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The ER22/23EK polymorphism in the glucocorticoid receptor gene is associated with a beneficial body composition and muscle strength in young adults.

Glucocorticoids play an important role in determining body composition. A polymorphism of the glucocorticoid receptor gene (in codons 22 and 23) has previously been found to be associated with relative glucocorticoid resistance, low cholesterol levels, and increased insulin sensitivity. In this study, we investigated whether this ER22/23EK polymorphism is associated with differences in body composition and muscle strength. We studied a cohort of 350 subjects who were followed from age 13 until 36 yr. We compared noncarriers and carriers of the ER22/23EK variant in anthropometric parameters, body composition, and muscle strength, as measured by arm pull tests and high jump from standing. We identified 27 (8.0%) heterozygous ER22/23EK carriers. In males at 36 yr of age, we found that ER22/23EK carriers were taller, had more lean body mass, greater thigh circumference, and more muscle strength in arms and legs. We observed no differences in body mass index or fat mass. In females, waist and hip circumferences tended to be smaller in ER22/23EK carriers at the age of 36 yr, but no differences in body mass index were found. Thus, the ER22/23EK polymorphism is associated with a sex-specific, beneficial body composition at young-adult age, as well as greater muscle strength in males.

Adolescent↗

[Development of muscle strength in knee, hip and ankle joints after ACL reconstruction].

INTRODUCTION: We searched for answers for following questions: How does the knee muscle strength change in dependence of post OP time after the same ACL-rehabilitation's program? Which changes in muscle strength occur in hip and ankle muscles after ACL? METHODS: In this study 69 patients with ACL-Reconstruction participated, mean 31 years. The Lysholm- and OAK-scores of all were good respectively very good. 28 patients were 3 - 6 months post OP (Gr. I), 20 were 6 - 12 months post OP (Gr. II), 21 was 12 - 24 months post OP (Gr. II). All patients were tested on the isokinetic Cybex 6000, for dynamic concentric strength and endurance. The evaluation parameters chosen were: max.moment at angle speed of 60 degrees /sec and endurance index at 120 degrees /sec, RESULTS: The analysis of the max. moment showed significant (P < 0.05) changes in both knee extension and flexion in all groups, in the hip flexors and extensors in group I, and hip flexors in group II and III. In the ankle joint we only found significant changes in the plantarflexors of group I. Looking at the endurance index we observed that many muscle groups of the injured leg presented higher values, however the difference is only significant in the knee flexors and extensors of group I and in the hip flexors of group III. CONCLUSION: Our study showed strength loss in both knee extensors and knee flexors in all patients who had undergone reconstruction surgery after the same ACL-rehabilitation's program. We can state that there is strength loss in hip and ankle muscles in 3 - 6 months post OP patients. A reduction of muscle strength at the hip flexor from all patients was seen after 12 months post-OP. It is suggested that the strength loss in the hip flexors could be due to bi-articular muscles surrounding the knee.This results has to be consider on the planning of strength training after ACL injuries.

Adult↗

A randomized, double-blinded, sham-controlled trial of postpartum extracorporeal magnetic innervation to restore pelvic muscle strength in primiparous patients.

OBJECTIVE: The purpose of this study was to determine the effects of extracorporeal magnetic innervation (ExMI) on pelvic muscle strength of primiparous patients. STUDY DESIGN: Primigravid patients were randomized to receive either active or sham ExMI postpartum treatments for 8 weeks. The main outcome measure was pelvic muscle strength measured by perineometry at baseline (midtrimester), 6 weeks (before treatments), 14 weeks, 6 months, and 12 months postpartum. Mixed randomized-repeated measures ANOVA was used to analyze the mean perineometry values between the 2 groups and across all 5 time periods. RESULTS: Fifty-one patients enrolled, and 18 were lost to attrition. There were no differences in demographics or delivery characteristics between the active and sham groups. There was an overall time effect, F(3,85) = 3.1, P = .049, but no group, F(1,31) = 0.007, P = .94, or (group)(time) interaction, F(3,85) = 1.8, P = .15. CONCLUSION: We found no differences in pelvic muscle strength between patients receiving active or sham ExMI treatments in the early postpartum period.

