Omid Rasouli - Academia.edu (original) (raw)

Papers by Omid Rasouli

Research paper thumbnail of Unintentional drifts during quiet stance and voluntary body sway

Experimental brain research, Jan 5, 2017

We explored unintentional drifts in voluntary whole-body sway tasks following the removal of visu... more We explored unintentional drifts in voluntary whole-body sway tasks following the removal of visual feedback. The main hypothesis was that the unintentional drifts were produced by drifts of referent coordinates for salient performance variables. Young healthy subjects stood quietly on a force platform and also performed voluntary body sway at 0.5 Hz both in the anterio-posterior and medio-lateral directions. Visual feedback on the center of pressure (COP) coordinate was provided and then turned off. During quiet stance trials, the subjects matched the initial COP coordinate with a target shifted by 3 cm anterior, posterior, left, or right from the coordinate during natural standing and activated the right tibialis anterior to 30% of its maximal voluntary contraction. During cyclical voluntary sway task, the nominal sway amplitude was always 4 cm while the midpoint was at one of the four mentioned locations. Removing visual feedback caused COP drifts during quiet stance trials that ...

Research paper thumbnail of Reliability of ultrasound measurement of automatic activity of the abdominal muscle in participants with and without chronic low back pain

Chiropractic & Manual Therapies, 2013

Background: Ultrasound (US) imaging has been considered as a non-invasive technique to measure th... more Background: Ultrasound (US) imaging has been considered as a non-invasive technique to measure thickness and estimate relative abdominal muscle activity. Although some studies have assessed the reliability of US imaging, no study has assessed the reliability of US measurement of automatic activity of abdominal muscles in positions with different levels of stability in participants with chronic low back pain (cLBP). The purpose of this study was to investigate within-day and between-days reliability of US thickness measurements of automatic activity of the abdominal muscles in asymptomatic participants and within-day reliability in those with cLBP.

Research paper thumbnail of Ultrasound measurement of deep abdominal muscle activity in sitting positions with different stability levels in subjects with and without chronic low back pain

Manual Therapy, 2011

The purpose of this study was to investigate the changes in the thickness of the transversus abdo... more The purpose of this study was to investigate the changes in the thickness of the transversus abdominis (TrA) and internal oblique (IO) muscles in three sitting postures with different levels of stability. The technique of ultrasound imaging was used for individuals with and without chronic low back pain (LBP). A sample of 40 people participated in this study. Subjects were categorised into two groups: with LBP (N ¼ 20) and without LBP (N ¼ 20). Changes in the thickness of tested muscles were normalized under three different sitting postures to actual muscle thickness at rest in the supine lying position and were expressed as a percentage of thickness change. The percentage of thickness change in TrA and IO increased as the stability of the sitting position decreased in both groups. However, the percentages of thickness change in all positions were less in subjects with LBP. There was a significant difference in thickness change in TrA when sitting on a gym ball between subjects with and without LBP but no difference was found when sitting on a chair. There was no significant difference in thickness change in IO in all positions between the two groups.

Research paper thumbnail of Reliability of the ultrasound measurements of abdominal muscles activity when activated with and without pelvic floor muscles contraction

Journal of back and musculoskeletal rehabilitation, 2014

Synergistic co-activation of the abdominal and pelvic floor muscles (PFM) has been shown in liter... more Synergistic co-activation of the abdominal and pelvic floor muscles (PFM) has been shown in literature. Some studies have assessed the reliability of ultrasound measures of the abdominal muscles. The aim of this study was to determine the reliability of ultrasound measurements of transverses abdominis (TrA) and obliquus internus (OI) muscles during different conditions (PFM contraction, abdominal hollowing manoeuvre (AHM) with and without PFM contraction) in participants with and without chronic low back pain (LBP). 21 participants (9 with LBP, 12 healthy) participated in the study. The reliability of thickness measurements at rest and during each condition and thickness changes and percentage of this changes at different conditions were assessed. The results showed high reliability of the thickness measurement at rest and during each condition of TrA and OI muscles, moderate to substantial reliability for the thickness change and percentage of thickness change of TrA, and fair to m...

Research paper thumbnail of Gross and fine motor function in fibromyalgia and chronic fatigue syndrome

Journal of Pain Research, 2017

This paper aimed to investigate motor proficiency in fine and gross motor function, with a focus ... more This paper aimed to investigate motor proficiency in fine and gross motor function, with a focus on reaction time (RT) and movement skill, in patients with fibromyalgia (FM) and chronic fatigue syndrome (CFS) compared to healthy controls (HC). A total of 60 individuals (20 CFS, 20 FM, and 20 HC), age 19-49 years, participated in this study. Gross motor function in the lower extremity was assessed using a RT task during gait initiation in response to an auditory trigger. Fine motor function in the upper extremity was measured during a precision task (the Purdue Pegboard test) where the number of pins inserted within 30 s was counted. No significant differences were found between FM and CFS in any parameters. FM and CFS groups had significantly longer RT than HC in the gait initiation (p=0.001, and p=0.004 respectively). In the Purdue Pegboard test, 20% in the FM group, 15% in the CFS groups, and 0% of HC group, scored below the threshold of the accepted performance. However, there were no significant differences between FM, CFS, and HC in this task (p=0.12). Compared to controls, both CFS and FM groups displayed significantly longer RT in the gait initiation task. Generally, FM patients showed the worst results in both tests, although no group differences were found in fine motor control, according to the Purdue Pegboard test.

