Prakriti Parijat

Effects of quadriceps fatigue on the biomechanics of gait and slip propensity

This study examines how lower extremity fatigue of the quadriceps alters gait variables related to slip propensity. Sixteen healthy young adults were recruited to walk across vinyl floor surfaces in states of fatigue and no fatigue. Kinematic and kinetic data were collected using a three-dimensional motion analysis system and force plates. The results indicated a significant increase in both the heel contact velocity and required coefficient of friction and a decrease in the transitional acceleration of the whole body center of mass and peak knee joint moment in the fatigue trials. Thus, suggesting that slip propensity could increase with fatigue. Additionally, there was increased knee flexion and reduced ankle dorsiflexion at the heel contact phase of the gait cycle during fatigue trials. These findings provide new insights into the biomechanical relationship between localized muscle fatigue and gait parameters associated with slip propensity. The present study concluded that localized muscle fatigue affects gait parameters and hence can be considered as a potential risk factor for slip-induced falls.

Effects of lower extremity muscle fatigue on the outcomes of slip-induced falls

Slip-induced fall accidents continue to be a significant cause of fatal injuries and economic losses. Identifying the risk factors causing slip-induced falls is key to developing better preventive measures to reduce fall accidents. Although epidemiological studies suggest localised muscle fatigue may be one of the risk factors for slip-induced falls, there has been no documented biomechanical study examining the relationship between fatigue and fall accidents. As such, the overall objective of the current study was to investigate the effects of localised muscle fatigue of the quadriceps on the slip initiation and slip recovery phases of slip-induced falls. Sixteen healthy, young participants were recruited to walk across a vinyl floor surface in two different sessions (fatigue and no fatigue). Kinematic and kinetic data were collected using a 3-D motion analysis system and force plates during both sessions. Results suggest that localised muscle fatigue of the quadriceps affected various kinematic and kinetic gait variables that are linked with a higher risk of slip-induced falls. Additionally, the results indicated that localised muscle fatigue of the knee extensor muscle caused a delayed response in producing an effective joint moment and base of support using the trailing limb to recover from a fall. The findings from this study indicate that localised muscle fatigue is a potential risk factor causing slip-induced falls.

EMG and Kinematic Responses to Unexpected Slips After Slip Training in Virtual Reality

The objective of the study was to design a virtual reality (VR) training to induce perturbation in older adults similar to a slip and examine the effect of the training on kinematic and muscular responses in older adults. Twenty-four older adults were involved in a laboratory study and randomly assigned to two groups (VR training and control). Both groups went through three sessions including baseline slip, training, and transfer of training on slippery surface. The training group experienced 12 simulated slips using a visual perturbation induced by tilting a VR scene while walking on the treadmill and the control group completed normal walking during the training session. Kinematic, kinetic, and electromyography data were collected during all the sessions. Results demonstrated the proactive adjustments such as increased trunk flexion at heel contact after training. Reactive adjustments included reduced time to peak activations of knee flexors, reduced knee coactivation, reduced time to trunk flexion, and reduced trunk angular velocity after training. In conclusion, the study findings indicate that the VR training was able to generate a perturbation in older adults that evoked recovery reactions and such motor skill can be transferred to the actual slip trials.

Can Virtual Reality Be Used As A Gait Training Tool For Older Adults

The objective of this study was to examine the effects of Virtual Reality (VR) habituation on the kinematic and gait variability changes in older adults. Sixteen healthy older adults participated in the study. The experiment consisted of walking session on a walkway, followed by walking on the treadmill with and without a head mounted display of a VR scene. Kinematic data were collected using a motion capture system. Additionally, a cyber-sickness questionnaire was administered to the participants during and after the experiment to evaluate motion sickness symptoms. Statistical analyses indicated an increased variability in stride length, stride velocity, and step width during the initial 5-10 min in the VR. Kinematic data indicated an increased ankle plantar flexion, knee flexion, and trunk flexion in the initial VR period. All parameters approximated normal treadmill walking within 20 min of VR walking. The cyber sickness scores indicated no presence of cyber sickness during or after the VR experiment. It was concluded that the habituation time in VR may have significant effect on gait behavior in older adults and therefore it should be considered while designing a VR locomotion training study.