Adult↗

Balance in single-limb stance in patients with anterior cruciate ligament injury: relation to knee laxity, proprioception, muscle strength, and subjective function.

BACKGROUND: It has been shown previously that an anterior cruciate ligament injury may affect postural control, measured by balance in single-limb stance. To our knowledge, no studies have reported the influence of measures of impairment on postural control after such an injury. PURPOSE: To assess the influence of knee laxity, proprioception, and muscle strength on balance in single-limb stance and to study the correlation between balance in single-limb stance and subjective estimation of extremity function. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 36 patients with a unilateral, nonoperated, nonacute anterior cruciate ligament injury were examined with regard to anterior knee laxity, proprioception, muscle strength, and stabilometry (amplitude and average speed of the center of pressure movements). Subjective estimation of extremity function was measured on a visual analog scale. RESULTS: The multiple regression analysis showed that high knee laxity values were associated with high amplitude values and low average speed. Poor proprioception and high muscle strength values were associated with low average speed among the women only. Low amplitude values correlated with better subjective function. CONCLUSION: Anterior knee laxity, proprioception, and muscle strength seem to play a role in maintaining balance in single-limb stance. Patients with low amplitude values in stabilometry were those with better subjective function.

Adolescent↗

Relationship between static muscle strength deficits and spasticity in stroke patients with hemiparesis.

The purpose of this retrospective investigation was to determine whether a relationship exists between static strength deficits in the shoulder medial (internal) rotator and elbow flexor muscles and spasticity in these muscles or their antagonists. We reviewed the records of the first 50 stroke patients with hemiparesis who met the entry criteria for the study and who were admitted over a four-month period of time. Static muscle strength was measured by hand-held dynamometry. Spasticity was graded on the Ashworth scale. Kendall's tau correlations were calculated between static muscle strength deficits and spasticity. Static strength deficits of the shoulder medial rotator and elbow flexor muscles were correlated (p less than .01) with the agonist muscles' spasticity, but not with the antagonist muscles' spasticity. Muscle group spasticity and strength deficits, therefore, appear to be covarying manifestations of cerebrovascular accidents. Clinicians, thus, may interpret an agonist muscle's capacity for force production in light of its own tone rather than that of its antagonist.

Adult↗

Muscle strength, physical fitness, and weight but not age predict femoral neck bone mass.

Hip fractures are the most serious complication of osteoporosis. Although low proximal femoral bone mineral density (BMD) does not cause hip fractures directly, it is clearly a prerequisite for the increased risk associated with aging. To investigate the mechanism of the age-related decline in proximal femoral bone mineral density, we have examined the relative importance of muscle strength, physical fitness, and body mass index (BMI) in addition to age in the determination of proximal femoral BMD in 73 healthy female volunteers age 20-75 years. Muscle strength was an independent predictor of BMD at all three sites in the proximal femur as well as in the lumbar spine and forearm; proximal femur BMD was also predicted by physical fitness. BMI was a positive predictor of bone mass at all sites. In the proximal femur, age was not an independent predictor of BMD at any site. In postmenopausal women muscle strength was a significant predictor of bone mass in the femur and forearm, but not in the spine. However, BMI remained predictive of bone mineral at all sites. Muscle strength, physical fitness, and weight appear to exert independent effects upon bone mass. Age effects may be mediated indirectly through associated changes in these factors. The integrated physical load on the skeleton may be a final common pathway.

Adult↗

Maximal isometric muscle strength: normative values and gender-specific relation to age.

To date, there have been very few studies on the age dependence of maximal isometric muscle strength (MIMS) in healthy subjects aged 20-80 years, based upon measurements of a large number of functional muscle groups (FMGs). Using a hand-held pull gauge it is possible to measure MIMS of nearly every FMG. The objectives of this study were to obtain normative values for MIMS, to evaluate differences in MIMS in relation to gender and body side and to compare the age dependence of muscle strength between women and men. In a convenience sample of 290 healthy women (aged 20-82 years) and 253 men (aged 21-79 years), MIMS of 51 FMGs was measured. For each FMG the age dependence of MIMS was depicted, side and gender specific, as percentile curves and was analysed using linear quantile regression analysis. MIMS was found to be significantly higher in men than in women and higher on the right than on the left side. A biphasic model with linear equations for strength medians was derived for each gender. The age at transition from phase 1 to phase 2 was 55 years (SD 8) for women and 49 years (SD 13) for men. During phase 1, MIMS did not decrease significantly. During phase 2, MIMS decreased in all FMGs in both genders with a steeper slope in women (-0.92) than in men (-0.63). The age dependence of MIMS differed significantly between women and men. The present study gives gender-specific equations which enable one to calculate normative values for MIMS, as measured with a pull gauge, based upon age. These normative values will allow an objective assessment of patients with diminished muscle strength as, for example, in myositis, rheumatoid arthritis and nerve root compression syndromes or in the elderly.

