Standing Versus Stepping-Exploring the Relationships Between Postural Steadiness and Dynamic Reactive Balance Control

Standing, Transition, and Walking Ability in Older Adults: The Case for Independently Evaluating Different Domains of Mobility Function

BACKGROUND

Independent mobility is a complex behavior that relies on the ability to walk, maintain stability, and transition between postures. However, guidelines for assessment that details what elements of mobility to evaluate and how they should be measured remain unclear.

METHODS

Performance on tests of standing, sit-to-stand, and walking were evaluated in a cohort of 135 complex, comorbid, and older adults (mean age 87 ± 5.5 years). Correlational analysis was conducted to examine the degree of association for measures within and between mobility domains on a subset of participants (n = 83) able to complete all tasks unaided. Participants were also grouped by the presence of risk markers for frailty (gait speed and grip strength) to determine if the level of overall impairment impacted performance scores and if among those with risk markers, the degree of association was greater.

RESULTS

Within-domain relationships for sit-to-stand and walking were modest (rho = 0.01-0.60). Associations either did not exist or relationships were weak for measures reflecting different domains (rho = -0.35 to 0.25, p > 0.05). As expected, gait speed differed between those with and without frailty risk markers (p < 0.001); however, balance and sit-to-stand measures did not (p ≥ 0.05).

CONCLUSIONS

This study highlights the need to independently evaluate different mobility domains within an individual as a standard assessment approach. Modest within-domain relationships emphasize the need to account for multiple, unique control challenges within more complex domains. These findings have important implications for standardized mobility assessment and targeted rehabilitation strategies for older adults.

Analysis of invoked slips while wearing flip-flops in wet and dry conditions: Does alternative footwear alter slip kinematics?

Minimal footwear has become more ubiquitous; however, it may increase slip severity. This study specifically examined the slipping kinematics of flip-flop sandals. Invoked slips from standing were evaluated in dry and wet tile, and a unique wet footbed + wet tile condition, with 40, 50, and 60% bodyweight (BW) committed to the slipping foot. Water did not alter peak slip velocity (PV) at 40% BW, but PV increased with greater slip-foot force on wet tile by ~1 m/s. Interestingly, when floor-contact was lost during the slip, the flip-flops could come off the heel. This decoupling occurred most often when both the tile and footbed were either dry or wet. Given that both decoupling and greater PV were observed on wet tile, slipping in flip-flops under wet conditions may have more serious consequences. The results highlight that slips may occur at both the foot-flip-flop, and flip-flop-tile interfaces.