Age-related mobility loss is joint-specific: an analysis from 6,000 Flexitest results

Although aging is commonly linked to a reduction in joint range of motion, it is unclear if all body joints behave similarly. To address this issue, the main purpose of this study was to compare age-related loss of mobility of seven body joints. A total of 6,000 participants (3,835 men and 2,165 women) aged 5 to 92 years took part in this study. The maximal passive range of motion of 20 movements was evaluated by Flexitest, and each movement was scored from 0 to 4. Composite scores were obtained for each of seven joints and for overall flexibility (Flexindex (FLX)) by adding individual movement scores. Confirming previous findings, FLX systematically decreased with aging (p < .001), with female participants being more flexible for all ages (p < 0.001) and having a more gradual, 0.6 % vs. 0.8 %/year, age reduction (p < .001). Starting at 30 and 40 years, respectively, for male and female participants, the relative contribution of each composite joint score to FLX dramatically changed. Shoulder contribution to FLX male's score went from 13.9 % at 28 years of age to only 5.2 % at 85 years of age. In general, proportionally, shoulder and trunk became less flexible, while elbow and knee mobility was preserved to a greater extent. Our findings indicated that age-related loss of mobility is rather joint-specific, which could be related to distinct routine usage patterns of the major body joints along life.