Adult↗

A pilot study comparing the effects of spinal manipulative therapy with those of extra-spinal manipulative therapy on quadriceps muscle strength.

OBJECTIVE: The objective of this study was to assess whether tibiofemoral joint manipulation is as effective as sacroiliac (SI) joint manipulation in increasing quadriceps muscle strength. DESIGN AND SETTING: Twenty subjects were divided into two groups of 10. After all base measurements of the maximum voluntary force of the quadriceps muscles were taken, subjects in group A received tibiofemoral joint manipulation and those in group B received ipsilateral SI joint manipulation. After these treatments, the maximum voluntary forces of the subjects' quadriceps muscles were retested. RESULTS: A significant improvement (P = .05) in quadriceps muscle strength was noted in the subjects who received an SI joint manipulation. CONCLUSION: This study showed a significant change within the SI joint manipulation group before and after the manipulation but did not show any significant difference between the groups (tibiofemoral joint vs SI joint manipulation) in increasing quadriceps muscle strength.

Adult↗

Muscle strength and mass of lower extremities in relation to functional abilities in elderly adults.

BACKGROUND: Functional and physiological declines in advancing age may be significant limiting factors in reduced physical activity. Sarcopenia of aging, as a normative process or disease, cannot entirely explain reduced physical activity in the elderly. OBJECTIVE: The purpose of the study was to investigate the relationship between muscle loss and reduction in functional abilities in elderly adults and also to determine whether an exercise program can improve functional performance and muscle quality. METHODS: Anthropometric measurements and sensorimotor testing were conducted on 28 volunteers (12 men and 16 women, 82.7 +/- 2.4 years of age) who were permanent residents in a skilled nursing facility. Twenty-nine elderly adults (79.3 +/- 3.5 years of age) served as a control, nonexercising group. Anthropometric measurements included: weight, height, body fat, and thigh circumference. The muscle strength was tested with a medical isokinetic system. We assessed two sensorimotor functions including a 'timed up-and-go' test and a 3-min distance walking test. The institutionalized participants undertook an exercise training program lasting 12 weeks. RESULTS: No significant changes were observed in thigh circumference, body weight, or percentage of body fat in either gender as a result of the exercise training. An improvement in muscle strength was noticed in 82% of the relatively younger group (79-83 years of age) under a slow voluntary contraction at 60 degrees /s (p < 0.05). Post-training results showed a significant improvement in performance in the two sensorimotor tests (p < 0.05). The correlation coefficients between muscle strength and functional ability were weak: r = 0.60 and r = 0. 57 for males and females, respectively. CONCLUSIONS: This study confirmed the positive effects of an exercise program on functional performance in older adults. The improvement in functional abilities did not correlate with muscle strength, body weight, or body fat.

Adipose Tissue↗

Impact of impaired inspiratory muscle strength on dyspnea and walking capacity in sarcoidosis.

