Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Yoon Hyuk Kim, Ariunzaya Dorj, Ahreum Han, Kyungsoo Kim, Kyung Wook Nha
Since the correlation between spinal and lower extremity alignments is high, high tibial osteotomy (HTO) surgery may also affect spinal alignment, where the spinal alignment parameters are the most important parameters for the evaluation of spinal disorders. In this study, the effect of HTO surgery on spinal alignment during gait was investigated by comparing spinal alignment parameters between patients with knee osteoarthritis (OA) and healthy young controls. Eight patients (age, 55.0±5.1 yrs; height, 160.3±7.0cm; weight, 71.3±14.1kg) with a medial compartment knee OA participated in the gait experiment two times approximately one week before and one year after HTO surgery and eight healthy young controls (age, 26.7±1.7 yrs; height, 163.4±6.5cm; weight, 58.4±11.3kg) participated only once. Cervical curvature angle, thoracic curvature angle, lumbar curvature angle, coronal vertical axis, and coronal pelvic tilt in the coronal plane and cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, and sagittal pelvic tilt in the sagittal plane were estimated using motion analysis system with skin markers. All spinal alignment parameters after HTO surgery were significantly closer to those of healthy young subjects than those before HTO, especially in the coronal plane. These findings suggest that the HTO had a positive effect on spinal alignment, as well as lower extremity alignment, and moreover, reduced the abnormality that may result in spinal problems such as degeneration or pain.
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Δευτέρα 16 Μαΐου 2016
Gait analysis of national athletes after anterior cruciate ligament reconstruction following three stages of rehabilitation program: Symmetrical perspective
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Maryam Hadizadeh, Saidon Bin Amri, Hamidreza Mohafez, Sharifah Roohi Ahmad, Abdul Halim Bin Mokhtar
This study aimed to objectively evaluate changes in gait kinematics, kinetics and symmetry among anterior cruciate ligament (ACL) reconstructed athletes during rehabilitation. Twenty two national athletes with ACL reconstruction and 15 healthy athletes were recruited for the study. Gait data were collected between the weeks 4-5, 8-9, and 12-13 post operation using three-dimensional motion analysis system. Five separate components, including knee range of motion (ROM), vertical ground reaction force (VGRF), their symmetries and knee extension moment were evaluated. One way and repeated measure multivariate analysis of variance (MANOVA) were used to analyze the knee ROMs. The VGRF and extension moment were tested using repeated measure ANOVA and independent sample t-test. Findings indicated significant alterations in all measured components between patients’ Test 1 and control group. Repeated measure analysis revealed significant effect for time in components of knee angular and VGRF (P<0.001), their symmetry index (P=0.03) and knee extension moment (P=0.045). Univariate outcomes demonstrated significant improvement in the injured limb's stance and swing (P<0.001), and single-stance (P=0.005) ROMs over time. Symmetry indexes of stance and swing ROMs, and VGRF reduced significantly by 26.3% (P=0.001), 17.9% (P<0.001), and 31.9% (P=0.03) respectively. After three months, Symmetry indexes of single-stance ROM and VGRF along with operated knee extension moment were the only variables which showed significant differences with control group. The rehabilitation program allowed national athletes to restore the operated limb's gait parameters except knee extension moment by 12-13 weeks post reconstruction; however, more time is required to normalize single-stance ROM and VGRF asymmetries.
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Source:Gait & Posture
Author(s): Maryam Hadizadeh, Saidon Bin Amri, Hamidreza Mohafez, Sharifah Roohi Ahmad, Abdul Halim Bin Mokhtar
This study aimed to objectively evaluate changes in gait kinematics, kinetics and symmetry among anterior cruciate ligament (ACL) reconstructed athletes during rehabilitation. Twenty two national athletes with ACL reconstruction and 15 healthy athletes were recruited for the study. Gait data were collected between the weeks 4-5, 8-9, and 12-13 post operation using three-dimensional motion analysis system. Five separate components, including knee range of motion (ROM), vertical ground reaction force (VGRF), their symmetries and knee extension moment were evaluated. One way and repeated measure multivariate analysis of variance (MANOVA) were used to analyze the knee ROMs. The VGRF and extension moment were tested using repeated measure ANOVA and independent sample t-test. Findings indicated significant alterations in all measured components between patients’ Test 1 and control group. Repeated measure analysis revealed significant effect for time in components of knee angular and VGRF (P<0.001), their symmetry index (P=0.03) and knee extension moment (P=0.045). Univariate outcomes demonstrated significant improvement in the injured limb's stance and swing (P<0.001), and single-stance (P=0.005) ROMs over time. Symmetry indexes of stance and swing ROMs, and VGRF reduced significantly by 26.3% (P=0.001), 17.9% (P<0.001), and 31.9% (P=0.03) respectively. After three months, Symmetry indexes of single-stance ROM and VGRF along with operated knee extension moment were the only variables which showed significant differences with control group. The rehabilitation program allowed national athletes to restore the operated limb's gait parameters except knee extension moment by 12-13 weeks post reconstruction; however, more time is required to normalize single-stance ROM and VGRF asymmetries.
