Age has no effect on ankle proprioception when movement history is controlled

Ankle proprioceptive deficits can contribute to increased fall risks in the elderly population. We investigated whether ankle proprioception alters with age in healthy people (n = 80, aged 19-80 yr). Previous studies report conflicting results, but none have considered that proprioceptive performance is affected by previous muscle contractions and length changes. Participants sat with their leg extended and foot rested on a motorized footplate. Three proprioceptive tests were performed: threshold for detection of passive movement, proprioceptive reaction time, and a test of matching joint position sense. Muscle spindle sensitivity was controlled by repetitively moving the ankle before each target angle. Reliability of these methods was tested. Linear regression showed no effect of age on proprioceptive acuity. Mean detection threshold was 0.13 +/- 0.10 degrees (mean +/- SD) and regression against age gave R-2 = 0.009 (P = 0.399). Mean reaction time was 0.251 +/- 0.054 s with R-2 = 0.004 (P = 0.597). Three measures were calculated for joint position sense (gamma-intercept, -13.3 +/- 9.4 degrees; slope. 1.15 +/- 0.45; R-2, 0.78 +/- 0.12). None were associated with age (R-2 = 0.02, P = 0.19; R-2 = 0.01, P = 0.36; R-2 = 0.019, P = 0.23, respectively). Most measures showed good to excellent reliability. Unexpectedly, our results suggest there is little effect of age on ankle proprioceptive performance in healthy community-dwelling people when proprioception is tested with passive movements and under controlled laboratory conditions. However, we cannot rule out that impairments in proprioceptive function may be evident in older people with poor function, that is, those classified as "fallers". NEW & NOTEWORTHY It is generally accepted that proprioceptive ability deteriorates with age, although not all data support this view. We tested proprioception using three reliable tests at the ankle in 80 adults (19-80 yr). For all tests, the effects of muscle thixotropy were controlled. Under these conditions, we found no difference in proprioceptive acuity between young and old people.