Innersoles / Insole / What are foot Innersoles?
Insole inserts or Innersoles are devices that are placed into shoes to control or correct abnormal lower limb motions and alignment. They are commonly known as Innersoles, orthotic insoles, functional foot Innersoles, insole inserts, orthoses and the incorrectly spelt innersoles (this is an incorrect spelling of the word Innersoles).
The most common abnormal motion that Innersoles correct is over pronation.
Conditions that Innersoles are used to treat include (but not limited to) plantar fasciitis, heel pain, metatarsalgia, shin pain, over pronation, flat feet and collapsed arches, bunions and achilles tendonitis.
Innersoles prevent movements that are excessive in both amount of movement and also in the speed of movement. For example pronation at the incorrect time of the gait (walking) cycle or pronation that happens too rapidly will cause over use of the foot, injury and foot pain. Both types of pronation can be controlled with foot Innersoles.
Functional foot Innersoles alter the way the foot interacts with the ground. The aim of using a foot insole is to relieve the amount of strain on the foot which will reduce foot pain. This achieved by supporting the anatomical arches of the foot.
Foot Innersoles are most effective when worn with well fitted supportive footwear. Even the most effective insole when placed into old worn out shoes will not function to its maximum.
“Ortho” is a Greek word meaning “to straighten”. Foot orthotics or foot orthoses are the devices used to support or/and straighten a foot to its natural position so that it functions correctly during the gait cycle.
To understand better the concept of foot orthotics, and how it helps to treat different foot and lower limb problems, first one needs to know certain definitions.
It is a branch of medical science that relates to the formation and application of orthosis or orthotic devices that are used to support and rectify the function of a part of the body whether trunk or any limb. Foot orthotics relate to the problems of foot and lower limb.
Professionals trained in the field of orthotics and having a profound knowledge of anatomy, physiology, gait analysis, material engineering etc. An orthotist is a technician that designs and manufactures orthotic devices.
A podiatrist is simply a “foot specialist”, who deals with all kinds of problems related to feet such as corns, bunions, heel spurs, arch problems, ingrown toenails, foot injuries, infections, deformities etc. His job is to treat such problems with medication, physiotherapy, orthotics or surgery.
Mechanics is the branch of physics concerned with the motion of bodies, in case of Biomechanics, the bodies are living as bio = life. So, foot biomechanics basically, relates to the study of foot movements and the effects of muscles and gravity on its skeletal structure.
A foot can move upwards (dorsiflexion) and downwards (plantarflexion); horizontally outwards (Abduction) and horizontally inwards (Adduction); twist outwards (Eversion) and twist inwards (Inversion).
These movements may occur alone or in combination. Pronation and Supination are the two terms used to define a combination of these movements.
Pronation is the upward and outward movement of the foot involving dorsiflexion, abduction and eversion.
Supination is a downward and inward movement of the foot involving plantarflexion, adduction and inversion of the foot.
Gait cycle comprises of one full step, starting when the heel of one foot strikes the ground and ending when heel of the same foot touches the ground again.
It comprises of a Stance Phase and a Swing Phase.
The stance phase of the gait cycle is the most important when talking about orthotics as this is when the foot is in contact with the ground.This is of course when and orthotic can alter the interaction between the foot and the ground.
The gait cycle consists of three sub-phases:
1. Contact phase: When the heel touches the ground till the foot lies flat on the ground. During this phase the foot, which is slightly supinated at the time of contact rapidly pronates (twits upward and outward) to get adapted to the ground and this movement also acts as a shock absorber.
2. Midstance phase:When the foot lies flat on the ground till the heal lifts up again. During this phase, the foot supinates (twists downwards and inwards) to support the weight of the body.
3. Propulsive or Take off phase: when the heel lifts up the ground till the toes lift up the ground. During this phase the foot continues to supinate (and is in a slightly supinated position when the heel strikes again on the ground).
Therefore, supination and pronation movements are part of a normal gait cycle. The problem starts when the foot pronates too much or pronates at an inappropriate time. This excessive pronation leads to problems such as plantar fasciitis, flat feet and collapsed arches, achilles tendonitis and many other foot and lower limb pains.
Over pronation is the most common biomechanical abnormality of the foot that is responsible for;
- pain in the leg, knee, hip and lower back region
- about 60-90% of all foot and lower limb problems associated with overuse injuries.