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Spatiotemporal, kinematic, force and muscle activation outcomes during gait and functional exercise in water compared to on land: A systematic review
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Sophie Heywood, Jodie McClelland, Paula Geigle, Ann Rahmann, Ross Clark
BackgroundExercises replicating functional activities are commonly used in aquatic rehabilitation although it is not clear how the movement characteristics differ between the two environments. A systematic review was completed in order to compare the biomechanics of gait, closed kinetic chain and plyometric exercise when performed in water and on land.MethodsDatabases including MEDLINE, CINAHL, SPORTDiscus, Embase and the Cochrane library were searched. Studies were included where a functional lower limb activity was performed in water and on land with the same instructions. Standardized mean differences (SMD) and 95% confidence intervals were calculated for spatiotemporal, kinematic, force and muscle activation outcomes.Findings28 studies included walking or running (19 studies), stationary running (three), closed kinetic chain exercise (two), plyometric exercise (three) and timed-up and go (one). Very large effect sizes showed self-selected speed of walking (SMD >4.66) and vertical ground reaction forces (VGRF) (SMD >1.91) in water were less than on land, however, lower limb range of movement and muscle activity were similar. VGRF in plyometric exercise was lower in water when landing but more similar between the two environments in propulsion. Maximal speed of movement for walking and stationary running was lower in water compared to on land (SMD>3.05), however was similar in propulsion in plyometric exercise.InterpretationDrag forces may contribute to lower self-selected speed of walking. Monitoring speed of movement in water assists in determining the potential advantages or limitations of aquatic exercise and the task specificity to land-based function.PROSPERO registration number: CRD42014015544
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Source:Gait & Posture
Author(s): Sophie Heywood, Jodie McClelland, Paula Geigle, Ann Rahmann, Ross Clark
BackgroundExercises replicating functional activities are commonly used in aquatic rehabilitation although it is not clear how the movement characteristics differ between the two environments. A systematic review was completed in order to compare the biomechanics of gait, closed kinetic chain and plyometric exercise when performed in water and on land.MethodsDatabases including MEDLINE, CINAHL, SPORTDiscus, Embase and the Cochrane library were searched. Studies were included where a functional lower limb activity was performed in water and on land with the same instructions. Standardized mean differences (SMD) and 95% confidence intervals were calculated for spatiotemporal, kinematic, force and muscle activation outcomes.Findings28 studies included walking or running (19 studies), stationary running (three), closed kinetic chain exercise (two), plyometric exercise (three) and timed-up and go (one). Very large effect sizes showed self-selected speed of walking (SMD >4.66) and vertical ground reaction forces (VGRF) (SMD >1.91) in water were less than on land, however, lower limb range of movement and muscle activity were similar. VGRF in plyometric exercise was lower in water when landing but more similar between the two environments in propulsion. Maximal speed of movement for walking and stationary running was lower in water compared to on land (SMD>3.05), however was similar in propulsion in plyometric exercise.InterpretationDrag forces may contribute to lower self-selected speed of walking. Monitoring speed of movement in water assists in determining the potential advantages or limitations of aquatic exercise and the task specificity to land-based function.PROSPERO registration number: CRD42014015544
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Control conditions for footwear insole and orthotic research
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Ryan T. Lewinson, Jay T. Worobets, Darren J. Stefanyshyn
Footwear insoles/orthotics alter variables associated with musculoskeletal injury; however, their clinical effectiveness is inconclusive. One explanation for this is the possibility that control conditions may actually produce biomechanical changes that induce clinical responses. The purpose of this study was to compare insole/orthotic control conditions to identify if variables at the ground, ankle and knee that are associated with injury, are altered relative to what participants would normally experience in their own shoes. Gait analysis was performed on 15 participants during walking and running while wearing (1) their own shoes, (2) #1 with a 3mm flat insole, (3) a standardized shoe, and (4) #3 with a 3mm flat insole, where external knee adduction moments, external knee adduction angular impulses, internal ankle inversion moments, and vertical ground reaction force loading rates were determined. Conditions 2–4 were expressed as percent changes relative to condition 1, and tests of proportions assessed if there was a significant number of individuals experiencing a biomechanically relevant change for each variable. Repeated-measures ANOVAs were used to identify group differences between conditions. The majority of movement-footwear-variable combinations contained a proportion of individuals experiencing biomechanically relevant changes compared to condition 1 that was significantly greater than the expected proportion of 20%. No systematic differences were found between conditions. This suggests that conditions 2-4 may alter biomechanics relative to baseline for many participants, but not in a consistent way across participants. It is recommended that participant's own footwear be used as control conditions in future trials where biomechanics are primary variables of interest.
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Source:Gait & Posture
Author(s): Ryan T. Lewinson, Jay T. Worobets, Darren J. Stefanyshyn
Footwear insoles/orthotics alter variables associated with musculoskeletal injury; however, their clinical effectiveness is inconclusive. One explanation for this is the possibility that control conditions may actually produce biomechanical changes that induce clinical responses. The purpose of this study was to compare insole/orthotic control conditions to identify if variables at the ground, ankle and knee that are associated with injury, are altered relative to what participants would normally experience in their own shoes. Gait analysis was performed on 15 participants during walking and running while wearing (1) their own shoes, (2) #1 with a 3mm flat insole, (3) a standardized shoe, and (4) #3 with a 3mm flat insole, where external knee adduction moments, external knee adduction angular impulses, internal ankle inversion moments, and vertical ground reaction force loading rates were determined. Conditions 2–4 were expressed as percent changes relative to condition 1, and tests of proportions assessed if there was a significant number of individuals experiencing a biomechanically relevant change for each variable. Repeated-measures ANOVAs were used to identify group differences between conditions. The majority of movement-footwear-variable combinations contained a proportion of individuals experiencing biomechanically relevant changes compared to condition 1 that was significantly greater than the expected proportion of 20%. No systematic differences were found between conditions. This suggests that conditions 2-4 may alter biomechanics relative to baseline for many participants, but not in a consistent way across participants. It is recommended that participant's own footwear be used as control conditions in future trials where biomechanics are primary variables of interest.
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Accuracy and reliability of the RGB-D camera for measuring walking speed on a treadmill
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): B. Fosty, G. Ben-Sadoun, G. Sacco, A. König, V. Manera, P. Foulon, J. Brisswalter, P.H. Robert, F. Bremond
AimRGB-D cameras (Red Green Blue+Depth) are widely employed in exergames designed to physically stimulate elderly people. Nevertheless, the intensity of the physical activity reached with the existing solutions is rarely sufficient to obtain a real impact on the physical fitness and thus on the health status of this population. In this context, a Point Cloud Based System (PCBS) has been developed to interface ordinary motorized treadmills with exergames through a simple RGB-D camera, to induce players to perform physical activities at higher intensities. The goal of this study was to assess the accuracy and reliability of PCBS to measure the walking speed of a subject on a standard motorized treadmill based on the image streams of an RGB-D camera.Methods36 participants performed three 10minutes walking exercises, divided in 5 blocks of 2minutes at the following constant ordered speeds: 0.42, 0.69, 0.97, 1.25 and 1.53m.s−1. The measured walking speeds are compared to those obtained through a Marker Based Control System (MBCS).ResultsResults showed a high system accuracy (bias: 0.013±0.015m.s−1), a good reliability (ICC=0.63-0.91) and a low variability (SEM=1-5%; MD=2.7-14%).DiscussionAccuracy and reliability of PCBS are consistent with those obtained in similar existing systems measuring gait parameters.ConclusionWithin the context of the development of exergames, PCBS may be combined with exergames to perform physical activities at sufficiently high intensities in the elderly population, in order to improve their physical health and possibly prevent/delay cognitive impairment.
