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Infographic. Remote running gait analysis
  1. Christopher Napier1,2,
  2. Tom Goom3,
  3. Alan Rankin4,5
  1. 1 Department of Physical Therapy, The University of British Columbia, Vancouver, British Columbia, Canada
  2. 2 Schools of Mechatronic Systems Engineering & Engineering Science, Simon Fraser University, Metro Vancouver, British Columbia, Canada
  3. 3 The Physio Rooms, Falmer, UK
  4. 4 Sports Medicine, Sport NI Sports Institute, Newtownabbey, UK
  5. 5 Sports Medicine NI, Belfast, UK
  1. Correspondence to Dr Christopher Napier, Department of Physical Therapy, The University of British Columbia, Vancouver BC V6T 1Z4, Canada; chris.napier{at}ubc.ca

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Physiotherapy has long followed a standard script. The patient is seen in-person at a clinic, a subjective history is taken and the physiotherapist completes a physical examination consisting of strength, range of motion, functional testing, etc to determine the cause of injury and prescribe an appropriate treatment plan. For running injuries, this assessment often includes an analysis—either on a treadmill or overground—of the patient’s running gait. When facilities and equipment are available, this may include three-dimensional (3D) motion capture and force plate analysis, which provides more detailed information about the biomechanics contributing to the presenting injury. Since most clinicians do not have access to this equipment, many use two-dimensional (2D) video analysis in the clinic.

Recent circumstances have pushed many of us to explore remote options using online platforms, such as telehealth. This has forced us to be more creative with how we assess and treat patients and presents an opportunity to evolve our practice. With most runners having access to a high-quality video camera on their phone or tablet, 2D motion capture can be performed remotely. Recent advances and access to wearable technology—inertial measurement units (IMUs), in particular—now allow remote measurement of forces and spatiotemporal data. Remote biomechanical running gait analysis is now a reality (figure 1).

Figure 1

Infographic: remote running gait analysis. 2D, two-dimensional.

There are some key considerations when performing remote running assessments. First, the 2D video capture should follow a standardised protocol that takes into account the location of the camera (behind, in front and to the side at a ~2 m distance—enough to visualise the runner from head to toe—and perpendicular to the runner) and the sampling frequency (120 frames per second or higher is recommended to capture rapid changes in joint angles).1 We recommend recording at least seven strides for each view.1 While this recommendation is based on the ability to calculate a stable mean value, a higher number of strides is also likely to expose any missteps or outliers so that the clinician can select a ‘typical’ stride for analysis. The analysis can be performed on a treadmill if the patient has access, otherwise they should stick to a flat, even surface at a constant speed (unless the goal is to assess on a specific surface or grade, eg, downhill running to assess for iliotibial band pain). Treadmills not only have the advantage of allowing for a greater number of strides to be captured and a constant velocity to be maintained, but also accurately reproduce spatiotemporal, kinematic and kinetic measures in overground running.2 However, in circumstances where the terrain or grade is thought to play a factor in the development of the injury, or when a runner is unaccustomed to treadmill running, overground assessment may provide a better overview of a runner’s gait. If performing the assessment on a treadmill, runners should warm up for at least 8 min before recording any data to ensure familiarity with the treadmill.2

A number of kinematic variables—especially in the sagittal plane—have been associated with kinetic risk factors of running-related injury.3 4 Measurement of these variables is useful when force plates are not available to measure ground reaction forces or when surrogate measures (eg, IMUs) do not adequately represent the applied forces (eg, peak braking force). There is evidence to suggest that several variables relevant to running injuries can be assessed using 2D video analysis and are significantly related to 3D measures. For example, frontal plane angles such as contralateral pelvic drop and hip adduction are strongly correlated with measurements using 3D motion capture.5 Footstrike pattern can also be assessed reliably by a single rater on 2D video.6 Using freely available software (eg, Kinovea), segment lines and joint angles can be overlaid on video to explain kinematics to patients. For a more in-depth overview of 2D video running gait analysis, including common variables and how to measure them, see Souza.7

Spatiotemporal measures such as step rate, ground contact time and step length can be measured reliably using an IMU.8 These sensors are also capable of measuring kinetics and their acceleration output has been correlated with ground reaction force measures from force plate analysis.9 Clinicians can send IMUs to the patient and prescribe a standard protocol. The patient can then upload data for the clinician to assess. If a gait retraining intervention is desired, the clinician can prescribe cues and reassess to determine if it has the desired effect before the patient returns the IMUs. All of this can be completed remotely with only a few pieces of equipment. When an IMU is not available, a wrist-worn smart watch may also be useful to measure certain spatiotemporal variables (eg, step rate, vertical oscillation) especially when paired with a footpod or waist-mounted accelerometer. These devices may also be used to give real-time biofeedback of these measures during gait retraining. Wearable devices enable the analysis of running biomechanics in the field and under various conditions, such as different terrain, footwear and gradients. Spatiotemporal and kinetic metrics can be uploaded remotely along with video footage to an online platform to allow the clinician to analyse and interpret the runner’s biomechanics.

It is important to understand the limitations of the technology being used. Wearable devices, in particular, are subject to limitations ranging from unknown validity of updates to firmware and software algorithms to impaired reliability/validity if inappropriately fixated on the runner.10 Clinicians are advised to seek out devices that have been validated against the gold standard for the metrics of interest.

Our new reality means we need to be more flexible with how we assess and provide treatment for our patients going forward. However, it is also an opportunity to expand our scope and reach. Remote running assessments that embrace currently available technology and evolving patient expectations are one example of how physiotherapists can get ahead of the curve. We hope that the accompanying graphic will help clinicians achieve this.

References

Footnotes

  • Twitter @runnerphysio

  • Contributors CN and TG proposed and drafted the initial paper; AR designed the infographic; all authors provided input to subsequent drafts of the paper and infographic.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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