Stiffer shoes show no clear energy savings in older adults
Peak ankle torque, the turning effect of force, rose about 10% in the stiffest shoes compared with standard shoes.
Limit: Stiffer shoes also weighed more, potentially offsetting energy savings from stiffness
Edited by Boris Djordjevic · AgingResearch.News
Nineteen older adults—nine women and 10 men, averaging 70 years old—took part in a randomized crossover trial. Each walked on a treadmill at 1.2 meters per second on level ground and 5-degree uphill and downhill slopes. Researchers compared standard shoes with shoes containing flat carbon fiber insoles 1.6 or 3.2 millimeters thick. Walking energy-use tests lasted at least five minutes per condition.
The stiffest shoes raised peak ankle torque by about 10% compared with standard shoes. Stiffer shoes reduced the rate of energy absorption near the toes but increased it across the foot and shoe as a whole. Knee and hip mechanics and walking energy use did not change consistently with stiffness.
Why it matters
Walking becomes more energy-demanding with age. The authors suggest that greater ankle torque with stiffer shoes could be useful for strengthening older adults’ calf muscles over time.
Caveats
These short treadmill tests did not assess long-term calf strengthening, and the insoles added weight as well as stiffness. The trial excluded people with conditions that limited their ability to walk unassisted for at least six minutes.
From the paper
- Participants
Nineteen (9F/10M, 70 ± 5.9 yrs, 73.8 ± 20.3 kg) older adults provided written informed) consent and participated in this IRB-approved study (University of Utah IRB #154429).
- Limitation
First, the older adults who participated in this study were free of neurological, musculoskeletal, and metabolic complications that substantially influenced their walking ability.
- Negative power magnitude distal to the forefoot
The foot+shoe structures distal to the forefoot center of mass performed a smaller magnitude of average negative power with increasing stiffness …
- Negative power distal to the hindfoot
… revealed a greater magnitude of average negative power in the Medium compared with the Low stiffness condition during Level (d = 0.74, p = 0.003) and Incline (d = 1.35, p = 0.001) walking …
- Peak ankle joint moment
With increasing footwear stiffness, the peak ankle moment increased …
- Net metabolic power
There was no statistically significant main effect of footwear stiffness (F(2,38) = 0.4888, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} ${\eta }_{p}^{2}=0.02$\end{document}ηp2=0.02, p = 0.6257) nor a slope × stiffness interaction effect (F(4,76) = 0.8457, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} ${\eta }_{p}^{2}=0.06$\end{document}ηp2=0.06 p = 0.4955) on net metabolic power …
Quoted word for word from the full text on PubMed Central.