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Source:Gait & Posture
Author(s): B. Fosty, G. Ben-Sadoun, G. Sacco, A. König, V. Manera, P. Foulon, J. Brisswalter, P.H. Robert, F. Bremond
AimRGB-D cameras (Red Green Blue+Depth) are widely employed in exergames designed to physically stimulate elderly people. Nevertheless, the intensity of the physical activity reached with the existing solutions is rarely sufficient to obtain a real impact on the physical fitness and thus on the health status of this population. In this context, a Point Cloud Based System (PCBS) has been developed to interface ordinary motorized treadmills with exergames through a simple RGB-D camera, to induce players to perform physical activities at higher intensities. The goal of this study was to assess the accuracy and reliability of PCBS to measure the walking speed of a subject on a standard motorized treadmill based on the image streams of an RGB-D camera.Methods36 participants performed three 10minutes walking exercises, divided in 5 blocks of 2minutes at the following constant ordered speeds: 0.42, 0.69, 0.97, 1.25 and 1.53m.s−1. The measured walking speeds are compared to those obtained through a Marker Based Control System (MBCS).ResultsResults showed a high system accuracy (bias: 0.013±0.015m.s−1), a good reliability (ICC=0.63-0.91) and a low variability (SEM=1-5%; MD=2.7-14%).DiscussionAccuracy and reliability of PCBS are consistent with those obtained in similar existing systems measuring gait parameters.ConclusionWithin the context of the development of exergames, PCBS may be combined with exergames to perform physical activities at sufficiently high intensities in the elderly population, in order to improve their physical health and possibly prevent/delay cognitive impairment.
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Improvements in spinal alignment after high tibial osteotomy in patients with medial compartment knee osteoarthritis
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Yoon Hyuk Kim, Ariunzaya Dorj, Ahreum Han, Kyungsoo Kim, Kyung Wook Nha
Since the correlation between spinal and lower extremity alignments is high, high tibial osteotomy (HTO) surgery may also affect spinal alignment, where the spinal alignment parameters are the most important parameters for the evaluation of spinal disorders. In this study, the effect of HTO surgery on spinal alignment during gait was investigated by comparing spinal alignment parameters between patients with knee osteoarthritis (OA) and healthy young controls. Eight patients (age, 55.0±5.1 yrs; height, 160.3±7.0cm; weight, 71.3±14.1kg) with a medial compartment knee OA participated in the gait experiment two times approximately one week before and one year after HTO surgery and eight healthy young controls (age, 26.7±1.7 yrs; height, 163.4±6.5cm; weight, 58.4±11.3kg) participated only once. Cervical curvature angle, thoracic curvature angle, lumbar curvature angle, coronal vertical axis, and coronal pelvic tilt in the coronal plane and cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, and sagittal pelvic tilt in the sagittal plane were estimated using motion analysis system with skin markers. All spinal alignment parameters after HTO surgery were significantly closer to those of healthy young subjects than those before HTO, especially in the coronal plane. These findings suggest that the HTO had a positive effect on spinal alignment, as well as lower extremity alignment, and moreover, reduced the abnormality that may result in spinal problems such as degeneration or pain.
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Source:Gait & Posture
Author(s): Yoon Hyuk Kim, Ariunzaya Dorj, Ahreum Han, Kyungsoo Kim, Kyung Wook Nha
Since the correlation between spinal and lower extremity alignments is high, high tibial osteotomy (HTO) surgery may also affect spinal alignment, where the spinal alignment parameters are the most important parameters for the evaluation of spinal disorders. In this study, the effect of HTO surgery on spinal alignment during gait was investigated by comparing spinal alignment parameters between patients with knee osteoarthritis (OA) and healthy young controls. Eight patients (age, 55.0±5.1 yrs; height, 160.3±7.0cm; weight, 71.3±14.1kg) with a medial compartment knee OA participated in the gait experiment two times approximately one week before and one year after HTO surgery and eight healthy young controls (age, 26.7±1.7 yrs; height, 163.4±6.5cm; weight, 58.4±11.3kg) participated only once. Cervical curvature angle, thoracic curvature angle, lumbar curvature angle, coronal vertical axis, and coronal pelvic tilt in the coronal plane and cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, and sagittal pelvic tilt in the sagittal plane were estimated using motion analysis system with skin markers. All spinal alignment parameters after HTO surgery were significantly closer to those of healthy young subjects than those before HTO, especially in the coronal plane. These findings suggest that the HTO had a positive effect on spinal alignment, as well as lower extremity alignment, and moreover, reduced the abnormality that may result in spinal problems such as degeneration or pain.
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Gait analysis of national athletes after anterior cruciate ligament reconstruction following three stages of rehabilitation program: Symmetrical perspective
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Maryam Hadizadeh, Saidon Bin Amri, Hamidreza Mohafez, Sharifah Roohi Ahmad, Abdul Halim Bin Mokhtar
This study aimed to objectively evaluate changes in gait kinematics, kinetics and symmetry among anterior cruciate ligament (ACL) reconstructed athletes during rehabilitation. Twenty two national athletes with ACL reconstruction and 15 healthy athletes were recruited for the study. Gait data were collected between the weeks 4-5, 8-9, and 12-13 post operation using three-dimensional motion analysis system. Five separate components, including knee range of motion (ROM), vertical ground reaction force (VGRF), their symmetries and knee extension moment were evaluated. One way and repeated measure multivariate analysis of variance (MANOVA) were used to analyze the knee ROMs. The VGRF and extension moment were tested using repeated measure ANOVA and independent sample t-test. Findings indicated significant alterations in all measured components between patients’ Test 1 and control group. Repeated measure analysis revealed significant effect for time in components of knee angular and VGRF (P<0.001), their symmetry index (P=0.03) and knee extension moment (P=0.045). Univariate outcomes demonstrated significant improvement in the injured limb's stance and swing (P<0.001), and single-stance (P=0.005) ROMs over time. Symmetry indexes of stance and swing ROMs, and VGRF reduced significantly by 26.3% (P=0.001), 17.9% (P<0.001), and 31.9% (P=0.03) respectively. After three months, Symmetry indexes of single-stance ROM and VGRF along with operated knee extension moment were the only variables which showed significant differences with control group. The rehabilitation program allowed national athletes to restore the operated limb's gait parameters except knee extension moment by 12-13 weeks post reconstruction; however, more time is required to normalize single-stance ROM and VGRF asymmetries.
