Try a new search

Format these results:

Searched for:

person:as54

Total Results:

32


Perioperating nurses and technicians' perceptions of ergonomic risk factors in the surgical environment

Sheikhzadeh, Ali; Gore, Chaitrali; Zuckerman, Joseph D; Nordin, Margareta
The aim of this study was to identify the magnitude and characteristics of work-related musculoskeletal complaints among perioperative nurses and technicians (PNT) and determine the associated ergonomic risk factors in the operating room (OR) environment based on self-report and focus group discussion. The 50 PNTs who participated in the study completed a self-report survey for musculoskeletal symptoms, Job Description Questionnaire, and Psychometric Evaluation Questionnaire, and participated in focus groups to discuss potential OR ergonomic risk factors. The results of the study demonstrated a high prevalence of work-related musculoskeletal disorders (WMSD) among PNTs, with lower back pain the most prevalent (84%) complaint, followed by ankle/foot (74%) and shoulder (74%) pain. In addition, lower back pain (31%), followed by ankle/knee (24%) pain were found to be the main causes of absenteeism from work. Participants suggested simple ergonomic and engineering solutions can be adopted to improve the work environment of PNTs
PMID: 19027099
ISSN: 1872-9126
CID: 93939

Peak biomechanical variables during bilateral drop landings: comparisons between sex (female/male) and fatigue (pre-fatigue/post-fatigue)

Pappas, Evangelos; Hagins, Marshall; Sheikhzadeh, Ali; Nordin, Margareta; Rose, Donald
BACKGROUND: Although anterior cruciate ligament (ACL) sprains usually occur during the initial phase of the landing cycle (less than 40 degrees knee flexion), the literature has focused on peak values of knee angles, vertical ground reaction force (VGRF), and muscle activity even though it is unclear what occurs during the initial phase of landing. OBJECTIVES: The objectives of this study were to determine the effects of sex (male and female) and fatigue (prefatigue/post-fatigue) on knee flexion angles at the occurrence of peak values of biomechanical variables [knee valgus angle, VGRF, and normalized electromyographic amplitude (NEMG) of the quadriceps and hamstring muscles] during a bilateral drop landing task. METHODS: Knee valgus angle, VGRF, and NEMG of the quadricep and hamstring muscles were collected during bilateral drop landings for twenty-nine recreational athletes before and after a fatigue protocol. RESULTS: Peak values of knee valgus, VGRF, and NEMG of medial and lateral hamstring muscles occurred during the late phase of the landing cycle (>40 degrees of knee flexion). Females in the post-fatigue condition exhibited peak VGRF at significantly less knee flexion than in the pre-fatigue condition. Males in the post-fatigue condition exhibited peak lateral hamstring muscles NEMG at significantly higher knee flexion than in the pre-fatigue condition. DISCUSSION AND CONCLUSION: Peak values of biomechanical variables that have been previously linked to ACL injury did not occur during the initial phase of landing when ACL injuries occur. No biomechanical variables peaked during the initial phase of landing; therefore, peak values may not be an optimal indicator of the biomechanical factors leading to ACL injury during landing tasks.
PMCID:2953325
PMID: 21509113
ISSN: 1558-6162
CID: 730142

Three-dimensional motion of the scapula and shoulder during activities of daily living

Sheikhzadeh, Ali; Yoon, Jangwhon; Pinto, Vivek J; Kwon, Young W
The purpose of this study was to describe 3-dimensional scapular motion during the activities of daily living (ADL) and the full range of arm motion, and to suggest a standardized method for evaluating scapular mobility. Eight healthy subjects between the ages of 25-40, with no prior history of shoulder pathology or surgery for the past 12 months, were recruited for this study. Touching 8 predetermined landmarks on the head and the trunk was used to simulate ADL. Touching the contralateral ear and contralateral shoulder resulted in the maximum scapular protraction 46 degrees (8 degrees) and 48 degrees (8 degrees), respectively, and the maximum degrees of the scapular anterior tilt, -11 degrees (4 degrees) and -11 degrees (5 degrees), respectively. Asking patients to reach to the back of the neck, and the contralateral shoulder, the clinician can evaluate the overall scapular mobility in all directions. A protocol controlling the performance variability during ADL tasks was suggested to improve the clinical evaluation of the shoulder joint complex. Findings of this study can guide clinicians to identify specific tasks which may relate to particular shoulder girdle dysfunction
PMID: 18774735
ISSN: 1532-6500
CID: 93940

Capability and recruitment patterns of trunk during isometric uniaxial and biaxial upright exertion

