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Results for “Muscle Strength”

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At least 361 records · Page 20Linked to original sources

PubMed1999

Changes in muscle strength in women following the menopause: a longitudinal assessment of the efficacy of hormone replacement therapy.

The effects of hormone deficiency at the menopause on muscle strength was examined in 10 healthy middle-aged women (1-3 years post-menopause) in a longitudinal trial over 39 weeks. Performance was compared with that of age-matched females (n=11) taking a course of hormone replacement therapy (HRT). Muscle strength of the quadriceps was measured isometrically at 90 degrees of knee flexion and at angular velocities of 1.05, 2.09 and 3.13 rad/s using an isokinetic dynamometer. Hand grip strength was assessed by means of a portable dynamometer. Measurements were taken every 13 weeks for 39 weeks. Significant decreases in isometric strength (-10%) and dynamic leg strength at 1.05 rad/s (-9%) were found in the post-menopausal women over 39 weeks. There was no change in strength in the HRT group. There were also no changes in leg strength at higher angular velocities or in grip strength for either the post-menopausal group or those taking HRT. While HRT preserved muscle strength, there was no evidence of a strengthening effect on skeletal muscle within this short period of treatment. A rapid loss of leg strength occurs post-menopausally in hormone-depleted women. HRT may offer protection against muscle weakness, although the hormone responsible for regulating strength is not evident using this model.

Exercise↗

PubMedDate not supplied

Chronic Achilles tendinitis and calf muscle strength.

We evaluated 10 men and 3 women (mean age, 44 +/- 8.5 years) with chronic Achilles tendinitis who underwent surgical treatment. Surgery was followed by immobilization in a weightbearing below-the-knee plaster cast for 6 weeks and a stepwise increasing strength training program. We prospectively studied calf muscle strength on the injured and noninjured sides preoperatively and at 16, 26, and 52 weeks postoperatively. Preoperatively, concentric peak torque in dorsiflexion at 90 deg/sec and plantar flexion at 225 deg/sec was significantly lower on the injured side. Postoperatively, concentric plantar flexion peak torque on the injured side increased significantly between Weeks 16 and 26 at 90 deg/sec but was significantly lower than the noninjured side from Weeks 16 to 52 at 90 and 225 deg/sec. Dorsiflexion peak torque at 90 and 225 deg/sec increased between Weeks 0 and 26 and was significantly higher on the injured side at Week 26. Eccentric plantar flexion peak torque was significantly lower on the injured side at Week 26 but not at 1 year. This prospective study demonstrates that 6 months of postoperative rehabilitation for chronic Achilles tendinitis is not enough to recover concentric and eccentric plantar flexion muscle strength compared with the noninjured side.

Achilles Tendon↗

PubMed2005

Improvement of muscle strength in osteoarthritic knee patients after intraarticular knee injection of hyaluronan.

OBJECTIVE: The objective of this study was to investigate whether the knee concentric and eccentric muscle strengths can be improved in patients with bilateral knee osteoarthritis after intraarticular hyaluronan injections. DESIGN: A total of 25 patients with bilateral knee osteoarthritis and with a radiographic Ahlbäck grading scale of I or II participated in this study. One session of intraarticular knee injection of hyaluronan was given to both knees (weekly intraarticular knee hyaluronan injections for a total of 5 wks). Knee concentric and eccentric muscle strengths were recorded between 10 and 90 degrees of knee flexion. The recordings were done on two angular velocities, 80 and 240 degrees/sec. This study took place in a tertiary medical center with a gait laboratory and a KIN-COM isokinetic dynamometer. RESULTS: An increase in concentric and eccentric muscle strength adjusted for body weight (P < 0.01) was observed in both knees, ranging between 5.1% and 27.7%. CONCLUSION: The decreased knee muscle contraction strength (concentric and eccentric) can be improved in knee osteoarthritis patients with an Ahlbäck grading scale of I or II after five weekly intraarticular knee injections of hyaluronan.

