Foot orthotics have been proven to help with the treatment of running-related musculoskeletal injuries. 70 to 80% of people with chronic knee injuries get substantial benefits from such items.
While several studies have shown a good amount of help with pain control, we do not really understand why the orthotics help so much. The mechanism remains unclear. The biomechanical changes are relatively small, and help to control rearfoot eversion, but only to a small degree. It has been hypothesized that they help to reduce the strain on our plantar fascia or help to reduce the midfoot kinematics - remember that most people show hypermobility there.
Some studies also concluded that there are no significant benefits of heat-molded orthotics compared to the non-molded ones.
As for the shoe itself, you have to consider your foot type and the mechanics associated when choosing an orthotic. You may first test an affordable, over-the-counter model to see if it brings you measurable benefits. Then decide to go for the tailor-made option to get the most of this approach.
At Hong Kong Sports Clinic, we do believe that such devices are better used temporary, to help controlling symptoms - reducing pain. We focus more on finding what could actively help with foot mechanics - joint mobility, muscle strength, etc.
Stay tuned as we move up the kinematic chain and discuss knee mechanics next!
Research is conflictual when it comes down to the type of shoe you wear, and the associated injury-rate.
Despite this fact, it makes sense to pick up a shoe that matches your foot type. Flat feet? Try the motion control type. High arch? Go for the neutral type. You obviously do not want to “aggravate” an existing condition.
Some good quality studies have randomized one of the three shoe types with one of the three foot types. Inc conclusion, the authors found a very similar distribution of injuries among all different groups.
What does this mean? Basically, you want to go for a shoe that matches your foot structure - common sense - but also, and maybe even more importantly, that feels really comfortable. Do not focus on the price too much. Try it and decide immediately if it fits you well, or not.
Statistically, most people have an inward forefoot flare after landing and should be fitted for a semi-curved or curved shoe.
A final note about barefoot/minimalist shoes running: there is, to this day, no evidence for benefits towards injury prevention. Some studies even showed an increase in the injury rate. Running with these shoes usually mean a change in technique - forefoot strike - that decreases the loads on the hip, but increases the loads around several foot areas. You want to be very progressive and careful when transitioning from regular to minimalist shoes.
As for many injuries, it is hard to identify one unique factor that puts you at risk of an overuse injury.
Remember the 4 main causes of pain with running? Let’s discuss each one.
Atypical foot mechanics: conflictual evidence exists. To this day, it would make sense but we cannot be sure that hyper-pronation, in isolation, puts you more at risk of getting injured.
Strength: when the foot pronates, the ankle unlocks and more muscle work is required to maintain stability. The tibialis posterior, if weak, will affect the control of the ankle joint movement. It also helps to support the arch of the foot. Therefore, a weaker tibialis posterior diminishes ankle stability and forces other muscles - like the soleus, part of your calf group - to work more, causing Achilles tendinopathy and/or overall calf tightness. It also adds stress to the plantar fascia, increasing the odds of plantar fasciitis development.
Anatomical alignment: because of the difference between static - or structural - alignment and dynamic - or functional - alignment, no study could clarify the real impact of flat/arched feet on the incidence of overuse injuries. Too many compensations may occur, especially from muscles, to exactly understand what may happen.
Flexibility: first ray hypomobility seems to be associated with increased rearfoot eversion. Reduced calf flexibility - or increased tightness- seems to be associated with increased energy absorption at the ankle during the first half of the stance. Which means more stress at the ankle.
In conclusion: with only one variable outside of its normal limits, it is unlikely to expect abnormal pronation patterns. But if you combine weak muscles, hypomobile joints, and flat feet, it can start to increase the load on various anatomical structures. And eventually leads to an injury.
During the first half of the stance, the midfoot and the forefoot do the majority of the work, in comparison to the rearfoot.
The natural movement associated with the rearfoot eversion is a combination of vertical and medial midfoot displacement.
This means that a tight arch will have you compensate with the rearfoot. The arch undergoes significant deformation for about 75% of the whole stance phase. A genuine good reason to work on the mobility and flexibility of your foot!
In order to make it up for the fixed heel bone in contact with the ground, the tibia has to rotate internally and the knee goes into flexion.
While pronation is normal for most runners, prolonged pronation may increase the risk of injury. If pronation continues after the midstance, a mechanical dilemma occurs at the knee joint. The tibia wants to externally rotate and the knee wants to extend, but because the foot has achieved more internal rotation than necessary, the hip starts to excessively rotate in order to keep good joint alignment at the knee.
