OBJECTIVE: Muscle strength training is one of the most common therapy methods in physical therapy programs, and the usual goal of this treatment is to improve muscle strength. Little attention has been paid, however, to the effects of strength training on the other components of motor performance. This study examined the effects of a 10-week strength training program on the motor performance of the hand, including reaction time, speed of movement, tapping speed, and coordination in normal healthy volunteers. DESIGN: Before-after trial. SUBJECTS AND SETTING: Sixteen healthy women volunteers aged 25 to 45 years participated. INTERVENTION: Subjects accomplished a 10-week muscle strength training program of the upper extremities. MAIN OUTCOME MEASURES: Reaction time, speed of movement, tapping speed, and coordination were measured three times on consecutive days, and muscle strength and electromyographic values of the right upper extremity were recorded once before the training period. After the training period, the same measurements were made as before the training. RESULTS: The 10-week strength training decreased choice reaction time by 6% (p
OBJECTIVE: To determine whether the somatosensory pathways are involved or not in konzo. METHODS: In 1998, 21 konzo subjects (15 females and 6 males; mean age 21 years) underwent a SEP study with a two-channel-equipment (Medtronic Keypoint, Denmark) whereas in 2000, 15 subjects (7 females and 8 males; mean age 21 years) participated in a study with a 4-channel-equipment. RESULTS: Most subjects (19/21 in 1998 and 12/15 in 2000) showed normal median SEPs. The remainders had no median cortical responses. All 21 subjects in 1998 and 9 out of 15 in 2000 showed abnormalities of tibial SEPs mainly consisting of absence of cortical responses, prolonged cortical latencies, and central sensory delay to the lumbar spine. Most subjects showed normal absolute latencies both at peripheral and spinal levels. The SEP findings did not correlate with the severity, neither the duration of konzo, nor the experience or not of sensory symptoms at the onset of the disease. CONCLUSION: Our findings are not specific of konzo. However, they suggest involvement of intracranial somatosensory pathways and point to similarities with other motor neuron diseases.
The aim of the present work was to identify possible associations between individual balances in the activity of the positive and negative reinforcement motivation systems using a method based on emotional modulation of the startle reaction (EMSR) by motivationally significant emotionally positive and negative contextual visual stimuli and measures of cardiovascular system activity. Studies were performed using healthy males (mean age 30.29 +/- 9.8 years) with normal and first-episode excessive increases in arterial blood pressure (systolic blood pressure to greater than 140 mmHg, diastolic to greater than 90 mmHg). Cluster analysis of EMSR data identified groups of individuals with different activity profiles for the positive and negative reinforcement systems. Groups of subjects with changes in the balance of activity towards a lower level of positive reinforcement system activity (smaller startle reflexes to positive contextual stimuli) or a higher level of negative reinforcement system activity (larger startle reactions to threatening contextual stimuli) showed significantly greater baseline SBP and DBP. The possible mechanisms of the modulatory influences of the balance of system activities on autonomic vascular regulatory processes are discussed.
Prolonged occupational standing has previously been associated with low back pain (LBP) development. The immediate effects of a bout of prolonged standing on subsequent functional movement performance have not been investigated. It is possible that including a period of prolonged standing may have acute, detrimental effects. The purpose of the study is to investigate the impact of a prolonged standing exposure on biomechanical profiles (trunk muscle activation, joint stiffness and kinematics) during three functional movements. A total of 23 volunteers without history of LBP performed lumbar flexion, single-leg stance and unloaded squat movements pre- and post 2 h of standing exposure. It was found that 40% of the participants developed LBP during the standing exposure. There was a decrease in vertebral joint rotation stiffness in lateral bending and increased centre of pressure excursion during unilateral stance following standing exposure. There may be adverse effects to prolonged standing if followed by activities requiring precise balance or resistance of side loads. STATEMENT OF RELEVANCE: Prolonged standing may result in decreases in balance reactions during narrow base conditions as well as in the capacity to effectively resist side-loads at the trunk. Consideration should be given when prolonged standing is included in the workplace.
In sports, like team handball, fatigue has been associated with an increased risk of anterior cruciate ligament (ACL) injury. While effects of fatigue on muscle function are commonly assessed during maximal isometric voluntary contraction (MVC), such measurements may not relate to the muscle function during match play. The purpose of this study was to investigate the effect of muscle fatigue induced by a simulated handball match on neuromuscular strategy during a functional sidecutting movement, associated with the incidence of ACL injury. Fourteen female team handball players were tested for neuromuscular activity [electromyography (EMG)] during a sidecutting maneuver on a force plate, pre and post a simulated handball match. MVC was obtained during maximal isometric quadriceps and hamstring contraction. The simulated handball match consisted of exercises mimicking handball match activity. Whereas the simulated handball match induced a decrease in MVC strength for both the quadriceps and hamstring muscles (P
Fighter pilots who are frequently exposed to severe cold ambient temperatures experience neck pain disabilities and occupational disorders more often than those who are not so exposed. We hypothesized that a cold-induced increase in muscle strain might lead to in-flight neck injuries. The aims of this study were to measure the level of cooling before takeoff and to determine muscle strain under Gz loading (0 to +4 Gz) at different temperatures.
