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1.
Providing an easy ingress–egress (I/E) movement remains a challenge for car designers. I/E has been largely studied in kinematics, but not in dynamics. This study proposes: (1) to evaluate and describe the motor torques developed in the lower limbs and lumbar joints during I/E motions and (2) to analyse the influence of the car geometry and subject anthropometry. An experiment was performed to observe 15 subjects of three anthropometrical groups getting in and out of a car mock-up simulating three different vehicle configurations. Motor torques were extracted using an inverse dynamics analysis. Both ingress and egress motions were primarily characterised by large torques. Overall, the taller a subject and the lower the seat of the vehicle were, the larger the peak torques were. Moreover, peak torques were higher for egress than ingress. These results are discussed in regard to the current knowledge on I/E ergonomics. 相似文献
2.
Vibhor Agrawal Christopher O'Toole Ignacio A. Gaunaurd Robert S. Gailey 《Ergonomics》2016,59(1):121-129
Current methods of quantifying the stand-to-sit activity (StTS) are resource intensive and have not been applied to unilateral transtibial amputees (TTAs). The purpose of this study is to define five phases of arm-rest assisted and unassisted StTS using simple instrumentation and implement this method for assessing TTA movement patterns. Twelve TTAs and 12 age-matched non-amputees performed StTS with and without arm-rest support. Symmetry of weight distribution between lower limbs was calculated for five StTS phases: Descent Initiation; Descent Deceleration; Seat-Contact; Stabilisation and Sitting. TTAs demonstrated an asymmetrical weight distribution pattern and a tendency to transfer weight to the intact limb during the course of the activity. Non-amputees had relatively higher symmetry and did not exhibit substantial weight shifts during the activity. Symmetry indices were similar for assisted and unassisted sitting in both subject groups. These results highlight a need for therapeutic interventions in TTAs for reducing loading asymmetries and associated co-morbidities. 相似文献
3.
Frederick EC 《Applied ergonomics》1984,15(4):281-287
Various features of the design of running shoes have been known to affect the performance and safety of athletes. The performance related effects of shoe design on traction and on the economy of locomotion are reviewed in this paper. Traction measurements in various types of running shoes and on various surfaces appear adequate for all but running on wet asphalt roads. Future designs should improve traction for those conditions. Effects on the economy of locomotion as small as 1% can be determined using conventional oxygen uptake measurements. The effect of carrying extra weight on the foot during running has been measured at 1% per 100 g per foot. The cost of carrying similar weights is much lower for walking or for running when the weight is carried nearer the body's centre of mass. Cushioning and other features of shoe design besides weight have been shown to have significant effects on the economy of locomotion. Optimum designs for maximising running performance should provide sufficient traction, minimal weight and maximum cushioning. 相似文献
4.
A new method is reported for human biodynamic measurement, which includes an improved motion measurement system via virtual marker technology and a wavelet algorithm to extract muscle activities from electromyography signals in vivo. Four channels of electromyography signals and twelve virtual markers motion data were collected when the subject did a standard gait experiment. Then, a wavelet algorithm was used to process raw electromyography signals and to extract muscle activity features. The results demonstrated that the proposed method could shorten the motion measurement experiment time and improve the measurement accuracy. The proposed wavelet algorithm could efficiently extract muscle activity features from electromyography signals. The reported method may be potentially used for the human biodynamic research and clinical biomechanics. Possible further improvements for this method are also discussed. 相似文献
5.
