Lower limb strength is associated with gait biomechanical abnormalities in older female fallers and non-fallers (original) (raw)
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Clinical Biomechanics, 2013
Objective: To determine the nervous activation, muscle strength, and biomechanical parameters that influence the cost of walking in older fallers and non-fallers. Methods: Maximal voluntary isokinetic torque was measured for the hip, knee and ankle of older women. Oxygen consumption was measured at rest and during 8 min of walking at self-selected speed. An additional minute of walking was performed to collect kinematic variables and the electromyographic signal of trunk, hip, knee, and ankle muscles, which was analyzed by the linear envelope. Cost of walking was calculated by subtracting resting body mass-normalized oxygen consumption from walking body mass-normalized oxygen consumption. Stride time and length, and ankle and hip range of motion were calculated from kinematic data. Findings: Older adult fallers had 28% lower knee extensor strength (p = 0.02), 47% lower internal oblique activation at heel contact (p = 0.03), and higher coactivation between tibialis anterior and gastrocnemius lateralis in each of the gait phases (p b 0.05). For fallers, a higher activation of gluteus maximus was associated with a higher cost of walking (r=0.55, pb 0.05 and r =0.71, p b 0.01, before and after heel contact, respectively). For non-fallers, an association between cost of walking and age (r =0.60, p =0.01) and cost of walking and thigh muscle coactivation (r =0.53, p=0.01) existed. Interpretation: This study demonstrated that there may be links between lower-extremity muscle weakness, muscle activation patterns, altered gait, and increased cost of walking in older fallers.
Motor readiness and joint torque production in lower limbs of older women fallers and non-fallers
Journal of Electromyography and Kinesiology, 2013
This study aimed to evaluate the motor response time and ability to develop joint torque at the knee and ankle in older women with and without a history of falls, in addition to investigating the effect of aging on these capacities. We assessed 18 young females, 21 older female fallers and 22 older female non-fallers. The peak torque, rate of torque development, rate of electromyography (EMG) rise, reaction time, premotor time and motor time were obtained through a dynamometric assessment and simultaneous electromyography. Surface EMGs of the rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), gastrocnemius lateralis (GL) and tibialis anterior (TA) muscles were recorded. Knee extension and flexion peak torques were lower in older fallers than in non-fallers. Knee extension and flexion and ankle plantarflexion and dorsiflexion peak torques were lower in both older groups than in the younger group. The rate of EMG rise of the BF and the motor time of the TA were lower and higher, respectively, in older fallers than in the younger adults. The time to reach peak torque in knee extension/flexion and ankle plantarflexion/dorsiflexion and the motor times of the RF, VL, BF and GL were higher in both older groups than in the younger groups. The motor time of the TA during ankle dorsiflexion and the knee extension peak torque were the major predictors of falls in older women, accounting for approximately 28% of the number of falls. Thus, these results further reveal the biomechanical parameters that affect the risk of falls and provide initial findings to support the prescription of exercises in fall prevention programs.
Age-Related Ankle Strength Degradation and Effects on Slip-Induced Falls
Each year there is an increasing incidence of slip and fall accidents, especially among the elderly population. Existing evidence has identified several aging effects related to slip and fall accidents, yet, the causes of these accidents with advancing age are still little known. The objective of this research was to investigate the factors influencing the initial phase of unexpected slips and falls in younger and older individuals. More specifically, the relationship between ankle strength, the ankle joint power to transfer the whole body center-of-mass during normal gait, and the likelihood of slip-induced falls was identified. The walking experiment and the ankle strength tests were conducted in the Locomotion Research Laboratory, Virginia Tech. Fourteen old (67-79 years old) and 14 young (19-35 years old) individuals participated in this study (7 male and 7 female for each age group).Within a subsequent 20-minute session of natural walking on a linear track, kinematic and kinetic data were collected synchronously. A slippery surface was introduced to the participant on the purpose of unexpected slip event. The ankle strength tests were performed using a dynamometer. The results indicated that ankle strength degradation in older individuals was related to the outcome of slips (i.e., higher frequency of falls). The results also indicated that older individuals' RCOF was less than their younger counterparts. However, older individuals fell more often than younger individuals. It is concluded that friction demand characteristics may not be a total deterministic factor of fall accidents. Thus, the further research should focus not only on the dynamic of slips, but also on the dynamics of falls.
Isokinetics and Exercise Science, 2016
BACKGROUND: Lower-extremity strength and neuromuscular parameters that are more affected with age and in individuals more prone to fall still needs to be identified in healthy physically active adults. OBJECTIVE: To investigate the ability of joint torque and muscle activity parameters to differentiate between physically active women, young, older non-fallers and older fallers; and their correlation with the number of falls in older women. METHODS: Measures were taken from concentric contractions during isokinetic sagittal plane movements at 90 • /s and 120 • /s. EMG from the rectus femoris, vastus lateralis, biceps femoris, lateral gastrocnemius and tibialis anterior were recorded. RESULTS: Overall young women were stronger, more powerful and presented lower muscle activation than older women fallers and non-fallers (all p < 0.04). Older women fallers had lower knee flexion and extension peak torque (p < 0.033) and power (p < 0.045), lower ankle dorsiflexion power (p = 0.04) and higher rectus femoris activation (p = 0.033) at 90 • /s than older women non-fallers; and all these variables were correlated with the number of falls (r = 0.32-0.49; p < 0.05). CONCLUSIONS: These findings may be useful for a better understanding of biomechanical risk factors for falls and for exercise-based fall prevention programs development.