BACKGROUND: Dyspnea and fatigue are frequent but poorly understood symptoms in sarcoidosis patients. This study was aimed at assessing the clinical impact of inspiratory muscle impairment on dyspnea and exercise tolerance. This is the first study using nonvolitional tests that are independent of the patient's cooperation and motivation in addition to volitional tests of inspiratory muscle strength in patients with sarcoidosis. METHODS: Peak maximal inspiratory mouth pressure (Pimaxpeak), maximal inspiratory pressure sustained for 1.0 s (Pimax1.0), twitch mouth pressure (TwPmo), lung function test results, blood gas measurements, 6-min walking distance (6MWD), and Borg dyspnea scale (BDS) scores were assessed in 24 male sarcoidosis patients and 24 healthy male control subjects matched for age and body mass index. RESULTS: Mean (+/- SD) Pimaxpeak (95.2 +/- 25.3% vs 124.6 +/- 23.4% predicted, respectively; p < 0.001) and Pimax1.0 (85.6 +/- 31.4% vs 125.8 +/- 26.8% predicted, respectively; p < 0.001) were lower in sarcoidosis patients compared to control subjects. TwPmo tended to be lower in sarcoidosis patients, and there were three patients who had TwPmo values of < 1.0 kPa, which is a strong indicator of inspiratory muscle weakness. The mean 6MWD was 582 +/- 97 m in sarcoidosis patients and 638 +/- 65 in control subjects (p = 0.025). The mean BDS score was higher in sarcoidosis patients (3.3 +/- 1.7 vs 0.2 +/- 0.5, respectively; p < 0.001). Compared to maximal inspiratory pressure, lung function parameters, and blood gas levels, TwPmo was the strongest predictor for 6MWD (r = 0.663; p = 0.003) and BDS score (r = 0.575; p = 0.012) in sarcoidosis patients following multiple linear regression analysis. CONCLUSIONS: Impairment of inspiratory muscle strength occurs in sarcoidosis patients, and has been suggested to be an important factor causing dyspnea and reduced walking capacity, but this is only reliably detectable when using nonvolitional tests of inspiratory muscle strength.

Adult↗

Hip adductor muscle strength in patients with varus deformed knee.

The isometric muscle strength of the muscles around 49 medial compartmental osteoarthritic knees of 32 women was measured quantitatively using a Musculater GT-50 (osteoarthritis group). The patients pushed up a pad containing an electrical sensor and values were compared with those obtained from the nonaffected knees of subjects (control group). The mean age of the patients in the osteoarthritis group was 62.3 years (range, 43-78 years). The control group consisted of 13 women (13 knees) with a mean age of 60.5 years (range, 49-73 years). In the osteoarthritis group, the medial joint space was preserved in 17 knees (Grade A), 23 knees had narrowing of the joint space (Grade 2), and nine knees showed joint space obliteration (Grade 3). Quadriceps strength was significantly weaker in Grade 2 knees than in Grade 0 knees; however, there was no significant difference in quadriceps to hamstrings ratio between each grade. The hip adductors to hamstrings ratio was significantly greater in Grade 2 knees than in Grade 0 knees, and was greater in Grade 3 knees than in Grade 0, Grade 1, and Grade 2 knees. The findings suggested that in patients with medial compartmental osteoarthritis of the knee, the hip adductor muscles may become strengthened to decrease varus decrease varus deformity of the limb.

Adult↗

Gender variations of body composition, muscle strength and power output in morbid obesity.

BACKGROUND: Motor capabilities are reduced in obese (OB) individuals, and this impairment may result also from quantitative variation of muscle mass due to alterations in body composition. OBJECTIVE: This study aims to evaluate the differences in body mass (BM) and composition, as well as in muscle strength (ST) and power output W(.) between OB and NW males and females, and to test the hypothesis that variations in body composition affect muscle performance in OB subjects. DESIGN AND METHODS: Body composition (determined by BIA with a two-compartment model), upper and lower limb maximum ST (evaluated with isotonic machines) and lower limb maximum anaerobic W(.) (measured with a jumping test) were studied in a group of 95 extremely OB subjects (OB: 28 males, 67 females; mean age+/-s.d.: 29.3+/-7.0 y; BMI: 41.2+/-4.4 kg/m(2)) and in a control group of 18 NW voluntary subjects (NW: eight males, 10 females; age: 30.3+/-5.3 y; BMI: 22.6+/-2.1 kg/m(2)). RESULTS: OB male and female subjects differed significantly with increases in BM being attained by a similar contribution of fat mass (FM) and fat-free mass (FFM) in male subjects, but mainly contributed by FM in female subjects. Compared with NW, both OB men and women had a greater amount of FFM (P<0.001) and, since a general linear correlation was found between ST and FFM (ST (N)=64.4 FFM (kg)-190.0, R(2)=0.612, P<0.001), they developed higher values of ST (P<0.05) than their respective NW counterparts. For the same reason, both OB and NW male subjects had higher ST (P<0.001) than their female counterparts. Correction for FFM eliminated all gender- and obesity-related ST differences. On the contrary, in spite of their higher absolute muscle strength, both OB men and women could develop absolute W(.) similar to that of NW subjects, and were notably less powerful per unit BM than NW subjects (P<0.001), women being most affected among the OB. CONCLUSIONS: Obesity-related variation in body composition differs considerably by gender, and is responsible for differences in muscle performance: the higher muscle strength observed in OB subjects (both men and women) and in male subjects (both OB and NW) is accounted for by a greater amount of FFM. Nonetheless, biomechanical limitations appear to impair muscle power development during jumping in OB individuals.