《Ergonomics》2012,55(7):1159-1166
Surface electromyography (EMG) is commonly used to study the loading of the forearm. Pro-supination movements cause surface electrodes to move in relation to the underlying muscles. We studied the effects of different electrode locations and forearm postures on the association between the EMG signals and external hand load in a laboratory experiment. Eleven subjects performed simulated work tasks with the forearm in neutral, pronated or supinated postures and with systematic variation of external load. The tasks included isometric gripping, pushing and pulling, and lifting and lowering weights. Surface EMG was recorded by six pairs of electrodes located on the forearm. The associations were studied using multiple regression models. EMG activity varied according to the forearm posture, location of electrodes and type of simulated task. Variation was lowest with a through-forearm setting of electrodes. This setting also showed the highest correlation between external loads and the EMG activity [coefficient of determination (R 2) = 0.25–0.66]. Practitioner Summary: Moving of surface electrodes in relation to the underlying muscles interferes with the assessment of loading in ergonomic settings. This laboratory experiment showed that a through-forearm location of electrodes seems to be an optimal option in the assessment of forearm loading. 相似文献
6.
《Ergonomics》2012,55(11):1043-1052
Trunk flexion results in adverse mechanical effects on the spine and is associated with a higher incidence of low back pain. To examine the effects of creep deformation on trunk behaviours, participants were exposed to full trunk flexion in several combinations of exposure duration and external load. Trunk mechanical and neuromuscular behaviours were obtained pre- and post-exposure and during recovery using sudden perturbations. Intrinsic trunk stiffness decreased with increasing flexion duration and in the presence of the external load. Recovery of intrinsic stiffness required more time than the exposure duration and was influenced by exposure duration. Reflexive trunk responses increased immediately following exposure but recovered quickly (~2.5 min). Alterations in reflexive trunk behaviour following creep deformation exposures may not provide adequate compensation to allow for complete recovery of concurrent reductions in intrinsic stiffness, which may increase the risk of injury due to spinal instability. Statement of relevance: An increased risk of low back injury may result from flexion-induced disturbances to trunk behaviours. Such effects, however, appear to depend on the type of flexion exposure, and have implications for the design of work involving trunk flexion. 相似文献
7.
张吉桥 《广东工业大学学报》2012,29(2):33-37
细胞移植是心肌组织工程中治疗心肌梗死的一种潜在的治疗方法.心脏补片不仅是种子细胞的载体,还可抑制心脏的膨胀扩张,以促进种子细胞对梗死心肌组织的修复再生.心脏补片的研制已经成为基础与临床医学、材料科学和生物力学等的交叉热点.本文评述了心脏补片的生物力学研究现状,并就本领域今后值得关注的问题进行展望. 相似文献
8.
9.
电测技术在人体骨骼力学性能分析中的应用 总被引:2,自引:0,他引:2
李英子 《哈尔滨理工大学学报》1998,3(2):101-103
用电测实验应力分析方法,对人体管状长骨的力学性质,以及骨折的钢板皮外固定治疗中的力学问题,进行测量与分析。其结果对于推进力学理论在医学方面的应用,以及临床治疗骨折,具有实用价值。 相似文献
10.
Practices and risks associated with operation of tie-down lashings in the vehicle transport industry
Load restraint systems in automobile transport utilise tie-down lashings placed over the car’s tyres, which are tensioned manually by the operator using a ratchet assembly. This process has been identified as a significant manual handling injury risk. The aim of this study was to gain insight on the current practices associated with tie-down lashings operation, and identify the gaps between current and optimal practice. We approached this with qualitative and quantitative assessments and one numerical simulation to establish: (i) insight into the factors involved in ratcheting; (ii) the required tension to hold the car on the trailer; and (iii) the tension achieved by drivers in practice and associated joint loads. We identified that the method recommended to the drivers was not used in practice. Drivers instead tensioned the straps to the maximum of their capability, leading to over-tensioning and mechanical overload at the shoulder and elbow. We identified the postures and strategies that resulted in the lowest loads on the upper body during ratcheting (using both hands and performing the task with their full body). This research marks the first step towards the development of a training programme aiming at changing practice to reduce injury risks associated with the operation of tie-down lashings in the automobile transport industry.
Practitioner Summary: The study investigated current practice associated with the operation of tie-down lashings through qualitative (interviews) and quantitative (biomechanical analysis) methods. Operators tended to systematically over-tension the lashings and consequently overexert, increasing injury risks. 相似文献