Vol. 21 • Issue 6 • Page 38
The ability to get from one place to another is essential to every animal. The speed at which travel takes place is essential to determining the success or failure of everything from food acquisition to escaping danger.
Gait requires input from the brain, spinal cord, peripheral nerves, muscular power and joint and cardiovascular health. Because all of these systems are required to coordinate gait, gait speed is an indicator of the health of many physiological systems.
In all animals, gait speed decreases with age. In humans, the speed of our mobility is predictive of so much more than if we will eat, or will be eaten.
Therapists typically measure gait by distance walked, amount of assistance needed and observation of gait quality. Sometimes therapists will use standardized tests like the Tinetti balance and gait evaluation, 6-minute walking test or the timed 'up and go' test (TUG).
But there is an easier and much more diagnostic way to evaluate gait. All it takes is a stopwatch, a tape measure and 20 meters of straight walking space. The test is cost effective and takes very little time to administer.
Timing a 10-meter walk, which provides a snapshot of gait velocity, is considered a scientifically reliable and valid test that works like a crystal ball to see everything from future health status to mortality. This test of self-selected walking speed (the directions to the patient are simple: "Walk as fast as you feel safe and comfortable") is safe, cost-effective (it takes just a few minutes), easy to learn and administer, and the results are easy to interpret.
The 10-Meter Walking Test Rules
Setting up the TMWT is easy. Simply mark off a straight line, 20 meters long. Then mark off the first and last 5 meters. Although you ask the patient to walk the entire 20 meters, only the middle 10 meters are recorded. The first and last 5 meters are used to eliminate periods of acceleration and deceleration.
The timing is best done when the patient is free of the distraction of the test itself.
Making subtle start- and stop-timing lines on the floor and choosing a silent stopwatch is recommended. As previously mentioned, the patient is instructed to walk at a self-selected speed. The instructions are simply "Walk to (mention a landmark), as fast as you feel comfortable and safe."
Timing starts as soon as the first part of either lower extremity passes the 5-meter mark. This requires the therapist to walk directly to one side of the patient to view the patient as he walks "through" an invisible coronal plane. Timing ends as soon as the first part of either lower extremity passes the 15-meter line.
Velocity is calculated as distance divided by time. For instance, if the patient walks 10 meters in nine seconds, the calculation is 10 (distance in meters) divided by nine (the number of seconds). The velocity of this patient is 1.1 meters per second. There are many online calculators that do the calculation automatically.
Once you've established a patient's speed of ambulation, what does it mean?
• The normal range for walking is 1.2 to 1.4 meters per second.
• If patients walk 10m in 50 seconds (that is 0.4 mph), they would be considered household ambulators.
• If patients walk 10m between 17 and 25 seconds (that is 0.92-1.3 mph), they are limited community ambulators.
• If patients walk 10 m between 12.5-10 seconds (that would be 1.8-2.2 mph), they are community ambulators.
• If patients walk 10 m in less than seven seconds (that would be more than 3 mph), they have the ability to cross a street. This is considered normal walking speed.
What is remarkable about testing gait speed is how much it reveals about patients. Here is a list of possible conclusions:
• A decline in gait speed predicts a decline in attention.
• An increase in gait speed predicts a substantial decline in mortality, while a decrease in gait speed predicts an increased chance of mortality.
• Gait speed correlates well with functional ability, future health status and the patient's confidence in balance.
• Gait speed predicts where discharge will take place (e.g., home, SNF), the chance of hospitalization, and an increase in medical costs, disability and mortality.
• Gait speed predicts the need for rehabilitation.
• Gait speed can be used to determine the effectiveness of a particular rehabilitation treatment option.
• Gait speed can be used as a surrogate for quality of gait; the faster the walking, generally speaking, the higher the quality of gait.
Also, as any therapist knows, gait speed is modifiable. Walking speed is not only predictive of decline, it can also predict improvement.
Fritz, S., & Lusardi, M. (2009). Walking speed: The sixth vital sign (white paper). Journal of Geriatric Physical Therapy, 32(2), 2-5. PubMed PMID: 20039582.
Studenski, S. (2009). Bradypedia: Is gait speed ready for clinical use? Journal of Nutritional Health and Aging, 13(10), 878-880. PubMed PMID: 19924347.
Peter G. Levine is co-director of the Neuromotor Recovery and Rehabilitation Laboratory (rehablab.org) and the author of Stronger After Stroke (Demos Health, 2008). He also conducts seminars teaching research-based, neuroplasticity-producing stroke recovery strategies. E-mail him at StrongerAfterStroke@yahoo.com.