In society, personal load carriage systems (backpacks) are commonly used to transport loads by foot, however, they have also been implicated in causing injuries. The aim of this study was to develop a model for load carriage which could be used to determine safety limits in humans. To start, a number of experiments were conducted to determine the appropriateness of using pressure mapping technology to measure peak and mean pressures acting on humans during load carriage limits. Tests of accuracy and repeatability were performed using three common pressure mapping technologies: capacitance, piezoresistive and resistive ink. Pressure mapping was tested statically and dynamically on a human-like flat surface, as well as on human shoulder-shaped model. Error was found to be ≥ 20% on static flat and curved surfaces and it rose to 36-51% under dynamic conditions. Since pressure mapping would require significant modifications before it could be used to study human load carriage, a psychophysical approach was used instead. For this approach, an epidemiological study of pain was conducted based on 48 subjects who used multiple backpack designs to complete occupationally relevant tasks. As a result, pain trends and new methods of data analysis were identified that had potential use on human trials. In a final study, pain mapping, quantification of pain intensity, and physiological/motor testing were conducted on humans performing endurance exercise with light to heavy payloads. Results showed that all subjects were able to exercise with a 15-35 kg payload for 45 minutes and with a 50 kg payload for 30 minutes, without stopping. As well, pain was found to be highest in the anterior acromial (shoulder) region, particularly for the 50 kg payload (mean peak pain = 3.4/10). Based on these findings, two models were proposed: an assertive model and a conservative model to allow prediction of human load carriage limits for endurance exercise. / Thesis (Ph.D, Rehabilitation Science) -- Queen's University, 2007-10-06 15:33:31.933

With the popularity of outdoor activities like hiking, the demands of certain types of employment, or being a student, an individual’s ability to carry a load is an important mobility consideration. By understanding the changes to an individual’s gait when supporting a backpack load, an individual’s ability to carry heavy loads for prolonged periods could be improved. Most biomechanical studies have examined the changes in able-bodied gait when carrying a load. However, research is lacking on the effect of backpack loads on amputee gait patterns. This project examined the effects of a backpack load on the gait patterns of unilateral transtibial amputees. Ten participants performed walking trials on four surfaces (level ground, uneven ground, walking up an incline, and walking down an incline), without a pack and with a pack. A total of 40 trials were collected per subject, with 10 trials collected on each surface. Three-dimensional motion data were collected with an eight-camera Vicon Motion Analysis system to describe limb motion as well as compare kinematic outcomes between tasks and conditions. Force platform data were collected during the level ground trials and used to calculate kinetic measures for both limbs. With the addition of the pack changes were seen on each surface, with different changes occurring to each limb. The ramp up surface created the most changes when comparing the two conditions. The only change seen across all four surfaces was a decrease in ankle dorsiflexion before push-off on the prosthetic limb. The two next most common changes were increases in knee and hip flexion during weight-acceptance.

With the popularity of outdoor activities like hiking, the demands of certain types of employment, or being a student, an individual’s ability to carry a load is an important mobility consideration. By understanding the changes to an individual’s gait when supporting a backpack load, an individual’s ability to carry heavy loads for prolonged periods could be improved. Most biomechanical studies have examined the changes in able-bodied gait when carrying a load. However, research is lacking on the effect of backpack loads on amputee gait patterns. This project examined the effects of a backpack load on the gait patterns of unilateral transtibial amputees. Ten participants performed walking trials on four surfaces (level ground, uneven ground, walking up an incline, and walking down an incline), without a pack and with a pack. A total of 40 trials were collected per subject, with 10 trials collected on each surface. Three-dimensional motion data were collected with an eight-camera Vicon Motion Analysis system to describe limb motion as well as compare kinematic outcomes between tasks and conditions. Force platform data were collected during the level ground trials and used to calculate kinetic measures for both limbs. With the addition of the pack changes were seen on each surface, with different changes occurring to each limb. The ramp up surface created the most changes when comparing the two conditions. The only change seen across all four surfaces was a decrease in ankle dorsiflexion before push-off on the prosthetic limb. The two next most common changes were increases in knee and hip flexion during weight-acceptance.

Participants were twelve 70+ kg male strength-trained athletes and one passenger child with a mass of 29 kg. The male participants walked three times over a force plate embedded in an eight metre walkway for each of three conditions: carrying no load, a 29 kg backpack, or a 29 kg passenger. Variables were compared using a repeated measures ANOVA test with a Bonferroni correction. Both load conditions produced compensatory trunk flexion; trunk flexion increased from no load to piggybacking to backpacking. Trunk range of motion was similar for no load and piggybacking, but increased to backpacking. The backpack load caused greater resultant and total magnitude of torque than the passenger load. The trunk extensors dominated with no load and piggybacking and the trunk flexors dominated with backpacking. Many of the significant differences between conditions suggest that piggybacking is biomechanically more similar to natural gait than is backpacking.

With the popularity of outdoor activities like hiking, the demands of certain types of employment, or being a student, an individual’s ability to carry a load is an important mobility consideration. By understanding the changes to an individual’s gait when supporting a backpack load, an individual’s ability to carry heavy loads for prolonged periods could be improved. Most biomechanical studies have examined the changes in able-bodied gait when carrying a load. However, research is lacking on the effect of backpack loads on amputee gait patterns. This project examined the effects of a backpack load on the gait patterns of unilateral transtibial amputees. Ten participants performed walking trials on four surfaces (level ground, uneven ground, walking up an incline, and walking down an incline), without a pack and with a pack. A total of 40 trials were collected per subject, with 10 trials collected on each surface. Three-dimensional motion data were collected with an eight-camera Vicon Motion Analysis system to describe limb motion as well as compare kinematic outcomes between tasks and conditions. Force platform data were collected during the level ground trials and used to calculate kinetic measures for both limbs. With the addition of the pack changes were seen on each surface, with different changes occurring to each limb. The ramp up surface created the most changes when comparing the two conditions. The only change seen across all four surfaces was a decrease in ankle dorsiflexion before push-off on the prosthetic limb. The two next most common changes were increases in knee and hip flexion during weight-acceptance.

