Foot pain will be defined as “an unpleasant sensory and emotional experience following perceived damage to any tissue distal to the tibia or fibula (below your shins); including bones, joints, ligaments, muscles, tendons, nerves, skin, etc” (Hawke & Burns, 2009).
The aim of the white paper summarised in this article is to assess what evidence exists for the efficacy of a vibrating insole such as Floave to reduce foot pain.
What is Floave?
Our team has been working on developing Floave which consists of a pair of smart insoles and their adjoining app and is aiming to improve your wellbeing and foot health at your fingertips.
All users need to do is connect the insoles to their phones and discover the variety of sessions Floave has to offer.
The effects of foot pain and what parts of the foot are affected.
Foot pain can be disabling, impair mood, behaviour, self-care ability and overall quality of life (QoL). Using the Manchester Foot Pain and Disability Index, one study found that 82% of those with disabling pain said they experienced a functional limitation (e.g. avoiding walking long distances), 86.4% had issues with pain intensity (e.g. doing everything but with more pain or discomfort), and 30% were concerned with foot appearance (Garrow et al. 2004).
Of individuals with disabling foot pain, the most common parts of the foot affected are the great toe, first metatarsal head, mid-foot/arch area and plantar surface of the heel.
Different parts of the foot are affected by different factors. Plantar fasciitis (pain on the bottom of your foot, around your heel and arch) is caused by repeated mechanical overloading and microtrauma. Risk factors are thought to include shortening of the calf muscles, overweight, long periods of employment in non-sedentary occupations, and foot deformities (Gutteck et al. 2019). Meanwhile, pain in the metatarsals (forefoot), also of mechanical origin, is usually associated with metatarsal misalignment or atrophy of the plantar fat pad (pad of fat at the base of the foot). Other underlying diseases (e.g. rheumatoid arthritis) can also cause pain in the forefoot.
Extrinsic factors often linked to foot pain include inappropriate footwear and occupational activities (Hawke & Burns, 2009). A recent systematic review has found that 63-72% of people wear incorrectly fitting shoes (Buldt & Menz, 2018). 84-91% of individuals wearing too loose or too tight shoes experience foot pain (Buldt & Menz, 2018).
Research has shown a higher risk of foot pain in groups such as older people (81%) and children with Down syndrome (46%) resulting from incorrect shoes fitting (Buldt & Menz, 2018). There is evidence older people’s feet have broader forefoot regions, flatter arches, and more deformities compared to young people (Kouchi et al. 1998; Echeita et al. 2016).
Who is affected by foot pain?
63.2% of people have some kind of problem with their feet, while 17-42% of adults are thought to be affected by foot pain (Hill et al. 2008; Badlissi et al. 2005). However, as most studies focus on sub-populations such as the elderly, the prevalence in the general population is unclear (Hawke & Burns, 2009).
A population-based cross-sectional survey of 3417 individuals aged 18-80 years old found that a similar number of men (20%) and women (24%) report foot pain and that in nearly half of cases this pain was disabling (Garrow et al. 2004). Garrow et al. also found that disabling foot pain increases with age, peaking at 55-64 years of age.
Additionally, people with foot disabilities are more likely to have a diagnosed chronic disease than those without foot disabilities (45.9 vs. 16.0%). Garrow et al. found that they were particularly likely to have osteoarthritis, heart disease, diabetes mellitus and rheumatoid arthritis (Garrow et al. 2004).
Treatments differ according to the foot complaint. For example, for plantar fasciitis, first line interventions are self-management techniques such as activity modifications (For those patients who stand for more than 8 hours per day, reduced activity levels and modified work shifts i.e. less than 8 hours should be advised), stretching, footwear advice, insoles, etc. If first line interventions lasting 6-12 weeks are not successful in reducing pain significantly, the clinician will prescribe an orthotic. If following second-line intervention for 12-24 weeks, no significant improvement is seen, third-line intervention will be night splints to be used for 12-16 weeks. Should this fail to produce an improvement, fourth-line interventions including steroid Injections, acupuncture, or Extracorporeal Shock Wave Therapy (ESWT), can be pursued prior to the final intervention of surgery (only after failure to improve on conservative interventions for at least 12 months) NHS (Sheffield Primary Care Trust: Plantar fasciitis- Clinical Pathway; Gutteck et al. 2019). >90% of chronically recurring plantar fasciitis cases can be treated successfully via surgery (Gutteck et al. 2019). Nonetheless, clinicians generally attempt to avoid such invasive procedures.
Can vibrations help achieve plantar pain reduction?
Vibratory analgesia describes the ability of vibration to reduce pain. Vibratory analgesia has been reported in both animals and humans (Doi et al. 2018; Lundeberg et al. 1987). Vibrations have been used to reduce pain in many parts of the body including the feet (see next section), neck (Beinert et al. 2018), forearms (Staud et al. 2011), and jaws (Bagherian & Sheikhfathollahi 2016). Although the exact mechanisms of vibratory analgesia are still disputed (Hollins et al. 2014), the classical theory is the Gate Control Theory of pain proposed by Melzack and Wall (Melzack & Wall 1965). This theory, simply put, states that non-painful stimuli like vibrations can essentially compete with painful stimuli and reduce pain.
Vibrations have been shown to dampen many different types of pain including cutaneous pain (superficial/skin pain), myalgia (muscle pain), and phantom limb pain (Lundeberg 1985; Lundeberg 1987; Bergomi et al. 2018). One example of pain reduction via a mechanism other than Gate Control Theory is reduction in muscle soreness after exercise. Multiple studies have shown that applying local vibrations using handheld or wearable devices like MyoVolt™ or
VITER VR-7N, ITO before or after exercise can reduce muscle soreness significantly for up to 72 hours (compared to those who exercised without vibrations) (Lu et al. 2019; Bakhtiary et al. 2006; Cochrane 2017). In this case, as the pain is reduced long after the vibrations were applied, it is likely a different mechanism underlying the pain reduction due to vibration.
Containing a wide range of vibrational patterns, Floave can reduce foot pain caused by a variety of factors. While few studies focus on vibrations for pain reduction in feet, vibrations in general in other parts of the body set a clear precedent for the use of vibration to relieve chronic foot pain. Especially considering the high prevalence of foot pain, in the general population, Floave has great potential to improve the lives of many users.
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