Adjuvants, Immunologic↗

PubMed2006

Effects of long term Tai Chi practice and jogging exercise on muscle strength and endurance in older people.

OBJECTIVES: To investigate the influence of regular Tai Chi (TC) practice and jogging on muscle strength and endurance in the lower extremities of older people. METHODS: Twenty one long term older TC practitioners were compared with 18 regular older joggers and 22 sedentary counterparts. Maximum concentric strength of knee flexors and extensors was tested at angular velocities of 30 degrees/s and 120 degrees/s. Ankle dorsiflexors and plantar flexors were tested at 30 degrees/s and the dynamic endurance of the knee flexors and extensors was assessed at a speed of 180 degrees/s. RESULTS: The differences in the muscle strength of the knee joint amongst the three experimental groups were significant at the higher velocity. The strengths of knee extensors and flexors in the control group were significantly lower than those in the jogging group and marginally lower than those in the TC group. For the ankle joint, the subjects in both the TC and jogging groups generated more torque in their ankle dorsiflexors. In addition, the muscle endurance of knee extensors was more pronounced in TC practitioners than in controls. CONCLUSION: Regular older TC practitioners and joggers showed better scores than the sedentary controls on most muscle strength and endurance measures. However, the magnitude of the exercise effects on muscles might depend on the characteristics of different types of exercise.

Age Factors↗

PubMed1978

Swelling of the upper extremity, function and muscle strength of shoulder joint following mastectomy combined with radiotherapy.

Swelling of the arm, mobility of the shoulder joint and muscle strength were examined in 76 patients with breast cancer 4.5 to 14 years (mean 8 years) after primary therapy. Marked arm swelling was found on the operated side in 31% of the patients operated by radical mastectomy and in 18% of those having undergone total mastectomy. The swelling was more marked in the upper arm than in the forearm. Patients irradiated postoperatively with a megavoltage technique showed more often and more oedema than those treated with a kilovoltage technique. Obese patients had more swelling than patients of normal weight. Of the various movements of the shoulder joint, abduction, adduction, flexion, extension, horizontal extension and internal rotation were significantly reduced on the operated side in comparison with the non-operated side, but the differences were not great. Neither swelling of the arm nor the patient's weight had any effect on the function of the shoulder joint, as expressed in terms of abduction. Of the muscle groups in the shoulder joint adductors, flexors and extensors were significantly weaker on the operated than on the non-operated side. The muscle strength of the operated side averaged 25% weaker than that of the control side. Swelling of the arm did not reduce the muscle strength of the shoulder joint.

Adult↗

PubMed1986

Isokinetic and isometric muscle strength in patients with rheumatoid arthritis. The relationship to clinical parameters and the influence of corticosteroid.

The isometric and isokinetic muscle strength of the legs in forty-six women with rheumatoid arthritis was measured using a Cybex II dynamometer. Twenty-six of the patients had been treated with corticosteroid - prednisone - some for several years (mean 8 years, range 1-35). Twenty-three healthy age-matched women served as a comparable group (controls). In patients treated with prednisone the mean maximal isokinetic muscle strength of the knee extensors was between 64 +/- 26 Nm (SD) and 43 +/- 18 Nm (SD) at the preset angular velocities 30 degrees/s and 180 degrees/s, respectively, which was a reduction to 54%-55% of that found in controls (p less than 0.001). In patients who had not received prednisone the mean maximal isokinetic strength was between 99 +/- 39 Nm (SD) and 67 +/- 27 Nm (SD) which was a reduction to 84%-86% of that found in controls (p less than 0.05). The force velocity curve showed a parallel decrease in maximal strength with increasing velocity when comparing patients with rheumatoid arthritis to controls. Also on measuring the isokinetic muscle strength of plantar flexors a significantly lower mean maximal torque was found in patients treated with prednisone, (33 +/- 21 Nm (SD) (p less than 0.01] as compared with a control group (50 +/- 28 Nm (SD]. The patients who had not been treated with prednisone showed a lower, but not significantly lower isokinetic strength of the plantar flexors, 46 +/- 22 Nm (SD) at a corresponding angular velocity, 30 degrees/s.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Music therapy as a treatment method for improving respiratory muscle strength in patients with advanced multiple sclerosis: a pilot study.

