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Results for “Muscle Strength”

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At least 217 records · Page 12Linked to original sources

PubMed1992

Determinants of isometric muscle strength in men of different ages.

Values of maximal isometric strength of five muscle groups and associated factors including occupational status, life style and health were studied in three groups of men aged from 31 to 35, 51 to 55, and 71 to 75 years. The results indicated significant differences between the age groups in isometric handgrip, elbow flexion, knee extension, trunk extension and trunk flexion strength. In the youngest group, the manual workers tended to have higher strength values in all muscle groups than the lower and higher status white collar workers, whereas among the middle-aged and oldest men the manual workers tended to have the poorest performance. Good self-rated health and the intensity of physical exercise during leisure were positively associated with muscle strength in the youngest and middle-aged groups whereas in the oldest group the most important variable was home gymnastics. The multivariate structural equation models of isometric strength differed somewhat among the age groups and in these models the above-mentioned variables accounted for from 33% to 43% of the variance in isometric strength within the age groups. The results illustrated the most important factors associated with isometric strength in samples of men of different ages and also provided suggestions as to how these determinants might influence comparisons between different age groups in respect of muscle strength.

Adult↗

PubMed2005

A TA-repeat polymorphism in the gene for the estrogen receptor alpha does not correlate with muscle strength or body composition in young adult Swedish women.

OBJECTIVES: There are conflicting data in the literature whether estrogens affect muscle strength. Prospective studies with hormone replacement therapy have not been able to convincingly demonstrate a muscular effect and the putative role of estrogen in the development of lean body mass is not established. Both lean mass and fat mass are known to be under strong genetic control and therefore we have investigated the relation between a TA-repeat in the gene for the estrogen receptor alpha (ERalpha) and muscle strength and body composition. METHODS: 175 healthy Swedish women, aged 20-39 were randomly selected from the population registry and included in the study. Body mass measurements (lean mass, fat mass, body weight and BMI) and muscle strength (quadriceps, hamstring and grip strength) were evaluated. The TA-repeat in the ERalpha gene was amplified by polymerase chain reaction. RESULTS: Alleles with a TA-repeat length of 16 repeats or shorter were denoted short (e), and repeat length of 17 repeats or longer were denoted long (E). Women homozygous for the short and long genotype were denoted ee (31%) and EE (21%), respectively, while heterozygous individuals were denoted Ee (48%). The frequencies were in Hardy-Weinberg equilibrium. No associations were found between ERalpha genotypes and muscle strength or body composition. CONCLUSION: The TA-repeat in the human ERalpha gene does not correlate with muscle strength or body mass measurements, indicating that body composition is not as sensitive to genetic variation in this receptor as other target organs for estrogen.

Adult↗

PubMed2003

[Relationship between lower extremity muscle strength and dynamic balance in people post-stroke].

UNLABELLED: The purpose of this study was to determine how lower extremity muscle weakness is related to post-stroke difficulties in balancing. METHODS: Dynamic balance of 30 people post-stroke and 30 neurologically sound people was assessed by the Functional Reach Test and the Timed Up and Go Test. Bilateral lower extremity muscle strength was measured in classical manual muscle testing positions using a Lafayette instrument. RESULTS: There was a weak correlation between lower extremity muscle strength and the Functional Reach Test: from r=0.05 to r=0.53 for the impaired extremity and from r=0.23 to r=0.53 for the sound extremity. Control group results were from r=0.51 to r=0.86. The correlation between lower extremity muscle strength and the Timed Up and Go Test was from r=-0.33 to r=-0.64 for the impaired extremity and from r=-0.35 to r=-0.58 for the sound extremity. Control group results in this testing situation were from r=-0.63 to r=-0.90. CONCLUSION: The results of the study indicate that the loss of lower extremity muscle strength as a result of cerebrovascular accident has a poor influence on dynamic balance problems in people post-stroke.

Aged↗

PubMed1996

High bone mass and altered relationships between bone mass, muscle strength, and body constitution in adolescent boys on a high level of physical activity.

We have recently demonstrated a general relationship between bone mass, muscle strength, and several body constitutional parameters in adolescent boys with a moderate exercise level. The present study was conducted to evaluate these previously described relationships in adolescent boys subjected to high physical activity and also to compare the bone mass of the same group with that of adolescents on a moderate level of physical activity. The reference group consisted of 24 boys, age 15.9 +/- 0.3 years, not training for more than 3 h per week. The ice hockey players consisted of 20 boys, age 15.9 +/- 0.3 years, from an ice hockey junior team training for about 10 h per week. The groups were matched according to age, pubertal stage, and weight. Areal bone mineral density (BMD) was measured in total body, head, humerus, spine, femur, and proximal femur using dual energy X-ray absorptiometry. BMD was significantly higher in the humerus (p < 0.01), femur (p < 0.05), and proximal femur (p < 0.05) in the high activity group. Furthermore, physical activity (h/week) was an independent predictor of humerus BMD (p < 0.01) and proximal femur BMD (p < 0.05), among all subjects investigated (n = 44). Isokinetic muscle strength of the quadriceps and hamstrings muscles was significantly higher in the high activity group (p < 0.05). In the reference group, there was a general strong independent relationship between BMD, muscle strength, and different body constitutional parameters. In the high activity group, muscle strength of the thigh independently predicted BMD of humerus and spine. Furthermore, in the same group, weight, BMI, and fat mass independently predicted only spine BMD. In conclusion, the higher BMD demonstrated in the ice hockey players seems to be site-specific and may well be associated with the type and magnitude of loading from predominantly ice hockey. High physical activity seems to weaken the relationship between BMD, muscle strength, and body constitution demonstrated in adolescent boys on a low or moderate level of physical activity.