Excessive contact pressure on the kneecap may then occur and put the runner at risk of cartilage deterioration and anterior knee pain.
Starting to talk about the foot makes perfect sense.
It all starts from here. Every time you land on the foot, the ground reaction force initiates there and moves up the kinematic chain.
The first half of running gait is referred to as an eccentric or cushioning phase, while the second half is referred to as a concentric or propulsion phase.
At impact, the foot is supinated - the outside part of it absorbs most of the initial shock. The foot is safe in a locked position. Just before midstance, the foot pronates and unlocks. Then, as the heel lifts off the ground to prepare for the toe-off, the foot supinates again, allowing the forefoot to become a rigid propulsor, helping the runner to move forward.
Pronation happens during the first half of the stance until the heel lifts off the ground. It combines ankle dorsiflexion, rearfoot version, and forefoot abduction.
Foot pronation is a necessary protective mechanism. It absorbs, adapts, and prepares. It allows impact forces to be diminished over time, helps the foot to handle uneven ground surfaces, and prepares for the propulsion phase by increasing the contact of the first ray of bones with the ground.
A large amount of speculation exists regarding the mechanisms of running injuries. Even though there is conflictual evidence in regard to the risk factors, some studies have provided good insights about what can cause runners to get injured.
The four important factors are as follow: biomechanical gait patterns, muscular strength, anatomical alignment, and tissue flexibility.
Given the complexity of running injuries, it is important to develop a systematic approach to the gait assessment.
It is also easy to understand how our daily life activity - or, for many of us with deskbound jobs, inactivity - can contribute to the puzzle. Sit too much and your hip muscles get shutdown. Wear tight shoes, with too much cushioning, and your feet become rigid and stiff.
In our next post, we will start with our first contact with the environment: the foot. Assessing foot mechanics is an important part of figuring out why you may have knee, hip, or even lower back pain.
Iliotibial band syndrome
Iliotibial band syndrome or ITBS is the second most common knee pain with runners and the most common one on the lateral side of the knee.
It has been suggested that the frictional forces between the ITB and the lateral femoral condyle/bone are the highest at 20-30 degrees of knee flexion. This happens during the first half of the stance phase of running.
Key facts of ITBS
To this day, we haven’t found any biomechanical difference in flexion/extension patterns with runners suffering from ITBS and pain-free runners.
The supposed role of the band is to stabilize the knee, resisting to hip adduction and knee internal rotation. Abnormal foot and/or hip mechanics can come into play.
At this point, we consider that one or a combination of the following can be at the root of causing ITBS: pelvic drop - from weaker hip abductor muscles - and atypical anatomical alignment - from excessive knee internal rotation, resulting in a knee collapse.
To sum it up
To help with solving a knee problem, we have to carefully look at your foot and your hip joints and muscles. In many cases of overuse injuries, a knee problem resonates with other upstream or downstream problems.
Patellofemoral pain syndrome
Patellofemoral pain syndrome or PFPS is one of the most common injuries in running and jumping. It accounts for half to two-thirds of running-related knee pain.
Despite being so common, its cause remains vague and discussed. The onset is often insidious, located around the kneecap. No specific cause has been constantly reported, other than overuse.
Key facts of PFPS
Women are twice as likely to sustain PFPS compared to men. A potential cause is that women may show increased hip internal rotation, leading to a reduced peak external knee rotation - more on that later. Women also have a greater amount of tibial external rotation during the stance phase.
All combined, this may result in joint misalignment and subsequent knee pain.
On top of this, a greater knee abduction - seen in most women - also adds to the stress applied to the patellofemoral joint during the run.
To sum it up
Women have a “natural” tendency for joint misalignment and increased loads, exacerbated by the running activity.
Almost half of the overuse running injuries are located at the knee. Patellofemoral pain - or PFP - is the most common, followed by iliotibial band friction syndrome - ITBS -, meniscal injuries and patellar tendinitis.
Among other common runners complains, we can describe plantar fasciitis, Achilles tendinitis, gluteus medius and hamstring injuries, as well as tibial stress fractures.
Even though very few overuse running injuries have an established cause, the fact that 80% occur below the knee suggests the existence of common mechanisms.
Finding the root cause of an injury is often a challenge, but within the next few posts, we are gonna try to outline the mechanics and interrelationships between strength, alignment, and flexibility for the 2 most common injuries runners have to face: PFP and ITBS.
Understanding more will help you to get why certain areas of your body require more attention than others. Attention to details can make a big difference in your recovery, or even prevent you from getting injured in the first place.
Stay tuned to learn more about these!