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Source:Gait & Posture
Author(s): Maryam Hadizadeh, Saidon Bin Amri, Hamidreza Mohafez, Sharifah Roohi Ahmad, Abdul Halim Bin Mokhtar
This study aimed to objectively evaluate changes in gait kinematics, kinetics and symmetry among anterior cruciate ligament (ACL) reconstructed athletes during rehabilitation. Twenty two national athletes with ACL reconstruction and 15 healthy athletes were recruited for the study. Gait data were collected between the weeks 4-5, 8-9, and 12-13 post operation using three-dimensional motion analysis system. Five separate components, including knee range of motion (ROM), vertical ground reaction force (VGRF), their symmetries and knee extension moment were evaluated. One way and repeated measure multivariate analysis of variance (MANOVA) were used to analyze the knee ROMs. The VGRF and extension moment were tested using repeated measure ANOVA and independent sample t-test. Findings indicated significant alterations in all measured components between patients’ Test 1 and control group. Repeated measure analysis revealed significant effect for time in components of knee angular and VGRF (P<0.001), their symmetry index (P=0.03) and knee extension moment (P=0.045). Univariate outcomes demonstrated significant improvement in the injured limb's stance and swing (P<0.001), and single-stance (P=0.005) ROMs over time. Symmetry indexes of stance and swing ROMs, and VGRF reduced significantly by 26.3% (P=0.001), 17.9% (P<0.001), and 31.9% (P=0.03) respectively. After three months, Symmetry indexes of single-stance ROM and VGRF along with operated knee extension moment were the only variables which showed significant differences with control group. The rehabilitation program allowed national athletes to restore the operated limb's gait parameters except knee extension moment by 12-13 weeks post reconstruction; however, more time is required to normalize single-stance ROM and VGRF asymmetries.
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Spatiotemporal, kinematic, force and muscle activation outcomes during gait and functional exercise in water compared to on land: A systematic review
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Sophie Heywood, Jodie McClelland, Paula Geigle, Ann Rahmann, Ross Clark
BackgroundExercises replicating functional activities are commonly used in aquatic rehabilitation although it is not clear how the movement characteristics differ between the two environments. A systematic review was completed in order to compare the biomechanics of gait, closed kinetic chain and plyometric exercise when performed in water and on land.MethodsDatabases including MEDLINE, CINAHL, SPORTDiscus, Embase and the Cochrane library were searched. Studies were included where a functional lower limb activity was performed in water and on land with the same instructions. Standardized mean differences (SMD) and 95% confidence intervals were calculated for spatiotemporal, kinematic, force and muscle activation outcomes.Findings28 studies included walking or running (19 studies), stationary running (three), closed kinetic chain exercise (two), plyometric exercise (three) and timed-up and go (one). Very large effect sizes showed self-selected speed of walking (SMD >4.66) and vertical ground reaction forces (VGRF) (SMD >1.91) in water were less than on land, however, lower limb range of movement and muscle activity were similar. VGRF in plyometric exercise was lower in water when landing but more similar between the two environments in propulsion. Maximal speed of movement for walking and stationary running was lower in water compared to on land (SMD>3.05), however was similar in propulsion in plyometric exercise.InterpretationDrag forces may contribute to lower self-selected speed of walking. Monitoring speed of movement in water assists in determining the potential advantages or limitations of aquatic exercise and the task specificity to land-based function.PROSPERO registration number: CRD42014015544
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Source:Gait & Posture
Author(s): Sophie Heywood, Jodie McClelland, Paula Geigle, Ann Rahmann, Ross Clark
BackgroundExercises replicating functional activities are commonly used in aquatic rehabilitation although it is not clear how the movement characteristics differ between the two environments. A systematic review was completed in order to compare the biomechanics of gait, closed kinetic chain and plyometric exercise when performed in water and on land.MethodsDatabases including MEDLINE, CINAHL, SPORTDiscus, Embase and the Cochrane library were searched. Studies were included where a functional lower limb activity was performed in water and on land with the same instructions. Standardized mean differences (SMD) and 95% confidence intervals were calculated for spatiotemporal, kinematic, force and muscle activation outcomes.Findings28 studies included walking or running (19 studies), stationary running (three), closed kinetic chain exercise (two), plyometric exercise (three) and timed-up and go (one). Very large effect sizes showed self-selected speed of walking (SMD >4.66) and vertical ground reaction forces (VGRF) (SMD >1.91) in water were less than on land, however, lower limb range of movement and muscle activity were similar. VGRF in plyometric exercise was lower in water when landing but more similar between the two environments in propulsion. Maximal speed of movement for walking and stationary running was lower in water compared to on land (SMD>3.05), however was similar in propulsion in plyometric exercise.InterpretationDrag forces may contribute to lower self-selected speed of walking. Monitoring speed of movement in water assists in determining the potential advantages or limitations of aquatic exercise and the task specificity to land-based function.PROSPERO registration number: CRD42014015544
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Control conditions for footwear insole and orthotic research
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Ryan T. Lewinson, Jay T. Worobets, Darren J. Stefanyshyn
Footwear insoles/orthotics alter variables associated with musculoskeletal injury; however, their clinical effectiveness is inconclusive. One explanation for this is the possibility that control conditions may actually produce biomechanical changes that induce clinical responses. The purpose of this study was to compare insole/orthotic control conditions to identify if variables at the ground, ankle and knee that are associated with injury, are altered relative to what participants would normally experience in their own shoes. Gait analysis was performed on 15 participants during walking and running while wearing (1) their own shoes, (2) #1 with a 3mm flat insole, (3) a standardized shoe, and (4) #3 with a 3mm flat insole, where external knee adduction moments, external knee adduction angular impulses, internal ankle inversion moments, and vertical ground reaction force loading rates were determined. Conditions 2–4 were expressed as percent changes relative to condition 1, and tests of proportions assessed if there was a significant number of individuals experiencing a biomechanically relevant change for each variable. Repeated-measures ANOVAs were used to identify group differences between conditions. The majority of movement-footwear-variable combinations contained a proportion of individuals experiencing biomechanically relevant changes compared to condition 1 that was significantly greater than the expected proportion of 20%. No systematic differences were found between conditions. This suggests that conditions 2-4 may alter biomechanics relative to baseline for many participants, but not in a consistent way across participants. It is recommended that participant's own footwear be used as control conditions in future trials where biomechanics are primary variables of interest.