Adult↗

The relationship between childhood growth, bone mass, and muscle strength in male and female adolescents.

In this population-based study, the relationship between childhood weight and height, and adolescent bone mass and muscle strength have been studied in 39 girls and 48 boys. Total body and femoral neck bone mass measurements (bone mineral content, BMC and bone mineral density, BMD) were made by dual X-ray absorptiometry. Quadriceps muscle strength was measured. Mean age at the time of measurement was 15.1 years for girls and boys. Results were individually linked to data on childhood (birth to 6 years of age) weight and height, taken from community health records. Childhood weight was found to be predictive of adolescent total body BMC (TBMC). However, this was not the case when correlating childhood weight and total body BMD (TBMD), suggesting that growth determines the size of the skeleton, whereas the density within that bone envelope is to a greater extent governed by other factors. Further, in a multiple regression model we found that the combined effect of childhood weight and height was significantly correlated with adolescent quadriceps muscle strength.

Absorptiometry, Photon↗

Measuring hand intrinsic muscle strength: normal values and interrater reliability.

BACKGROUND: The intrinsic muscles of the hand are of interest in spinal cord injury (SCI) and other myelopathies, because they are innervated by the most caudal cord segments innervating the upper limb. In addition, abnormalities of the peripheral nervous system, such as peripheral nerve entrapments, often affect hand intrinsic muscle strength of SCI patients. Therefore, measuring hand intrinsic strength may allow for early diagnosis of neurologic decline. METHODS: A method was developed for measuring strength of hand intrinsic muscles with a handheld myometer. With the use of a handheld myometer, this study examined the distribution of strength measurements for second-digit abductors, fifth-digit abductors, and thumb opposers in able-bodied participants and in individuals with weakness. The quantitative measurements were compared with manual muscle test scores and interrater reliability is described for these hand intrinsic strength measurements. Thirty-one able-bodied individuals participated (17 men, 14 women; mean age = 37.7 years). In addition, 24, patients with SCI participated (23 men, 1 woman; mean age = 53.5 years; 9 with paraplegia and 14 with tetraplegia as a primary diagnosis). The Bland-Altman method was used to test for interrater reliability. RESULTS: Mean strength of able-bodied participants was 5.0 kg for second-digit abduction, 3.1 kg for fifth-digit abduction, and 5.0 kg for thumb opposition, and the lower limits of normal were 3.0, 1.8, and 3.4 kg, respectively. The 95th percentile of interrater differences were 29.3% for second-digit abduction, 38.5% for fifth-digit abduction, and 43.7% for thumb opposition. CONCLUSION: Abnormal hand intrinsic strength should be suspected if values are lower than the 5th percentile values listed above or if strength change exceeds the 95th percentile for interrater differences shown above. These quantitative hand strength measurements may allow for earlier diagnosis of secondary neurologic complications and may aid in monitoring neurologic recovery in persons with SCI.

Adult↗

Kinematics of the double-leg-lowering test for abdominal muscle strength.