Esta investigación plantea un escenario de negocio de importación de ventas minorista, dónde la idea del negocio es distribuir de manera exclusiva una marca de mochilas con modelos innovadores líder en el mercado extranjero al mercado nacional, a fin de poder construir una identidad que sitúe la marca en el top of mind de nuestro mercado objetivo. Este trabajo está estructurado con los siguientes temas que representan cada uno un capítulo de esta investigación los cuales son: los aspectos generales del negocio con visión global, planeamiento estratégico analizando los factores internos y externos, investigación y validación del mercado objetivo, plan de marketing y publicidad de la marca, planeamiento de las operaciones de importación, estructura organizacional y recursos humanos, y el plan económico del financiamiento. El objetivo es comprobar la viabilidad de este negocio a través de un examen detallado de indicadores relevantes que nos permitan mostrar la rentabilidad del proyecto propuesto. / This research covers an import business of retail, which the aim idea is the exclusive distribution of the most important foreign brand of innovate backpacks to the national market and lastly make an identity to put us in the target market’s top of mind. This project contains these important topics which represent each chapter like: General aspects of global business, strategic plan about the thorough analysis of the internal and external factors, target market research and work out, advertising plan of brand, import operations plan, organizational structure and human resources, ultimately financial economic plan. The main focus is proving the feasibility of this business through a detailed examination of relevant indicators which show the proposed project profitability. / Trabajo de investigación

Although there has been a great deal of research on binocular distance perception (Foley, 1980; Gogel, 1977), a number of questions remain unexplored. One such question involves how our ability to perceive distances is influenced by fitness and stress (internal and external). Previous research has shown that kinesthetic stress (via backpack weight) influences a person’s ability to accurately guess distances (Proffitt, Bhalla, Gossweiler, & Midgett, 2003). This research did not only attempt to replicate previous work, but also extend it by exploring potential interactions between fitness level and mental stress on distance perception, a combination that is often encountered by soldiers, firefighters, and rescue workers. Mental stress was measured using the State Anxiety Inventory test (Spielberger, Reheiser, & Sydeman, 1995) and cardiovascular fitness was measured using MET scores (Jurca et al., 2005). Physical stress was manipulated by asking participants to estimate distances and then walk blindly to the target while carrying a backpack weighing 20% of their weight. We were unable to replicate Proffitt. We did however find a positive correlation between cardiovascular fitness and error in the second block of the blind walking task for the heavy backpack condition, r(22) = -.45, p = 0.03.

From the first idea, to research and comparing with other backpacks with foldable function (tele, usárna), and with backpacks associated with urban and streetwear function, I designed a backpack with a practical and functional design which opens questions of personal vs. public space. It plays with the question of lifestyle as a focal point of marketing. It speaks to young people, who spend their time in the city public space and occupy it in their own way. Technical parameters of the backpack are dependent of its functional needs, but the first idea came out of the needs of a modern young nomad, exploring the city public space.

Heavy backpacks have been suggested to have a pathogenic role in experience of low back pain among children. We have conducted a repeated-measure study to investigate the backpack-induced changes in lumbo-pelvic coordination of forty gender-balanced college age students when they walked and jogged on a treadmill with two different types of backpacks: normal and ergonomically modified. The backpack-induced changes in lumbo-pelvic coordination were larger when carrying an ergonomically modified vs. a normal backpack as well as when jogging versus walking. The larger changes in lumbo-pelvic coordination when carrying an ergonomically modified backpack were likely due to kinematic restraints imposed by rigidity and enhanced attachments devised in the backpack for increased comfort. Given the role of lower back biomechanics in low back pain, the effects of such larger mechanical abnormalities in the lower back when carrying an ergonomically-modified backpack on risk of low back pain among children requires further investigation.

Military load carrying has occupied the attention of military developers, researchers and commanders over centuries. The Army backpack remains the means of carriage for ammunition and rations for the soldier in the field. The traditional rationale for its use has been that the infantry soldier must be able to sustain himself in combat and live independently for days at a time without resupply. At the Royal Military College, Duntroon (RMC), the mission is to produce men and women who are capable and effective officers and soldiers. The weight of the pack with the items required at RMC is often in excess of 40 kg. In evaluating the effectiveness of current practice, this thesis takes an anthropometric perspective in exploring the historical, physiological and social context of current loads carried by Australian soldiers, It does not, however, evaluate the content of the load itself. Research methods include: a/. Systematic examination of past research findings on the social and physiological aspects of military load carrying since the Roman Centurions. b/. Biophysical tesing of nine soldiers, using a battery of physiological tests to determine heart rates and energy expenditure at various loads. c/. A survey of 100 soldiers from the Royal Military College, Duntroon and in-depth interviews with a sample of four experienced soldiers to obtain the views of the load carriers. The research concludes that the optimum approach to load carrying, and so to the design of the Army backpack, is that it be task-and soldier-specific. This runs directly counter to the longstanding Army traditions of preparing all soldiers for every possible contingency in battle and regarding all soldiers as equivalent units. The study findings offer some specific directions in which the design of the army backpack can be improved. / Master of Science (Hons)