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  • Study: For Individuals With Knee OA, 3 Tests Can Predict Ability to Walk 6k Steps a Day

    Getting individuals with knee osteoarthritis (OA) to walk regularly is a crucial component in reducing knee pain, improving physical function, and staving off comorbidities such as cardiovascular disease. But how can a clinician know if a patient is capable of meeting minimum walking recommendations? Authors of a recent study believe it may come down to performance on 3 simple tests.

    In a study of 1,925 participants with or at risk for knee OA, researchers sought to link performance on the 5 times sit-to-stand test, the 20-meter walk test, and the 400-meter walk test to walking patterns outside the clinic. Participants ranged in age from 56 to 74 years, with an average age of 65. The study was e-published ahead of print in Arthritis Care and Research (abstract only available for free).

    Participants were given accelerometers and instructed to wear the devices during waking hours for 7 consecutive days. Participants' accelerometer data were later reviewed and compared with their performance on the 3 tests. Researchers divided participants into 2 groups—those who averaged 6,000 or more steps a day and those who averaged fewer than 6,000 steps. Here's what they found:

    • The overall steps-per-day average for all participants was 6,166 steps a day, but there was wide individual variation—by nearly 3,000 steps above or below the average.
    • Just over half (54%) of participants walked 6,000 or more steps a day.
    • Average performance on the tests were 10.5 seconds on the 5 times sit-to-stand test, 1.33 meters per second for the 20-meter walk test, and 306 seconds on the 400-meter walk test.
    • Each additional 1 second it took for a participant to complete the 5 times sit-to-stand test was associated with walking 130 fewer steps a day.
    • Walking 0.1 meter slower during the 20-meter walk test was associated with walking 342 fewer steps a day.
    • Each additional 10 seconds it took for a participant to complete the 400-meter walk test was associated with walking 125 fewer steps a day.

    The bottom line, according to researchers: taking longer than 12 seconds to complete the sit-to-stand test, walking slower than 1.22 meters per second during the 20-meter walk test, or taking longer than 5.22 minutes to walk 400 meters are reliable indicators that an individual with knee OA may not have sufficient physical function to reach the 6,000 steps-per-day walking goal.

    That, authors believe, is where the role of the physical therapist could make a big difference.

    "One possible implication of our study is [that] referral to rehabilitation, such as physical therapy, may be of benefit to those with or at risk of knee OA not meeting 1 or more of these physical function thresholds," authors write. "[Common] interventions that are employed by physical therapists are effective to improve physical function in people with knee OA."

    Authors of the study include APTA members Hiral Master, PT, MPH; Louise Thoma, PT, DPT; Meredith Christiansen, PT, DPT; Emily Polakowski, MS, SPT; Laura Schmitt, PT, DPT; and Daniel White, PT, ScD, MSc.

    Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.


    • Great use of benchmarks to predict functional community ambulation, but who uses a 20 M walk test to determine gait speed OR asks their patients to walk 1/4 mile (400M)? We would use a shorter gait speed test (10M or 4 M) and a 6 Minute Walk Test for distance.

      Posted by Glen Newman on 11/8/2017 3:32 PM

    • Very important findings. Thanks for this meaningful research.

      Posted by Tim Kauffman on 11/8/2017 8:16 PM

    • Interesting. But you have to consider that not walking > 6000 leads to these results in the tests, as opposed to assuming that not doing well on these tests results is predictive of not walking more than 6000 steps. Its a matter of causal direction and predictive direction. For example, perhaps by starting to walk more than 6000 steps people would improve their ability on these 3 tests. As written there is an implication that if someone cannot do well on these tests that they have a lower likelihood of being capable of walking more than 6000 steps in a day and that was not studied in this research.

      Posted by Sean Collins on 11/10/2017 8:42 AM

    • The summary of the article says anyone not meeting one of these criteria should be referred to physical therapy. What physician performs a 5 x sit to stand let alone a 400-meter walk? I see these data being relevant to physical therapists, albeit minimally: it seems there are copious other articles that are very similar (e.g. those with knee pain walk slower, don't ascend stairs, etc). Most of us PTs know this already without a study to back it up!

      Posted by Sean Wells on 11/10/2017 12:05 PM

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