Background/Purpose: Physical function and balance often decline in older adults, and joint hypermobility, a condition in which joint range of motion is greater than normal, may be related to impaired physical function and balance.  This cross-sectional study examined the association of joint hypermobility with measures of lower extremity function (standing balance and walking time) in a community-based cohort of older adults.   

Methods: Data were collected during 2003-2010 from Johnston County Osteoarthritis Project participants.  The Beighton criteria were used to assess hypermobility at nine body sites: the trunk and bilaterally for the first and fifth fingers, elbows, and knees. General joint hypermobility (GJH) was defined as a Beighton score ≥4 (range 0-9).  Knee hypermobility was defined as hyperextension of at least one knee, and trunk hypermobility was defined as the ability to place ones palms on floor during forward trunk flexion with knees extended. Physical function outcomes were: 8-foot walk (unable to do or ≥3.5 seconds [s] vs. <3.5 s), standing balance (full tandem unable to do or <10 s vs. 10+ s), and functional reach test (<28.0 cm vs. ≥28.0 cm).  Separate logistic regression models were used to estimate associations between joint hypermobility and physical function, adjusting for age, body mass index (BMI), sex, race (African American vs. White), self-reported physical activity from standard questionnaire (≥150 vs. <150 minutes moderate physical activity per week), and presence/absence of symptomatic osteoarthritis (sxOA) separately at the knee and hip.

Results: Data were available for 1695 participants (6.5% with GJH, mean age 69 years, mean BMI 31 kg/m², 67% women, 31% African American, 38% achieving ≥150 minutes of moderate physical activity per week, 23% knee sxOA, 127% hip sxOA). In unadjusted analyses, presence of GJH was associated with the better-performing groups for tandem stance time and 8-foot walk time, but associations were no longer statistically significant in adjusted models (see Table). Knee hypermobility models, both unadjusted and adjusted, showed no statistically significant differences in physical function measures.  Crude models of trunk hypermobility were associated with better functional reach and 8-foot walk time, but results were attenuated and not statistically significant after adjusting for covariates.  

Conclusion: While unadjusted models indicated associations of GJH with balance and walk-time, once covariates were taken into account, particularly age, the associations were attenuated. Trunk hypermobility (signifying increased hamstring flexibility) may be a marker of better lower body physical function and balance. Prospective studies may determine how the presence or absence of joint hypermobility relates to physical function and balance over time.