Respiratory muscle weakness, predominantly of the expiratory muscles, is characteristic of individuals with advanced multiple sclerosis and can result in difficulty in clearing secretions and repeated episodes of pneumonia. This pilot study evaluated the effectiveness of music therapy in strengthening respiratory muscles through an emphasis on diaphragmatic breathing and coordination of breath and speech. Twenty patients were randomly assigned to one of two groups: one that received music therapy or one that attended music appreciation sessions. Participants' inspiratory and expiratory muscle strength was measured by testing mouth pressure before and after the intervention. The experimental group showed some improvement in terms of expiratory muscle strength, in contrast to the control group, which showed deterioration. The results were not statistically significant, however. Patients in both groups exhibited considerable weakness in their expiratory muscles, and results for 79% of the participants were below 30% of the predicted values. Variability, a major confounding factor that resulted in reduced statistical power, led the investigators to suggest an intercenter collaboration to amass sufficient numbers of patients for a future study. Early manifestation of respiratory muscle weakness warrants inclusion of respiratory muscle testing in examination protocols and early intervention efforts.

Adult↗

PubMed1995

Testosterone administration to elderly men increases skeletal muscle strength and protein synthesis.

Aging men develop a significant loss of muscle strength that occurs in conjunction with a decline in serum testosterone concentrations. We investigated the effects of testosterone administration to six healthy men [67 +/- 2 (SE) yr] on skeletal muscle protein synthesis, strength, and the intramuscular insulin-like growth factor I (IGF-I) system. Elderly men with serum testosterone concentrations of 480 ng/dl or less were given testosterone injections for 4 wk to produce serum concentrations equal to those of younger men. During testosterone administration muscle strength (isokinetic dynamometer) increased in both right and left hamstring and quadricep muscles as did the fractional synthetic rate of muscle protein (stable-isotope infusion). Ribonuclease protection assays done on total RNA from muscle showed that testosterone administration increased mRNA concentrations of IGF-I and decreased mRNA concentrations of insulin-like growth factor binding protein-4. We conclude that increasing testosterone concentrations in elderly men increases skeletal muscle protein synthesis and strength. This increase may be mediated by stimulation of the intramuscular IGF-I system.

Aged↗

PubMed1999

Early changes in muscle strength after total knee arthroplasty. A 6-month follow-up of 30 knees.

We studied 30 patients with arthrosis in one knee operated on with a cemented (n 26) or an uncemented total knee arthroplasty (TKA) (n 4). Full weight-bearing from the first postoperative day was allowed in all patients, and they received standard postoperative physiotherapy. 1 week prior to surgery, and after 3 and 6 months, isokinetic and isometric muscle strength in both legs were measured, using a Cybex 6000 dynamometer. Isokinetic tests showed a bilateral, significant, and progressive increase (30-53%) in flexor muscle strength most pronounced in the operated legs. Isokinetic extensor strength increased significantly (14-18%) in the operated legs, while in the contralateral legs, a limited increase was found. Isometric flexion strength significantly decreased in the operated knees (17%). Isometric extension strength showed a temporary decrease at 3 months, which returned to the preoperative level. No significant change in isometric strength was observed in the contralateral legs. The knee pain during the muscle strength measurements decreased significantly from the preoperative level, which may indicate that the substantial pain relief within 3 months after a TKA is an important factor for evaluation of muscle strength.

Aged↗

PubMed1996

[Evaluation of the inspiratory muscle strength using the nasal pressure of the sniff].

