Documents muscle testing 19 results

"PURPOSE:
Anterior cruciate ligament (ACL) injuries often occur in women during cutting maneuvers to evade a defensive player. Gender differences in knee kinematics have been observed, but it is not known to what extent these are linked to abnormal neuromuscular control elsewhere in the kinetic chain. Responses to defense players, which may be gender-dependent, have not been included in previous studies. This study determined the effects of gender and defense player on entire lower extremity biomechanics during sidestepping.
METHODS:
Eight male and eight female subjects performed sidestep cuts with and without a static defensive opponent while 3D motion and ground reaction force data were recorded. Peak values of eight selected motion and force variables were, as well as their between-trial variabilities, submitted to a two-way (defense x gender) ANOVA. A Bonferroni-corrected alpha level of 0.003 denoted statistical significance.
RESULTS:
Females had less hip and knee flexion, hip and knee internal rotation, and hip abduction. Females had higher knee valgus and foot pronation angles, and increased variability in knee valgus and internal rotation. Increased medial ground reaction forces and flexion and abduction in the hip and knee occurred with the defensive player for both genders.
CONCLUSIONS:
A simulated defense player causes increased lower limb movements and forces, and should be a useful addition to laboratory protocols for sidestepping. Gender differences in the joint kinematics suggest that increased knee valgus may contribute to ACL injury risk in women, and that the hip and ankle may play an important role in controlling knee valgus during sidestepping. Consideration of the entire lower extremity contributes to an understanding of injury mechanisms and may lead to better training programs for injury prevention."

"This study evaluated screwdrivers with different handle designs and blade lengths. 10 men and 10 women voluntarily participated. A repeated-measures experiment design was employed. The three independent factors were sex of user, handle (four types), and blade length (130, 170, and 210 mm). The dependent measures were the maximum supination torque under a static task and the %MVC of EMG responses in biceps brachii and flexor digitorum, and a discomfort rating for the upper extremity under the dynamic task. Analysis showed that the in-line screwdriver with the combined characteristics of large handle diameter (3.8-4.1 cm), smooth rubber covering handle surface, triangular (or circular) shape, and adequate handle length (11 cm) had the greatest supination torque and a smaller discomfort rating than the screwdriver with the pistol-grip handle. Blade length was not significantly related to any dependent measure."

"The task of wall painting produces considerable risk to the workers, both male and female, primarily in the development of upper extremity musculoskeletal disorders. Insufficient information is currently available regarding the potential benefits of using different paint roller designs or the possible adverse effects of painting at different work heights. The aim of this study was to investigate the influence of gender, work height, and paint tool design on shoulder muscle activity and exerted forces during wall painting. Ten young adults, five male and five female, were recruited to perform simulated wall painting at three different work heights with three different paint roller designs while upper extremity muscle activity and horizontal push force were recorded. Results demonstrated that for female participants, significantly greater total average (p = 0.007) and integrated (p = 0.047) muscle activity was present while using the conventional and curly flex paint roller designs compared to the proposed design in which the load was distributed between both hands. Additionally, for both genders, the high working height imposed greater muscular demands compared to middle and low heights. These findings suggest that, if possible, avoid painting at extreme heights (low or high) and that for female painters, consider a roller that requires the use of two hands; this will reduce fatigue onset and subsequently mitigate potential musculoskeletal shoulder injury risks."

"Battery powered bed movers are becoming increasingly common within the hospital setting. The use of powered bed movers is believed to result in reduced physical efforts required by health care workers, which may be associated with a decreased risk of occupation related injuries. However, little work has been conducted assessing how powered bed movers impact on levels of physiological strain and muscle activation for the user. The muscular efforts associated with moving hospital beds using three different methods; powered StaminaLift Bed Mover (PBM1), powered Gzunda Bed Mover (PBM2) and manual pushing were measured on six male subjects. Fourteen muscles were assessed moving a weighted hospital bed along a standardized route in an Australian hospital environment. Trunk inclination and upper spine acceleration were also quantified. Powered bed movers exhibited significantly lower muscle activation levels than manual pushing for the majority of muscles. When using the PBM1, users adopted a more upright posture which was maintained while performing different tasks (e.g. turning a corner, entering a lift), while trunk inclination varied considerably for manual pushing and the PBM2. The reduction in lower back muscular activation levels may result in lower incidence of lower back injury."

"This article presents a comparative analysis of easy-to-use methods for assessing musculoskeletal load and the risk for developing musculoskeletal disorders. In all such methods, assessment of load consists in defining input data, the procedure and the system of assessment. This article shows what assessment steps the methods have in common; it also shows how those methods differ in each step. In addition, the methods are grouped according to their characteristic features. The conclusion is that the concepts of assessing risk in different methods can be used to develop solutions leading to a comprehensive method appropriate for all work tasks and all parts of the body. However, studies are necessary to verify the accepted premises and to introduce some standardization that would make consolidation possible."