Research paper thumbnail of Unintentional drifts during quiet stance and voluntary body sway

Experimental brain research, Jan 5, 2017

We explored unintentional drifts in voluntary whole-body sway tasks following the removal of visu... more We explored unintentional drifts in voluntary whole-body sway tasks following the removal of visual feedback. The main hypothesis was that the unintentional drifts were produced by drifts of referent coordinates for salient performance variables. Young healthy subjects stood quietly on a force platform and also performed voluntary body sway at 0.5 Hz both in the anterio-posterior and medio-lateral directions. Visual feedback on the center of pressure (COP) coordinate was provided and then turned off. During quiet stance trials, the subjects matched the initial COP coordinate with a target shifted by 3 cm anterior, posterior, left, or right from the coordinate during natural standing and activated the right tibialis anterior to 30% of its maximal voluntary contraction. During cyclical voluntary sway task, the nominal sway amplitude was always 4 cm while the midpoint was at one of the four mentioned locations. Removing visual feedback caused COP drifts during quiet stance trials that ...

Research paper thumbnail of Reliability of ultrasound measurement of automatic activity of the abdominal muscle in participants with and without chronic low back pain

Chiropractic & Manual Therapies, 2013

Background: Ultrasound (US) imaging has been considered as a non-invasive technique to measure th... more Background: Ultrasound (US) imaging has been considered as a non-invasive technique to measure thickness and estimate relative abdominal muscle activity. Although some studies have assessed the reliability of US imaging, no study has assessed the reliability of US measurement of automatic activity of abdominal muscles in positions with different levels of stability in participants with chronic low back pain (cLBP). The purpose of this study was to investigate within-day and between-days reliability of US thickness measurements of automatic activity of the abdominal muscles in asymptomatic participants and within-day reliability in those with cLBP.

Research paper thumbnail of Ultrasound measurement of deep abdominal muscle activity in sitting positions with different stability levels in subjects with and without chronic low back pain

Manual Therapy, 2011

The purpose of this study was to investigate the changes in the thickness of the transversus abdo... more The purpose of this study was to investigate the changes in the thickness of the transversus abdominis (TrA) and internal oblique (IO) muscles in three sitting postures with different levels of stability. The technique of ultrasound imaging was used for individuals with and without chronic low back pain (LBP). A sample of 40 people participated in this study. Subjects were categorised into two groups: with LBP (N ¼ 20) and without LBP (N ¼ 20). Changes in the thickness of tested muscles were normalized under three different sitting postures to actual muscle thickness at rest in the supine lying position and were expressed as a percentage of thickness change. The percentage of thickness change in TrA and IO increased as the stability of the sitting position decreased in both groups. However, the percentages of thickness change in all positions were less in subjects with LBP. There was a significant difference in thickness change in TrA when sitting on a gym ball between subjects with and without LBP but no difference was found when sitting on a chair. There was no significant difference in thickness change in IO in all positions between the two groups.

Research paper thumbnail of Reliability of the ultrasound measurements of abdominal muscles activity when activated with and without pelvic floor muscles contraction

Journal of back and musculoskeletal rehabilitation, 2014

Synergistic co-activation of the abdominal and pelvic floor muscles (PFM) has been shown in liter... more Synergistic co-activation of the abdominal and pelvic floor muscles (PFM) has been shown in literature. Some studies have assessed the reliability of ultrasound measures of the abdominal muscles. The aim of this study was to determine the reliability of ultrasound measurements of transverses abdominis (TrA) and obliquus internus (OI) muscles during different conditions (PFM contraction, abdominal hollowing manoeuvre (AHM) with and without PFM contraction) in participants with and without chronic low back pain (LBP). 21 participants (9 with LBP, 12 healthy) participated in the study. The reliability of thickness measurements at rest and during each condition and thickness changes and percentage of this changes at different conditions were assessed. The results showed high reliability of the thickness measurement at rest and during each condition of TrA and OI muscles, moderate to substantial reliability for the thickness change and percentage of thickness change of TrA, and fair to m...

Research paper thumbnail of Gross and fine motor function in fibromyalgia and chronic fatigue syndrome

Journal of Pain Research, 2017

This paper aimed to investigate motor proficiency in fine and gross motor function, with a focus ... more This paper aimed to investigate motor proficiency in fine and gross motor function, with a focus on reaction time (RT) and movement skill, in patients with fibromyalgia (FM) and chronic fatigue syndrome (CFS) compared to healthy controls (HC). A total of 60 individuals (20 CFS, 20 FM, and 20 HC), age 19-49 years, participated in this study. Gross motor function in the lower extremity was assessed using a RT task during gait initiation in response to an auditory trigger. Fine motor function in the upper extremity was measured during a precision task (the Purdue Pegboard test) where the number of pins inserted within 30 s was counted. No significant differences were found between FM and CFS in any parameters. FM and CFS groups had significantly longer RT than HC in the gait initiation (p=0.001, and p=0.004 respectively). In the Purdue Pegboard test, 20% in the FM group, 15% in the CFS groups, and 0% of HC group, scored below the threshold of the accepted performance. However, there were no significant differences between FM, CFS, and HC in this task (p=0.12). Compared to controls, both CFS and FM groups displayed significantly longer RT in the gait initiation task. Generally, FM patients showed the worst results in both tests, although no group differences were found in fine motor control, according to the Purdue Pegboard test.