THE BIOMECHANICS OF RUNNING: 3 COMMON TECHNIQUE FAULTS

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Running is one of the most accessible sports for people trying to increase their physical activity levels, and has significantly increased in popularity over the years. However, unlike learning how to swim, to play golf or to ski, most don’t ‘properly’ learn how to run as a beginner, and often re-visit proper running technique as an intermediate-level runner or when faced with injury. This blog article will help you understand in depth the biomechanics of running and what to look out for when it comes to running technique.

Before we start, here’s a list of running terminology that is handy to know for this blog:
Gait cycle: The period from initial contact of one foot to the next initial contact of the same foot
Heel contact/foot strike- The moment each foot strikes the ground with each step
Midstance- The moment after Initial Contact when the whole foot is in contact with the group
Heel off- After Flat foot when the heel leaves the ground
Toe off- After heel-off when the toes leave the ground so that the leg can swing into the next step
Stance phase- The phase when the leg is in contact with the ground
Swing phase- The phase when the leg is in the air. Split into Initial and Terminal phases.
Step- Successive initial contacts of one foot to the opposite foot
Stride- Successive initial contacts of the same foot 
Cadence: Equal to the number of steps per unit time (usually steps/min)
Velocity: Running speed
Running economy: The amount of oxygen utilised per minute of running.
Concentric contraction- The muscle shortens as it engages to produce movement
Eccentric contraction- The muscle lengthens as it engages to stabilise a moving joint

What happens during each gait cycle?

If you are striving to improve your running speed, or maybe you need to rehab a certain injury, then it helps to have a deeper understanding of how the body moves and works during each gait cycle. This allows you to make sense of why you may need to do certain strength exercises or to change your running technique in a certain way.

Image 1: Adapted from Melbourne Sports and Allied Health Clinic

The following breaks down the different phases of the gait cycle and the mechanics of your body in each of these phases:

Heel contact to mid stance (1-2 in image 1)

  • The ankle starts to flex and pronates (In positive way) to absorb shock (This is the most important phase for shock absorption)
  • Tibialis Anterior (TA) contracts to bring the shin forwards over the foot, while the calf eccentrically controls the shin
  • The adductors (groin), quads and hamstrings are activated eccentrically to stabilise the movement

Mid stance to heel off (2-3 in image 1)

  • The body’s centre of mass moves forwards over the foot
  • The ankle reaches maximum pronation
  • Eccentric contraction of the hamstrings and quads to stabilise the knee

Heel off to toe off (3-4 in image 1)

  • The ankle goes into supination (Opposite of pronation) and windlass mechanism is activated to create a rigid foot to push-off the ground (Toe-off)
  • The calf contracts to help with push-off and running economy. On top of that, the hamstrings, quads, glutes and TA transition from a stabilising function to a concentric function to help with push-off.

Initial Swing (5 in image 1)

  • The quads and hip flexors contract concentrically to swing the leg forwards
  • The glutes work to stabilise the pelvis
  • TA helps to keep the foot up, and prevents catching on the ground

Terminal Swing (6 in image 1)

  • Almost all the muscles of the lower limb activate in this phase to straighten the hip, knee and ankle for the next initial contact. The adductors and hamstring work to stabilise and decelerate the forward moving leg. 

What determines good biomechanics?

When looking at running biomechanics, there are many things you can look at:

  • How the body segments are moving in relation to each other and the ground
  • Joint angles of the ankle, knee and hips + upper body in each phase of the gait cycle
  • Stride measurements such as length, cadence, etc
  • Force absorption capacities
  • Force plate measurements (Eg Pressure points, forces exerted)
  • EMG or observational muscular recruitment and more
Image 2: Force plate measurements (East Devon Sports Therapy)

Here’s a few things to consider when it comes to running biomechanics.

  1. There is NO text-book perfect running technique. There are certain techniques that are known to reduce forces in certain joints and muscle groups, or may improve economy, but isn’t always 100% as where forces are reduced, forces may increase in other areas.
  2. Instead of ONE perfect running technique, there is an acceptable RANGE of running variations. Examples are a running cadence between 160 and 185, rather than ONLY 180; or variations in foot strike patterns since new research shows that heel striking isn’t actually less efficient than midfoot/forefoot strike after all! Only when someone is exhibiting biomechanics that is on the extreme ends of the spectrum, and is obviously inefficient, risking injury or if they are already suffering from injury, then such circumstance calls for an immediate running technique change.
  3. Running technique changes are often made too often when unnecessary. When someone has been running in a particular way without any problems, then a change in technique will actually cause short-term inefficiency and can potentially shift forces onto unsuspecting joints/tendons/muscles, increasing the risk of overuse injuries such as tendinopathies or friction syndromes, etc. It is often best to leave the runner as is if they are within the acceptable range of running technique variations, unless they are already experiencing injury and need the technique modification to rehab that specific site.
  4. Running technique is important, but in terms of performance and injury risk, sits below training programming and strength training in its impact and priority. Make sure the other two factors are well considered and at a high-level before turning your focus to your running technique.

