Impact & vibration of running footwear

• Main Author: Sze, Jason Jun Liang
• Other Authors: Leong Kah Fai
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/141254
• Institution: Nanyang Technological University

Running has been popularized in the 1970s concurred with the first introduction of technical running footwear products which encouraged runners to taking up in the sport. This led to intensive research from universities and laboratories to understand and link impact with cushioning of running footwear. Current research primarily focused on rearfoot and midfoot modifications, lacking emphasis on forefoot cushioning. External factors such as vibration also played an important role in running as perceived vibration may influence the runner’s gait patterns which in turn may resulted in running related injuries. The relationship between impact and vibration has not been studied, therefore resulted in the need to design and develop a jig to study the correlation between impact and vibration. The objective of the project was to design and develop a jig to conduct an experiment to study impact and vibration in the forefoot region of running footwear. A customized shoe last was designed and developed. Five selected running footwear were used to conduct forefoot impacted drop tests. Data from the forefoot impacted drop tests were collected and filtered necessarily before comparison to prior data from heel impacted drop tests. The project also sought to find a correlation between impact acceleration and vibration acceleration of running footwear in the forefoot region. The results from the forefoot impact drop tests revealed that the Asics Gel-DS Trainer 24 received the highest peak impact force and the Nike Zoom Fly SP received the lowest peak impact force. There was also found to be insignificant correlation between impact acceleration and vibration acceleration (R² = 0.0377). The Brooks Levitate 2 that utilized a Polyurethane (PU) midsole recorded the highest percentage of energy return of 76.02% in the forefoot region. The Nike Free 5.0 and Asics Gel-DS Trainer 24 received similar mean loading rate in the forefoot region of 238.26 N/ms and 236.64 N/ms respectively. According to the experimental results, peak impact force appeared to be affected by the type and thickness of materials used for running footwear midsole cushioning systems. The design of running footwear also seemed to affect the load it attenuates. However, there was insignificant correlation found between impact and vibration of running footwear in the forefoot region from this study. The experiment was conducted on a small sample size of five footwear which did not fully represented the variety of running footwear available in the market. The limitation of devices used in the experiment could also result in precision of data collection. Thus, a larger sample size with better sensitivity of devices could be used for future development of the project.