry differences across speed. The only parameter for which asymmetry was statistically greater (p\u3c0.05) during maximal speed than all other speeds was effective vertical stiffness, in which the level of asymmetry increased incrementally with speed (r2=0.97). Therefore the hypothesis that asymmetries would increase with speed for all key parameters is rejected. Bilateral asymmetries in effective vertical stiffness appeared to be related to asymmetries in both vertical and A/P propulsive impulse at maximal speed. Furthermore, asymmetries in effective vertical stiffness may force runners to resort to a less stable and less coordinated gait, limiting their ability to further increase stride frequency, and thus limiting maximal speed

DEVELOPMENT OF A PROTOTYPE SMART APPAREL TO QUANTIFY RUNNING GAIT IN THE DAILY TRAINING ENVIRONMENT

Running gait kinetics and kinematics can be measured in the lab using force-instrumented treadmills and 3D motion capture. However, these tools are not feasible for use in the daily training environment of recreational and elite runners and track athletes. An inertial sensor-based prototype wearable smart garment (SG) has been developed to solve this problem. The purpose of this study was an initial assessment of SG compared to a force treadmill (FT) where foot-ground kinetics and temporal measures relevant to running were examined. Vertical ground reaction force, step time, and contact time showed “good to excellent” mean absolute percent error (\u3c 6%), while step impulse did not (\u3e 10%). All variables showed strong correlations between SG and FT (r \u3e 0.85). The initial prototype smart garment is a viable option for the measurement of running biomechanics outside of the lab