No description available.

Psychophysics is defined as the scientific study of the relationship between stimuli and sensation. It has been used extensively over the last three decades for evaluation and design of manual materials handling tasks in many industries. Despite this, much is still not known about how subjective ratings, the core of the psychophysical methodology, relate to physical (biomechanical) loads. A fundamental assumption of this method is that humans are capable of estimating biomechanical and physiological loads that are placed on the body. Based on this assumption, estimates that are obtained through the methodology are used as an indicator of physical loads and stresses, and are assumed to be related to injury risk. An experiment was performed to achieve two primary goals:1) determine the correspondence between biomechanical loads (moments at the elbow, shoulder and torso) and subjective ratings of joint loads, as well as subjectively determined maximal loads and 2) determine whether any particular joint (i.e. low back, shoulder, elbow) is the limiting factor when a subject determines a maximally acceptable load. Participants were instructed to pose in four different postures, one serving as a baseline (neutral, or 'familiar') posture, while the remaining three varied moments at the elbow, shoulder and torso. While in each of these postures, participants determined a maximum acceptable static load (MASL). Ratings of perceived exertions for specific joints were also reported, as well as whole body ratings while supporting various fractions of the MASL. Experimental findings indicated that subject and posture effects neared significance as main effects on the magnitude of MASL. Strength was shown to be, at best, a weak predictor of MASL. Though no conclusive evidence was found to indicate that a specific joint is the limiting factor when determining maximum acceptability, trends in the data suggested that the low back and shoulder are possible candidates. Overall, the results of the study indicated that humans consider more than simple joint moments when forming perceptions of efforts and acceptability during static load handling. / Master of Science

A flexible and passive exoskeleton is presented in this paper. The exoskeleton uses carbon fiber beams to provide an energetic return to its wearer and relieve their lower back muscles. The design of the exoskeleton and potential elastic mechanisms are described, and the results of biomechanical testing are given. The exoskeleton decreased the erector spinae muscle activity by 21-39.7%. / MS

No description available.

Digitized by Kansas Correctional Industries

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

This report focuses on three parts which are market research, marketing- and sales strategies, and product development for a start-up company in Italy called ARS Meccanica Dolomiti and their new product, Quikky. The main objective was to find a strategy which the company could use to attract customers. In the market research both potential customers and competitors were identified. Similar products that could be a threat for the product were also investigated. Most of the information came through own research via Internet. However, a visit to the CeMAT fair in Hannover was also helpful since potential customers, competitors and other partners were gathered at the same place. The main results from this research are that there are a lot of potential customers for the product. The reason for this is that it was discovered that the product could be used in different application areas, resulting in a broader market for the product. However, there are many competitors since the product is mostly directed towards the lifting industry which is already an attractive market. As for the product development it was early recognised that the product could be designed in many different ways. Both mini Quikky and symmetric Quikky, which are two new versions of the original Quikky, could be new products that the company could sell. By having several versions of the product, the company can more easily attract customers. / Rapporten fokuserar på tre områden som är att utföra en marknadsundersökning, marknadsförings- och försäljnings- strategi samt produktutveckling för ett nystartat företag i Italien, ARS Meccanica Dolomiti och deras nya produkt, Quikky. Målet med arbetet var att komma fram till en strategi som företaget kan använda för att locka till sig kunder. I marknadsundersökningen identifierades både potentiella kunder samt konkurrenter. Liknande produkter som kan utgöra ett hot undersöktes också. Det mesta av informationen kom genom egna undersökningar via Internet. Ett besök till CeMAT mässan i Hannover var även mycket hjälpsam, då en hel del potentiella kunder, konkurrenter och andra samarbetspartner var samlade på ett och samma ställe. Resultatet visar på att det finns en hel del potentalla kunder för produkten. Anledningen till detta är att produkten kan användas i olika tillämpningsområden vilket medför att en större marknad blir möjlig. Nackdelen är att det redan finns många konkurrenter då produkten främst är riktad mot lyftindustrin som är en attraktiv marknad. När det gäller produktutveckling blev det snabbt tydligt att produkten kan utformas på flera andra sätt. Både mini Quikky samt symmetriska Quikky, är två nya versioner av den ursprungliga designen. Dessa två kan vara produker som ARS Meccanica kan sälja. Genom att ha flera versioner av produkten, kan företaget dessutom attrahera till sig fler kunder.

