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Results for “Muscle Strength”

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PubMed2005

Drugs to facilitate recovery of neuromuscular blockade and muscle strength.

Several drugs that quicken recovery from neuromuscular blockade caused by vecuronium in anesthetized patients are reviewed. Ulinastatin, a protease inhibitor, is thought to promote the release of acetylcholine at the neuromuscular junction and increases hepatic blood flow and urine volume. For this reason, ulinastatin quickens recovery from neuromuscular blockade in anesthetized patients receiving vecuronium. Additionally, pretreatment with ulinastatin avoids prolongation of vecuronium-induced neuromuscular blockade in patients with hepatic cirrhosis. Gabexate mesilate is also a protease inhibitor. During a continuous infusion of gabexate mesilate, recovery from neuromuscular blockade was quickened. Amino acid-enriched solution supplies energy to the skeletal muscles and causes an increase in muscle strength. An infusion of amino acid-enriched solution hastens recovery from neuromuscular blockade in anesthetized patients. When amino acids supply energy to the skeletal muscles, they simultaneously produce heat in the skeletal muscles. This thermal generation may be closely related to fast recovery from neuromuscular blockade. Amino acid-enriched solution makes recovery from neuromuscular blockade quick and avoids hypothermia during general anesthesia. Milrinone, a phosphodiesterase III inhibitor, is supposed to increase the release of acetylcholine at the neuromuscular junction and make the neuromuscular junction sensitive to acetylcholine. Therefore, recovery from neuromuscular blockade is hastened. Nicorandil enhances membrane K+ conductance in skeletal muscle and increases contraction of the skeletal muscle. Thus, nicorandil quickens recovery from neuromuscular blockade.

Amino Acids↗

PubMed1991

Interobserver agreement in the assessment of muscle strength and functional abilities in Guillain-Barré syndrome.

In studies of Guillain-Barré syndrome, functional deficit is usually assessed according to a functional scale consisting of several categories. The level of interobserver agreement in this scoring method is not known; furthermore, this method seems to be insensitive when applied to bedridden and artificially ventilated patients. We have developed an additional score (MRC-sumscore), reflecting muscle strength in general. Both scoring methods, tested in Guillain-Barré patients, have an almost perfect interobserver agreement. For the functional score kappa = 0.85, and for the MRC-sumscore r2 = 0.96. The MRC-sumscore is easily assessed and more sensitive than the functional score when patients are bedridden or artificially ventilated.

Humans↗

PubMed2005

A comparison of training methods to increase neck muscle strength.

OBJECTIVE: To compare two neck strength training modalities. BACKGROUND: Neck injury in pilots flying high performance aircraft is a concern in aviation medicine. Strength training may be an effective means to strengthen the neck and decrease injury risk. METHODS: The cohort consisted of 32 age-height-weight matched participants, divided into two experimental groups; the Multi-Cervical Unit (MCU) and Thera-Band tubing groups (THER), and a control (CTRL) group. Ten weeks of training were undertaken and pre-and post isometric strength testing for all groups was performed on the MCU. Comparisons between the three groups were made using a Kruskal-Wallis test and effect sizes between the MCU and the THER groups and the THER and CTRL groups were also calculated. RESULTS: The MCU group displayed the greatest increase in isometric strength (flexion 64.4%, extension 62.9%, left lateral flexion 53.3%, right lateral flexion 49.1%) and differences were only statistically significant (p<0.05) when compared to the CTRL group. Increases in neck strength for the THER group were lower than that shown in the MCU group (flexion 42.0%, extension 29.9%, left lateral flexion 26.7%, right lateral flexion 24.1%). Moderate to large effect sizes were found between the MCU and THER as well as the THER and CTRL groups. CONCLUSIONS: This study demonstrated that the MCU was the most effective training modality to increase isometric cervical muscle strength. Thera-Band tubing did however, produce moderate gains in isometric neck strength.

Adult↗

PubMed1999

Quadriceps muscle strength, contractile properties, and motor unit firing rates in young and old men.

Changes with age in the voluntary static and dynamic strength of the quadriceps muscle group have been well characterized, and the importance of the muscle group for locomotion and independent living have been highlighted in both normal human aging and in clinical studies. Surprisingly few studies of this muscle group have described age-related changes in voluntary activation ability using twitch interpolation and changes in stimulated contractile properties, and none have assessed the influence of old age on motor unit firing rates. We compared in 13 young (mean age 26 years) and 12 old (mean age 80 years) men the voluntary isometric strength, stimulated contractile properties, and average steady state motor unit firing rates in the quadriceps muscle. Maximum voluntary contraction (MVC) force and twitch tension were approximately 50% lower in the old men, but contractile speed was only approximately 10% slower than in the young men. There was no difference in the ability of either group to activate the quadriceps to a high degree (94-96%). At all isometric force levels tested (10%, 25%, 50%, 75%, and 100% MVC), there were no differences in mean motor unit firing rates. In both groups, the range of firing rates was similar and not large ( approximately 8 Hz at 10% MVC and 26 Hz at MVC). Thus, the substantial age-related weakness in this muscle does not seem to be related to changes in neural drive.