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Source:Gait & Posture
Author(s): Ryan T. Lewinson, Jay T. Worobets, Darren J. Stefanyshyn
Footwear insoles/orthotics alter variables associated with musculoskeletal injury; however, their clinical effectiveness is inconclusive. One explanation for this is the possibility that control conditions may actually produce biomechanical changes that induce clinical responses. The purpose of this study was to compare insole/orthotic control conditions to identify if variables at the ground, ankle and knee that are associated with injury, are altered relative to what participants would normally experience in their own shoes. Gait analysis was performed on 15 participants during walking and running while wearing (1) their own shoes, (2) #1 with a 3mm flat insole, (3) a standardized shoe, and (4) #3 with a 3mm flat insole, where external knee adduction moments, external knee adduction angular impulses, internal ankle inversion moments, and vertical ground reaction force loading rates were determined. Conditions 2–4 were expressed as percent changes relative to condition 1, and tests of proportions assessed if there was a significant number of individuals experiencing a biomechanically relevant change for each variable. Repeated-measures ANOVAs were used to identify group differences between conditions. The majority of movement-footwear-variable combinations contained a proportion of individuals experiencing biomechanically relevant changes compared to condition 1 that was significantly greater than the expected proportion of 20%. No systematic differences were found between conditions. This suggests that conditions 2-4 may alter biomechanics relative to baseline for many participants, but not in a consistent way across participants. It is recommended that participant's own footwear be used as control conditions in future trials where biomechanics are primary variables of interest.
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Accuracy and reliability of the RGB-D camera for measuring walking speed on a treadmill
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): B. Fosty, G. Ben-Sadoun, G. Sacco, A. König, V. Manera, P. Foulon, J. Brisswalter, P.H. Robert, F. Bremond
AimRGB-D cameras (Red Green Blue+Depth) are widely employed in exergames designed to physically stimulate elderly people. Nevertheless, the intensity of the physical activity reached with the existing solutions is rarely sufficient to obtain a real impact on the physical fitness and thus on the health status of this population. In this context, a Point Cloud Based System (PCBS) has been developed to interface ordinary motorized treadmills with exergames through a simple RGB-D camera, to induce players to perform physical activities at higher intensities. The goal of this study was to assess the accuracy and reliability of PCBS to measure the walking speed of a subject on a standard motorized treadmill based on the image streams of an RGB-D camera.Methods36 participants performed three 10minutes walking exercises, divided in 5 blocks of 2minutes at the following constant ordered speeds: 0.42, 0.69, 0.97, 1.25 and 1.53m.s−1. The measured walking speeds are compared to those obtained through a Marker Based Control System (MBCS).ResultsResults showed a high system accuracy (bias: 0.013±0.015m.s−1), a good reliability (ICC=0.63-0.91) and a low variability (SEM=1-5%; MD=2.7-14%).DiscussionAccuracy and reliability of PCBS are consistent with those obtained in similar existing systems measuring gait parameters.ConclusionWithin the context of the development of exergames, PCBS may be combined with exergames to perform physical activities at sufficiently high intensities in the elderly population, in order to improve their physical health and possibly prevent/delay cognitive impairment.
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Source:Gait & Posture
Author(s): B. Fosty, G. Ben-Sadoun, G. Sacco, A. König, V. Manera, P. Foulon, J. Brisswalter, P.H. Robert, F. Bremond
AimRGB-D cameras (Red Green Blue+Depth) are widely employed in exergames designed to physically stimulate elderly people. Nevertheless, the intensity of the physical activity reached with the existing solutions is rarely sufficient to obtain a real impact on the physical fitness and thus on the health status of this population. In this context, a Point Cloud Based System (PCBS) has been developed to interface ordinary motorized treadmills with exergames through a simple RGB-D camera, to induce players to perform physical activities at higher intensities. The goal of this study was to assess the accuracy and reliability of PCBS to measure the walking speed of a subject on a standard motorized treadmill based on the image streams of an RGB-D camera.Methods36 participants performed three 10minutes walking exercises, divided in 5 blocks of 2minutes at the following constant ordered speeds: 0.42, 0.69, 0.97, 1.25 and 1.53m.s−1. The measured walking speeds are compared to those obtained through a Marker Based Control System (MBCS).ResultsResults showed a high system accuracy (bias: 0.013±0.015m.s−1), a good reliability (ICC=0.63-0.91) and a low variability (SEM=1-5%; MD=2.7-14%).DiscussionAccuracy and reliability of PCBS are consistent with those obtained in similar existing systems measuring gait parameters.ConclusionWithin the context of the development of exergames, PCBS may be combined with exergames to perform physical activities at sufficiently high intensities in the elderly population, in order to improve their physical health and possibly prevent/delay cognitive impairment.
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Improvements in spinal alignment after high tibial osteotomy in patients with medial compartment knee osteoarthritis
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Yoon Hyuk Kim, Ariunzaya Dorj, Ahreum Han, Kyungsoo Kim, Kyung Wook Nha
Since the correlation between spinal and lower extremity alignments is high, high tibial osteotomy (HTO) surgery may also affect spinal alignment, where the spinal alignment parameters are the most important parameters for the evaluation of spinal disorders. In this study, the effect of HTO surgery on spinal alignment during gait was investigated by comparing spinal alignment parameters between patients with knee osteoarthritis (OA) and healthy young controls. Eight patients (age, 55.0±5.1 yrs; height, 160.3±7.0cm; weight, 71.3±14.1kg) with a medial compartment knee OA participated in the gait experiment two times approximately one week before and one year after HTO surgery and eight healthy young controls (age, 26.7±1.7 yrs; height, 163.4±6.5cm; weight, 58.4±11.3kg) participated only once. Cervical curvature angle, thoracic curvature angle, lumbar curvature angle, coronal vertical axis, and coronal pelvic tilt in the coronal plane and cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, and sagittal pelvic tilt in the sagittal plane were estimated using motion analysis system with skin markers. All spinal alignment parameters after HTO surgery were significantly closer to those of healthy young subjects than those before HTO, especially in the coronal plane. These findings suggest that the HTO had a positive effect on spinal alignment, as well as lower extremity alignment, and moreover, reduced the abnormality that may result in spinal problems such as degeneration or pain.