Test subjects' (n = 14) skin temperature (T(skin)) over the trapezoids was measured before the walk to the aircraft and again in the cockpit (air temperature -14 degrees C). The subjects then performed trampoline exercises in two different ambient temperatures (-2 degrees C and +21 degrees C) after a 30-min period at the respective temperatures. EMG activity of the sternocleidomastoid (SCM), cervical erector spinae (CES), trapezoid (TRA), thoracic erector spinae (TES) muscles, and Tskin of the SCM and TRA were measured.
Tskin over the trapezoids decreased from 30.1 +/- 1.7 degrees C to 27.8 +/- 2.6 degrees C (p
OBJECTIVE: To assess the long term impact of obstetric anal sphincter rupture on the frequency of anal and urinary incontinence and to identify factors to predict women at risk. DESIGN: An observational study. SETTINGS: Departments of Obstetrics and Gynaecology and of Surgery D, Glostrup County University Hospital, Denmark. PARTICIPANTS: Ninety-four consecutive women who had sustained an obstetric anal sphincter rupture. INTERVENTIONS: Assessment of history, anal manometry, anal sphincter electromyography and pudendal nerve terminal motor latency at three months postpartum A questionnaire regarding anal and urinary incontinence was sent two to four years postpartum. MAIN OUTCOME MEASURES: The frequency of anal and urinary incontinence and risk factors for the development of incontinence. RESULTS: Thirty of 72 women (42%) who responded had anal incontinence two to four years postpartum; 23 (32%) had urinary incontinence and 13 (18%) had both urinary and anal incontinence. Overall, 40 of 72 women (56%) had incontinence symptoms. The occurrence of anal incontinence was associated with pudendal nerve terminal motor latencies of more than 2.0 ms, and the occurrence of urinary incontinence was associated with the degree of rupture, the use of vacuum extraction and previous presence of urinary incontinence. Seventeen women had subsequently undergone a vaginal delivery in relation to which four (24%) had aggravation of anal incontinence, and three (18%) had aggravation of urinary incontinence. Of the women with incontinence, 38% wanted treatment but only a few had sought medical advice. CONCLUSIONS: Obstetric anal sphincter rupture is associated with a risk of approximately 50% for developing either anal or urinary incontinence or both. The prediction of women at risk is difficult. Information and routine follow up of all women with obstetric anal sphincter rupture is mandatory.
A review of the biofeedback literature was made and proposals for use in optometry advanced. To this end electromyograph units can be connected to an apparatus which gives a reward when a patient performs proper eye movements. By this means, patients who undergo visual training become conscious of their eye movements. As a reinforcement, they are rewarded by music or the motion of toys when they give the right answer. Application of the system in cases of strabismus, limitation of gaze, convergence insufficiency or excess, ptosis, and other cases are discussed. Methodological and financial advantages of incorporation of biofeedback reinforcement into visual training are enumerated.
The study was performed to investigate the relationship between perceived muscle tension and electromyographic hyperactivity and to what extent electromyographic (EMG) hyperactivity relates to personality traits in fibromyalgics. Thirty-six females with fibromyalgia performed isokinetic maximal forward flexions of the shoulder combined with surface EMG recordings of the trapezius and infraspinatus muscles. Signal amplitude ratio and peak torque were calculated in the initial and endurance test phases. Pain intensity, perceived general and local shoulder muscle tension, and personality traits using the Karolinska Scales of Personality were assessed pre-test. Neither perceived muscle tension nor muscular tension personality trait correlated with EMG muscle hyperactivity. Perceived general muscle tension correlated with aspects of anxiety proneness (including muscle tension) of the Karolinska Scales of Personality. Pain intensity interacted with many of the variables. We propose that when patients with fibromyalgia report muscle tension that they may be expressing something other than physiological muscle tension.
Forty-seven copper smelter workers, exposed to airborne arsenic for 8-40 years, were examined clinically with electromyography, and the motor and sensory conduction velocities in their arms and legs were determined. Fifty age-matched industrial workers not exposed to arsenic formed a reference group. The level of arsenic in the air at the smeltery was estimated to be below 500 micrograms/m3 before 1975 and approximately 50 micrograms/m3 thereafter. Urine analyses of arsenic showed a mean value of 71 micrograms/l (1 mumol/l) in the exposed group; this value is lower than that found in earlier studies reporting clinically detectable neuropathy. Only minor neurological and electromyographic abnormalities were found. A slightly reduced nerve conduction velocity in two or more peripheral nerves was more common among the arsenic workers than the referents, and a statistically significant correlation between cumulative exposure to arsenic and reduced nerve conduction velocity in three peripheral motor nerves was found. This occurrence was interpreted as a sign of slight subclinical neuropathy. In conclusion the risk of clinically significant neuropathy is small when exposure is kept below 50 micrograms/m3 in workroom air. The subclinical findings may be of interest in relation to the prevention of early adverse health effects from arsenic exposure.