Comparison of Lower Limb Strength in Younger and Older Female Adults
Revista Brasileira de Ciência e Movimento, 2017
Introduction: Age-related weakness results in slow movements, altered motor control, and higher sense of effort during activities of daily living. Thus, when an older adult performs tasks closer to the maximum functional capacity it may contribute to the onset of fatigue and increased risk of falling. Objective: The present study aimed to compare lower limb strength and strength ratio (isokinetic strength/isometric strength) in younger and older adults. Methods: The maximum isometric and isokinetic strength were assessed at hip, knee and ankle joints at sagittal plane. Peak isometric and isokinetic torque were normalized by body mass (Nm.kg-1) and strength ratio was calculated dividing the maximum isokinetic strength over the maximum isometric strength of each joint in each movement. Results: Younger adults had 11.6% higher ankle extension strength ratio (p = 0.013) and 17.6% higher ankle flexion strength ratio (p = 0.001) than older female adults. The isometric peak torque was high...
Kinetic alterations independent of walking speed in elderly fallers
Archives of Physical Medicine and Rehabilitation, 2000
To determine if joint kinetic gait alterations in fallers persist when they attempt to walk at a faster speed that is more comparable with nonfallers&amp;#39; comfortable walking speed. Retrospective, case-control study. Stereophotogrammetric and force platform data were collected. A gait laboratory. Sixteen elderly subjects who had at least 2 falls in the last 6 months from an unclear cause and 23 elderly subjects with no history of repeated falls. Differences in all major peak joint kinetic (moment and power) values during the gait cycle between elderly nonfallers walking at comfortable speed and elderly fallers walking at (1) comfortable and (2) fast speed. Statistically significant differences present at both comfortable and fast walking speeds were present in 4 sagittal plane parameters. There was an increase in peak external hip flexion moment in stance, a reduction in peak hip extension moment, a reduction in knee flexion moment in preswing, and a reduction in knee power absorption in preswing. The presence and persistence of 4 specific alterations in sagittal plane joint kinetics at both comfortable and fast walking speeds imply specific intrinsic pattern differences and allow for new insights into the mechanics of gait in elderly people who fall. The presence of these alterations also suggests they may serve as potential identifiable markers to detect those who may be at risk for falls.
The effect of exercise on gait patterns in older women
Journals of Gerontology Series A-biological Sciences and Medical Sciences, 1996
Background. This study was undertaken to determine (a) whether a program of regular exercise can improve gait patterns in older women, and (b) whether any such improvement in gait is mediated by increased lower limb muscle strength. Method. A 22-week randomized controlled trial of exercise was conducted as part of the Randwick Falls and Fractures Study in Sydney, Australia. Subjects were 160 women aged 60-83 years (Mean age 71.1, SD = 5.2) who were randomly recruited from the community. Exercise and control subjects were tested prior to and at the end of the trial. At initial testing, exercisers and controls performed similarly in the strength and gait parameters. They were well matched in terms of age and a number of health and lifestyle characteristics. Results. At the end of the trial, the exercise subjects showed improved strength in five lower limb muscle groups, increased walking speed, cadence, stride length, and shorter stride times as indicated by both reduced swing and stance duration. There were no significant improvements in any of the strength or gait parameters in the controls. Within the exercise group, increased cadence was associated with improved ankle dorsiflexion strength, and increased stride length was associated with improved hip extension strength. Exercise subjects with initial slow walking speed showed greater changes in velocity, stride length, cadence, and stance duration than those with initial fast walking speed. Conclusion. These findings show that exercise can increase gait velocity and related parameters in older persons, and that part of this increase may be mediated by improved lower limb muscle strength.
The influence of lower extremity joint torque on gait characteristics in elderly men
Archives of Physical Medicine and Rehabilitation, 2000
Objective: To examine the relation between certain lower extremity isokinetic muscle torque capabilities and selected stride characteristics for a group of elderly, sedentary men. Study Design: Descriptive analysis of convenience sample. Setting: Veterans Administration (VA) ambulatory care center. Subjects: Eighty-one elderly men, capable of independent ambulation, were recruited from outpatient clinics and the local community (mean age, 74.7yr). Main Outcome Measures: Maximal isokinetic torque in the sagittal plane of hip, knee, and ankle muscles; stride characteristics of speed, stride length, and cadence recorded during walking at a self-selected velocity. Results: Stepwise regression analysis revealed that hip extension torque was the only significant independent predictor for free walking speed, stride length, and cadence, and accounted for 37% (r ϭ .611), 35% (r ϭ .590), and 12% (r ϭ .341) of the total variance, respectively. Other joint torques correlated with gait parameters but did not add significantly to the multivariate model. Conclusions: Hip extension torque was the only significant independent predictor for free walking velocity, stride length, and cadence in this group. These results support the idea that strengthening the hip extensors may improve stride characteristics in elderly individuals.