The point to consider here is that about 60 to 70 percent of general population is estimated to over pronate to some degree. Due to over pronation during gait cycle, legs rotate internally leading to irregular movements in the knee joint. This in turn causes the pelvis to lean forward increasing tension on the lower back muscles.
Therefore, a little disorganized or irregular foot movement can lead to pain in lower legs, knee joints, hips and lower back.
Now let us define foot orthotics and learn how they act to alleviate foot problems in the light of above-mentioned details.
Foot orthosis is a device used to:
– Act as a cushion or pad temporarily for painful foot conditions and/or
– support and align the foot during gait cycle to correct over-pronation and thus prevent or treat various biomechanical foot problems.
How Orthotic devices help:
An orthotic device helps by preventing collapse of the arches (over-pronation) and rolling inwards of ankles during gait cycle. By doing this, it keeps the feet and ankles aligned correctly during foot movements, which prevents the inward tilt or bending of ankles, knees and legs during walking or running etc. This restores the natural function of the feet and stabilizes the whole lower extremity biomechanics.
Which problems can orthotics help?
In the past decade, medical research has clearly established the relation between faulty foot movements and pain in heels, knee joints and lower back.
Foot orthotics can help with;
- Heel pain, arch pain, plantar fasciitis, corns, calluses, bunions, hammertoes, heel spurs
- Tendonitis, Shin splints, knee pain, cramping, aching or tired legs
- Certain types of lower back pain
- Neuroma, geriatric or diabetic foot problems (protects and provides comfort)
- Preventing abnormal foot development in children due to flat foot, out toeing or in toeing problems
Foot orthoses are recommended for;
- Those having to stand most of the time or walk long distances;
- Athletes, especially runners, as they are exposed to a lot of overuse injuries caused by over pronation
- People more prone to over pronation because of muscle weakness, age, obesity or pregnancy
How effective are foot orthoses:
Foot orthotics have been proved to be an effective modality in the treatment of mechanical lower limb pain. In a retrospective study, the outcomes of orthotic treatment were compared to four other treatment methods. It was established that
- 96% patients were pain free with the use of prescription foot orthotics
- 94% patients were still using orthotic devices
- 70% patients were able to achieve their former activity level with the use of foot orthotics
Donatelli RA, Hurlburt C, Conaway D, St Pierre R. Biomechanical foot orthotics: a retrospective study. J Orthop Sports Phys Ther. 1988;10(6):205-12.
Types of Orthotic Devices Soft: used as a pad or cushion
Semi-flexible: serve both as a cushion and support and to correct the foot movements. Preferred by athletes as these are permanent, more resilient than rigid orthotics and do not give blisters
Rigid: very durable and require very few alterations and are used for correctional purposes. These are however, not advised for athletes as these are unforgiving and may lead to stress fractures and other foot problems.
Foot orthoses are either:
- These are available over the counter like ergonx insoles
- These are soft or semi flexible, and are fabricated from rubber, polyethylene or silicone.
- These are made according to average foot sizes.
- Helpful in cases where over the counter orthotics are unsuccessful.
- These are made specifically for individual patients and are comparatively expensive.
- These are prescribed and supplied by podiatrists
- These can also be fabricated with relatively rigid materials and are therefore more durable.
Custom made orthoses can either be Accommodative orthoses, made from relatively soft and flexible materials such as rubber, plastic foams, cork etc. these are basically used to act as a cushion or pad to relieve pressure and pain from a painful area on the sole of the foot, however, they may also be used for correctional purposes.
Alternatively, these can be Functional orthoses, made of semi-rigid to rigid plastic or graphite. These are basically used to correct functional abnormalities, however, they may also support or cushion a painful area on the sole. These are relatively thin and fit into a number of shoe types. These are comparatively more durable however, they are more difficult to adjust.
How to use Orthoses:
It takes time to get adjusted to a new orthotic device and conditioning is important.For this reason, orthotics are introduced gradually such as wearing them one hour on the first day, two hours on the second and thus increasing the time daily. Orthotics should be completely comfortable after 2 weeks. Eevery individual may respond differently.
An over the counter orthosis would usually last from one to two years, however this depends on patient size and activity level.
Foot orthotics are not the solution to every foot problem and they might help with some problems but may not cure them. Moreover, using a properly fitted shoe will add to the support given by an orthotic which will help to speed your recovery.