Adolescent↗

PubMed1997

Hemodialysis treatment may improve inspiratory muscle strength and endurance.

Chronic renal failure can result in a variety of conditions leading to muscle weakness. However, little is known about inspiratory muscle performance and the acute effects of hemodialysis on the muscles. We investigated the inspiratory muscle performance in chronic renal failure patients undergoing maintenance dialysis. Static inspiratory pressures and inspiratory muscle endurance were determined in 21 patients (13 men and 8 women), before and after dialysis. Inspiratory muscle strength before dialysis was significantly reduced in all subjects but one (mean +/- SEM, PImax = 52.9% of predicted). Following dialysis, the static inspiratory pressure was increased in 18 patients, decreased in 1 patient and remained unchanged in 2. Inspiratory muscle endurance was almost normal before dialysis (mean +/- SEM, PmPeak/PImax = 66.1%). Following dialysis, the inspiratory muscle endurance increased in 13 patients, decreased in 5 patients and remained unchanged in 3. There was no significant correlation between inspiratory muscle strength and the time on chronic hemodialysis. We conclude that in patients with chronic renal failure receiving maintenance hemodialysis there is predialysis reduction in inspiratory muscle strength and less significant reduction in the endurance. Both the inspiratory muscle strength and endurance significantly increased following hemodialysis in most but not all of the subjects. The dialysis-induced changes in biochemical parameters may exert opposing effects on inspiratory muscle performance. This might explain the diversity of the results obtained in this study and studies performed by others.

Adult↗

PubMed2006

A method for comparing manual muscle strength measurements with joint moments during walking.

This paper describes a protocol for dynamometer assisted manual muscle testing of the major muscle groups of the lower extremity and its application to 11 able-bodied children who also had conventional gait analysis to obtain joint kinetics. Data from the manual muscle testing was processed in such a way that the results for maximum muscle strength (grade 5) and resistance against gravity alone (grade 3) were presented in Nm/kg allowing direct comparison with conventional joint kinetics. The strength measurements of the hip muscles and the knee extensors were between two and three times the moments exerted during normal walking. Those of the knee flexors and dorsiflexors were about five times the joint moments. Measured plantarflexor strength was only just greater than the moment exerted during walking. These results, particularly those for the plantarflexors, question how valid it is to use measures of isometric muscle strength as indicators of muscle function during activity. The study also compares grade 3 muscle strength with both grade 5 strength and the maximum joint moments. For all muscle groups tested grade 3 muscle strength was less than the maximum moment exerted during normal walking. For the plantarflexors it was less than 1% of that moment. The study demonstrates that reliable isometric muscle testing is possible in able-bodied children but requires considerable care and is time consuming. More work is required to understand how measurements made in this way relate to how muscles function during activity.

Biomechanical Phenomena↗

PubMed2004

Neck muscle strength and endurance in fighter pilots: effects of a supervised training program.

INTRODUCTION: Cervical discomfort is common among pilots of high performance aircraft. An exercise program was introduced to increase the strength and endurance of the neck muscles. The purpose of this study was to analyze whether coaching or reinforcement strategies by a physical therapist was associated with improvement in neck muscle strength, endurance, and neck complaints in two cohorts of fighter pilots performing regular neck muscle exercises. METHODS: A reinforced group (RG) of 20 pilots (24-40 yr) at an Air Force base received weekly encouragement to perform their standardized exercise program three times per week. A non-reinforced reference group (NRG) of 20 pilots (23-37 yr) from another Air Force base carried out the same program without any supervision. Both groups performed the training program for 6-8 mo. Before and after the training period, isometric measurements of the neck flexors and neck extensors were performed in both groups. RESULTS: After the completion of the 6-8 mo training period, the RG pilots significantly increased their neck muscle strength (flexors: M = 3.9 nm, p = 0.000 and extensors: M = 5.0 nm, p = 0.001) as well as endurance in their neck extensors (M = 53 s, p = 0.000). The NRG pilots significantly decreased both strength (M = 11.5 nm, p = 0.0001) and endurance (M = 33 s, p = 0.003) of their neck extensors. Furthermore, the NRG pilots did not show any significant change of their neck flexor strength. No significant changes in the frequency of neck complaints were reported in either group throughout the entire study period. CONCLUSION: The reinforced training program increased the strength and endurance of the appropriate muscle groups. In order to draw any further conclusions concerning reducing neck complaints, a longer observation period with a larger group of pilots might be needed. However, it is likely that there is an individual correlation between strength and endurance of the neck muscles and neck pain, which means that any rehabilitation program should be tailored for each individual.