Sheikhzadeh, Ali; Parnianpour, Mohamad; Nordin, Margareta
BACKGROUND: Work-related risk factors of low back disorders have been identified to be external moments, awkward postures, and asymmetrical dynamic lifting amongst others. The distinct role of asymmetry of load versus posture is hard to discern from the literature. Hence, the aim of this study is to measure isometric trunk exertions at upright standing posture at different exertion level and degree of asymmetry to further delineate the effects of exertion level and asymmetry on neuromuscular capability response. METHODS: Fifteen healthy volunteers randomly performed trunk exertions at three levels (30%, 60%, and 100% of maximum voluntary exertion and five different angles (0 degrees , 45 degrees , 90 degrees , 135 degrees , and 180 degrees ) of normalized resultant moments. During each trial, the normalized EMG activity of 10 selected trunk muscles was quantified. FINDINGS: The EMG activity of the 10 trunk muscles was significantly (P<0.001) affected by the level of exertion and angle of normalized resultant moment, and their interactions. The controllability of the torque generation was reduced in biaxial exertions. The capability to generate and control the required trunk moments is significantly lowered during biaxial trunk exertions, while all muscles present higher EMG activity. These results suggest that the trunk muscles will be taxed higher while performing biaxial exertion tasks, increasing muscle fatigue possibly leading to a higher probability of low back injury. INTERPRETATION: The prediction of biaxial trunk performance based on uniaxial data will result in an overestimation of capability and controllability of the trunk during physically demanding tasks. This study provides a better understanding of the potential mechanisms of injury during asymmetrical and biaxial trunk exertion during work-related tasks
PMID: 18207293
ISSN: 0268-0033
CID: 76351

Effects of aging on Type II muscle fibers: a systematic review of the literature

Brunner, Florian; Schmid, Annina; Sheikhzadeh, Ali; Nordin, Margareta; Yoon, Jangwhon; Frankel, Victor
The authors conducted a systematic review of the literature for scientific articles in selected databases to determine the effects of aging on Type II muscle fibers in human skeletal muscles. They found that aging of Type II muscle fibers is primarily associated with a loss of fibers and a decrease in fiber size. Morphological changes with increasing age particularly included Type II fiber grouping. There is conflicting evidence regarding the change of proportion of Type II fibers. Type II muscle fibers seem to play an important role in the aging process of human skeletal muscles. According to this literature review, loss of fibers, decrease in size, and fiber-type grouping represent major quantitative changes. Because the process of aging involves various complex phenomena such as fiber-type coexpression, however, it seems difficult to assign those changes solely to a specific fiber type
PMID: 17724398
ISSN: 1063-8652
CID: 76352

Biomechanical differences between unilateral and bilateral landings from a jump: gender differences

Pappas, Evangelos; Hagins, Marshall; Sheikhzadeh, Ali; Nordin, Margareta; Rose, Donald
OBJECTIVE: To determine the effect of landing type (unilateral vs. bilateral) and gender on the biomechanics of drop landings in recreational athletes. DESIGN: This study used a repeated measures design to compare bilateral and unilateral landings in male and female athletes. A repeated measures multivariate analysis of variance (type of landing*gender) was performed on select variables. SETTING: Biomechanics laboratory. PARTICIPANTS: Sixteen female and 16 male recreational athletes. MAIN OUTCOME MEASURES: Kinetic, kinematic, and electromyographic (EMG) data were collected on participants while performing bilateral and unilateral landings from a 40-cm platform. RESULTS: Compared to bilateral landings, subjects performed unilateral landings with increased knee valgus, decreased knee flexion at initial contact, decreased peak knee flexion, decreased relative hip adduction, and increased normalized EMG of the rectus femoris, medial hamstrings, lateral hamstrings, and medial gastrocnemius (P < 0.005). During both types of landing, females landed with increased knee valgus and normalized vertical ground reaction force (VGRF) compared to males (P < 0.009), however, the interaction of landing type*gender was not significant (P = 0.29). CONCLUSIONS: Compared to bilateral landings, male and female recreational athletes performed unilateral landings with significant differences in knee kinematic and EMG variables. Female athletes landed with increased knee valgus and VGRF compared to males during both types of landing
PMID: 17620779
ISSN: 1050-642x
CID: 76353

Biomechanics of the hip and the knee

Chapter by: Sheikhzadeh A
in: Musculoskeletal disorders in the workplace : principles and practice by Nordin M; Pope MH; Andersson G [Eds]
Philadelphia PA : Mosby Elsevier, 2007
pp. 273-287
ISBN: 0323026222
CID: 5133

The effect of gender and fatigue on the biomechanics of bilateral landings from a jump: peak values

