Running related injuries to the lower extremities are linked to external forces that are acting on the body during running, as a result of running style, footwear, running surface etcetera. There appears to be a difference in running style between professional, faster runners and slower, less experienced runners. It appears that the faster runners do not strike the ground with their heel, and run with a so-called “fore foot striking”. Joggers tend to strike their heels heavily on the ground, making use of the heels of conventional running shoes. Despite the cushioned heel of the shoe, joggers send a shock through the heel, knee, hip and spine of the quantity of 2-3 times their body weight with every step. Excessive rear foot striking causes a sudden increase in vertical ground reaction force (Fz, impact force), when the foot contacts the ground. This causes the majority of running "overuse injuries", also called "repetitive strain injuries" .The reduction in initial ground reaction force as seen in mid-foot strikers and forefoot strikers has been linked to a lower incidence of injuries. The Heelless running shoe used the principle of forefoot striking to minimize the ground reaction force. Although there appears to be a relation between impact forces and running related injuries, much remains unclear about the exact mechanisms that link running biomechanics and kinematics to running related injuries.
To determine if the Heelless shoe does what it is supposed to do, kinematical and biomechanical analyses are necessary. Based on the assumptions above, the Heelless shoe will be tested in a laboratory situation at Roessingh Research and Development in which the following research question will be answered:
What are the biomechanical and kinematical effects of wearing the Heelless shoe during walking and running at a voluntarily chosen speed and at a fixed speed, compared to walking and running barefoot and in conventional running shoes?
Because there is not much consensus about the exact influence of footwear on running style, kinematics and biomechanics a comprehensive approach is necessary. Therefore a broad spectrum of measurement techniques will be used to evaluate the Heelless shoe kinematical and biomechanical. Roessingh Research and Development has substantial knowledge and experience in gait analysis using techniques such as ground reaction force measurement, motion analysis (VICON), Electro Myo Graphy and in-sole pressure sensors. In addition oxygen uptake will be measured to determine physiological effects of running in the Heelless shoe. As such, influences of the heelless shoes on all parameters linked to running biomechanics and kinematics will be studied. Subjects will be measured while being barefoot and while wearing conventional measured to fit conventional running shoes and compared to the newly developed Heelless shoes during walking and running in the gait laboratory on a straight, level walkway of 10 m. In addition measurements will be performed on a treadmill. Subjects will be equipped with in sole pressure-measurement system, Vicon motion capture markers and EMG electrodes. In addition Force measurements will be performed to measure the global ground reaction force and oxygen uptake will be measured to determine physiological effects.