Running biomechanics: Through the mind of a physio
Running biomechanics:
Through the mind of a physio
Running biomechanics play an important role in the development of injuries. Performing a running analysis on injured runners is crucial in developing treatment strategies.
Although running injuries are multi factorial, this blog will focus on how we as physio’s assess the mechanical risk factors of running.
At Jannali Physiotherapy & Sports Injury Clinic, we will always try to assess someone’s running technique on the treadmill using video analysis from a back and side view. We will try and replicate the speed at which the runner experiences symptoms, and if they experience symptoms on a hill, we will always incline the treadmill.
From the BACK VIEW we will assess the following:
1. Base of support.
We try to encourage runners to not cross their feet over (scissoring pattern) when they run and aim to imagine a ‘line’ in the centre of the treadmill which they are not to cross. Going over this line may increase your risk of developing running injuries such as lateral hip pain, ilio-tibial band friction syndrome and tibial stress fractures.
2. Heel eversion. (Component of foot pronation)
Several studies have linked heel eversion to various running injuries such as plantar fasciopathy, Achilled tendinopathy and tibial stress fractures. It’s also important to measure the rate of heel eversion (aka are you landing on the outside of your foot and then collapsing in quite rapidly)
3. Foot progression angle (aka the position of the foot during landing, Toe in vs. toe out)
It’s quite common for people to run with their foot pointed slightly out. We tend to take this measurement with a grain of salt and only take this into consideration in combination with other mechanics, symptoms and if someone is showing excessive toe in/toe out
4. Heel whips (aka the angle of the foot during toe off and swing phase of running)
Similar to the foot progression angle we tend to take this measurement with a grain of salt and only take this into consideration in combination with other mechanics, symptoms and if someone is showing an excessive heel whip. Often if you’re correcting this by the time you land and load the foot, it doesn’t hold as much clinical weight than if you aren’t correcting this by the time you land
5. Knee window (aka knee valgus, knocked knee’s)
A narrow or small knee window can be a big driver hip, knee and ankle pain. The knee window does not need to be large, however we generally try to encourage patient’s to imagine being able to fit a small tennis ball between their knees. We certainly do not advocate for a closed knee window.
6. Pelvic drop
This is your ability to keep your pelvis/hips level when you run. Excessive pelvic drop during running contributes to many running injuries and can be a sign of weak gluteals/hip and core musculature
From the SIDE VIEW we assess the following:
7. Foot strike pattern
Foot strike patterns can be characterised as forefoot striker, mid-foot striker or heel striker. There is limited evidence that a particular foot strike pattern is more or less likely to directly cause an injury, HOWEVER, data suggests that runners with a heel strike pattern developed more overuse injuries when compared with runners with a forefoot strike pattern. We tend to assess this case by case and always consider what symptoms the patient is experiencing and if the strike pattern could be driving their symptoms. We will never change someone’s strike pattern just for the sake of it and we tend not to change a forefoot straight to a hell striker – this is too big of a change.
8. Foot inclination angle at initial contact
This is the angle created by the sole of the show and the treadmill at initial contact. This is particularly important in estimating ground reaction forces during running. Specifically, a higher inclination angle (aka lifting toes up) was found to be related to higher knee extensor (quadriceps activation), increased knee energy absorbed (load going through knee), higher vertical ground reaction force (load coming up) and a greater braking impulse (aka higher forces/load is correlated with higher foot inclination)
9. Tibial (shin) angle at mid stance (aka loading)
This is the vertical alignment of the shin during mid-stance phase of running. For a runner that suffers from impact related running injuries (e.g – shin splints), an extended tibia (shin) is not ideal. A vertical or fixed tibia (shin) allows the runner to dissipate impact more readily through knee flexion.
10. Knee flexion during stance
This is different in every runner. Some runners might hit peak knee flexion earlier or later than others. In general, normal knee flexion approaches approx 45 deg at mid stance. We tend to educate people that if their knee flexion angle is less than 45 degrees during mid-stance/loading it may suggest reduced load absorption.This is particularly important in combination with the tibial shin angle for people who are experiencing impact related running injuries (e.g – shin splints).
11. Hip extension during late stance (aka toe off)
Some common compensations we see if someone is unable to extend their hip adequately are increased lower back extension (lower back pain), reduced gluteal activation, reduced flexibility of hip flexors, bounding, overstriding and increased cadence/step rate. The amount of hip extension requirement can be dramatically different between runners and is always’s never looked at in isolation. Hip extension should always be assessed in combination with other joint mechanics.
12. Trunk lean
Overstriding is when a runner’s ankle lands in front of their centre of mass. We tend to encourage runners to land underneath their hip or give cues such as ‘imagine a pole going straight down from your hip to your ankle’). Increased stride length has been found to be associated with an increase in tibial stress fractures (shin splints).
14. Vertical displacement of the centre of mass
Increased vertical displacement has been associated with an increase in vertical ground reaction force, braking impulse and increase knee extension (poor for absorbing load). Often ‘bounders’ have an increase in vertical displacement as they try to increase their ‘foot time. This can be easily fixed by increasing cadence/step rate.
Other variables we will always look out for are auditory (loud vs not loud can be related to higher forces/impact), cadence/step rate (we might count how many steps you perform on each leg over a 1 minute period). Assessing running technique can be very complicated and often we see people making changes for the worse, particularly if they don’t need to. If you are experiencing any running symptoms we encourage you to book in for a thorough running assessment with a physio.