Planes of Movement
When we look at how running mechanics ‘break down’, we like to ‘categorize’ the issues into one of 3 biomechanical ‘planes’:
In general running is a Sagittal Plane movement. So when optimizing efficiency in runners we can consider 2 very general categories of considerations:
1) How to move efficiently in The Sagittal Plane – We strive to achieve the right ‘proportions’ of contribution from all joints (trunk, hip, knee, ankle). Common problems may include overstriding, insufficient hip extension during push off, ineffective trunk lean (too much or too little).
2) How to minimize sloppy movement in the Frontal and Transverse plane – Runners should train to minimize movement in these planes as it (usually) represents wasted energy, and may make the athlete more prone to certain injuries.
In an attempt to shed some light on how we break down these various plane of movement with our runners, let’s look at a few very common issues in each plane.
Some common Sagittal Plane problems include:
- Over striding
- Improper ankle position at initial contact
- Excessive vertical displacement (i.e. “Bounce”)
Over striding essentially means that ‘loading response’ takes place with the ground contact in front of the bodies center of mass.
With over striding we see increased GRF, increased loading rates, excessive ankle dorsiflexion, and impaired knee flexion at impact. All of these factors are associated with an increased risk of injury.
Just as one example, consider the graph to the right.
This looks at compressive forces under the knee cap while running. The light grey line represents a forefoot strike pattern. Dark Grey represents a heel striker. The very top dotted line represents a heel striker who is over striding – the difference is BIG.
Overstriding is associated with an increased chance of anterior knee pain, future knee injury , stress fracture It sets the runner up for future knee injury
Not only that, but it’s inefficient! Over striding increases the breaking impulse. Remember, this means more work required from the runner just to maintain current speed.
Improper ankle position at initial contact can lead to a number of issues. Too much ankle dorsiflexion (toe elevated) can cause anterior compartment syndrome tibial stress fractures and plantar fasciitis
Too much plantar flexion (toes pointed down) by contrast can lead to Achilles tendon injury and foot (metatarsal) fractures
Excessive “bounce” can also be a problem. As you can imagine, this leads to increased GRF and load rates, increasing risk for ‘impact injuries’ such as stress fracture.
Also, it is inefficient! Running is all about forward movement. All energy spent propelling your body up into the air is wasted energy. Watch almost any world-class runner and you will see very little up & down movement.
There are a slew of other considerations to look at in the sagittal plane – proper knee flexion at initial contact, knee flexion at mid-stance,
hip extension at terminal stance, hip & knee flexion during swing phase, trunk lean, etc… For those looking for an in-depth assessment of there gait, please click here for more information about our runner’s assessment, or contact us to set up an appointment.
The frontal plane is the ‘side-to-side’ plane of movement.
Some common Frontal Plane problems include:
- Dynamic Knee Valgus
- Pelvic Drop
Dynamic Valgus (or medial collapse of the knee) is a common issue we see in runners.
Excessive knocking in of the knee can lead to ligament injuries, accelerate meniscus as well as articular cartilage degeneration, and in younger runners it increases the risk for Patellofemoral pain and/or Patellar tendonitis.
Researchers have found that an increase in dynamic valgus of 10 degrees during the stance phase of running, resulted in a 45% increase in peak pressure within the knee. Over time, excessive frontal plane movement at the knee may contribute to the onset of osteoarthritis.
If your knees touch at mid-stance (when one leg is swinging past the other) you likely have an issue here. We want to maintain a ‘window’ between the knees when parallel.
Strength training (especially the gluteal muscles) can have a big effect here.
Pelvic Drop is a very common frontal plane problem.
Minimal or no drop is ideal. 5-10 degrees is potentially a problem. > 10 degrees almost certainly should be addressed.
There is good research to indicate that excessive pelvic drop increases the risk of a number of injuries – in particular Patellofemoral pain – but also, medial knee ‘issues’, ITBS and LBP.
There are other considerations in the frontal plane as well – excessive calcaneal eversion, lateral trunk lean, cross-over gait pattern, etc… For those looking for an in-depth assessment of there gait, please click here for more information about our runner’s assessment, or contact us to set up an appointment.
The transverse plane is a ‘cross-section’. It is the rotational plane of movement for our trunk and limbs; And, it includes rotatory movements (such as ‘pronation’ and supination’) in the foot.
Some common Frontal Plane problems include:
- Excessive pronation
- Too little pronation
- Pelvic Rotation
Pronation is a word that has been given a bad rap. Pronation basically refers to the turning out of the heel and the flattening of the arch.
On one hand, excessive pronation is probably an issue. It has been associated with Achilles tendonopathy , patellofemoral pain and medial tibial stress syndrome.
However, there is also a large pool of evidence that, the majority of the time, pronation is not necessarily a ‘dysfunction’ that needs to be resolved.
One particularly great study looking at this was a study on almost 1000 beginner runner. These ‘new’ runners were classified as ‘severe supinators’, ‘supinators’, ‘neutral’, ‘pronators’ and ‘severe pronators’. They were all given neutral shoes (the same shoe) and followed for a year. What they found was that the ‘Pronators’ group actually had a lower rate of injury (even though the shoes had no built in ‘correction’ The authors concluded that “a pronated foot position is, if anything, an advantage with respect to running injuries.” The foot position that was associated with the lowest injury rates was ~ 7-10 deg of ‘eversion’ (pronation).
Multiple studies have investigated the link b/w pronation and injury rates only to show little>no link.
However, ‘severe’ pronation is likely a problem. Not olnly that, if a runner presents with an injury related to the mechanics of foot pronation (e.g. shin splints, Achilles Tendonitis, Plantar Fasciitis, etc) we must consider that their ‘ideal’ may not be the same as the average ‘ideal’ across a large population.
For much more detail on this topic, and the related conversation of ‘how to pick out the right running shoe’ – click here.
Pelvic Rotation is another common transverse plane problem found particularly in female runners. You can usually pick this on out your running partner. The pelvic is twisting side-to-side while running. Typically we expect to see more of a sinusoidal movement in the pelvic girdle. However, weakness of the trunk musculature, and/or tightness of the hip flexor muscles can lead to compensatory pelvic rotation.
Not only is this is a risk factor for LBP, but is very inefficient!
There are other considerations in the transverse plane as well – excessive trunk rotation, shoulder ‘cross-over’, femoral internal rotation, etc… For those looking for an in-depth assessment of there gait, please click here for more information about our runner’s assessment, or contact us to set up an appointment.