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north-queensland-cowboys-logo“The running symmetry is outstanding.  Being able to quantify and show our athletes, and they can see a number they need to improve on will be a great help.  Tariq Sims after 2 broken legs will get enormous benefit from this.  We can see he is favouring one leg but being able to quantify that and show him will help.  Because Tariq has struggled with 2 broken legs back to back his gait to him seems good but to be able to show him the data will help his mindset as he looks to improve!”


Paul Bowman | High Performance Manager 

North Queensland Toyota Cowboys



Gaining a deeper insight into an athlete ́s running mechanics and the changes in their mechanics due to injury, fatigue or other limitations, provides critical information to maximise performance. This insight is now available through the GPSports Running SymmetryAnalysis.

GPSports delivers an analysis of the athlete’s Running Symmetry based on information derived from both the accelerometer and GPS sensors. The software identifies, quantifies and compares the forces at ground contact (foot strike) on the right and left side during running.

The percentage difference, between the left and right stride is reported to the user as ‘Imbalance’. For example, a score of ‘zero’ represents a symmetrical running stride. That being, a series of foot strikes where the left is the same as the right side. A ‘5% Right’ score reflects an asymmetrical stride, specifically a 5% greater load on the right side, compared with the left.

To complete the analysis GPSports identifies a specified number of foot strikes in sequence combined with settings to control for change in direction and speed as these events are known to not be symmetrical.

The goal is to establish a tight normal range for each athlete and identify changes at an individual level.

Practical Applications

Rehabilitation – See changes over time as the athlete improves during the process of rehabilitation

Return to Play – Use Running Symmetry as an objective return to play marker

Athlete Screening – Use Running Symmetry on a weekly basis to identify changes in running mechanics

Quality Analysis

  1. GPSports Unit Fit – This analysis relies heavily on quality data. Ensure the unit is tightly fitted to the body to minimise bouncing of the unit. Ideally, wear a GPSports vest.
  2. Running Surface – An undulating or irregular surface will influence results as the athlete will adapt as required. For consistent results ensure a consistent surface
  3. Straight Line Running –Straight line running as by nature it is more symmetrical that nonlinear running. For consistent results run in straight lines
  4. Constant Speed – Significant acceleration and decelerations are generally not symmetrical activities and are usually excluded for the analysis. For consistent results run at reasonable constant speeds. 

Internal Investigations

Can The Analysis Differentiate Healthy From Rehabilitation Populations?

As part of our internal validation project 1100 samples of straight line field based running were analysed using the GPSports Team AMS software. The data set included 550 healthy (normal) and 550 rehabilitating athletes and athletic general population.

The graph below represents the 1100 samples in 2 groups where each running series was plotted with speed (km/h) on the Y axis and percentage imbalance on the X axis. Positive and negative results represent right and left side bias respectively. Note, Speed Thresholds of 12km/h and 10km/h were used for the Normal and Rehabilitation groups respectively. A Minimum Foot Strike Threshold of 20 was used for both groups (see Team AMS Settings).

The graph shows a clear difference between the Normal group (Avg. 2.2% Imbalance, St.Dev 1.4) and the Rehabilitation group (Avg. 5.6% Imbalance, St.Dev 4.3). 


When we observe the individual subject data the same trend was present. This graph shows the individual average Imbalance. Each subject had a minimum of 20 series (i.e. 20 distinct runs) included in the analysis and in most cases a clear difference between Normal and Rehabilitation subjects was observed. 



At this stage the evidence suggests the GPSports Running Symmetry Analysis can differentiate symmetrical and non-symmetrical running gait. Based on the above information GPSports uses a ‘normal’ range of 5% Imbalance when presenting results in SPI IQ. Like many variables, an individual’s change in score is perhaps more important than comparison to ‘normal’.

Further Investigations

At this stage we are looking to engage a university partner to run an independent project to investigate the accuracy of our analysis against a gold standard measure. 

Team AMS Running Symmetry Interface

This analysis can be run on any session files or splits in Team AMS. Depending on the settings used in Team AMS, the analysis will identify the series (sequences) of foot strikes that meet the criteria.

This information is displayed in the Running Symmetry tab of Team AMS. 



Team AMS Settings


o Min. Speed – the minimum speed for the data to be considered for analysis (default setting 12km/h)

o Min. # Foot Strikes – the minimum number of consecutive foot strikes to determine a series to be analysed (default setting 10 foot strikes)

o Indoor Mode – Ignore GPS Data – this setting omits line and speed control from the analysis and can be used for treadmill or indoor running.

Summary of Results

o Series Count – the number of foot strike series (sequences) that meet the criteria for the analysis o Total Foot Strikes – the total number of foot strikes included in the analysis
o Imbalance – average percentage difference between left and right legs, based on all series
o Standard Deviation – based on Imbalance scores of all identified series

Matching Foot Strike Series Table

Provides summary information about every series successfully detected by the analysis o Start, End Time & Duration – Time markers of the running series
o Foot Strikes – the number of foot strikes in the series
o Distance – distance travelled during the series

o Avg. Speed – Average speed of the particular running series
o Max. Speed – Maximum speed of the particular running series
o Imbalance – % difference between left & right leg for the particular series 

SPI IQ Interface

Running Symmetry variables are available as SPI IQ table variables. Displayed here in the 2 columns on the

right of the table. Table variables can be renamed to suit the user. 



Running Symmetry (Side Bar) Graph – shows the Imbalance, as calculated in Team AMS. Error bars represent the standard deviation of scores for that particular player. Red lines represent the ‘normal’ range. 



Running Symmetry (Bar) Graph – shows Imbalance for a single athlete for the selected period. For group reports the bars show groups average and the error bars represent the maximum and minimum values of the group. 




Are you ready to dominate your league or sport?  To find out more about how GPSports SPI HPU unit and SPI IQ software can benefit your team CLICK HERE to have one of our Human Performance Specialists talk to you about your team and  how GPSports can meet your specific needs.

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