Is Walking Speed Really the 6th Vital Sign? The Walking Speed Test
Published: 04 June 2017
Published: 04 June 2017
Every time we turn a corner or pass over a threshold, or have a conversation about the grandkids, Robert’s steps falter and die. He doesn’t trip. He doesn’t freeze. He doesn’t wobble his centre of mass outside his base of support.
And yet, it is immediately obvious that he is not a candidate for discharge directly to home from the hospital. A pit stop in inpatient rehab is needed.
How do I know?
He walks too slowly.
Measuring walking speed seems like a simple test but, it is a robust one.
The walking speed test consists of exactly what its name specifies - patients are measured on the speed with which they can walk a specific distance. Its simplicity and ease of use have made it a popular test for assessing everything from functional status to the need for rehabilitation.
Therapists have coined the phrase ‘the sixth vital sign’ as a useful way to describe the powerfully predictive nature of walking speed (Middleton, Fritz & Lusardi 2015).
Authors have gone so far as to compare it to the blood pressure test in its versatility, predictive capabilities and ease of administration (Fritz & Lusardi 2009). It’s hard to imagine another test that can be completed in under two minutes in almost all settings and can give as much information as the measurement of walking speed.
When evaluating the standards of a test, it is useful to look at the safety, cost-effectiveness, ease of use and ease of interpretation. A walking speed test marks-off all of these boxes.
Walking speed is a great predictor of future health. A Japanese study found that older adults with a slow walking speed were at a higher risk of future disability (Shimada et al. 2015).
Improving your patient’s performance on the walking speed test can also improve overall results in rehabilitation. A recent study on the effects of increasing walking speed times in post-stroke rehabilitation showed that the capacity for distance walking (such as that needed for community ambulation) was enhanced when walking speed increased (Awad 2014). This goes to show that measuring walking speed over short distances is an easy way for physiotherapists and nurses to gauge progress in bigger tasks like long-distance walking.
In addition to providing valuable information about mobility and disease progression, walking speed is also associated with cognition. A study found that walking speed and cognition run parallel to each other (Gale et al. 2014). Whenever the researchers found less decline in walking speed over time, they also found less decline in cognitive function.
Middleton, Fritz and Lusardi (2015) have charted out an inexpensive way to perform the walk test in most locations.
The test should be conducted on a stretch of straight path. The timed distance is recommended to be 5 to 10 metres, with acceleration and deceleration zones included before and after the testing area for a more accurate result (Middleton, Fritz & Lusardi 2015).
The patient is cued to walk at a comfortable speed and continue walking until reaching the end of the allocated distance. Timing begins the moment the first limb crosses the testing line and ends the moment the first limb leaves it (Fritz & Lusardi 2009).
The deceleration zone prevents the patient from slowing down to ‘stop on a dime’ at the end of the test strip, which may skew the test.
A wireless device known as the WiGait was designed to improve accuracy in walking speed tests. Using wireless signals that reflect off the patient’s body, the WiGait is able to accurately record speed, stride length, and gait patterns. Gone are the days of recording speed with a stopwatch or doing mental math to find the patient’s speed with a GPS (MIT 2017).
The information harvested using WiGait can be used to predict disease progression. By analysing patterns in stride, you can also predict falls risk in your patients (MIT 2017).
The other advantage this technology offers is a completely hands-off approach. There’s no need to hook patients into a complex machine to analyse their gait patterns; the device is simply mounted on a wall (MIT 2017).
Walking speed tests may also have use outside of rehabilitation settings. For example, if city planners know the average walking speed of their community ambulators, they might be able to adjust stoplights to accommodate the average speed, hopefully reducing traffic accidents (Duke Forward 2015).
The simple nature of walking speed tests make them a tool every physiotherapist and nurse should have in their back pocket.
Convinced? Pull out a tape measure, mark off a stretch of hall, buy a stopwatch and go!