STUDY DESIGN: Prospective descriptive study. OBJECTIVE: To investigate the kinematics of the double-leg-lowering (DLL) test of abdominal muscle strength. BACKGROUND: Adequate strength of the abdominal muscles is necessary for many household, occupational, and sports activities. Therapists, therefore, need valid measures of abdominal muscle strength. METHODS AND MEASURES: A convenience sample of 17 subjects (7 women, 10 men) was tested. Using reflective spheres to identify specific body segments, subjects were videotaped while performing DLL under 2 conditions: attempting (controlled) prevention of anterior pelvic tilting versus not attempting (uncontrolled) prevention of anterior pelvic tilting. Videotape was analyzed using the PEAK 5 2-dimensional system. RESULTS: The pelvis tilted anteriorly by the time the extremities were lowered a mean 3.6 degrees, regardless of condition. No significant difference in anterior pelvic tilting was associated with the 2 DLL conditions (F = 2.95, P = 0.105) but pelvic tilting did increase significantly as the lower extremities were lowered from vertical (F = 98.41, P < 0.001). CONCLUSIONS: There appears to be a natural tendency for the pelvis to tilt anteriorly from very early in the DLL maneuver. As healthy young subjects do not appear able to prevent the tilting, the scoring system associated with the DLL test should be questioned.

Abdominal Muscles↗

Muscle strength in male athletes aged 70-81 years and a population sample.

Muscle strength characteristics of different muscle groups were studied in active male strength-trained (ST, n = 14), speed-trained (SP, n = 16), and endurance-trained (EN, n = 67) athletes aged between 70 and 81 years. A population sample of similar age (n = 42) served as a control group. The isometric forces for hand grip, arm flexion, knee extension, trunk extension, and trunk flexion were higher for the athletes than the controls and higher for the ST than EN group. The SP athletes showed higher values in knee extension and trunk flexion than the EN group. When the isometric muscle forces were related to lean body mass, significant differences still existed between the athletes and controls. However, the differences between the ST and EN groups disappeared. The elevation of the body's centre of gravity in the vertical jump was also higher for the athletes than the controls. The SP group performed better in the vertical jump than either the ST or EN group. The results showed that the athletes who trained not only for strength and speed but also for endurance had superior muscle function compared to the average male population of the same age. Although the strength and speed athletes generally showed the highest muscle strength in absolute terms, the endurance athletes also preserved excellent strength characteristics related to body mass.

Aged↗

Vitamin D deficiency and muscle strength in male alcoholics.

1. Chronic alcoholism may be complicated by proximal muscle weakness associated with a selective atrophy of type II skeletal muscle fibres. The histopathological findings are non-specific as identical changes are seen in proximal muscle weakness associated with various metabolic myopathies, including osteomalacia. 2. The maximum voluntary contraction (MVC) of the dominant quadriceps and plasma 25-hydroxycholecalciferol [25-(OH)D] were measured in male alcoholics and control subjects to determine whether vitamin D deficiency contributed to proximal muscle weakness. 3. In both groups MVC declined with age and was related to body build. The distribution of plasma 25-(OH)D was skewed in alcoholics, with the mean significantly lower than in control subjects. Seventeen per cent of patients (but none of the control subjects) had pronounced biochemical deficiency [plasma 25-(OH)D less than 10 nmol/l]. 4. Alcoholics were significantly weaker than control subjects, even after correcting for the effects of age, height and weight. The severity of associated liver disease (cirrhosis vs no cirrhosis) did not influence muscle strength. Variation in plasma 25-(OH)D and albumin made an insignificant contribution to the difference in MVC observed between patients and control subjects. 5. We conclude that proximal muscle strength is reduced in chronic alcoholism but that this is not due to associated vitamin D [25-(OH)D] deficiency or alcoholic cirrhosis.

Adult↗

[Changes and the clinical significance of muscle strength after different proportion tibial neurotomy].

OBJECTIVE: To study the changes of the muscle strength after the selective tibial neurotomy and the relationship between the changes and the quantities of neurotomy, and to discuss the clinical significances. METHODS: Twenty-four normal SD rats were divided into 4 groups with 6 in each. In group A, the left tibia nerve were cut off by 80%. 60% in group B, 40% in group C, 20% in group D, with the right as the control side. After 6 weeks measure the strength of the crural triceps and the weight of them. RESULTS: In all the groups muscle weight and muscle strength decreased. 88.2% strength decreased on the average in group A, 54.2% in group B, 19.5% in group C, 4.7% in group D. CONCLUSION: It will not damage strength of the crural triceps to cut off below 40% tibial nerve in SD rats.

Animals↗