Background: Older adults walk more slowly than healthy young adults at fast and normal walking speeds. These age-associated changes in mobility impact upon daily function. A slower gait, for example, may reduce the older adult’s ability to safely cross at traffic intersections due to the time restriction. Recent research has demonstrated whole body vibration (WBV) can improve the strength and power (Roelants, Delecluse & Verschueren, 2004; Russo et al., 2003; Verschueren, Roelants, Delecluse, Swinnen, Vanderschueren & Boonen, 2004) of community dwelling elderly females, and the mobility of nursing home residents (Bautmans, Van Hees, Lemper & Mets, 2005; Bruyere et al., 2005). To date, no published research has examined the impact WBV has on the gait parameters of community dwelling elderly females. The research was conducted in three phases. Phase One – Development of a WBV Platform: This phase outlines the development of a WBV platform (ACUWBV) that was designed and built for this research. A unique aspect of the ACUWBV was the method of adjusting WBV amplitude and therefore intensity. Current WBV technology, using tilting oscillations, requires the individual to increase their stance width. The ACUWBV allowed for the adjustment of WBV amplitude while maintaining the same stance width. The reliability and accuracy of the ACUWBV eccentric cam was measured during this phase of the research. Although an intraclass correlation coefficient of 0.4 was calculated and is considered an indication of low reliability, calculations of typical error (TE -95% error range) for each amplitude indicated the error to be small in the overall precision of the instrument. Specifically, at a frequency of 20 Hz, the expected WBV acceleration ranges for amplitudes of 0.5 mm and 1.0 mm were 7.58 m.s-2 to 8.85 m.s-2 (TE = 0.02 mm) and 16.90 m.s-2 to 17.53 m.s.-2 (TE = 0.01 mm), respectively. Phase Two – Pilot Study: This phase established the response of elderly community-dwelling female fast gait to WBV. Seven elderly female participants attended three WBV sessions per week for three weeks. Participants performed fast walks over an electronic walkway (GAITRite) at the end of each WBV session. A time-series graph displayed a linear increase in stride velocity over the three week intervention period. Conversely, stride time, stance time and double support time exhibited linear decreases. However, stride time (p=0.04) and stance time (p=0.04) were the only variables that exhibited a significant difference. It was concluded that the linear changes in stride velocity, stride time, stance time and double support time warranted further investigation with a larger sample size within a longer intervention period. Phase Three – Major Study: Phase three was an extension of phase two. This WBV intervention study was performed over a twelve week period. Twenty-two elderly female participants were placed in one of two groups. Group one (placebo/WBV; Group; n=12) was exposed to a placebo intervention for the first six weeks followed by a six week WBV intervention. Group two (Group WBV/placebo; n=10) was exposed to WBV for the first six weeks and a placebo intervention for the following six weeks. Group placebo/WBV exhibited no change in stride velocity during the placebo period, but a seven per cent increase during the six week WBV period (p=0.005). The changes in stride velocity coincided with increases in stride length (p=0.017), and reductions in stride time (p=0.007), stance time (p=0.001) and double support time (p=0.001). Group WBV/Placebo demonstrated stride velocity to increase by five per cent during the WBV period. Although the time-series graphs demonstrated improvements in stride velocity to be associated with decreases in stride time, stance time, and double support time, the changes failed to reach significance. Single support time and stride length showed no change over the WBV period. The improvements shown by group WBV/placebo from the first six weeks of WBV were maintained during the six week placebo (detraining) period. In summary, WBV was an effective intervention for enhancing the walking speed of community dwelling elderly female gait. This form of exercise may have positive outcomes on the daily function of elderly females, which in turn may improve their quality of life.

