How many times can you stand up from a chair using only one leg?
This test, called the one-leg rise test or the single-leg sit-to-stand, is an especially useful functional test. It demonstrates how strong your muscles are relative to your particular height, weight, and body type. In fact, in middle aged individuals with knee pain but no arthritis, the number of single-leg rises an individual can perform has been shown to predict the development of knee osteoarthritis (OA). In a 2004 study by Thorstensson et al., the number of single-leg rises performed by subjects who had no OA at the time predicted the development of OA even when controlling for factors like age, sex, and BMI. The median number of single-leg rises in the group who developed OA was 17, while the median number in the group that did not develop OA was 25. A 2015 study by Culvenor et al. further showed that the number of single-leg rises performed by adults who had an ACL reconstruction one year prior predicted pain and ability three years after surgery. In this study, 22 one-leg rises was used as the cutoff score.
So if you can't perform 25 single-leg sit-to-stands, does that mean you're definitely going to get knee OA? No, there are a variety of factors that influence the development of knee OA, and not everyone in the study who did less than 25 repetitions developed OA. However, this quick test can give you some easy insight into one aspect of your current risk level.
So provided you feel safe performing the test or have someone close by if you need help, give the one-leg rise test a try. There are some rules:
Use a standard chair or stool that places your knee at about a 90 degree angle when seated. A low couch will make the test harder, and using a tall chair is cheating.
The foot in contact with the ground cannot move from its spot during the test.
You have to use good muscle control to get up. No trunk momentum allowed.
Arms hang by your side. No trying to get momentum from flailing arms either.
You have to use good muscle control coming down. If you flop or crash land, that repetition does not count.
The knee of the "up" leg should stay straight and off the ground throughout the test. If you decide to switch legs to test the other side, a five-minute break is allowed.
How many could you do? Hopefully you are happy with your results and can build on this success to keep moving and getting stronger. If you're not where you want to be, you can change that! Feel free to contact us or your local physical therapist to see what you can do to reduce your risk of OA.