Functional limitation, postural stability, and muscle recruitment of different categories of obesity were evaluated while performing an assembly workstation task. Three workstations, those designed for the 5th, 50th, and 95th percentile workers based on anthropometric data tables, were included in the study. Functional limitation was measured using electro-goniometers and the maximum frontal functional reach (MFFR) evaluation to measure the difference in joint angles, forces plates were used to study the differences in postural stability, and EMG was used to evaluate the muscle recruitment of the soleus, frontal deltoid, and trapezius muscles. Also, a regression analysis was performed to evaluate if production efficiency rate could be predicted based on body mass index (BMI) group, gender, pace type, workstation configuration and 13 body dimensions. The results revealed that the body joint angles and muscle activation parameters were not significantly different based on the main factor BMI groups; however, significant differences were found in the two-way interactions of the BMI groups and the other factors. In regard to postural stability, the results indicated that the obese class 2 and obese class 3 groups anterior posterior sway was significantly larger than the normal weight groups. The results also revealed differences based on gender for the joint angles and muscle activation when performing the small part assemblies; however, postural sway was not affected by gender differences. Pace type (self –paced or timed-paced) significantly affected the postural stability and muscle activation when performing the work task. These differences in pace type were most prevalent when comparing the 95th percentile workstation configuration against the 5th percentile workstation configuration. In regards to productivity, gender, weight, waist-to-hip ratio and pace type seem to have a large role in the production efficiency rate. Even though an individual's BMI and the workstation layout were found to impact the body functional limitation and stability, the results showed that it doesn't affect production efficiency rate performance.

This diploma thesis is focused on the vestibular system and its influence on postural musculature. The theoretical section contains an overview of modern findings concerning the vestibular system and its impact on other parts of the organism. Besides anatomical and physiological findings, the theoretical section also contains a research section which includes studies on the vestibular system, posture, stretching and their mutual effects. The main focus of the practical section is to prove the influence of the vestibular system on musculature, mainly the extensors and flexors of the lower limbs. Affecting the vestibular system causes lengthening of the ischiocrural muscles and shortening of the hip flexors (musculus rectus femoris). In this study, we tested 39 probands and measured their results after rotational vestibular stimulation. The measurements were taken goniometrically in the hip and knee joints. Dynamic parameters of the spine were also measured, along with Thomayers distance in metric values. The results have been statistically and graphically evaluated. It was proven that the vestibular system has a large statistical impact on the ischiocrural muscles as well as the frontal thigh muscles. An influence of the vestibular system on the paravertebral muscles was however not proven. In the...

This study examined the acute effects of whole-body corrective exercise on postural alignment in a sample of 50 male participants (18-30 y) displaying asymmetrical postural deviations. All participants were randomly assigned to either a non-exercise control (n = 25) or corrective exercise treatment (n = 25) group. A three-dimensional motion analysis Vicon system was employed to quantify standing postural alignment at the beginning and end of a 6 d study. Postural misalignments were determined in degrees of symmetry (tilt) and rotation using horizontal and vertical virtual plumb lines for the following locations: hip (ASIS), leg (greater trochanter), shoulder (acromion process), and head (ear). The treatment group completed five corrective exercise sessions on separate days which included 11 exercises (requiring about 60 min per session to complete). The control group performed no intervention and maintained a normal lifestyle. At the commencement of the study there were no significant differences in the degree of postural misalignment between the control and treatment groups at any of the postural measurements. At the conclusion of the treatment period (following the five sessions of corrective exercise), there were no significant differences in any of the postural alignments of any of the postural measurements between the treatment and control groups. For example, all of the following postural measurements were not significantly different (critical F ≥ 4.24;df = 1,25) between groups: hip (ASIS) tilt (F = 0.05), hip (ASIS) rotation (F = 0.15), greater trochanter tilt (F = 1.58), greater trochanter rotation (F = 0.33), shoulder tilt (F = 2.63), shoulder rotation (F = 0.07), head tilt (F = 2.39), and head rotation (F = 2.79). The results of this study suggest that five sessions of corrective exercise were insufficient to significantly improve standing postural alignment. In addition, this study appears to be the first to document whole-body postural alignment using 3D video analysis.

