Age-related changes in strength and somatosensation during midlife: rationale for targeted preventive intervention programs.

Age-related changes in strength and somatosensation have a negative impact on balance with advanced age. Knowledge of the decades of life when strength and somatosensation show initial and subsequent reductions could inform balance assessment and targeted preventive intervention. We report a cross-sectional study investigating strength and somatosensation of 316 healthy women aged 20-80 years. Demographics, health profile, and activity level were recorded. Strength of quadriceps, hip abductors and adductors, and lower limb somatosensation (tactile acuity, vibration threshold, and joint position error) were measured. Significant age-related changes in strength and somatosensory function were identified, even when demographic variables of activity level, weight, number of reported conditions, medications used, and history of falls were included as covariates. Tested muscles achieved peak force in women in their 40s and then trending reductions presented for those in their 50s and 60s, with significant reductions by the 70s. Tactile acuity, vibration sensitivity, and joint position sense for a non-weight-bearing toe-matching task were significantly reduced by the 40s or 50s, with further reductions by either the 60s or 70s. For the weight-bearing replication task, joint position error was significantly increased by the 60s. A main effect of activity level and body weight was identified for strength measures, and weight also had a main effect for most of the somatosensory modalities. These findings can inform health professionals to use knowledge of early and any subsequent reductions in muscle strength and somatosensation, along with effects of demographics, to develop targeted, innovative programs across the mid-life, a preclinical change period for balance, to promote healthier aging.