Pappas, Evangelos; Sheikhzadeh, Ali; Hagins, Marshall; Nordin, Margareta
Female athletes are substantially more susceptible than males to suffer acute non-contact anterior cruciate ligament injury. A limited number of studies have identified possible biomechanical risk factors that differ between genders. The effect of fatigue on the biomechanics of landing has also been inadequately investigated. The objective of the study was to examine the effect of gender and fatigue on peak values of biomechanical variables during landing from a jump. Thirty-two recreational athletes performed bilateral drop jump landings from a 40 cm platform. Kinetic, kinematic and electromyographic data were collected before and after a functional fatigue protocol. Females landed with 9 degrees greater peak knee valgus (p = 0.001) and 140% greater maximum vertical ground reaction forces (p = 0.003) normalized to body weight compared to males. Fatigue increased peak foot abduction by 1.7 degrees (p = 0.042), peak rectus femoris activity by 27% (p = 0.018), and peak vertical ground reaction force (p = 0.038) by 20%. The results of the study suggest that landing with increased peak knee valgus and vertical ground reaction force may contribute to increased risk for knee injury in females. Fatigue caused significant but small changes on some biomechanical variables. Anterior cruciate ligament injury prevention programs should focus on implementing strategies to effectively teach females to control knee valgus and ground reaction force. Key pointsFemale athletes landed with increased knee valgus and VGRF which may predispose them to ACL injury.Fatigue elicited a similar response in male and female athletes.The effectiveness of sports injury prevention programs may improve by focusing on teaching females to land softer and with less knee valgus.
PMCID:3778703
PMID: 24149228
ISSN: 1303-2968
CID: 730162

The effects of breath control on maximum force and IAP during a maximum isometric lifting task

Hagins, Marshall; Pietrek, Markus; Sheikhzadeh, Ali; Nordin, Margareta
BACKGROUND: Evidence exists linking breath control to increases in intra-abdominal pressure and lumbar stability. Weight-lifting experts use this evidence as a rationale to suggest that increases in lumbar stability afforded by specific forms of breath control can influence the amount of force produced by the trunk. No studies have examined this issue. Therefore, this study determined whether voluntary control of the breath is related to maximal trunk extension force and if maximal force is correlated to intra-abdominal pressure. METHODS: Thirteen men and 20 women (mean age: 25.6 years (5.5)) performed a maximal isometric trunk exertion in a knee bent posture using voluntary breath conditions: (1) inhalation prior to exertion with hold during exertion; (2) exhalation prior to exertion with hold during the exertion; (3) inhalation prior to the exertion with exhalation during the exertion. A subset of subjects (n=11) were also simultaneously measured for intra-abdominal pressure. Separate repeated measures ANOVA were used to determine the effects of breath conditions on force and intra-abdominal pressure. Pearson coefficients were used to determine the correlation between force and intra-abdominal pressure. FINDINGS: Breath control did not significantly affect isometric force production (P=.089) but did affect intra-abdominal pressure (P=.003). Correlations between force and intra-abdominal pressure in each breath condition were low (range: 0.152-0.583). INTERPRETATION: Although breath control was shown to influence intra-abdominal pressure, it does not appear to influence isometric trunk extension force in a knees bent position. Further, the intra-abdominal pressure produced in such efforts appears to be unrelated to the amount of force produced
PMID: 16757073
ISSN: 0268-0033
CID: 72170

The potential value of blood biomarkers of intervertebral disk metabolism in the follow-up of patients with sciatica

Balague, Federico; Nordin, Margareta; Schafer, Dominique; Sheikhzadeh, Ali; Lenz, Mary Ellen; Thonar, Eugene M A
STUDY DESIGN: This is a prospective study with a follow-up period of 4 years. OBJECTIVES: The study aimed to evaluate the possible clinical utility of three biomarkers [i.e., keratan sulfate (KS), hyaluronan, and cartilage oligomeric matrix protein] measured in peripheral blood in severe acute sciatica at intake and follow-up. SUMMARY OF BACKGROUND: Our previous study and others have pointed out the interest of different laboratory tests in the acute phase of sciatica. Several blood biomarkers have been reported useful in the long-term follow-up of patients with osteoarthritis. We have found no information about the potential interest of these tests in spinal disorders. METHODS: Patients were admitted to the hospital for intensive conservative management of acute sciatica (n=82). A subgroup of patients (n=33) was selected based on the duration of symptoms at visit 1, and included those with the shortest (n=24) as well as those with the longest (n=9) duration of sciatica. Blood samples were drawn, centrifuged, and the plasma frozen. Antigenic KS, hyaluronan, and cartilage oligomeric matrix protein were measured by ELISA. Patients were re-evaluated at an average of 4.3 years (range: 2.1-6.8 years). RESULTS: Thirty-three subjects with an average age of 49.2+/-10.2 years participated. At intake, levels of the three biomarkers evaluated were within the range of normal values. No significant differences were found between the results of patients with a short history of sciatica (< or =3 weeks) and those with a long duration of symptoms (>20 weeks). At follow-up, a significant increase (P<0.05) in all three biomarkers was found. CONCLUSIONS: A single measurement of these three biomarker molecules does not seem to have any diagnostic or therapeutic relevance in patients with acute radicular compression. The significance of the increase in all three biomarkers after a mean follow-up of 4.3 years is unclear; it might reflect metabolic processes involved in degenerative spinal disorders. Even though we found no correlation with clinical outcome, we believe that more research is needed
PMCID:3489342
PMID: 15990991
ISSN: 0940-6719
CID: 72172