In this report we investigate how well a smartphone can be used to detect the standing-to-kneeling and kneeling-to-standing postural transitions. Possible applications include measuring time spent kneeling in certain groups of workers prone to knee-straining work. Accelerometer and gyroscope data was recorded from a group of 10 volunteers while performing a set of postural transitions according to an experimental script. The set of postural transitions included the standing-to-kneeling and kneeling-to-standing transitions, in addition to a selection of transitions common in knee-straining occupations. Using recorded video, the recorded data was labeled and segmented into a data set consisting of 3-second sensor data segments in 9 different classes. The classification performance of a number of different LSTM-networks were evaluated on the data set. When evaluated in a user-specific setting, the best network achieved an overall classification accuracy of 89.4 %. The network achieved precision 0.982 and recall 0.917 for the standing-to-kneeling transitions, and precision 0.900 and recall 0.900 for the kneeling-to-standing transitions. When the same network was evaluated in a user-independent setting it achieved an overall accuracy of 66.3 %, with precision 0.720 and recall 0.746 for the standing-to-kneeling transitions, and precision 0.707 and recall 0.604 for the kneeling-to-standing transitions. The network was also evaluated in a setting where only accelerometer data was used. The achieved performance was similar to that achieved when using data from both the accelerometer and gyroscope. The classification speed of the network was evaluated on a smartphone. On a Samsung Galaxy S7 the average time needed to perform one classification was 38.5 milliseconds. The classification can therefore be done in real time. / I denna rapport undersöks möjligheten att använda en smartphone för att upptäcka posturala övergångar mellan stående och knästående ställning. Ett möjligt användningsområde för sådan detektion är att mäta mängd tid spenderad knäståendes hos vissa yrkesgrupper. Accelerometerdata och gyroskopdata spelades in från en grupp av 10 försökspersoner medan de utförde vissa posturala övergångar, vilka inkluderade övergångar från stående till knästående ställning samt från knästående till stående ställning. Genom att granska inspelad video från försöken markerades bitar av den inspelade datan som tillhörandes en viss postural övergång. Datan segmenterades och gav upphov till ett dataset bestående av 3 sekunder långa segment av sensordata i 9 olika klasser. Prestandan för ett antal olika LSTM-nätverk utvärderades på datasetet. Det bästa nätverket uppnådde en övergripande noggrannhet av 89.4 % när det utvärderades användarspecifikt. Nätverket uppnådde en precision av 0.982 och en återkallelse av 0.917 för övergångar från stående till knästående ställning, samt en precision av 0.900 och en återkallelse av 0.900 för övergångar från knästående till stående ställning. När samma nätverk utvärderades användaroberoende uppnådde det en övergripande noggrannhet av 66.3 %, med en precision av 0.720 och återkallelse av 0.746 för övergångar från stående till knästående ställning, samt en precision av 0.707 och återkallelse av 0.604 för övergångar mellan knästående och stående ställning. Nätverket utvärderades också i en konfiguration där enbart accelerometerdata nyttjades, och uppnådde liknande prestanda som när både accelerometerdata och gyroskopdata användes. Nätverkets klassificeringshastighet utvärderades på en smartphone. När klassificeringen utfördes på en Samsung Galaxy S7 var den genomsnittliga körningstiden 38.5 millisekunder, vilket är snabbt nog för att utföras i realtid.

Our walking patterns must be adjusted continuously in everyday living, whether for maneuvering on slippery surfaces or stepping over cracks on the street. Walking becomes more challenging as it requires more energy to lift and accelerate the body due to additional loads on the body as we move through space. This dissertation investigates gait, stability, and adaptation in adults with range of adiposity. First, we studied how people with obesity adapt to spatial (obstacle crossing) and temporal (metronome walking) task constraints during walking over-ground. Results indicated that people prioritized a spatial over temporal constraint when attempting to meet both constraints at the same time. Second, we tested how massive weight loss affects gait and stability. We measured how bariatric surgery patients walked and crossed obstacles before and one year after surgery. Findings indicated that massive weight loss improved not only gait but also postural stability during gait. Third, we quantified whole-body rotational characteristics in adults with obesity through changes in angular momentum quantities during steady-state walking. I found that angular momentum (1) was greater in adults with higher BMI, (2) was highly regulated by foot placement, and (3) did not change with walking speed. Taken together these results suggest that gait and stability can be adapted. These findings may help to develop interventions to target specific walking deficits in patients with mobility limitations such as obesity.

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