<p>Hospitals have limited budgets, making the cost of an examination important. A whole-body MRI scan is much less expensive than a PET-CT scan, making the MRI desirable in cases when the result from the MR machine will be sufficient. Also, unlike CT, MRI does not rely on ionizing radiation, which is known to increase the risk of developing cancer.</p><p>To make the most out of the MRI results, an efficient visualization of the data is important. The goal of this project was to develop an application that would facilitate radiologists’ evaluation of whole-body MRI data of lymphoma patients. This was achieved by introducing a fused image between two types of MRI images, offering simplified loading of all the study MRI data and creating a rotatable maximum intensity projection from which points can be selected and zoomed to in other types of images.</p><p>Unfortunately the loading of the data and some parts of the interaction is somewhat slow, which is something that needs to be addressed before this application could become a possibly useful tool for the radiologists.</p>

<p>Abstract 1.</p><p>The purpose of this study was to investigate the effects whole body vibrations on maximal strength, power output and neuromuscular activity in m. pectoralis major during bench press.</p><p>Participants consisted of 35 male and 9 female military high school students (m=23, 1 years). On the basis of initial maximal performances in bench press the participants was divided into two experiments groups and one control group. Intervention groups performed a specifically designed push up program on a vibrating plate respectively a step board during 12 weeks</p><p> </p><p>Initial load at 60 % of 1 RM showed an average of 46, 5 kg. All groups showed an average increase of 13 kg for each person after 12 weeks. Initial value for power output showed a mean of 265 watt, which also showed an increase with an average of 7 watt (with a load equivalent of 60 % of 1 RM at the current test occasion), respectively an increase of 41 watt (with the load performed during the first test occasion). A positive correlation existed between the load at 60 % of 1 RM and achieved power output. No significant differences between groups were exposed concerning estimated maximum strength or power output in bench press. </p><p>All participants showed an increase in strength development, indicating that vibration stimuli could be compared to traditional push ups training without vibrations. Vibrations seem to have more effects on the magnitude of recruited motor units, why vibrations training could be a good complement to established strength training.</p><p>Abstract 2. </p><p>The purpose of this study was to investigate the effects whole body vibrations on strength development, power output and neuromuscular activity in m. pectoralis major during bench press. The purpose was also to examine what roll self-efficacy plays in strength tasks. </p><p>Participants consisted of 35 male and 9 female military high school students (m=23, 1 years). On the basis of initial maximal performances in bench press the participants was divided into two experiments groups and one control group. Intervention groups performed a specifically designed push up program on a vibrating plate respectively a step board during 12 weeks. All participants answered a battery of questionnaires concerning backgrounds, motives for sport participation, self-efficacy and efficacy sources. </p><p>Initial load at 60 % of 1 RM showed an average of 46, 5 kg (sd = 13, 8). All groups showed an average increase of 13 kg for each person after 12 weeks. Initial value for power output showed a mean of 265 watt, which also showed an increase with an average of 7 watt (with a load equivalent of 60 % of 1 RM at the current test occasion), respectively an increase of 41 watt (with the load performed during the first test occasion). A positive correlation existed between the load at 60 % of 1 RM and achieved power output. No significant differences between groups were exposed concerning estimated maximum strength or power output in bench press. Gender differences showed that men lifted significantly heavier loads at 60 % of 1RM compared to women. </p><p>No significant differences could be seen between the groups concerning self efficacy. Gender differences were exposed concerning self-efficacy to push ups with a pat. The efficacy sources “performance accomplishments” was valuated to be the most influential to form self-efficacy expectations. A strong positive relationship between “performance accomplishments” and achieved self-efficacy to push ups with pats were shown. Self-efficacy to push ups with a pat also correlated positively with power output and performed 60 % of 1 RM in bench press. </p><p>All participants showed an increase in strength development, indicating that vibration stimuli could be compared to traditional push ups training without vibrations. Vibrations seem to have more effects on the magnitude of recruited motor units, why vibrations training could be a good complement to established strength training. Participants relatively high self-efficacy to strength tasks is probably a result of performance accomplishments in there own strength straining rather than the intervention training. Positive relationships between self-efficacy and power output as well as performed 60 % of 1 RM in bench press, indicating that high self-efficacy have a positive influence on strength performance. </p><p>Keywords: estimated maximal strength (1RM), neuromuscular activity, power output, self-efficacy.</p>

