Although physical activity is known to ease the painful symptoms of knee osteoarthritis (OA) – a common cause of pain and joint stiffness – only one in 10 people regularly exercise, says scientists, whose recent study dissects what contributes to patients’ inactivity.
Researchers from the University of South Australia found that people with knee OA unconsciously believe that activity may be dangerous to their condition, despite medical advice telling them otherwise, and that of those they surveyed, 69% with knee pain had stronger implicit (unconscious) beliefs that exercise was dangerous than the average person without pain.
Their finding – published in the journal Pain – not only highlights the conflicted nature of pain and exercise, but also that what people say and what people think, deep down, may be entirely different things, the team said.
Brian Pulling, lead researcher and UniSA PhD candidate based at South Australian Health and Medical Research Institute (SAHMRI), said the findings provide valuable insights for clinicians treating people with knee OA.
“Research shows that physical activity is good for people with knee OA, but most people with this condition do not move enough to support joint or general health,” he said.
“To understand why, research studies typically use questionnaires to assess fear of moving. But unfortunately, questionnaires are limited – what we feel deep down (and how our system naturally reacts to something that is threatening) may be different to what we report. And we still know that many people are avoiding exercise, so we wanted to know why.”
To assess this, the researchers developed a tool that can detect and evaluate people’s implicit beliefs about exercise; that is, whether they unconsciously think activity is dangerous for their condition.
“We found that that even among those who said they were not fearful about exercise, they held unconscious beliefs that movement was dangerous,” he said.
“Our research shows that people have complicated beliefs about exercise, and that they sometimes say one thing if asked directly yet hold a completely different implicit belief.
“People are not aware that what they say doesn’t match what they choose on the new task; they are not misrepresenting their beliefs.
“This research suggests that to fully understand how someone feels about an activity, we must go beyond just asking directly, because their implicit beliefs can sometimes be a better predictor of actual behaviour than what people report. That’s where our tool is useful.”
The online implicit association test presents a series of words and images to which a participant must quickly associate with being either safe or dangerous. The tool intentionally promotes instant responses to avoid deliberation and other influencing factors (such as responding how they think they should respond).
Associate Professor Tasha Stanton said the new tool has the potential to identify a group of people who may have challenges increasing their activity levels and undertaking exercise.
“What people say and what people do are often two different things,” she added.
“Having access to more accurate and insightful information will help health professionals better support their patients to engage with activity and exercise. It may also open opportunities for pain science education, exposure-based therapy, or cognitive functional therapy…things that would not usually be considered for someone who said that they were not scared to exercise.”
Study details
People with painful knee osteoarthritis hold negative implicit attitudes towards activity
Brian Pulling, Felicity Braithwaite, Tasha Stanton et al.
Published in Pain on 16 April 2024
Abstract
Negative attitudes/beliefs surrounding osteoarthritis, pain, and activity contribute to reduced physical activity in people with knee osteoarthritis (KOA). These attitudes/beliefs are assessed using self-report questionnaires, relying on information one is consciously aware of and willing to disclose. Automatic (ie, implicit) assessment of attitudes does not rely on conscious reflection and may identify features unique from self-report. We developed an implicit association test that explored associations between images of a person moving/twisting their knee (activity) or sitting/standing (rest), and perceived threat (safe vs dangerous). We hypothesised that people with KOA would have greater implicit threat–activity associations (vs pain-free and non-knee pain controls), with implicit attitudes only weakly correlating with self-reported measures (pain knowledge, osteoarthritis/pain/activity beliefs, fear of movement). Participants (n = 558) completed an online survey: 223 had painful KOA (n = 157 female, 64.5 ± 8.9 years); 207 were pain free (n = 157 female, 49.3 ± 15.3 years); and 99 had non-KOA lower limb pain (n = 74 female, 47.5 ± 15.04 years). An implicit association between “danger” and “activity” was present in those with and without limb pain (KOA: 0.36, 95% CI 0.28-0.44; pain free: 0.13, 95% CI 0.04-0.22; non-KOA lower limb pain 0.11, 95% CI −0.03 to 0.24) but was significantly greater in the KOA group than in the pain free (P < 0.001) and non-KOA lower limb pain (P = 0.004) groups. Correlations between implicit and self-reported measures were nonsignificant or weak (rho = −0.29 to 0.19, P < 0.001 to P = 0.767). People with painful KOA hold heightened implicit threat–activity associations, capturing information unique to that from self-report questionnaires. Evaluating links between implicit threat–activity associations and real-world behaviour, including physical activity levels, is warranted.
See more from MedicalBrief archives:
No link between physical activity and knee osteoarthritis — Meta-analysis
Running actually lowers inflammation in knee joints
High impact training can help ‘dicky’ knees