The measurement of oesophageal pressure during maximal sniffs (Poes sniff) is useful to assess inspiratory muscle strength. The aim of this study was to develop a noninvasive test of inspiratory muscle strength based on the sniff manoeuvre. The sniff nasal inspiratory pressure (SNIP) was measured through a plug occluding one nostril during sniffs performed through the contralateral nostril. In 10 normal subjects and in 12 patients with neuromuscular or skeletal disorders, the SNIP reliably reflected the Poes sniff. Nasal mucosa congestion was induced in four normal subjects by nebulization of increasing doses of histamine. The SNIP accurately reflected Poes sniff when nasal congestion was moderate, but failed to do so when congestion was severe. Reference values of SNIP were established in a group of 160 healthy subjects aged 20-80 years. For both men and women, SNIP was negatively correlated with age, and was similar in the sitting and in the supine positions. SNIP was higher than maximal inspiratory pressure (P1 max) in most subjects, but the wide limits of agreement showed that these two methods are not interchangeable but complementary. The SNIP represents a useful noninvasive test of inspiratory muscle strength.

Adult↗

PubMed2001

Physiological assessment of muscle strength in vitro after direct injection of doxorubicin into rabbit sternocleidomastoid muscle.

Doxorubicin chemomyectomy is a potent method for the permanent removal of a muscle or group of muscles after direct local injection, and has been used successfully to treat blepharospasm and hemifacial spasm patients. The efficacy of doxorubicin chemomyectomy on reducing muscle strength after direct injection of doxorubicin into rabbit sternocleidomastoid muscle was tested. One- and 6-month postinjection force assessment was performed in vitro to measure alterations in peak twitch and tetanic force generation, as well as fatigue responses for the treated muscles compared to control. There were significant reductions of both twitch and tetanic peak amplitudes in the doxorubicin-treated muscles. One month after treatment, the decreases in force were greater after 2 mg doxorubicin injections than after 1 mg doxorubicin. While there was a significant reduction in force generation after doxorubicin treatment, fatigue resistances for the doxorubicin-treated muscles were increased compared to the controls. There were significant reductions in muscle mass after doxorubicin treatment, and by 6 months, the myosin heavy chain isoform distribution was similar to normal sternocleidomastoid, except for an increase in slow myosin-positive fibers. Doxorubicin chemomyectomy resulted in a significant reduction in functional force generation in the treated sternocleidomastoid muscles. These findings suggest a potential clinical use of doxorubicin chemomyectomy to treat cervical dystonia patients.

Animals↗

PubMed1987

Muscle morphology with special reference to muscle strength in post-polio subjects.

The main histopathologic finding is large grouping of type I and type II fibers. Subjects with low muscle strength had a large number of type I fibers. Large fibers were found especially in men with low muscle strength. The oxidative enzymatic activity was reduced. The findings suggest a compensatory process, with an increased number of type I fibers in subjects, a large reduction in muscle strength, and also an increase in the fiber size. There is a sex difference in the fiber hypertrophy.

Adult↗

PubMed1994

[Postoperative pulmonary complications in patients undergoing thoracic surgery with special reference to preoperative respiratory muscle strength and nutrition].

Postoperative pulmonary complications in patients undergoing thoracic surgery were examined along with their preoperative respiratory muscle strength and nutrition. Respiratory muscle strength was assessed by maximum inspiratory (MIP) and expiratory (MEP) pressures. Nutrition was assessed by serum levels of albumin and total cholesterol. The examined cases include 51 cases of lung tumors, 8 cases of mediastinal tumors, 9 cases of empyema, 3 cases of esophageal cancer, 2 cases of chest wall tumors, and 2 cases of giant bulla. Preoperative respiratory muscle training increased both MIP and MEP significantly (p < 0.01). Thirteen patients who had postoperative pulmonary complications had significantly lower values (p < 0.01), and did not show significant increases in either MIP or MEP even after training. The cases which experienced complications also showed significantly lower preoperative serum levels of albumin and total cholesterol (p < 0.01). Therefore, patients with respiratory muscle weakness and poor nutrition have a higher risk of postoperative pulmonary complications.

