No description available.

The effect of heavy load carriage on pulmonary function at rest and on breathing pattern and lung volumes during graded exercise was studied. Fifteen males completed treadmill tests to measure VO2peak with and without a 25-kg pack. Subsequently, each subject completed short periods of treadmill walking in loaded and unloaded conditions at intensities equivalent to 55, 65, 75 and 85% of VO2peak. At rest, in the loaded condition, forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) both were reduced by 3% with no change in FEV1/FVC. During exercise with the pack, tidal volume (VT) and end-inspiratory lung volume (EILV) were reduced by 14 and 5%, respectively, while ventilation (VE) was maintained by a 9% increase in breathing frequency (Bf). Rating of perceived exertion (RPE) was always higher during the loaded trial, despite identical oxygen consumption (VO2) and heart rate (HR) responses. During graded exercise under heavy load up to 85% of VO2peak, breathing pattern is altered to maintain VE while respiratory mechanics were not altered.

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

No description available.

The aim of the study was to examine the muscle activities of fifteen male participants (23.44 ±2.63 years) during unilateral hockey bag load carrying of different weights (10%, 20%, and 30% bodyweight) and sizes (small and large). Walking without a hockey bag was the control condition. The results showed that increased peak and integrated EMG occurred with an increased load weight in the semitendinosus, gastrocnemius, rectus abdominis, and vastus medialis. The left rectus femoris and left semitendinosus were both significantly greater than the right corresponding muscle. Carrying the large hockey bag produced greater peak EMG in the right rectus abdominis and the right rectus femoris, whereas the right vastus medialis showed a larger peak EMG in the small hockey bag. It was concluded that the posterior-lateral carrying style of hockey bag load carriage explained the results being similar to both backpack and side pack load carriage studies.

Title: EMGs of Back Muscles in Relation with Different Settings of the Straps of Backpacks Objectives: The aim of this study is to compare the electrical activity of chosen muscles during the gait with student backpack and during the different types of placing the backpack on the back in the vertical plane. The second aim is to find what it the best type of the backpack placement on the back based on the electrical activity. Methods: This thesis is an analytical-experimental research. In the theoretical part, there is a review of available sources relating to existing studies about load carriage, especially backpack carrying. It is preferentially about school type of backpaks, the recommended load limit, the way of placing a backpack on the back and the way of placing a load in the backpack. In the experimental part, there are methods used during experiment. The surface electromyografy was chosen as a experimental method. M. trapezius pars descendens, m. erector spinae and m. rectus abdomis were chosen for recording the EMG signal. The data were recorded during the gait with the backpack of 10% of proband's weight and during 3 different types of backpack placement. The upper type of placement was placed with the centre of the backpack in the level of seventh thoracic vertebra (T7), the middle type...

The aim of this study was to determine the combined effects of high-heeled shoes and load carriage on gait and posture adaptation. Furthermore, the adaptation of gait and posture to the combined two conditions was examined by a comparison of the measured parameters between experienced and novice groups. 30 participants underwent a quantitative measurement of temporospatial, kinematic, and kinetic parameters of hip, knee, and ankle on both loaded and unloaded limbs using 3D motion analysis. Double support time and stride length increased during high-heeled gait and the magnitude of alteration was greater with a load. Increased plantarflexion was main cause of raised heel. Ankle plantarflexor moment increased with high-heeled but decreased with load carriage. As a result, plantarflexor moment diminished, in addition knee extensor moment exaggerated further. Hip extensor moment increased with heel height but not with load weight, however, hip angle was affected only by the load.

The aim of the study was to examine the muscle activities of fifteen male participants (23.44 ±2.63 years) during unilateral hockey bag load carrying of different weights (10%, 20%, and 30% bodyweight) and sizes (small and large). Walking without a hockey bag was the control condition. The results showed that increased peak and integrated EMG occurred with an increased load weight in the semitendinosus, gastrocnemius, rectus abdominis, and vastus medialis. The left rectus femoris and left semitendinosus were both significantly greater than the right corresponding muscle. Carrying the large hockey bag produced greater peak EMG in the right rectus abdominis and the right rectus femoris, whereas the right vastus medialis showed a larger peak EMG in the small hockey bag. It was concluded that the posterior-lateral carrying style of hockey bag load carriage explained the results being similar to both backpack and side pack load carriage studies.

The aim of this study was to determine the combined effects of high-heeled shoes and load carriage on gait and posture adaptation. Furthermore, the adaptation of gait and posture to the combined two conditions was examined by a comparison of the measured parameters between experienced and novice groups. 30 participants underwent a quantitative measurement of temporospatial, kinematic, and kinetic parameters of hip, knee, and ankle on both loaded and unloaded limbs using 3D motion analysis. Double support time and stride length increased during high-heeled gait and the magnitude of alteration was greater with a load. Increased plantarflexion was main cause of raised heel. Ankle plantarflexor moment increased with high-heeled but decreased with load carriage. As a result, plantarflexor moment diminished, in addition knee extensor moment exaggerated further. Hip extensor moment increased with heel height but not with load weight, however, hip angle was affected only by the load.

Professional furniture movers must carry objects of all shapes, sizes and weights. When carrying boxes between a house and the moving van, professional movers will carry boxes two different ways. The first way is holding the box in their hands in front of their body, and the second way is holding the box behind them and leaning forward so the box can rest on their backs while walking. The Mover’s Assistive Device (MAD) is an aid developed to decrease the effort of movers when carrying boxes and has been shown to reduce the amount of needed grip strength. The goals of this research were to compare the effects of technique (carrying in front or behind the body) as well as the effects of using the MAD on the way movers coordinate their 1) legs and 2) trunk and hips. Movement was tracked using a camera system and reflective markers attached to the participants. In study 1 ten male participants completed the four different carrying conditions on a treadmill. The different segments of the leg did not change coordination patterns between the front and back carries, however, the coordination was more stable (similar across all steps) in the front carry. When participants used the MAD, their legs moved in a more coordinated motion than when they did not use the MAD, and is considered to be useful in maintaining balance and control while carrying a box. In study 2 thirteen male participants completed the four different carrying conditions on a treadmill. The trunk and the hips did not change coordination between the front and back carries, but they became more coordinated when participants were wearing the MAD. A more coordinated motion between the trunk and hips is suggested to be beneficial to low back health. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2012-10-01 21:43:33.045