The Ergonomics Research Group at Queen’s University, supported by the Workplace and Safety Insurance Board, has been developing an on-line system to estimate peak and cumulative joint loading in the workplace. This study will aid the project by examining the muscle activation levels (MALs) in upper extremity and trunk muscles during a manual lifting task using both hands. It was hypothesized that MAL’s are correlated with the magnitude of the load in the hands and thus could be used to predict the load which in turn will be used to predict the lower back moments. Alterations in the muscle activation patterns due to lifting different loads were examined. Electromyographic signals (EMG) and kinematic data were recorded from different sites on the trunk and upper limb as subjects lifted a load from the floor to a shelf using squat, stoop and freestyle lift techniques. All raw EMG data were processed to obtain the linear envelopes (LE) which provides estimates of the MAL’s. The peak, mean and area of the linear envelopes were calculated. Using regression analysis, a relationship between the parameters and load lifted was found to exist. A non-linear parallel cascade type architecture was used to develop a model to predict the load in the hands. The model uses the EMG parameters as inputs and fits the data via linear and non-linear cascades to the output, i.e. the load in the hands. A model was successfully developed for the squat lift posture using the area, peak and mean of the zero-normalized EMG LE recorded from the erector spinae (L4 level), with a prediction error of ± 1.03kg and for the stoop posture, a prediction error of ± 2.34kg. Given the predicted loads, moments in the lower back were computed using the method of Hof (1992). / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2007-09-28 16:15:23.077

Background Obesity is associated with an increased risk of back pain, attributed to elevated mechanical load. Back injury risk is also determined by movement patterns (kinematics) and physiological factors (exertion, muscle activation). Lifting, particularly repetitive, is the most frequently cited injurious activity. However, in spite of the obvious relation, a paucity of information exists quantifying the interaction of obesity and repetition during lifting. Purpose To determine the effects of obesity and repetition on mechanical, kinematic and physiological lifting outcomes. Methods: An individual-specific, biomechanical model (based upon 3D photogrammetry) was developed to estimate the effect of obesity on back load during lifting (study 1). Lifting strategy and physiological outcomes related to obesity were examined in a fixed-pace, repetitive lifting task (study 2). The effect of task constraints on lifting strategy of high and normal BMI individuals were determined (study 3), followed by an evaluation of muscle activation responses during a repetitive trunk motion similar to that encountered during lifting (study 4). Results: Obesity-specific alterations of important determinants of back load (inertia, CMloc) were revealed. Obesity was related to a substantial increase in back load (M=+197.3, SE=16.8 Nm about L5/S1), however the effect differed across lifting tasks. The lifting strategy of high-BMI individuals was characterized by an increased distance to the external mass (M=+4.7, SE=1.8 cm) and shorter lift duration (M=230, SE=130 msec), with increased cardiovascular effort (M=+7.4, SE=3.4% HRmax) but no change in perceived exertion. Lifting frequency was not a major determinant of lifting strategy, however strategy was influenced by the presence and type of external pacing. A phase-specific, rapid alteration in muscle activation response was evident in the MMG signal during the initial repetitions of a repetitive trunk motion. Conclusion: The effect of obesity during lifting is task-dependent, and cannot be attributable solely to mechanical factors. Future studies should consider tasks that are unconstrained, and examine the initial familiarization period of repetitive tasks, specifically the lowering phase of motions. These findings have relevance to back injury mechanisms related to obesity and the design of injury prevention programs for individuals with a high BMI.

Background Obesity is associated with an increased risk of back pain, attributed to elevated mechanical load. Back injury risk is also determined by movement patterns (kinematics) and physiological factors (exertion, muscle activation). Lifting, particularly repetitive, is the most frequently cited injurious activity. However, in spite of the obvious relation, a paucity of information exists quantifying the interaction of obesity and repetition during lifting. Purpose To determine the effects of obesity and repetition on mechanical, kinematic and physiological lifting outcomes. Methods: An individual-specific, biomechanical model (based upon 3D photogrammetry) was developed to estimate the effect of obesity on back load during lifting (study 1). Lifting strategy and physiological outcomes related to obesity were examined in a fixed-pace, repetitive lifting task (study 2). The effect of task constraints on lifting strategy of high and normal BMI individuals were determined (study 3), followed by an evaluation of muscle activation responses during a repetitive trunk motion similar to that encountered during lifting (study 4). Results: Obesity-specific alterations of important determinants of back load (inertia, CMloc) were revealed. Obesity was related to a substantial increase in back load (M=+197.3, SE=16.8 Nm about L5/S1), however the effect differed across lifting tasks. The lifting strategy of high-BMI individuals was characterized by an increased distance to the external mass (M=+4.7, SE=1.8 cm) and shorter lift duration (M=230, SE=130 msec), with increased cardiovascular effort (M=+7.4, SE=3.4% HRmax) but no change in perceived exertion. Lifting frequency was not a major determinant of lifting strategy, however strategy was influenced by the presence and type of external pacing. A phase-specific, rapid alteration in muscle activation response was evident in the MMG signal during the initial repetitions of a repetitive trunk motion. Conclusion: The effect of obesity during lifting is task-dependent, and cannot be attributable solely to mechanical factors. Future studies should consider tasks that are unconstrained, and examine the initial familiarization period of repetitive tasks, specifically the lowering phase of motions. These findings have relevance to back injury mechanisms related to obesity and the design of injury prevention programs for individuals with a high BMI.