Abstract 1. The purpose of this study was to investigate the effects whole body vibrations on maximal strength, power output and neuromuscular activity in m. pectoralis major during bench press. Participants consisted of 35 male and 9 female military high school students (m=23, 1 years). On the basis of initial maximal performances in bench press the participants was divided into two experiments groups and one control group. Intervention groups performed a specifically designed push up program on a vibrating plate respectively a step board during 12 weeks Initial load at 60 % of 1 RM showed an average of 46, 5 kg. All groups showed an average increase of 13 kg for each person after 12 weeks. Initial value for power output showed a mean of 265 watt, which also showed an increase with an average of 7 watt (with a load equivalent of 60 % of 1 RM at the current test occasion), respectively an increase of 41 watt (with the load performed during the first test occasion). A positive correlation existed between the load at 60 % of 1 RM and achieved power output. No significant differences between groups were exposed concerning estimated maximum strength or power output in bench press. All participants showed an increase in strength development, indicating that vibration stimuli could be compared to traditional push ups training without vibrations. Vibrations seem to have more effects on the magnitude of recruited motor units, why vibrations training could be a good complement to established strength training. Abstract 2. The purpose of this study was to investigate the effects whole body vibrations on strength development, power output and neuromuscular activity in m. pectoralis major during bench press. The purpose was also to examine what roll self-efficacy plays in strength tasks. Participants consisted of 35 male and 9 female military high school students (m=23, 1 years). On the basis of initial maximal performances in bench press the participants was divided into two experiments groups and one control group. Intervention groups performed a specifically designed push up program on a vibrating plate respectively a step board during 12 weeks. All participants answered a battery of questionnaires concerning backgrounds, motives for sport participation, self-efficacy and efficacy sources. Initial load at 60 % of 1 RM showed an average of 46, 5 kg (sd = 13, 8). All groups showed an average increase of 13 kg for each person after 12 weeks. Initial value for power output showed a mean of 265 watt, which also showed an increase with an average of 7 watt (with a load equivalent of 60 % of 1 RM at the current test occasion), respectively an increase of 41 watt (with the load performed during the first test occasion). A positive correlation existed between the load at 60 % of 1 RM and achieved power output. No significant differences between groups were exposed concerning estimated maximum strength or power output in bench press. Gender differences showed that men lifted significantly heavier loads at 60 % of 1RM compared to women. No significant differences could be seen between the groups concerning self efficacy. Gender differences were exposed concerning self-efficacy to push ups with a pat. The efficacy sources “performance accomplishments” was valuated to be the most influential to form self-efficacy expectations. A strong positive relationship between “performance accomplishments” and achieved self-efficacy to push ups with pats were shown. Self-efficacy to push ups with a pat also correlated positively with power output and performed 60 % of 1 RM in bench press. All participants showed an increase in strength development, indicating that vibration stimuli could be compared to traditional push ups training without vibrations. Vibrations seem to have more effects on the magnitude of recruited motor units, why vibrations training could be a good complement to established strength training. Participants relatively high self-efficacy to strength tasks is probably a result of performance accomplishments in there own strength straining rather than the intervention training. Positive relationships between self-efficacy and power output as well as performed 60 % of 1 RM in bench press, indicating that high self-efficacy have a positive influence on strength performance. Keywords: estimated maximal strength (1RM), neuromuscular activity, power output, self-efficacy.

No description available.

Hospitals have limited budgets, making the cost of an examination important. A whole-body MRI scan is much less expensive than a PET-CT scan, making the MRI desirable in cases when the result from the MR machine will be sufficient. Also, unlike CT, MRI does not rely on ionizing radiation, which is known to increase the risk of developing cancer. To make the most out of the MRI results, an efficient visualization of the data is important. The goal of this project was to develop an application that would facilitate radiologists’ evaluation of whole-body MRI data of lymphoma patients. This was achieved by introducing a fused image between two types of MRI images, offering simplified loading of all the study MRI data and creating a rotatable maximum intensity projection from which points can be selected and zoomed to in other types of images. Unfortunately the loading of the data and some parts of the interaction is somewhat slow, which is something that needs to be addressed before this application could become a possibly useful tool for the radiologists.