Adult↗

PubMed2002

Test-retest reliability in isokinetic muscle strength measurements of the shoulder.

Test-retest reliability is important for long-term follow-up; however, data on the reliability of isokinetic dynamometry of the shoulder are scarce. Twenty subjects (50% male) were measured; 10 with asymmetrical use of the arms (mean age 27 years) and 10 used their arms symmetrically (mean age 32 years). A Biodex dynamometer (Multi joint system 2) was used. Abduction/adduction and external/internal rotation were measured following a standardized protocol. Performed scheme: two sessions with a 2-week interval, all measurements were done with 60 degrees/second (5 repetitions) and respectively 120 degrees/second and 180 degrees/second (10 repetitions). Differences in the mean peak torques, split for muscle group and gender were significant. Intraclass correlation coefficients ranged from 0.69 to 0.92. This implies good to excellent reliability in research on groups. To determine test-retest reliability of two consecutive individual measurements smallest detectable differences (SDD) were computed and ranged from 21% to 43%. It is questionable whether the SDDs are small enough to detect real changes in muscle strength.

Adolescent↗

PubMed1975

Back pain and isometric back muscle strength of workers in a Danish factory.

105 factory workers (38 females and 67 males) have been questioned about their frequency of back pain. 60% of the females and 61% of the males have previously experienced episodes of back pain. 21% of the females and 37% of the males have been absent from work due to back pain. The incidence of back pain is not related to age, height, sort of work, or isometric muscle strength of the back (IS). For the males the incidence rises with increasing weight, i.e. combination of height and obesity, but is not related to any two single factors. For the females there is no correlation between the incidence of pain and weight. IS is correlated to height and age in the males but not in the females. Standards for IS are presented and suggested as a guide to evaluation of the working capabilities of individual subjects with back pain.

Adult↗

PubMed2002

Change in muscle strength explains accelerated decline of physical function in older women with high interleukin-6 serum levels.

OBJECTIVES: To test whether accelerated sarcopenia in older persons with high interleukin (IL)-6 serum levels plays a role in the prospective association between inflammation and disability found in many studies. DESIGN: Cohort study of older women with moderate to severe disability. PARTICIPANTS: Six hundred twenty older women from the Women's Health and Aging Study in whom information on baseline IL-6 serum level was available. MEASUREMENTS: Self-report of functional status, objective measures of walking performance, and knee extensor strength were assessed at baseline and over six semiannual follow-up visits. Potential confounders were baseline age, race, body mass index, smoking, depression, and medical conditions. RESULTS: At baseline, women with high IL-6 were more often disabled and had lower walking speed. After adjusting for confounders, women in the highest IL-6 tertile (IL-6>3.10 pg/mL) were at higher risk of developing incident mobility disability (risk ratio (RR) = 1.50, 95% confidence interval (CI) = 1.01-2.27), disability in activities of daily living (RR = 1.41, 95% CI = 1.01-1.98), and severe limitation in walking (RR = 1.61, 95% CI = 1.09-2.38) and experienced steeper declines in walking speed (P <.001) than women in the lowest IL-6 tertile (IL-6 < or =1.78 pg/mL). Decline in knee extensor strength was also steeper, but differences across IL-6 tertiles were not significant. After adjusting for change over time in knee extensor strength, the association between high IL-6 and accelerated decline of physical function was no longer statistically significant. CONCLUSIONS: Older women with high IL-6 serum levels have a higher risk of developing physical disability and experience a steeper decline in walking ability than those with lower levels, which are partially explained by a parallel decline in muscle strength.

Activities of Daily Living↗

PubMed2005

Does the size of the vaginal probe affect measurement of pelvic floor muscle strength?

