Nicholas S Frank1, Stephen D Prentice2, Jack P Callaghan2. 1. Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada. Electronic address: nfrank@uwaterloo.ca. 2. Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
Abstract
BACKGROUND: Understanding how footwear cushioning influences movement stability may be helpful in reducing injuries related to repetitive loading. RESEARCH QUESTION: The purpose of this study was to identify the relationship between running experience and midsole cushioning on local dynamic stability of the ankle, knee and hip. METHODS: Twenty-four trained and novice runners were recruited to run on a treadmill for five minutes at the same relative intensity. Midsole thickness (thick/thin) and stiffness (soft / hard) were manipulated yielding four unique conditions. Lyapunov exponents were estimated using the Wolf algorithm from sagittal ankle, knee and hip kinematics. RESULTS: Trained runners had increased movement stability in all shoe conditions compared to their novice counterparts. Midsole thickness and stiffness, overall, did not affect movement stability within each of the running groups. Novice runners displayed decreased movement stability at the hip while running in the thick/soft running shoes. It was found that running experience has a greater influence on movement stability in the lower limbs compared to the midsole characteristics that were manipulated in this experiment. The hip was most stable followed by the knee and the ankle highlighting decreased stability in distal joints. CONCLUSIONS: It appears that midsole design within current design ranges do not have the ability to influence movement stability.
BACKGROUND: Understanding how footwear cushioning influences movement stability may be helpful in reducing injuries related to repetitive loading. RESEARCH QUESTION: The purpose of this study was to identify the relationship between running experience and midsole cushioning on local dynamic stability of the ankle, knee and hip. METHODS: Twenty-four trained and novice runners were recruited to run on a treadmill for five minutes at the same relative intensity. Midsole thickness (thick/thin) and stiffness (soft / hard) were manipulated yielding four unique conditions. Lyapunov exponents were estimated using the Wolf algorithm from sagittal ankle, knee and hip kinematics. RESULTS: Trained runners had increased movement stability in all shoe conditions compared to their novice counterparts. Midsole thickness and stiffness, overall, did not affect movement stability within each of the running groups. Novice runners displayed decreased movement stability at the hip while running in the thick/soft running shoes. It was found that running experience has a greater influence on movement stability in the lower limbs compared to the midsole characteristics that were manipulated in this experiment. The hip was most stable followed by the knee and the ankle highlighting decreased stability in distal joints. CONCLUSIONS: It appears that midsole design within current design ranges do not have the ability to influence movement stability.