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Source:Gait & Posture
Author(s): Yoon Hyuk Kim, Ariunzaya Dorj, Ahreum Han, Kyungsoo Kim, Kyung Wook Nha
Since the correlation between spinal and lower extremity alignments is high, high tibial osteotomy (HTO) surgery may also affect spinal alignment, where the spinal alignment parameters are the most important parameters for the evaluation of spinal disorders. In this study, the effect of HTO surgery on spinal alignment during gait was investigated by comparing spinal alignment parameters between patients with knee osteoarthritis (OA) and healthy young controls. Eight patients (age, 55.0±5.1 yrs; height, 160.3±7.0cm; weight, 71.3±14.1kg) with a medial compartment knee OA participated in the gait experiment two times approximately one week before and one year after HTO surgery and eight healthy young controls (age, 26.7±1.7 yrs; height, 163.4±6.5cm; weight, 58.4±11.3kg) participated only once. Cervical curvature angle, thoracic curvature angle, lumbar curvature angle, coronal vertical axis, and coronal pelvic tilt in the coronal plane and cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, and sagittal pelvic tilt in the sagittal plane were estimated using motion analysis system with skin markers. All spinal alignment parameters after HTO surgery were significantly closer to those of healthy young subjects than those before HTO, especially in the coronal plane. These findings suggest that the HTO had a positive effect on spinal alignment, as well as lower extremity alignment, and moreover, reduced the abnormality that may result in spinal problems such as degeneration or pain.
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Gait analysis of national athletes after anterior cruciate ligament reconstruction following three stages of rehabilitation program: Symmetrical perspective
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Maryam Hadizadeh, Saidon Bin Amri, Hamidreza Mohafez, Sharifah Roohi Ahmad, Abdul Halim Bin Mokhtar
This study aimed to objectively evaluate changes in gait kinematics, kinetics and symmetry among anterior cruciate ligament (ACL) reconstructed athletes during rehabilitation. Twenty two national athletes with ACL reconstruction and 15 healthy athletes were recruited for the study. Gait data were collected between the weeks 4-5, 8-9, and 12-13 post operation using three-dimensional motion analysis system. Five separate components, including knee range of motion (ROM), vertical ground reaction force (VGRF), their symmetries and knee extension moment were evaluated. One way and repeated measure multivariate analysis of variance (MANOVA) were used to analyze the knee ROMs. The VGRF and extension moment were tested using repeated measure ANOVA and independent sample t-test. Findings indicated significant alterations in all measured components between patients’ Test 1 and control group. Repeated measure analysis revealed significant effect for time in components of knee angular and VGRF (P<0.001), their symmetry index (P=0.03) and knee extension moment (P=0.045). Univariate outcomes demonstrated significant improvement in the injured limb's stance and swing (P<0.001), and single-stance (P=0.005) ROMs over time. Symmetry indexes of stance and swing ROMs, and VGRF reduced significantly by 26.3% (P=0.001), 17.9% (P<0.001), and 31.9% (P=0.03) respectively. After three months, Symmetry indexes of single-stance ROM and VGRF along with operated knee extension moment were the only variables which showed significant differences with control group. The rehabilitation program allowed national athletes to restore the operated limb's gait parameters except knee extension moment by 12-13 weeks post reconstruction; however, more time is required to normalize single-stance ROM and VGRF asymmetries.
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Source:Gait & Posture
Author(s): Maryam Hadizadeh, Saidon Bin Amri, Hamidreza Mohafez, Sharifah Roohi Ahmad, Abdul Halim Bin Mokhtar
This study aimed to objectively evaluate changes in gait kinematics, kinetics and symmetry among anterior cruciate ligament (ACL) reconstructed athletes during rehabilitation. Twenty two national athletes with ACL reconstruction and 15 healthy athletes were recruited for the study. Gait data were collected between the weeks 4-5, 8-9, and 12-13 post operation using three-dimensional motion analysis system. Five separate components, including knee range of motion (ROM), vertical ground reaction force (VGRF), their symmetries and knee extension moment were evaluated. One way and repeated measure multivariate analysis of variance (MANOVA) were used to analyze the knee ROMs. The VGRF and extension moment were tested using repeated measure ANOVA and independent sample t-test. Findings indicated significant alterations in all measured components between patients’ Test 1 and control group. Repeated measure analysis revealed significant effect for time in components of knee angular and VGRF (P<0.001), their symmetry index (P=0.03) and knee extension moment (P=0.045). Univariate outcomes demonstrated significant improvement in the injured limb's stance and swing (P<0.001), and single-stance (P=0.005) ROMs over time. Symmetry indexes of stance and swing ROMs, and VGRF reduced significantly by 26.3% (P=0.001), 17.9% (P<0.001), and 31.9% (P=0.03) respectively. After three months, Symmetry indexes of single-stance ROM and VGRF along with operated knee extension moment were the only variables which showed significant differences with control group. The rehabilitation program allowed national athletes to restore the operated limb's gait parameters except knee extension moment by 12-13 weeks post reconstruction; however, more time is required to normalize single-stance ROM and VGRF asymmetries.