Investigation of Biomechanical Characteristics of Older Adults: Effects of Gender and Driving Status

The purpose of this study was to investigate the biomechanical differences in the ability to generate force between older drivers and non-drivers. The study examined differences in ankle, hip and upper body torque generation between gender and driving groups with respect to driving posture. Twenty-four older adults aged 65 years and older were recruited for participation in this study. Strength and reaction time data were collected using a Biodex Dynamometer. The data was analyzed to report peak torque generation at the ankle, hip, and steering wheel along with peak reaction times and head-neck flexibility. The results indicated a significant decrease in peak torque measurements, and increase in the reaction time in non-drivers as compared to drivers. Gender differences were found in the hip and upper body torque, with females at a lower strength level than males. No significant differences were found between gender and driving status for the head neck flexibility.

Knee joint kinetics during reactive recovery: effects of localized muscle fatigue

The purpose of this study was to investigate the effects of localized muscle fatigue on the knee joint kinetics during reactive recovery efforts from a slip perturbation. Sixteen healthy young participants were recruited to walk across an unexpected slippery vinyl floor surface in two different sessions (Fatigue and No fatigue). Kinematic and kinetic data were collected using a three-dimensional video analysis system and force plates during both sessions. An inverse dynamic model was developed to assess joint moment and joint power of the knees during reactive recovery period of slip-induced falls. The results demonstrated an increase in the peak knee joint moment and peak knee joint power generation in the fatigue slip trials. There were four reported falls in the fatigue session. The study concluded that localized muscle fatigue adversely affects the knee joint kinetics and can be considered a risk factor for slip induced falls. These findings provide new insights to the biomechanical relationship between knee kinetics and localized muscle fatigue.

Influence of Localized Muscle Fatigue of the Knee Joint on Gait Parameters Related to Slip Propensity

Existing epidemiological evidence suggests that localized muscle fatigue might be considered as an intrinsic risk factor that causes lack of balance control leading to falls. The goal of the study was to examine how localized muscle fatigue of the knee joint (quadriceps) alters gait parameters that are related to slip propensity. Sixteen healthy young participants were recruited to walk across a vinyl floor surface in two different sessions (Fatigue and No fatigue). Kinematic and kinetic data were collected using a three-dimensional video analysis system and force plates during both sessions. The fatigue session results indicated a substantial increase in heel contact velocity (HCV) and required coefficient of friction (RCOF), as well as a decrease in the transitional acceleration of the whole body COM (TA), walking velocity (WV), and step length (SL). In addition, a positive correlation was observed between RCOF and HCV. These findings provide new insights into the biomechanical relationship between localized muscular fatigue and gait parameters linked with slip propensity. The study concluded that localized muscular fatigue affects gait parameters and hence can be considered as a potential risk factor for slip-induced falls.

EFFECTS OF QUADRICEPS FATIGUE ON KNEE JOINT KINETICS DURING SLIP INDUCED FALLS

INTRODUCTION Occupationally induced localized muscular fatigue (LMF) has been recently identified as one of the major intrinsic factors contributing to slip and fall accidents [1]. Although there has been a reduction of heavy work due to growing technological advances, some occupations such as construction, and forestry still demand intense physical work. Literature indicates that a third of the U.S. workforce exerts significant physical strength as part of their jobs, and experience fatigue at their work places [2]. While epidemiological studies link the incidence of slip-induced falls with LMF, the mechanism associated with fatigue and its relationship with slip-induced fall accidents still remains unclear. The purpose of the present study was to examine how lower extremity fatigue (quadriceps femoris) alters joint moment and increases slip severity.