3 common technique faults

There are many ways that running gait can be inefficient or incorrect, causing poor performance and recurrent injuries. This blog will cover the three most common running faults that I see amongst runners in clinic, and are easy for you to recognise when looking at footage of yourself running, or when people watching other runners out on the Tan or on the bike tracks around Melbourne.

  1. Knee valgus

Knee valgus is also known ‘knock knees’, and is seen as the foot strikes the ground or during midstance where the knees collapse inwards towards the other.

This can occur due to various reasons – It can stem from weak foot/ankle muscles that are unable to absorb the initial shock, causing excessive pronation of the foot and subsequent knee collapse. The other main reason is weakness of the hip muscles, particularly glute med which then results in inward collapse and rotation of the thigh on single leg stance (Aka every step during running), and the subsequent knock knee effect.

Image 3: Knee valgus with knee knocking together (Running-physio)

It can be subtle, or can be quite obvious in runners. Look out for the knees from a back view, particularly upon foot strike of each foot. Sometimes, when the knees are collapsed inwards, the feet flick outwards with toe-off.

Not only is this inefficient due to sideways forces that wastes energy, it is also highly stressful for the lower limb to be rotating and twisting with each step, causing wear of the joint surfaces and excess stress to the tendons, ligaments and muscles of the lower limb. Over time, this can cause many of the common running injuries.

Treatment: Strength training is the best way to combat this, since the root cause of knee valgus is often strength deficiencies in the hip, knee or ankle/foot muscles. All the exercises of the big 10 targets these muscles to improve overall strength in running.

You can also engage in running gait re-training, focusing on cues to such as straight or wide knees.

2. Overstriding

Overstriding occurs when someone runs with big steps and strikes the ground too far in front of their body, usually with a heel-strike and a backwards-angled shin. This is often due to poor habit, and leads to:

  • Braking forces with each step, causing excess energy expenditure and slowing you down.
  • High impact forces into the heel, shins and knees – Increasing the risk of certain injuries such as calcaneal bursitis, shin splints, runners knee etc.
Image 4: Overstriding is seen when the foot lands too far in front of the body. (Pose running)

Overstriding is best visualised from a side-view, as you can see the angle of the shin and how far the foot is in front of your body’s midline upon foot strike.

Luckily, overstriding is a fault that can be improved with some simple cues, such as landing more with a midfoot/forefoot, taking smaller steps, ‘pulling’ with your legs rather than ‘pushing’ etc.

3. Crossover stepping

Crossover stepping is when someone runs with their feet crossing each other across the body’s midline as they foot strike. This can be due to poor habit, but also due to poor strength in the hip muscles.

Image 5: Crossover stepping (Runners Connect)

Running with the legs crossing over each other, creating a subtle X shape increases the risk of tripping, and excessively loads certain structures such as the shins and knees.

The best way to combat crossover stepping is through strength training of the hip musculature, particularly the glute max and glute med that is targeted in the big 10. Specific gait retraining techniques to run on either side of a white line on the ground, or to run with straight/wide feet is also effective.

How should I look into my own running technique?

  • Option 1. Go to a trained professional who has the right technology to look at all aspects of your running gait, and then analyse it for you with a trained, clinical perspective
  • Option 2. If you are to look at your own running technique, film yourself running outdoors on a flat surface, in slow-motion and in a fatigued state (After 15-30 minutes of running). You are best to film yourself from the front, side and back angles to capture all the relevant aspects of running technique. Make sure to get the camera down in line with the ankles and knees, rather than at chest height angled down at the legs. A lot of companies do running gait analyses on a treadmill, but on a treadmill, step length, cadence, and stance phase is often higher, and vertical movement is reduced, so this can skew the unbiased results that you are after.

At the end of the day, remember that running technique is acceptable within a range of technique variations, and that there isn’t ONE type of technique you should be chasing. It’s quite individualised depending on your body proportions, your injury history etc. The best thing you can go by is comfort, and know that if you want to truly improve your running performance, it’s only one piece of a much bigger puzzle, so make sure you consider all the other contributions to performance too!

Happy running!!

Trang is a Physiotherapist & Strength and Conditioning Coach, with a special interest in strength and conditioning for endurance athletes, improving movement and biomechanics, and treating overuse injuries in runners. If you would like to book in for an Initial Assessment or enquire about coaching programs, click here.