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Spatiotemporal, kinematic, force and muscle activation outcomes during gait and functional exercise in water compared to on land: A systematic review
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Sophie Heywood, Jodie McClelland, Paula Geigle, Ann Rahmann, Ross Clark
BackgroundExercises replicating functional activities are commonly used in aquatic rehabilitation although it is not clear how the movement characteristics differ between the two environments. A systematic review was completed in order to compare the biomechanics of gait, closed kinetic chain and plyometric exercise when performed in water and on land.MethodsDatabases including MEDLINE, CINAHL, SPORTDiscus, Embase and the Cochrane library were searched. Studies were included where a functional lower limb activity was performed in water and on land with the same instructions. Standardized mean differences (SMD) and 95% confidence intervals were calculated for spatiotemporal, kinematic, force and muscle activation outcomes.Findings28 studies included walking or running (19 studies), stationary running (three), closed kinetic chain exercise (two), plyometric exercise (three) and timed-up and go (one). Very large effect sizes showed self-selected speed of walking (SMD >4.66) and vertical ground reaction forces (VGRF) (SMD >1.91) in water were less than on land, however, lower limb range of movement and muscle activity were similar. VGRF in plyometric exercise was lower in water when landing but more similar between the two environments in propulsion. Maximal speed of movement for walking and stationary running was lower in water compared to on land (SMD>3.05), however was similar in propulsion in plyometric exercise.InterpretationDrag forces may contribute to lower self-selected speed of walking. Monitoring speed of movement in water assists in determining the potential advantages or limitations of aquatic exercise and the task specificity to land-based function.PROSPERO registration number: CRD42014015544
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Source:Gait & Posture
Author(s): Sophie Heywood, Jodie McClelland, Paula Geigle, Ann Rahmann, Ross Clark
BackgroundExercises replicating functional activities are commonly used in aquatic rehabilitation although it is not clear how the movement characteristics differ between the two environments. A systematic review was completed in order to compare the biomechanics of gait, closed kinetic chain and plyometric exercise when performed in water and on land.MethodsDatabases including MEDLINE, CINAHL, SPORTDiscus, Embase and the Cochrane library were searched. Studies were included where a functional lower limb activity was performed in water and on land with the same instructions. Standardized mean differences (SMD) and 95% confidence intervals were calculated for spatiotemporal, kinematic, force and muscle activation outcomes.Findings28 studies included walking or running (19 studies), stationary running (three), closed kinetic chain exercise (two), plyometric exercise (three) and timed-up and go (one). Very large effect sizes showed self-selected speed of walking (SMD >4.66) and vertical ground reaction forces (VGRF) (SMD >1.91) in water were less than on land, however, lower limb range of movement and muscle activity were similar. VGRF in plyometric exercise was lower in water when landing but more similar between the two environments in propulsion. Maximal speed of movement for walking and stationary running was lower in water compared to on land (SMD>3.05), however was similar in propulsion in plyometric exercise.InterpretationDrag forces may contribute to lower self-selected speed of walking. Monitoring speed of movement in water assists in determining the potential advantages or limitations of aquatic exercise and the task specificity to land-based function.PROSPERO registration number: CRD42014015544
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Control conditions for footwear insole and orthotic research
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): Ryan T. Lewinson, Jay T. Worobets, Darren J. Stefanyshyn
Footwear insoles/orthotics alter variables associated with musculoskeletal injury; however, their clinical effectiveness is inconclusive. One explanation for this is the possibility that control conditions may actually produce biomechanical changes that induce clinical responses. The purpose of this study was to compare insole/orthotic control conditions to identify if variables at the ground, ankle and knee that are associated with injury, are altered relative to what participants would normally experience in their own shoes. Gait analysis was performed on 15 participants during walking and running while wearing (1) their own shoes, (2) #1 with a 3mm flat insole, (3) a standardized shoe, and (4) #3 with a 3mm flat insole, where external knee adduction moments, external knee adduction angular impulses, internal ankle inversion moments, and vertical ground reaction force loading rates were determined. Conditions 2–4 were expressed as percent changes relative to condition 1, and tests of proportions assessed if there was a significant number of individuals experiencing a biomechanically relevant change for each variable. Repeated-measures ANOVAs were used to identify group differences between conditions. The majority of movement-footwear-variable combinations contained a proportion of individuals experiencing biomechanically relevant changes compared to condition 1 that was significantly greater than the expected proportion of 20%. No systematic differences were found between conditions. This suggests that conditions 2-4 may alter biomechanics relative to baseline for many participants, but not in a consistent way across participants. It is recommended that participant's own footwear be used as control conditions in future trials where biomechanics are primary variables of interest.
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Source:Gait & Posture
Author(s): Ryan T. Lewinson, Jay T. Worobets, Darren J. Stefanyshyn
Footwear insoles/orthotics alter variables associated with musculoskeletal injury; however, their clinical effectiveness is inconclusive. One explanation for this is the possibility that control conditions may actually produce biomechanical changes that induce clinical responses. The purpose of this study was to compare insole/orthotic control conditions to identify if variables at the ground, ankle and knee that are associated with injury, are altered relative to what participants would normally experience in their own shoes. Gait analysis was performed on 15 participants during walking and running while wearing (1) their own shoes, (2) #1 with a 3mm flat insole, (3) a standardized shoe, and (4) #3 with a 3mm flat insole, where external knee adduction moments, external knee adduction angular impulses, internal ankle inversion moments, and vertical ground reaction force loading rates were determined. Conditions 2–4 were expressed as percent changes relative to condition 1, and tests of proportions assessed if there was a significant number of individuals experiencing a biomechanically relevant change for each variable. Repeated-measures ANOVAs were used to identify group differences between conditions. The majority of movement-footwear-variable combinations contained a proportion of individuals experiencing biomechanically relevant changes compared to condition 1 that was significantly greater than the expected proportion of 20%. No systematic differences were found between conditions. This suggests that conditions 2-4 may alter biomechanics relative to baseline for many participants, but not in a consistent way across participants. It is recommended that participant's own footwear be used as control conditions in future trials where biomechanics are primary variables of interest.
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Accuracy and reliability of the RGB-D camera for measuring walking speed on a treadmill
Publication date: Available online 16 May 2016
Source:Gait & Posture
Author(s): B. Fosty, G. Ben-Sadoun, G. Sacco, A. König, V. Manera, P. Foulon, J. Brisswalter, P.H. Robert, F. Bremond
AimRGB-D cameras (Red Green Blue+Depth) are widely employed in exergames designed to physically stimulate elderly people. Nevertheless, the intensity of the physical activity reached with the existing solutions is rarely sufficient to obtain a real impact on the physical fitness and thus on the health status of this population. In this context, a Point Cloud Based System (PCBS) has been developed to interface ordinary motorized treadmills with exergames through a simple RGB-D camera, to induce players to perform physical activities at higher intensities. The goal of this study was to assess the accuracy and reliability of PCBS to measure the walking speed of a subject on a standard motorized treadmill based on the image streams of an RGB-D camera.Methods36 participants performed three 10minutes walking exercises, divided in 5 blocks of 2minutes at the following constant ordered speeds: 0.42, 0.69, 0.97, 1.25 and 1.53m.s−1. The measured walking speeds are compared to those obtained through a Marker Based Control System (MBCS).ResultsResults showed a high system accuracy (bias: 0.013±0.015m.s−1), a good reliability (ICC=0.63-0.91) and a low variability (SEM=1-5%; MD=2.7-14%).DiscussionAccuracy and reliability of PCBS are consistent with those obtained in similar existing systems measuring gait parameters.ConclusionWithin the context of the development of exergames, PCBS may be combined with exergames to perform physical activities at sufficiently high intensities in the elderly population, in order to improve their physical health and possibly prevent/delay cognitive impairment.
