Differences between Proximal and Distal Muscle Activity of the Lower Limbs of Community-dwelling Women during the 6-minute Walk Test

Kinematic characteristics during gait in frail older women identified by principal component analysis

Frailty is associated with gait variability in several quantitative parameters, including high stride time variability. However, the associations between joint kinematics during walking and increased gait variability with frailty remain unclear. In the current study, principal component analysis was used to identify the key joint kinematics characteristics of gait related to frailty. We analyzed whole kinematic waveforms during the entire gait cycle obtained from the pelvis and lower limb joint angle in 30 older women (frail/prefrail: 15 participants; non-frail: 15 participants). Principal component analysis was conducted using a 60 × 1224 input matrix constructed from participants’ time-normalized pelvic and lower-limb-joint angles along three axes (each leg of 30 participants, 51 time points, four angles, three axes, and two variables). Statistical analyses revealed that only principal component vectors 6 and 9 were related to frailty. Recombining the joint kinematics corresponding to these principal component vectors revealed that frail older women tended to exhibit greater variability of knee- and ankle-joint angles in the sagittal plane while walking compared with non-frail older women. We concluded that greater variability of knee- and ankle-joint angles in the sagittal plane are joint kinematic characteristics of gait related to frailty.

Differences in predictors for gait speed and gait endurance in Parkinson's disease

INTRODUCTION

Both gait speed and gait endurance directly impact independence and community engagement for individuals with Parkinson's disease (PD). However, factors accounting for variability in gait speed and gait endurance performance are unclear. The purpose of this study was to investigate whether key factors associated with gait speed in individuals with PD also predicted gait endurance.

METHODS

Community dwelling ambulatory individuals with PD were recruited for a single session. Key measures included 10 Meter Walk Test (10MWT) and 6 Minute Walk Test (6MWT) and key factors: age, disease severity [Movement Disorders Society United Parkinson's Disease Rating Scale (motor scale only) (MDS-UPDRS motor)], plantar flexor strength [Calf Raise Senior (CRS)], fatigue [Fatigue Severity Scale (FSS)], cognition [Montreal Cognitive Assessment (MoCA)], and balance [Four Square Step Test (FSST)]. Multiple linear regression analyses were conducted to determine clinical relationships.

RESULTS

Seventy-two individuals with PD (mean (standard deviation) (age = 70.83 (7.91) years; 50 males; MDS-UPDRS motor = 30.67 (13.50)) completed all assessments. The model predicting gait speed was significant, F(6, 65) = 15.143, p <.001, accounting for 54 % of the variance. Of the predictor variables age, MDS-UPDRS motor, CRS, MoCA and FSST scores were significant predictors. The model predicting gait endurance was significant, F(6, 65) = 15.608, p <.001, accounting for 55 % of the variance. Of the predictor variables, age, MDS-UPDRS motor scale, and CRS scores were significant predictors.

DISCUSSION

Gait speed and gait endurance are similarly influenced by age, motor impairment, and plantarflexion strength. However, cognition and balance were predictors only of gait speed, which may suggest unique task differences exist between gait speed and gait endurance.

Influences of trunk flexion on mechanical energy flow in the lower extremities during gait

[Purpose] The time-series waveforms of mechanical energy generation, absorption, and transfer through the joints indicate how movements are produced and controlled. Previous studies have used these waveforms to evaluate and describe the efficiency of human movements. The purpose of this study was to examine the influence of trunk flexion on mechanical energy flow in the lower extremities during gait. [Subjects and Methods] The subjects were 8 healthy young males (mean age, 21.8 ± 1.3 years, mean height, 170.5 ± 6.8 cm, and mean weight, 60.2 ± 6.8 kg). Subjects walked at a self-selected gait speed under 2 conditions: normal gait (condition N), and gait with trunk flexion formed with a brace to simulate spinal curvature (condition TF). The data collected from initial contact to the mid-stance of gait was analyzed. [Results] There were no significant differences between the 2 conditions in the mechanical energy flow in the knee joint and negative mechanical work in the knee joint. However, the positive mechanical work of the knee joint under condition TF was significantly less than that under condition N. [Conclusion] Trunk flexion led to knee flexion in a standing posture. Thus, a strategy of moving of center of mass upward by knee extension using less mechanical energy was selected during gait in the trunk flexed posture.

Factors associated with the 6-minute walk test in nursing home residents and community-dwelling older adults

[Purpose] The main objective of this study was to determine the contributions and extent to which certain physical measurements explain performance in the 6-minute walk test in healthy older adults living in a geriatric nursing home and for older adults dwelling in the community. [Subjects] The subjects were 122 adults aged 65 and older with no cognitive impairment who were independent in their daily activities. [Methods] The 6-minute walk test, age, body mass index, walking speed, chair stand test, Berg Balance Scale, Timed Up-and-Go test, rectus femoris cross-sectional area, Short Physical Performance Battery, and hand-grip strength were examined. [Results] Strong significant associations were found between mobility, lower-limb function, balance, and the 6-minute walk test. A stepwise multiple regression on the entire sample showed that lower-limb function was a significant and independent predictor for the 6-minute walk test. Additionally, lower-limb function was a strong predictor for the 6-minute walk test in our nursing home group, whereas mobility was found to be the best predictor in our community-dwelling group. [Conclusion] Better lower-limb function, balance, and mobility result in a higher distance covered by healthy older adults. Lower-limb function and mobility appeared to best determine walking performance in the nursing home and community-dwelling groups, respectively.