BACKGROUND: The most commonly used method to measure pelvic floor muscle (PFM) strength is vaginal squeeze pressure. There are, however, several apparatuses available for this purpose, and sizes of the probes differ significantly. The aim of the present investigation was to assess whether the size of two commonly used vaginal probes influences measurement of PFM strength. METHODS: Twenty female physical therapy students, mean age 25.1 years (range 21-38), participated in the study. All were able to contract the PFM, as assessed by means of vaginal palpation and observation of inward movement of the perineum. Two measuring devices with different lengths and diameters, the Peritron and the Camtech, were used in order to assess vaginal squeeze pressure. Each woman performed six contractions with each apparatus. RESULTS: Mean maximum squeeze pressure for the whole group with the Camtech was 19.7 cm H(2)O (95% CI: 16.5-22.9) and with the Peritron 36.5 cm H(2)O (95% CI: 31.7-41.3), P < 0.01. Nine women preferred the Camtech, four preferred the Peritron, and seven did not have any specific preferences. CONCLUSIONS: Measurements of vaginal squeeze pressure differ depending on the vaginal probe used. Results from published studies using various probes should, therefore, not be compared or combined in systematic reviews or meta-analysis.

Adult↗

PubMed2002

Mice lacking the adenosine A1 receptor are anxious and aggressive, but are normal learners with reduced muscle strength and survival rate.

Behavioural assessment of mice lacking adenosine A1 receptors (A1Rs) showed reduced activity in some phases of the light-dark cycle, reduced exploratory behaviour in the open-field and in the hole-board, increased anxiety in the plus maze and dark-light box and increased aggressiveness in the resident-intruder test. No differences were found in spatial reference and working memory in several Morris water maze tasks. Both mutant mice had reduced muscle strength and survival rate. These results confirm the involvement of adenosine in motor activity, exploratory behaviour, anxiety and aggressiveness. A1Rs also appear to play a critical role in ageing-related deterioration.

Adenosine↗

PubMed2001

Motor block in regional anaesthesia. Quantification by muscle strength at the ankle joint.

A device based on a load cell was constructed to measure the strength of foot dorsiflexion and plantarflexion. Performance of the device was evaluated for both movements. The influence of foot position within the device, its use over a 30-min period at 30-s intervals and the effect of the removal and reapplication of the device on measured force of dorsiflexion and plantarflexion was studied in six volunteers. Both dorsiflexion and plantarflexion are suitable movements on which to base a device to quantify the density of motor block during the onset and offset of neuraxial block. Dorsiflexion has a number of advantages: muscle strength is independent of knee position, and therefore a below-knee device can be constructed; strength of dorsiflexion is less affected by the foot position; we found the device easier to apply using dorsiflexion as the heel tended to self-locate; innervation of the muscles responsible for dorsiflexion involves fewer spinal segments.

Adult↗

PubMed1988

Weekly cuirass ventilation improves blood gases and inspiratory muscle strength in patients with chronic air-flow limitation and hypercarbia.

We studied the effects of an 8-h, once-a-week schedule of cuirass ventilation (CV) in 5 patients with advanced chronic air-flow limitation and chronic hypercarbia (PaCO2, 58.6 +/- 10.1 mm Hg; mean +/- SD). Repeated measurements of arterial blood gases, maximal inspiratory mouth pressure (P1max), 12-min walking distance, and respiratory cycle were performed during a 1-month run-in period. Quality of life and transdiaphragmatic pressure were measured once. All patients completed the planned 4-month study. Four of them were ventilated for longer periods because CV could not be discontinued at the end of the study. PaCO2 showed a significant fall starting during the first month; PaO2 significantly increased from the second month, whereas P1max significantly rose from the third month on. Maximal transdiaphragmatic pressure increased in the 2 patients with abnormal baseline values. The fall in PaCO2 was associated with an increase in tidal volume because of a longer inspiratory time. Significant improvements in quality of life and in the 12-min walking distance were observed. We conclude that weekly CV improves blood gases, inspiratory muscle strength, and clinical conditions of patients with chronic air-flow limitation and chronic hypercarbia, probably because of correction of chronic inspiratory muscle fatigue.

Blood Gas Analysis↗

PubMed2005

Muscle strength response to strength training is influenced by insulin-like growth factor 1 genotype in older adults.

