Running Patterns Change As Shoes Wear Out

Researchers at University of Texas and Nanyang Technological University investigated the biomechanical effects of running using new versus worn out shoes. They also compared three types of cushioning footwear – air, gel and spring.

Dr. Kong and his team studied 24 runners (14 men and 10 women). They ran 200 miles in the same pair of shoes with an assigned cushion. The cushion consisted either of air, gel or spring. They were tested on a 20m laboratory runway; running at 4.5ms^-1 (16.2 kph or approximately 3.7 minute kilometre pace) using a force platform and a motion capture system.

Pre and post-reading of the stance time by using force data, external loads by maximum vertical force, and loading rate and kinematic changes on angles of the torso, hip, knee and ankle were calculated during the run.

Results

The results showed that for worn-shoes there was an increase in stance time. There was also decreased torso leaning forward (running more upright) and less forward lean during toe- off. A decrease in maximum ankle dorsiflexion and increase in ankle plantarflexion during toe-off was also observed.

But there was no change in knee and hip angles found in all three types of cushioning footwear. The was also no change either new or worn shoes.

The researchers suggested that runners modify their running pattern to adapt to the condition of the shoes (decrease in cushioning during wearing out process) to maintain constant external loads. The adaptation changes among different types of shoes cushioning in running were similar. Therefore, types of shoes cushioning should not be the main factor to consider when choosing a pair of running shoes.

Reference:

Running in new and worn shoes: a comparison of three types of cushioning footwear, P W Kong, N G Candelaria, D R Smith, British Journal of Sports Medicine 2009;43:745-749