[Systematic review article of Berlin Bedrest studies about prolonged bedrest effects on lower limb musculoskeletal system]

Many studies have been carried out about bedrest and its effects on different systems including musculoskeletal,neuromuscular,cognition and vascular systems throughout the world.The purpose of this paper is to review systematically all Berlin Bedrest Studies on musculoskeletal system.The focus of this review is mainly Second Berlin Bedrest Study [2[nd] BBRS] supported by European Space Agency[ESA].Such studies provide a chance to study the specific effects of immobilization without interference of other diseases. A literature search was carried out using MEDLINE and ESA database to assess existing literature about the effect of bedrest on musculoskeletal system published by Berlin Bedrest Studies.It has been searched for efficacy of interventions as high load resistive exercise and whole body vibration,as well. Fourty six articles have been found from 2000 to 2011year: 2 articles in 2000 and 2003,the other ones between 2005 to 2011. Seventeen articles were related to muscle and intervention on it,three ones about bone and related intervention on it,four ones related to both bone and muscle and twenty two ones about the other systems such as heart,vesseles,sleep and cognition. According to study results,bedrest has widespread effects on musculoskeletal system specially in early bedrest. These effects remain up to 180 days after bedrest course.Thus,high load resistive exercise and vibration should be prescribed in early stage of bedrest to reduce the detrimential effects of prolonged bedrest

effect of lifting on trunk muscles motor control in athlete and non-athlete subjects

Spinal injury especially during occupational lifting is one of the most common neuromuscular disorders in the general population of the world. Asymmetric motions of trunk frequent bending and twisting, lifting and forceful activities contribute to spine disorders. Sport as a comprehensive activity might be able to cause less force to the spine and decrease spinal injuries. The purpose of present study was to determine the effect of lifting on motor control pattern during combined symmetric and asymmetric trunk motions on athlete and non-athlete subjects. Seventeen non-athlete female subjects and seventeen athlete female subjects performed to lift four loads [5,7,9, 12 kilogram] at symmetric and asymmetric conditions. Under each condition temporal parameters of motor control were measured on flexor and extensor of trunk muscles. In two groups of athletes and non-athletes with increasing load, muscles begin their activity faster [P<0.05]. No significant change was found at asymmetric condition. Also, in athletes premotor time of muscles during lifting was less than non-athletes. With increasing load, according to the feed forward control mechanism and awareness of subjects from amount of loads, muscles quickly prepared to contract for starting the movement. It seems that the response of movement on the neuromotor system of athletes is preprogrammed and automatic due to sport experience. Actually muscles have anticipation activity

Theoretical study of possible solutions for addressing the kinetic redundancy in lumbar spine by central nervous system

This is mainly achieved by the way that central nervous system [CNS] uses the redundancy in musculoskeletal system. The kinetic redundancy in human musculoskeletal systems is a significant property by which central nervous system achieves many complementary goals. In this study, by explaining the definition and role of uncontrolled manifold for movement kinematics, the kinetic redundancy concept is explored in mathematical terms. The null space of the kinetically redundant system when certain joint moment and/or stiffness are needed is derived and discussed. In this paper, the mathematical methods have been developed for a simpler planar biomechanical model with 3 muscles in which the explained concepts have been utilized

Co-activation of muscles in biomechanical modeling

Muscles co-activation is a significant concept often used in the studies of spine and knee joint biomechanics and rehabilitation. Researchers and clinicians use this measure to design rehabilitation strategies and/or evaluate clinical interventions. In this paper, biomechanical and physiological consequences of co-activation of muscles are discussed succinctly using a number of illustrative examples. The paper shall further demonstrate the need for more cooperation and interaction between clinicians and biomechanical engineers for development of better biomechanical models, assisting the development of new experimental designs and more precise methods of evaluating neuromuscular performance during functional tasks

Inter tester and intra tester reliability of eight sacroiliac joint static and dynamic and three pain provocation tests

The purpose of this study was to determine the inter tester and intra tester reliability of 5 static and 3 dynamic palpation tests, and three pain provocation tests used to diagnose sacroiliac joint dysfunction. Five static palpation tests, namely palpation and assessment of the levels of the 1] posterior superior iliac spine [PSIS] in standing position, 2] PSIS in sitting position, 3] anterior superior iliac spine [ASIS] in standing position, 4] Medial Maleolus [MM] in supine position, and 5] MM in long sitting position, and three dynamic [motion palpation] tests, 1] the Gillet test, 2] the standing flexion test, and 3] the sitting flexion test were performed on ten asymptomatic subjects by four examiners. Each test was performed four times by each examiner resulting in 1280 assessments in total. Pain provocation tests were posterior pelvic pain provocation test [PPPPT] or posterior shear test, patric test, and hip resisted abduction test. The Study included twenty women with chronic low back pain, aged between 20 to 30 years. Each of pain provocation tests were performed two times by two examiners. Reliability was determined using Kappa Statistic which allows assessment of observer agreement for more than two examiners and multiple examiners. Intra examiner agreement of static palpation tests revealed a range of reliability from slight to good. Kappa coefficient yielded intra examiner agreement that ranged between slight to good for the PSIS in standing position [0.18-0.75], slight to moderate for the ASIS [0.15-0.5], and slight to fair [0.1-0.35] for other static and all motion palpation tests. Inter examiner reliability of all the static and dynamic tests did not exceed slight reliability [0.0-0.2]. Kappa value for intertester reliability of posterior shear test, patric test, and hip resisted abduction test for right limb was 0.7, 0.7, and 0.6, and for left one was 0.7, 0.78, 0.34, respectively, and the mean value of kappa for intratester reliability was between 0.75 and 0.91. The results of this study suggest that the reliability of palpation and assessment of the levels of the PSIS, ASIS, and MM in static positions, and the gillet, standing flexion, and sitting flexion tests as indicators of sacroiliac joint dysfunction still remain questionable. Therapists should reconsider the usefulness of evaluation techniques that rely on the assessment of the anatomical symmetry of bony landmarks of the innominates in static and dynamic conditions. About pain provocation tests, the results showed that posterior shear and hip resisted abduction tests are reliable tests to diagnose the pathology in the sacroiliac joints. The reliability of patric test that commonly used to determine the sacroiliac joints pathologies is in under question