Search results for "body regions"
showing 10 items of 693 documents
Changes of electrically elicited reflexes in hand and forearm muscles in man.
1987
Cutaneo-muscular reflexes with short and long latency excitatory phases following digital nerve stimulation were observed in the first dorsal interosseus muscle of the hand in healthy subjects. The short latency reflex was obtained also with the H-reflex method in the flexor carpi radialis muscle, stimulating the median nerve, with a mean latency (+/- SE) of 15.4 +/- 0.5 ms. The height of the subject correlated with the H-reflex latency. The amplitudes of maximal M-response and maximal H-reflex were higher in athletes than in normals. During weak voluntary contraction of the muscle studied the 50% H-reflex amplitude increased and during passive stretching of wrist flexors the resting amplit…
Foot Strike Pattern, Step Rate, and Trunk Posture Combined Gait Modifications to Reduce Impact Loading during Running
2019
Elevated impact loading can be detrimental to runners as it has been linked to the increased risk of tibial stress fracture and plantar fasciitis. The objective of this study was to investigate the combined effects of foot strike pattern, step rate, and anterior trunk lean gait modifications on impact loading in runners. Nineteen healthy runners performed 12 separate gait modification trials involving: three foot strike patterns (rearfoot, midfoot, and forefoot strike), two step rates (natural and 10% increased), and two anterior trunk lean postures (natural and 10-degree increased flexion). Overall, forefoot strike combined with increased step rate led to the lowest impact loading rates, a…
Cytochrome P450 regulation by hepatocyte nuclear factor 4 in human hepatocytes: A study using adenovirus-mediated antisense targeting
2001
Abstract Hepatocyte nuclear factor 4 (HNF4) is a member of the nuclear receptor super-family that has shown activating effects on particular cytochrome P450 (CYP) promoters from several species. However, its role in the regulation of human CYPs in the liver is still poorly understood, as no comprehensive studies in human-relevant models have been performed. In the present study, we have investigated whether HNF4 plays a general role in the expression of 7 major CYP genes in primary cultured human hepatocytes. To this end, we developed an adenoviral vector for efficient expression of HNF4 antisense RNA. Transduction of human hepatocytes with the recombinant adenovirus resulted in a time-depe…
Evidence of a preprogrammed deactivation of the hamstring muscles for triggering rapid changes of posture in humans
1997
Normal subjects were asked to make rapid flexions of the legs from a stationary initial standing posture in a self-paced mode. Because this movement implicates a rapid change in posture, questions were asked about the type of central command which must include the rupture of the erect posture and the accomplishment of the goal directed movement. Movements of the different segments of the body were recorded and analyzed using the optoelectronic ELITE system. Electromyographic (EMG) activities of 8 muscles of the lower limb on one side were recorded, rectified and integrated. The time relationships of the different EMG signals (activation or deactivation) were analyzed with respect to selecte…
Ketorolac, diclofenac, and ketoprofen are equally safe for pain relief after major surgery
2002
Background Ketorolac is approved for the relief of postoperative pain but concerns have been raised over a possible risk of serious adverse effects and death. Two regulatory reviews in Europe on the safety of ketorolac found the data were inconclusive and lacked comparison with other non-steroidal anti-inflammatory drugs. The aim of this study was to compare the risk of serious adverse effects with ketorolac vs diclofenac or ketoprofen in adult patients after elective major surgery. Methods This prospective, randomized multicentre trial evaluated the risks of death, increased surgical site bleeding, gastrointestinal bleeding, acute renal failure, and allergic reactions, with ketorolac vs di…
Electromechanical behaviour of human muscles in vertical jumps
1982
The relationships of muscle structure to the potentiation of myoelectrical activity and to the use of prestretching in five lower limb muscles were studied in different vertical jumping conditions. The subjects for the study were six male students, divided according to the muscle fiber distribution in m. vastus lateralis into “fast” and “slow” groups. The subjects performed vertical jumps (1) from a static squatting position (SJ), (2) with a preliminary counter movement (CMJ) and (3) after dropping (DJ) from five different heights. Myoelectrical (EMG) activity was recorded from mm. gluteus maximus, vastus lateralis, vastus medialis, rectus femoris and gastrocnemius in each jumping condition…
Reorganization of cortical motor area in prior polio patients
1999
Focal transcranial magnetic stimulation (TMS) was used to study the motor maps of upper limb muscles in 7 adult patients with a history of paralytic poliomyelitis. The aim of the study was to verify the potential for long-term cortical reorganization of a selective peripheral motor neuron lesion suffered early in life.Patient selection was based on the prevalent involvement of proximal muscles in only one of the upper limbs. Motor evoked potentials (MEPs) were recorded from deltoid and abductor pollicis brevis (APB) muscles. Each muscle map was characterized by area (no. of excitable positions), volume (the sum of MEP amplitudes at all scalp positions), maximal amplitude (the highest MEP re…
Immediate effects of active cranio-cervical flexion exercise versus passive mobilisation of the upper cervical spine on pain and performance on the c…
2014
This study compared the immediate effects of an assisted plus active cranio-cervical flexion exercise (exercise group) versus a passive mobilisation plus assisted cranio-cervical flexion (mobilisation group) on performance of the cranio-cervical flexion test (CCFT), cervical range of motion (ROM) and pain in patients with chronic neck pain. Eighteen volunteers with chronic idiopathic neck pain participated in the study and were randomised to one of the two intervention groups. Current level of pain, cervical ROM and pain perceived during movement, pressure pain threshold (PPT) and surface electromyography (EMG) during performance of the CCFT were measured before and immediately after the in…
Contribution of the tendinous tissue to force enhancement during stretch–shortening cycle exercise depends on the prestretch and concentric phase int…
2005
When the prestretch intensity and concentric work are increased in stretch-shortening cycle (SSC) exercises, the utilization of the elastic energy can increase during the concentric phase. In order to further understand this process during SSC exercises, the interaction between fascicle-tendinous tissues (TT) of the vastus lateralis (VL) muscle was examined under different prestretch and rebound intensity drop jumps. Ten male subjects participated in the study. Direct VL fascicle lengths (N = 10) and in vivo patellar tendon force (N = 1) were measured together with the electromyographic (EMG) activity of VL during the trials. With increasing drop height but the same rebound height condition…
Effect of innervation zones in estimating biceps brachii force-EMG relationship during isometric contraction
2012
Measuring muscle forces in vivo is invasive and consequently indirect methods e.g., electromyography (EMG) are used in estimating muscular force production. The aim of the present paper was to examine what kind of effect the disruption of the physiological signal caused by the innervation zone has in predicting the force/torque output from surface EMG. Twelve men (age 26 (SD ±3)years; height 179 (±6)cm; body mass 73 (±6)kg) volunteered as subjects. They were asked to perform maximal voluntary isometric contraction (MVC) in elbow flexion, and submaximal contractions at 10%, 20%, 30%, 40%, 50% and 75% of the recorded MVC. EMG was measured from biceps brachii muscle with an electrode grid of 5…