"ObjectivesWe aimed to investigate the relationship of task variation during dental work history with pinch grip strength among dentists.MethodsWe measured pinch grip strength among 295 female Finnish dentists aged 45–63 years. Variation in dental work tasks during work history was empirically defined by cluster analysis. Three clusters of task variation emerged: low (most work time in restoration treatment/endodontics), moderate (about 50% in the former and 50% in prosthodontics/periodontics/surgery), and high (variable tasks including administrative duties). Hand radiographs were examined for the presence of OA in the wrist and each joint of the 1–3rd fingers. Information on hand-loading leisure-time activities, and joint pain was obtained by questionnaire. Glove size was used as a proxy for hand size. BMI (kg/m2) was based on measured weight and self-reported height.ResultsDentists with low variation of work task history had an increased risk of low pinch grip strength in the right hand (OR 2.3, 95% CI 1.2–4.3), but not in the left (1.13, 0.62–2.08), compared to dentists with high task variation, independent of age, hand size, hand-loading leisure-time activities, BMI and symptomatic hand OA.ConclusionThe dentists with the most hand-loading tasks were at an increased risk of low pinch grip strength, independent of e.g. symptomatic hand OA. It is advisable among dentists to perform as diverse work tasks as possible to reduce the risk of decreased pinch grip strength."

"Non-neutral wrist posture is a risk factor of the musculoskeletal disorders among computer users. This study aimed to assess internal loads on hand and forearm musculature while tapping in different wrist postures. Ten healthy subjects tapped on a key switch using their index finger in four wrist postures: straight, ulnar deviated, flexed and extended. Torque at the finger and wrist joints were calculated from measured joint postures and fingertip force. Muscle stresses of the six finger muscles and four wrist muscles that balanced the calculated joint torques were estimated using a musculoskeletal model and optimization algorithm minimizing the squared sum of muscle stress. Non-neutral wrist postures resulted in greater muscle stresses than the neutral (straight) wrist posture, and the stress in the extensor muscles were greater than the flexors in all conditions. Wrist extensors stress remained higher than 4.5 N/cm² and wrist flexor stress remained below 0.5 N/cm² during tapping. The sustained high motor unit recruitment of extensors suggests a greater risk than other muscles especially in flexed wrist posture. This study demonstrated from the perspective of internal tissue loading the importance of maintaining neutral wrist posture during keying activities."

"There is a lack of pragmatic methods to assess musculoskeletal load risks when planning for production when there is no human operator to observe that performs the tasks. Existing methods are generally either expensive computer manikin software that is complicated to learn and use, simple digital human models for static and episodic analysis best used by trained ergonomists or methods in need of full-scale prototypes for observation.

The suggested method in this report is intended to be used by production engineers who are interested in ergonomics and involved in pre-production planning. The ideal situation is when there is room for changes in both product and workplace design, the ambition exists to achieve high productivity and the insight exists that this is best accomplished when the designs are optimized over both production time and operator load.

A concept of a complete tool is sketched, incorporating a simple CAD tool for workplace design, a language to describe the intended tasks to be carried out and a knowledge based system for prompting the operator for needed input data and for analysis of the expected musculoskeletal load. ..."

(From the author's abstract)

"The aim of this systematic review was to survey methods to assess the functional capacity of the musculoskeletal system within the context of work, daily activities, and sport. The following key words and synonyms were used: functional physical assessment, healthy/disabled subjects, and instruments. After applying the inclusion criteria on 697 potential studies and a methodological quality appraisal, 34 studies were included. A level of reliability > 0.80 and of > 0.60 resp 0.75 and 0.90, dependent of type of validity, was considered high. Four questionnaires (the Oswestry Disability Index, the Pain Disability Index, the Roland–Morris Disability Questionnaire, and the Upper Extremity Functional Scale) have high levels on both validity and reliability. None of the functional tests had a high level of both reliability and validity. A combination of a questionnaire and a functional test would seem to be the best instrument to assess functional capacity of the musculoskeletal system, but need further examined."(Authors' abstract)

"The aim of the study was to establish insight into work exposures that cause shoulder and neck pain among occupational groups that have low biomechanical exposure and experience work stress from client/customer contact, among other exposures. Four occupational groups were studied, in health care (n = 20), retail (n = 22), banking (n = 26), and university secretaries (n = 26), a total of 94 volunteers. Thirty-nine were classified as pain-afflicted in the shoulder and neck, while 55 were pain-free. The subjects' perceptions of biomechanical and psychosocial exposures were established by use of quantitative questionnaires and by explorative interviews with open-ended questions, covering the same themes. Heart rate and trapezius EMG were recorded over a full workday and the following leisure period. Trapezius median and static activity during work were 3.3% and 0.3% EMGmax, only marginally higher than trapezius activity in the leisure period (2.7% and 0.2% EMGmax). The quantitative questionnaire did not identify any variable that correlated with shoulder and neck pain except perceived general tension. The interviews established that the interaction with clients or customers was an important source of work stress. Such stress appeared to be a complex entity not easily characterized by established psychosocial questionnaires. The physiological variables were at most weakly elevated in periods with high stress as compared to periods with low stress. The authors caution against relying on standardized quantitative questionnaires and/or physiological recordings to characterize work stress in occupations with emotional stress through client/customer service work. "