Adult↗

PubMed2004

Role of exogenous and endogenous trophic factors in the regulation of extraocular muscle strength during development.

PURPOSE: Weak eye muscles can cause ophthalmic disorders, and in particular, strabismus. Exogenous trophic factors such as cardiotrophin (CT)-1 and insulin-like growth factor (IGF) have been shown to increase the contractile force of adult heart and skeletal muscles, respectively. In the current study, the effects of endogenous and exogenous trophic factors on extraocular muscle strength and mass were examined in the developing chicken. METHODS: Superior rectus and superior oblique muscles of hatchling chicks were treated in vivo either to increase levels of trophic factors CT-1, IGF-I, glial cell line-derived neurotrophic factor (GDNF), or brain-derived neurotrophic factor (BDNF), or to decrease their levels with neutralizing antibodies and binding proteins. Forty-eight hours after factors were injected into the orbit, the contractile force of dissected muscles was measured in vitro and the morphology of muscle fibers was compared between control and treated muscles. RESULTS: Treatment with CT-1 or IGF-I significantly increased the mean single-twitch force generation and these trophic factors increased muscle fiber diameters when compared to control muscles. A cocktail of antibodies and binding proteins, directed against endogenous IGF-I, GDNF, and CT-1, significantly decreased mean single-twitch force. This cocktail slightly, but significantly, reduced muscle fiber diameters within treated extraocular muscles. CONCLUSIONS: Endogenous trophic factors regulate and/or maintain extraocular muscle force through a rapid mechanism that appears to involve changes in muscle mass and specifically enlargement of muscle fiber diameters. CT-1 and IGF-I may be considered promising candidate trophic factors for therapeutic strengthening of eye muscles in the developing extraocular muscle system.

Animals↗

PubMed1988

Inspiratory muscle strength in asthma.

Augmentation of inspiratory muscle strength (Pimax) represents an adaptive response to airway obstruction. We explore the possibility that respiratory muscle weakness may herald hospital admission during acute bronchospasm. The Pimax measured 81 +/- 25 percent of a predicted value in 20 patients with acute bronchospasm (forced expiratory volume in one second, 36 +/- 17 percent predicted). Pimax was related to both hyperinflation (functional residual capacity, as percent predicted) and body weight (subjects were 122 +/- 29 percent ideal body weight), but not to the degree of airway obstruction per se. Furthermore, measurements of axial (craniocaudal) motion of the rib cage and asynchrony of rib cage and abdominal motions during tidal breathing did not correlate with either the degree of air flow obstruction or Pimax. We conclude that little if any respiratory muscle weakness occurs with bronchospasm. Furthermore, Pimax does not correlate with the degree of airway obstruction and does not explain abnormalities of rib cage and abdominal motion associated with asthma.

Abdominal Muscles↗

PubMed1996

The changes in muscle strength and relaxation time after a comprehensive rehabilitation program for patients with myotonic dystrophy.

Myotonic dystrophy is a muscular disorder characterized by muscle weakness and myotonia. Myotonia manifests with abnormally slow relaxation after strong voluntary contraction of the muscles. In our previous study we reported that quinine sulfate provided therapeutic benefit to myotonia and a home exercise program based on muscle strengthening exercises improved muscle strength. The purpose of this study was to determine the effect of a multi-therapeutic program in patients with myotonic dystrophy. For six months, seven patients with myotonic dystrophy received heat therapy, were given psychologic intervention using relaxation techniques, were trained at home, and were given quinine sulfate. The changes in muscle strength and relaxation time between the post-six-months home exercise program combined with quinine sulfate therapy, and the post-six months multi-therapeutic program, were assessed from the first dorsal interossei, the elbow flexors, and the knee extensors. The results were as follows: 1) The mean muscle strength of the each of the three muscles after the six months multi-therapeutic program was improved but was not significant compared with the post-six-months home exercise program combined with quinine sulfate therapy. 2) The mean relaxation time of each of the three muscles after the six months multi-therapeutic program was significantly reduced compared with the home exercise program combined with quinine sulfate therapy. In conclusion, the multi-therapeutic program undertaken in this study was the better program for the patients with myotonic dystrophy.

