Cushioned running shoes and ground contact times?
Some running shoes “increase ground contact times compared to barefoot conditions” and “could prevent or control the risk of leg problems” according to a new piece of research published in the Journal of the Medical Behaviour of Biomedical Materials.
The study sought to evaluate how different cushioned shoes interact with ground contact times for each phase of gait. “Minimalist”, “Boost”, “EVA”, “Air Chamber” and “Pronation Control” cushioned shoes were all compared against each other and against barefoot on 30 healthy male recreational runners.
The authors found that all cushioned shoes increased ground contact time compared to barefoot with the “Air Chamber” increasing heel contact time for the longest during walking and increasing propulsion phase ground contact time for the longest while running. There is no evidence in this paper that these changes prevent or control injury.
What do you advise your patients about running shoes?
A recent editorial published in The British Journal of Sports Medicine is worth a read, stating that "While we anticipate that evidence to support specific running shoe prescription paradigms might soon emerge, we caution against overstating the benefits or harms of any existing or future shoe paradigms to runners."
The article highlights the fact that for the past 40 years different running shoes have been prescribed depending on foot morphology in the attempt to reduce injury. However, according to 5 high quality RCTs, injuries have not been prevented. There are plenty of other studies to conflict and support this, however, it is clear that no running shoe paradigm is set in stone. Interestingly, the authors note that selecting running shoes based on comfort rather than foot morphology is gaining popularity.
Measuring stiffness in clubfeet
A new study published in Clinical Biomechanics has devised a system called the “Torque-Displacement-Handpiece” to measure ankle and subtalar joint stiffness in patients with club feet and deemed it precise and reliable.
The authors highlight that while clinicians often refer to club feet as being “stiffer”, there is no objective measurement to determine stiffness. They went on to investigate the newly developed 'Torque-Displacement-Handpiece' along with an adjusted 'Abduction Dorsiflexion Mechanism' clubfoot-brace which “made it possible to move a foot over two rotational axis, while continuously capturing the applied torque and the achieved angulation.” The gradient of the torque / angulation graph was then used as a measure for joint stiffness.
17 club feet in 11 patients were assessed along with 11 patients with 22 healthy feet. Findings suggested that it was possible to measure torque, angulation and stiffness both reliably and precisely and “Clubfeet have higher ankle stiffness compared to healthy controls.”