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Source:Gait & Posture
Author(s): B. Fosty, G. Ben-Sadoun, G. Sacco, A. König, V. Manera, P. Foulon, J. Brisswalter, P.H. Robert, F. Bremond
AimRGB-D cameras (Red Green Blue+Depth) are widely employed in exergames designed to physically stimulate elderly people. Nevertheless, the intensity of the physical activity reached with the existing solutions is rarely sufficient to obtain a real impact on the physical fitness and thus on the health status of this population. In this context, a Point Cloud Based System (PCBS) has been developed to interface ordinary motorized treadmills with exergames through a simple RGB-D camera, to induce players to perform physical activities at higher intensities. The goal of this study was to assess the accuracy and reliability of PCBS to measure the walking speed of a subject on a standard motorized treadmill based on the image streams of an RGB-D camera.Methods36 participants performed three 10minutes walking exercises, divided in 5 blocks of 2minutes at the following constant ordered speeds: 0.42, 0.69, 0.97, 1.25 and 1.53m.s−1. The measured walking speeds are compared to those obtained through a Marker Based Control System (MBCS).ResultsResults showed a high system accuracy (bias: 0.013±0.015m.s−1), a good reliability (ICC=0.63-0.91) and a low variability (SEM=1-5%; MD=2.7-14%).DiscussionAccuracy and reliability of PCBS are consistent with those obtained in similar existing systems measuring gait parameters.ConclusionWithin the context of the development of exergames, PCBS may be combined with exergames to perform physical activities at sufficiently high intensities in the elderly population, in order to improve their physical health and possibly prevent/delay cognitive impairment.
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2016 Student Research Forum Winners
On Friday, April 15, 2016, the five recipients of the 2016 Student Research Forum (SRF) Awards gave five outstanding podium presentations. The SRF has been in existence for about a decade, and would not be possible without funding in part by the American Academy of Audiology Foundation (AAAF) and an underwriting grant from Plural Publishing, Inc. Each year, the SRF awardees are selected through a rigorous review process from a competitive pool of exciting student research from across the country.
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Intensity statistics of very high frequency sound scattered from wind-driven waves
The interaction of vhf 100–1000 kHz underwater sound with the ocean surface is explored. The bistatic forward scatter of 300 kHz sound is measured in a wind driven wave channel. Fluctuations in arrival amplitude are described by the scintillation index (SI) which is a measure of arrival intensity variance. SI initially increases with wind speed but eventually saturates to a value of 0.5 when the root-mean-square (rms) roughness is 0.5 mm. An adjusted scintillation index (SI*) is suggested that accounts for the multiple arrivals and properly saturates to a value of 1. Fluctuations in arrival time do not saturate and increase proportionately to the dominant surface wave component. Forward scattering is modeled at frequencies ranging from 50 to 2000 kHz using the Helmholtz-Kirchhoff integral with surface wave realizations derived from wave gauge data. The amplitude and temporal statistics of the simulated scattering agree well with measured data. Intensity saturation occurs at lower wind speeds for higher frequency sound. Both measured and modeled vhf sound is characterized by many surface arrivals at saturation. Doppler shifts associated with wave motion are expected to vary rapidly for vhf sound however further analysis is required.
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Effects of noise, reverberation and foreign accent on native and non-native listeners' performance of English speech comprehension
A large number of non-native English speakers may be found in American classrooms, both as listeners and talkers. Little is known about how this population comprehends speech in realistic adverse acoustical conditions. A study was conducted to investigate the effects of background noise level (BNL), reverberation time (RT), and talker foreign accent on native and non-native listeners' speech comprehension, while controlling for English language abilities. A total of 115 adult listeners completed comprehension tasks under 15 acoustic conditions: three BNLs (RC-30, RC-40, and RC-50) and five RTs (from 0.4 to 1.2 s). Fifty-six listeners were tested with speech from native English-speaking talkers and 59 with native Mandarin-Chinese-speaking talkers. Results show that, while higher BNLs were generally more detrimental to listeners with lower English proficiency, all listeners experienced significant comprehension deficits above RC-40 with native English talkers. This limit was lower (i.e., above RC-30), however, with Chinese talkers. For reverberation, non-native listeners as a group performed best with RT up to 0.6 s, while native listeners performed equally well up to 1.2 s. A matched foreign accent benefit has also been identified, where the negative impact of higher reverberation does not exist for non-native listeners who share the talker's native language.
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Radiation efficiency of plates subjected to turbulent boundary layer fluctuations
The modal averaged radiation efficiency of a rectangular plate subjected to turbulent boundary layer fluctuations is discussed in this letter. Numerical results demonstrate that below the hydrodynamic coincidence frequency, the modal averaged radiation efficiency will be larger with the increase of the convectionvelocity, and an increase of the structural damping will increase the modal averaged radiation efficiency at sub-critical frequencies.
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Estimation of saxophone reed parameters during playing
An approach for the estimation of single reed parameters during playing, using an instrumented mouthpiece and an iterative method, is presented. Different physical models describing the reed tip movement are tested in the estimation method. The uncertainties of the sensors installed on the mouthpiece and the limits of the estimation method are studied. A tenor saxophone reed is mounted on this mouthpiece connected to a cylinder, played by a musician, and characterized at different dynamic levels. Results show that the method can be used to estimate the reed parameters with a small error for low and medium sound levels (piano and mezzoforte dynamic levels). The analysis reveals that the complexity of the physical model describing the reed behavior must increase with dynamic levels. For medium level dynamics, the most relevant physical model assumes that the reed is an oscillator with non-linear stiffness and damping, the effect of mass (inertia) being very small.
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Geometrical parameter combinations that correlate with early interaural cross-correlation coefficients in a performance hall
The previous binaural data of the authors measured inside two multi-purpose performance halls are re-analyzed using regression in this study. It is done in an attempt to establish a framework that can improve the prediction of early interaural cross-correlation coefficients (IACCs), but with as little measurement effort and parameters as possible. The results show that regression models consist of linear combinations of polynomials of geometrical parameters, when used together with the measurement schemes suggested previously by the authors, are sufficient for predicting the IACCs to within engineering tolerance. The predictions are better than those obtained previously by the neural network approach of the authors. The relative importance of the geometrical parameters in the prediction of IACCs is also investigated.
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