Travel time has generally been regarded as an unproductive period, representing a means-to-an-end in order to engage in activities at specific destinations. Rapid developments in mobile technology have provided people with innovative ways to multi-task and engage in meaningful activities while travelling. Rail transportation specifically, offers passengers advantages over other means of transportation as there is no need to focus on driving tasks. Due to the increase in passenger numbers and limited seating availability in train carriages, over one third of rail passengers are required to stand while travelling (DfT, 2013). The vibration to which rail passengers are exposed has been shown to interfere with the performance of activities and for standing passengers, it is often necessary to use postural supports such as holding on to grab rails or leaning on walls in order to maintain stability. The overall aim of the research is to evaluate the influence of whole-body vibration (WBV) exposure and standing posture on the performance of manual control tasks and the associated subjective workloads experienced by rail passengers. The use of supports, such as a backrest in seated postures, has been found to influence the response of the human body to WBV exposure, yet no reported studies have investigated the effects of postural supports on the response of the body in standing postures. Understanding how the body is affected in these conditions would increase the current state of knowledge on the biomechanical responses of the human body to vibration exposure and provide improved representation of standing postures within vibration standards (for example, ISO2631-4 (2001)) and guidelines for device interface design. A field study, using direct observation, was conducted to assess the behaviour of standing rail passengers and determine the characteristics of typical vibration exposures. This information provided the basis for the design of four subsequent laboratory studies. The main investigations of the laboratory studies were the influence of WBV exposure on objective performance measures, such as task completion time and error rate, and subjective workloads (for example, NASA TLX) for a range of manual control tasks. One of these laboratory studies evaluated the influence of various postural supports (for example, backrests) on the biomechanical responses of standing individuals. Measurements obtained during the field investigation indicated that the vibration exposures did not exceed the EU Physical Agents Exposure Action Value (EAV) and therefore posed little risk of injury. Vibration magnitudes in the horizontal directions (x- and y-axes) were higher than in the vertical direction (z-axis) and it was necessary for standing passengers to alter behaviours and use supports in order to maintain stability while travelling. The results of the laboratory studies indicated that in conditions where decrements in task performance occurred, the extent to which performance was degraded increased progressively with increases in vibration magnitude. There were conditions (for example, in the continuous control task and the Overhead Handle supported posture in the serial control task) where vibration exposure showed no significant influence on performance measures. This suggested that individuals were able to adapt and compensate for the added stress of vibration exposure in order to maintain performance levels however, this occurred at the expense of mental workload. The workload experienced by the participants increased with corresponding increases in magnitude. Vibration frequency-dependent effects in performance and workload were found to match the biomechanical responses (apparent mass and transmissibility) of the human body and resemble the frequency weightings described in the standards (ISO2631-1 (1997)). During the serial control task, the postures which demonstrated the greatest decrements to performance (for example, Lean Shoulder and Lean Back ) corresponded to the same postures that showed the greatest influence on the biomechanical responses of the body. It was concluded therefore, that measurements of the biomechanical responses to WBV could be used to offer predictions for the likelihood of activity interference. Consideration should however, be given to the applicability of this research before these results can be generalised to wider contexts. Further validation is recommended for future work to include different conditions in order to substantiate the findings of this research.

Whole-body vibration (WBV) was recently introduced as a potential modality for strengthening bones, and this thesis was set out to investigate whether it plays a role in the prevention of postmenopausal bone loss. First, effects of WBV on bone mineral density (BMD) were systematically evaluated in previous randomized controlled trials (RCTs) in postmenopausal women. Second, a RCT of 202 postmenopausal women with primary osteopenia not on bone medications was conducted to investigate the effects of WBV at 0.3g and 90 Hz versus 0.3g and 30 Hz versus controls on various bone outcomes, as measured by dual-energy x-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT), and quantitative ultrasound (QUS). In the systematic evaluation of previous RCTs, statistically significant increase in areal BMD (aBMD) at the hip was found in postmenopausal women receiving WBV versus controls, but the effect was small and may have been due to study bias. Also, WBV was not found to influence aBMD at the lumbar spine or volumetric BMD (vBMD) at the distal tibia in the systematic evaluation. In the RCT conducted in this thesis, no statistically significant effects of WBV were found on aBMD at the femoral neck, total hip or lumbar spine, as measured by DXA, or on vBMD or bone structure parameters at the distal tibia or distal radius, as measured by HR-pQCT. Further in this RCT, a statistically significant decrease was observed in QUS attenuation at the calcaneus in women receiving 90 Hz or 30 Hz WBV compared to controls. This may have been due to heel bone or soft tissue damage, although the effect was small and may not be clinically important. In conclusion, this investigation of postmenopausal women did not find clinically relevant benefits of WBV on osteoporotic-prone skeletal sites, including the hip, spine, tibia or radius, while potentially harmful effects on heel bone and/or soft tissue was observed in response to WBV. Thus based on this thesis, WBV is currently not recommended for the prevention of bone loss in community-dwelling postmenopausal women with primary osteopenia.

