Ankle complex proprioception and plantar cutaneous sensation in older women with different physical activity levels

Ankle complex proprioception and plantar sole sensitivity have been separately reported to be essential sensory components in balance control among the elderly. However, their inter-relationship is still unknown. Further, although optimal proprioceptive ability has been related to regular physical exercise, the association between physical activity (PA) levels, ankle proprioceptive acuity and plantar cutaneous sensation is unclear. Therefore, this study aims to compare ankle proprioceptive acuity and plantar cutaneous sensitivity scores between groups of older women with different PA levels, and to determine any relationships between plantar sole cutaneous sensitivity, ankle proprioceptive performance and PA levels. 68 older female participants were recruited who were distributed over three PA levels: highly active, moderately active, and inactive. PA level was assessed by the International Physical Activity Questionnaire. Ankle proprioceptive acuity was tested in full weight-bearing stance using the ankle Active Movement Extent Discrimination Apparatus (AMEDA) and plantar cutaneous sensitivity was assessed with the Nylon Semmes-Weinstein monofilaments test. Results showed that ankle proprioceptive acuity scores were strongly positively related to plantar sole sensitivity scores (r = 0.80, p < 0.001; effect size: η² = 0.715), and both scores correlated with PA level. In conclusion, plantar cutaneous sensitivity and ankle complex proprioception were strongly correlated in older females with different levels of physical activity, suggesting that the former may be an integral part of the latter. Given the previously reported contribution of AMEDA ankle proprioceptive acuity to sport performance level, the health of the plantar sole of the foot may be important as a performance determinant.