EFFECT OF AGE AND ACTIVITY ON KNEE-JOINT PROPRIOCEPTION

Falls lead to significant morbidity and mortality in persons older tha n 65 years of age. Impaired proprioception may be a contributing facto r to falls, and this may be influenced by the level of habitual physic al activity. The primary purpose of this study was to investigate knee joint proprioception among young volunteers and active and sedentary elderly volunteers. Knee joint proprioception was measured through rep roduction of static knee angles using a Penny and Giles(TM) electrogon iometer. The secondary purpose of this investigation was to test the r eproducibility of the Penny and Giles(TM) electrogoniometer in measuri ng static knee angles. Sixteen young subjects (age range, 19-27 years) and 24 elderly subjects (age range, 60-86 years) participated. Subjec ts were given a screening history and physical examination to exclude neuromuscular or vestibular disorders or lower limb injuries. Knee joi nt proprioception was measured two times during one week. The elderly group was separated into active and sedentary subgroups based on their level of activity during the past year. The electrogoniometer was pla ced laterally across the dominant knee joint. From the prone position each subject attained one of ten randomly predetermined knee joint ang les from 10 degrees to 60 degrees. The subject then returned to the st arting position and reproduced the test angle. The absolute angular er ror (the absolute difference between the test angle and subject percei ved angle of knee flexion) was determined. A positive correlation was found between control visits for all subjects (r = 0.88), and signific ant differences were observed between young (mean, 2.01 +/- 0.46 degre es) and active-old (mean, 3.12 +/- 1.12 degrees; P < 0.001), young and sedentary-old (mean, 4.58 +/- 1.93 degrees; P < 0.001), and active-ol d and sedentary-old (P < 0.03). These findings demonstrate that the Pe nny and Giles(TM) electrogoniometer is a reproducible device for measu ring knee joint angles in both young and elderly subjects. Furthermore , we found that proprioception is diminished with age and that regular activity may attenuate this decline. One strategy to reduce the incid ence of poor proprioception and fall with ageing may be regular exerci se.