Strength training (ST) is considered an intervention of choice for the prevention and treatment of sarcopenia. Reports in the literature have suggested that the insulin-like growth factor I protein (IGF-I) plays a major role in ST-induced skeletal muscle hypertrophy and strength improvements. A microsatellite repeat in the promoter region of the IGF1 gene has been associated with IGF-I blood levels and phenotypes related to IGF-I in adult men and women. To examine the influence of this polymorphism on muscle hypertrophic and strength responses to ST, we studied 67 Caucasian men and women before and after a 10-wk single-leg knee-extension ST program. One repetition maximum strength, muscle volume via computed tomography, and muscle quality were assessed at baseline and after 10 wk of training. The IGF1 repeat promoter polymorphism and three single-nucleotide polymorphisms were genotyped. For the promoter polymorphism, subjects were grouped as homozygous for the 192 allele, heterozygous, or noncarriers of the 192 allele. After 10 wk of training, 1-repetition maximum, muscle volume, and muscle quality increased significantly for all groups combined (P < 0.001). However, carriers of the 192 allele gained significantly more strength with ST than noncarriers of the 192 allele (P = 0.02). There was also a nonsignificant trend for a greater increase in muscle volume in 192 carriers than noncarriers (P = 0.08). No significant associations were observed for the other polymorphisms studied. Thus these data suggest that the IGF1 promoter polymorphism may influence the strength response to ST. Larger sample sizes should be used in future studies to verify these results.

Aged↗

PubMed2006

Energy demands of walking in persons with postpoliomyelitis syndrome: relationship with muscle strength and reproducibility.

OBJECTIVES: To describe the energy demands of walking in subjects with postpoliomyelitis syndrome (PPS) in comparison with the demands in healthy subjects, and to assess the reproducibility of walking energy measurements. DESIGN: Four repeated measurements with a 1-week interval between each measurement. SETTING: Outpatient clinic of a university hospital. PARTICIPANTS: Fourteen subjects with PPS and 14 age- and sex-matched healthy subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Walking speed and energy cost of walking. The correlation parameter was lower-extremity muscle strength sum (MSS). The reproducibility parameters were standard error (SE) of measurement and smallest detectable difference (SDD). RESULTS: Walking speed in subjects with PPS (61.8 m/min) was significantly lower (-28%) and energy cost (4.8 J.kg(-1).m(-1)) was significantly higher (40%) than in healthy subjects. MSS correlated strongly with energy cost (r=-.84, P=.000), explaining 71% of the variance. The SE of measurement of energy cost measurements ranged between 1.7% and 3.4% for PPS subjects and between 1.2% and 2.4% for healthy subjects. The SDD ranged between 4.6% and 9.4% for PPS subjects and between 3.3% and 6.6% for healthy subjects, depending on the number of repeated measurements that were considered. CONCLUSIONS: Energy cost of walking in subjects with PPS is strongly related to the extent of muscle weakness in the lower extremities. Although variability was greater for PPS subjects than for healthy subjects, reproducibility of energy cost measurements was high. Therefore, metabolic assessment of energy cost of walking is a sensitive tool that can reveal clinically relevant changes even in the condition of a person with PPS.

Adult↗

PubMed1990

Changes in muscle strength and speed of an unloaded movement after various training programmes.

The effect of three different training programmes on the maximal speed of an unloaded movement (a karate punch) was studied. Three movement variables were selected: maximal speed of the hand (Vh,max), maximal speed of the shoulder (Vs,max) and elbow extension speed (theta E) simultaneous with Vh.max. The programmes were: training group 1 (TG 1, n = 8) - karate students, dynamic heavy progressive resistance exercise (incline situp and incline bench press) + punch bag exercise; training group 2 (TG 2, n = 8)-karate students, punch bag training; training group 3 (TG 3, n = 5)-no karate experience, dynamic heavy progressive resistance exercise (as in TG 1). The movement variables were calculated from chrono-cyclo photographic recordings of the punches (100 Hz). The level of significance was set at 5%. Sixteen weeks of training gave the following results: significant increases in dynamic strength in all the training groups (14%-53%). In TG 1 the Vh.max increased significantly from 8.49 m.s-1, SD 1.19 to 9.35 m.s-1, SD 1.29 (10%); Vs.max increased significantly in TG 1 by 32% (2.18 m.s-1, SD 0.56 to 2.87 m.s-1, SD 0.98) and in TG 2 by 14% (2.40 m.s-1, SD 0.61 to 2.74 m.s-1, SD 0.52), and in TG 3 theta E at Vh,max increased significantly from 28.6 rad.s-1, SD 4.3 to 32.2 rad.s-1, SD 4.5 (13%). No significant relationships between the changes in maximal muscle strength and the changes in movement speed were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Effects of captopril chronic intake on the aerobic performance and muscle strength of normotensive trained subjects.

Fifteen normotensive athletes specializing in dynamic sports took part in a randomized double-blind and cross-over study: captopril (50 mg/24 h) vs placebo. Each treatment lasted one month. Maximal exercise tests on cycle ergometer were performed at the end of each period. No significant differences were observed in the maximal values of oxygen uptake, power, heart rate or blood lactate value. The anaerobic threshold, defined as the exercise intensity which corresponded to a 4 mmol.l-1 blood lactate level was unchanged. With captopril, the end-of-exercise systolic and diastolic BP were slightly altered (NS). Lower limb muscle strength, as explored with a Cybex isokinetic system, was not modified by captopril intake. The results indicate that maximal aerobic performance and isokinetic strength of the lower limbs are not altered by captopril chronic administration (50 mg/day) in normotensive trained subjects.