In this study the exposure of mining vehicle operators, on an opencast goldmine in Tanzania, to certain hazards specific to their occupation was assessed. The aim was to quantify these levels of exposure in order to estimate the risk of health effects but also to report levels of these hazards that exist on mining vehicles. Three different hazards with different physiological effects were assessed and it included exposure to whole-body vibration, A-weighted noise and low frequency noise. In each case correctly calibrated instrumentation was used and internationally accepted methods were followed. It was found that mining vehicles commonly exposed operators to levels of whole-body vibration within and above the ISO Health Guidance Caution Zone (HGCZ) and above the ropean action level, which indicates the need for intervention and control. These levels are a cause for concern and will likely lead to health effects. Noise that damages human hearing (A-weighted noise) was present in high levels on mining vehicles, in each case being higher than the permissible exposure limit of 85 dB(A). Thus operators of mining vehicles are exposed to noise levels that will damage their hearing in time. A potential hazard in the occupational world, low frequency noise, was also included in the assessment. Literature indicates that low frequency noise is capable of causing many human health effects and thus levels on mining vehicles were reported in order to give an indication of what levels may be expected in this department of mining. It was found that much of the sound energy measured on vehicles was located in the low frequency range. In the lowest frequency band measured, Leq levels of more than 100 dB(Z) were commonly found. Controls should be implemented as far as is reasonably practicable to ensure that operators are not exposed above recommended or permissible levels for each hazard. These controls can include good maintenance of vehicles and roads to reduce whole-body vibration, sound proofing of vehicle cabs along with hearing protection devices to protect hearing and further research regarding the exposure and health effects caused by low frequency noise. Following literature indicating the physiological effects of low frequency noise exposure and also the presence thereof in different occupations, it is concluded that A-weighted noise measurements alone can not be used when quantifying the risk involved in a given acoustical environment. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2009

In this study the exposure of mining vehicle operators, on an opencast goldmine in Tanzania, to certain hazards specific to their occupation was assessed. The aim was to quantify these levels of exposure in order to estimate the risk of health effects but also to report levels of these hazards that exist on mining vehicles. Three different hazards with different physiological effects were assessed and it included exposure to whole-body vibration, A-weighted noise and low frequency noise. In each case correctly calibrated instrumentation was used and internationally accepted methods were followed. It was found that mining vehicles commonly exposed operators to levels of whole-body vibration within and above the ISO Health Guidance Caution Zone (HGCZ) and above the ropean action level, which indicates the need for intervention and control. These levels are a cause for concern and will likely lead to health effects. Noise that damages human hearing (A-weighted noise) was present in high levels on mining vehicles, in each case being higher than the permissible exposure limit of 85 dB(A). Thus operators of mining vehicles are exposed to noise levels that will damage their hearing in time. A potential hazard in the occupational world, low frequency noise, was also included in the assessment. Literature indicates that low frequency noise is capable of causing many human health effects and thus levels on mining vehicles were reported in order to give an indication of what levels may be expected in this department of mining. It was found that much of the sound energy measured on vehicles was located in the low frequency range. In the lowest frequency band measured, Leq levels of more than 100 dB(Z) were commonly found. Controls should be implemented as far as is reasonably practicable to ensure that operators are not exposed above recommended or permissible levels for each hazard. These controls can include good maintenance of vehicles and roads to reduce whole-body vibration, sound proofing of vehicle cabs along with hearing protection devices to protect hearing and further research regarding the exposure and health effects caused by low frequency noise. Following literature indicating the physiological effects of low frequency noise exposure and also the presence thereof in different occupations, it is concluded that A-weighted noise measurements alone can not be used when quantifying the risk involved in a given acoustical environment. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2009