Adolescent↗

PubMedDate not supplied

Evaluation of neck muscle strength with a modified sphygmomanometer dynamometer: reliability and validity.

OBJECTIVE: Determine test-retest reliability, normative data and clinical validity of isometric muscle strength testing in the neck with a modified sphygmomanometer dynamometer (MSD). DESIGN: Analytic survey. Paired trials of various muscle strength tests were conducted on convenience samples of normal subjects and consecutive samples of symptomatic subjects. SETTING: Outpatient chiropractic research clinic. PATIENTS/SUBJECTS: For study 2, 40 normal male subjects, average age 25 +/- 2 yr, were studied for reliability and normative data. For study 3, 24 symptomatic patients, 12 males and 12 females, average age 39 +/- 7 yr, were studied, 8 with "whiplash"-type injuries (average duration 22.5 wk) and 16 with nontraumatic chronic neck pain (average duration 110 wk). INTERVENTION: No therapeutic intervention is reported. MAIN OUTCOME MEASURE: Pressure levels generated by subjects against a modified sphygmomanometer-type dynamometer as measured in kilopascals. RESULTS: Study 1. Repeated paired trials of a standardized weight column (20 lbs) produced a coefficient of variation of 0.84% and virtually no difference between the means of the first vs. second trials. Study 2. High test-retest correlation coefficients were found for all ranges of motion (.79-.97). Right-to-left asymmetry in rotation and lateral flexion was within 6-8%. The flexion/extension ratio was .57:1, indicating that in normal subjects, flexion was approximately 40% lower than extension. Lower cutoffs were established as the mean--1 SD as follows (in kPa): flexion--3300, extension--5800, rotation--5200 and lateral flexion--6200. Coefficients of variation ranged from 25 to 29%. Study 3. Differences between paired trials were analyzed by intraclass coefficients, which were very high (.95-.99), and by percentages, which ranged from 4 to 10.4%, with an average of 7%, indicating a high degree of test-retest consistency. The mean values for all symptomatic subjects for flexion, extension, right rotation and right lateral bending were all well below the normal cutoff values as found in study 2. The flexion/extension ratio for whiplash subjects was 0.25:1.00, which is half of that of normal subjects. CONCLUSIONS: The MSD has been found to be a reliable instrument for the evaluation of isometric muscle strength in the neck in normal and symptomatic subjects. Normative values for absolute test levels, bilateral symmetry and flexion/extension ratios have been determined. A symptomatic group demonstrated significant deviations from these norms in the form of reduced strength levels and reduced flexion/extension ratios, while still maintaining very high levels of test-retest consistency and bilateral symmetry. The MSD appears very promising in the evaluation of neck-injured patients.

Adult↗

PubMed1987

Muscle strength in girls with congenital adrenal hyperplasia.

To assess whether exposure to excessive adrenal androgens increases muscle strength in girls with congenital adrenal hyperplasia, eighteen girls with 21 hydroxylase type congenital adrenal hyperplasia (CAH), aged 4.3-12.1 years were studied and compared with 78 healthy control girls aged 4-16 years. Maximum voluntary isometric strength was measured using a muscle testing chair, and the highest value from at least three attempts with each leg was recorded. Height and weight were also measured in the patients and controls. When compared with normal girls of similar age, some of the girls with CAH seemed unusually strong, but this difference was less marked when the CAH girls were compared with controls of similar weights. However, our data suggest that girls diagnosed later in childhood may have unusual muscle strength.

Adolescent↗