Arch flexibility and gait

Members do not see these Ads. Sign Up.

Apparently, medial arch flexibility, and flexibility at the Navicular/medial Cuneiform joint in particular, may be key to upright gait . A well written summary of recent research can be found via the link provided . https://www.popsci.com/health/foot-arch-walking-human-evolution/

Basically this -
Tibia sits on Talus .
Heel lifts and arch flattens so upper surface of talus and tibia point forwards .
Arch tissues reestablish more arched foot shape by recoil/intrinsic foot muscle contraction.
Tibial aspect of talus now points more vertically, tibia also more upright.

 

The paper to which the previous post refers was recently published by Lauren Welte et al https://doi.org/10.3389/fbioe.2023.1155439

Here are a couple of quotes from a review of the paper -

“We thought originally that the spring-like arch helped to lift the body into the next step,” study co-author and University of Wisconsin-Madison biomechanical engineer Lauren Welte said in a statement. “It turns out that instead, the spring-like arch recoils to help the ankle lift the body.”

So it could be that one of the roles of the intrinsic foot muscles (among many ) is not about propelling the COM forwards but facilitating the ankle in this role . The intrinsics are required to put the tibia in the correct position at toe off . The intrinsics don't need to be big powerful muscles to do this but they must be strong enough and work alongside a flexible arch.

"Surprisingly, they found that a rigid arch without recoil caused the foot to prematurely leave the ground, likely decreasing the efficiency of the calf muscle. A rigid arch also leaned the ankle bones too far forward. A forward lean looks more like the posture of walking chimpanzees instead of the straight upright stance of a human gait."


Figure 1

FIGURE 1. (A) The center of mass (COM) propulsion hypothesis suggests that both arch recoil and the foot’s levering ability can raise the COM. (B) The foot levers around the fulcrum metatarsophalangeal joint.
An alternative hypothesis to explain the role of late stance foot arch recoil is that its shape and plantarflexion mobility are critical for allowing the ankle and proximal segments to achieve postures required for efficient locomotion (Lim and Park, 2018)

 

A recent paper on foot core strengthening found that this type of exercise could reduce running injuries of the lower limb by half.

Might it be that strengthening the arch supporting muscles of the foot helps with arch recoil/recovery close to toe off and allows a more favourable orientation of the tibia to be achieved ? Runners with stronger feet run with a more upright tibia and not with the tibia tending towards a more chimpanzee like orientation .

Interestingly ,if you take the IFM out of the equation using an LA block, runners can still manage but use a more pronounced "hip swinging strategy".

A number of papers have shown strengthening the IFM can help with PFP in the knee .

 

This sentence should end in a ? .

Another mechanism which helps arch recoil/recovery is the windlass mechanism . As the toes dorsiflex near toe off the PF wraps around the met heads and helps re-establish a more pronounced medial arch .

But what if shoes have toe springs . These allow the foot to move through toe off with less toe dorsiflexion which presumably means less windlass activity, less pronounced medial arch, and a less favorably orientated tibia. And that might lead to problems!

 

So Welte et al feel that the navicular /medial cuneiform joint is key to medial arch flexibility and this this flexibility may in turn be key to tibial orientation through toe off . So you need energy storing tissues and a functional joint to give effective arch recoil .

But what of conditions that affect joint mobility such as diabetes (glycation of ligaments ) ,arthritis and even aging. How can a non mobile navicular /medial cuneiform joint be mobilized ?