A new study finds that special insoles can offer a new way to improve balance and coordination. The insoles electrically stimulate feet with gentle electrical vibrations that the user cannot feel, but can affect a person’s stride, boost stability, and improve balance.

The study participants underwent strenuous activity while wearing these insoles and adjusted walking strides in a pattern to enhance balance and stability. The study was published online in Medicine & Science In Sports & Exercise.

The insoles work using a process called stochastic resonance (SR), a method for amplifying a weak signal by adding ‘white noise’ across a spectrum of frequencies. The vibrations are unnoticeable but they provide a signal update to the users’ sole that upgrades enhanced performance during walking movements.

According to Daniel Miranda, the lead author of the new study and a Technology Development Fellow at the Wyss Institute at Harvard University in Massachusetts, “Somebody who’s 65 or 70 (years old) who’s generally healthy may have some sensory deficits due to the natural aging process”. It made sense that studies would investigate how this technology could help older people with decreased sensitivity recover some of what they had lost. Miranda and his colleagues were keen on exploring the device further, particularly on younger people and athletes.

The technology had progressed a lot since the experiments first started, allowing for acutators and sensors to be installed comfortably inside a thin, flexible insole made of traditional insole materials, which could fit smoothly inside a shoe. This enabled a more flexible and precise testing of a wider range of activities.

Scientists observed the participants and applied electrical impulses during different times of the day; while they were walking on an inclined treadmill, at a peak performance period, before they became tired and fatigued.

Since the vibrations were of such low amplitude that the individuals barely noticed them, the scientists figured that they weren’t purposely changing the way they walked. Hence the device proved to be an accurate walking aid.

The researchers found that whenever they sent electrical signals through the insoles there was a 10% improvement in the gait mechanism called step-width variability, which is important in keeping balance. The variations in step-width help improve stability whilst walking.

This is quite a significant study since it opens a gate for future research, especially research to improve performance of athletes. Using the insoles to increase sensation for a more stable gait could be especially beneficial when fatigue has reduced normal sensitivity to stimuli.

A better balance could help improve body posture, which could prove quite beneficial for people with hunched backs. This technology could also greatly benefit obese people, individuals affected by Parkinson’s and elderly people as well, since all of them have difficulty keeping their balance.

Better balance could also help prevent further injuries from falls. “Improving the balance-control mechanism has the potential to translate to reducing injury or risk of injury, but those studies still need to be done,” Miranda said.

What Is The Gait Cycle?

We never pay much attention to our walking patterns since we have been practicing them since the day we first learnt to walk and have been walking without thinking too much about them. But it’s much more complicated than that.

Walking is actually a complex series of co-ordinated movements involving muscles and joints of the upper and lower body. The way each person walks or runs is known as their gait. A gait cycle consists of 2 steps, 1 with the right foot and 1 with the left foot i.e. from right foot initial contact through right limb stance phase and swing phase and ends at right foot initial contact.

Stance phase is the phase in which the foot is firmly placed on the ground, which makes up 60% of the entire gait cycle. Swing phase is the phase in which the foot is in midair, and out of contact from the ground. The phase where both feet are firmly planted on the ground accounts for 10-12% of the entire cycle. This phase is known as double support. The 1st double support starts at initial contact and ends when the opposite foot leaves the ground at toe off. The 2nd double support begins as the opposite limb contacts the ground and ends when the limb in question leaves the ground at toe off. The first double support ends when one of the two feet lifts from the ground toe up.