Adult↗

PubMed2006

Enhanced novelty-induced activity, reduced anxiety, delayed resynchronization to daylight reversal and weaker muscle strength in tenascin-C-deficient mice.

Tenascin-C (TNC) is an extracellular matrix protein with multiple and important functions during development and in the adult. We here present a study on the behaviour of TNC-deficient (knockout, KO) mice. Longitudinal experiments including tests for circadian activity, exploration, state and trait anxiety, motor coordination and cognition were performed. KO mice showed increased reactivity to explore a novel environment and decreased anxiety. Spontaneous circadian activity was unaffected, but KO mice showed delayed resynchronization to daylight reversal. TNC deficiency caused weaker muscle strength, whereas gait, coordination and motor learning were unaltered. Short- and long-term memory in the fear conditioning task and working memory in the spontaneous alternation test were normal in KO mice. KO mice showed impaired memory recall in the step-down, but not in the step-through, passive avoidance task. Ethological observation of mice behaviour and principal component analyses indicated that the higher novelty- and stress-induced active responses of KO mice account for their poorer performance in passive avoidance tasks, whereas cognitive abilities are unaltered. The present study extends and corrects previous results, and is an example of how an ethological approach allows a precise description and interpretation of the behavioural alterations of mutant mice.

Aggression↗

PubMed1992

Effect of a beta 2-agonist (broxaterol) on respiratory muscle strength and endurance in patients with COPD with irreversible airway obstruction.

The effect of broxaterol, a new beta 2-agonist, on respiratory muscle endurance and strength was studied in a double-blind, placebo-controlled, randomized crossover clinical trial in 16 patients with chronic obstructive pulmonary disease (COPD) with irreversible airway obstruction (FEV1 = 57.1 percent of predicted). One patient withdrew from the study because of acute respiratory exacerbation. Inspiratory muscle strength was assessed by maximal inspiratory pressure (MIP) and endurance time was determined as the length of time a subject could breathe against inspiratory resistance (target mouth pressure = 70 percent of MIP, Ti/Ttot = 0.4). Broxaterol (B) or placebo (P) was given orally for seven days at the dose of 0.5 mg three times a day with a washout period of 72 h between study treatments. Measurements were performed before administration of B or P and 2 h (six patients) or 8 h (nine patients) after the end of each treatment. No significant changes in FEV1 or FRC were observed after B or P suggesting that diaphragmatic length was maintained constant with each treatment. The MIP did not significantly change, while endurance time increased after B in the patients tested at 2 h (from 234.8 +/- 48.1 s to 284.0 +/- 48.0 s, p less than 0.05) and at 8 h (from 187.2 +/- 31.1 s to 258.2 +/- 40.4 s, p less than 0.005). No changes were observed after P. Minute ventilation, airway occlusion pressure (P0.1), integrated electromyographic activities of the diaphragm (Edi), and intercostal parasternals (Eic) (normalized to the value obtained during MIP) showed no change during the endurance run with different treatments. We conclude that in a group of COPD patients with irreversible airway obstruction, B significantly improves respiratory muscle endurance, and that this does not arise as a result of an effect on neuromuscular drive or pulmonary mechanics, but may be mediated by peripheral factors.

Adrenergic beta-Agonists↗

PubMed1983

The effects of chronic hyperinflation, nutritional status, and posture on respiratory muscle strength in cystic fibrosis.

We measured maximal static inspiratory and expiratory pressures (PImax and PEmax) in 25 patients with cystic fibrosis (CF) and 80 normal control subjects to determine whether chronic hyperinflation and malnutrition reduce PImax and PImax/PEmax, respectively. In addition, we examined the effect of posture on pressures generated. We used a diminution in PEmax as an index of a malnutrition effect on pressures generated. The patients with CF, although significantly hyperinflated (ratio of residual volume to total lung capacity, 0.49), generated PImax values similar to those of the control subjects (p greater than 0.05). Despite evidence of malnutrition (mean body mass percentile, 78%) the PEmax values of patients with CF and those of control subjects were comparable (p greater than 0.05). There was no postural effect on pressures generated in the normal subjects or the CF group as a whole. We conclude that respiratory muscle strength is normal or supranormal in CF, despite chronic hyperinflation and malnutrition.

Adolescent↗