Accidents, Occupational↗

PubMed1999

Gender differences in muscle strength & endurance in young Indian adults.

Muscle strength was studied in 70 males and 53 females between the ages of 17-30 yr, using a handgrip dynamometer. In a subset group of 31 males and 20 females, muscle endurance during sustained isometric contraction was studied using a load cell based handgrip dynamometer coupled to a polygraph. The males had a significantly greater muscle mass and lower body fat as compared to the females. Males had close to twice the handgrip strength of females in absolute terms (P < 0.01) and this difference persisted after correction for forearm muscle area (P < 0.05). In contrast, the rate of decline of muscle strength during sustained isometric contraction was lower in females as compared to males (P < 0.05), suggestive of greater skeletal muscle endurance in females. Physical activity patterns were not a determinant of skeletal muscle function. These findings are consistent with gender specific muscle fibre characteristics reported in literature in other racial groups.

Adolescent↗

PubMed2001

Vitamin D status, trunk muscle strength, body sway, falls, and fractures among 237 postmenopausal women with osteoporosis.

The aim of this study was to identify factors associated with fractures in patients with postmenopausal osteoporosis. The overall hypothesis was that trunk muscle strength, body sway and hypovitaminosis D would influence daily activities and the likelihood of falls and fractures. - In 237 women (mean age 62.9+/-7.4 years) osteoporosis was defined by a T-score at the femoral neck below -2.5 SD. Trunk muscle strength was determined using isokinetic dynamometry and body sway was measured according to Lord et al. Limitations in everyday life were assessed and the history of falls was documented. A fracture was defined as a vertebral height reduction of more than 20% or at least 4 mm. The assessment was carried out using the Spine Deformity Index (SDI) and was confirmed by an experienced radiologist. Pearson coefficients of correlation were calculated. - After correction for age, significant associations were found for body sway and 25-hydroxyvitamin D (p<0.001), body sway and falls (p<0.001), body sway and rib fractures (p<0.01), trunk muscle strength and limitations in everyday life (p<0.001), trunk muscle strength and SDI (p<0.001), trunk muscle strength and bone density (p<0.001), and bone density and 25-hydroxyvitamin D (p<0.001). No significant correlation was found for trunk muscle strength and 25-hydroxyvitamin D (p=0.712). - Findings suggest that hypovitaminosis D is associated with increased body sway and an elevated risk for falls and falls-related fractures. Musculoskeletal rehabilitation should include strengthening exercises for the trunk muscles and training of neuromuscular co-ordination and balance.

Accidental Falls↗

PubMedDate not supplied

Back muscle strength and weight limits in lifting burdens.

When lifting loads, the muscles of the back, rather than the ligaments and the bony structures of the spine, should overcome the gravitational forces. Formulas, based on measurements of the back muscle strength for prediction of maximum loads to be lifted, have been worked out and tested in practical situations. From tests with 50 male and female subjects, the simplest prediction formulas for maximum loads were as follows: for men, maximum load = 1.10 X isometric back muscles strength; for women, maximum load = 0.95 x isometric back muscle strength minus 8 kg.

Adult↗

PubMed1988

Isometric and isokinetic muscle strength, anthropometry and physical activity in 8 and 13 year old Swedish children.

Isometric muscle strength of the hand-grip and of trunk flexion and extension, and isokinetic torque of elbow and knee flexion and knee extension were assessed in a random sample of 8 and 13 year old Swedish children. The results were compared with respect to sex and age in absolute terms and relative to weight, height2 and estimates of lean body mass and cross-sectional muscle area. Daily physical activity was also estimated. The muscle strength variables were in general found to be very similar in the 8 year old boys and girls. In the 13 year old group the boys were generally stronger than the girls, in both absolute and relative terms, except for similar torque values during knee extension. The absolute and relative muscle strength and torque values were higher in the older than in the younger children, with the exception of trunk strength per unit of body weight and of lean body mass, which were similar in boys of both ages and significantly lower in the older than in the younger girls. No significant correlation was found between the estimates of physical activity and isometric and isokinetic muscle strength and torque.

Adolescent↗

PubMed2004

Relationships between muscle strength and bone mineral density of three body regions in sedentary postmenopausal women.

This cross-sectional study was designed to investigate correlations between muscle strength and regional bone mineral density (BMD) in sedentary postmenopausal women. Sixty-two women who ranged in age from 41 to 76 years were investigated. Hip and trunk muscle strength was measured by isokinetic dynamometry. Grip strength of the nondominant hand was measured using a hand-held dynamometer. Bone mineral density of the lumbar spine, femur, and distal radius was measured by dual-energy X-ray absorptiometry. Only the correlation between hip abductor strength and femoral BMD was significant (P = 0.009, r = 0.327). There was no correlation between trunk muscle strength and lumbar vertebral BMD or between grip strength and distal radius BMD. Subjects with osteoporosis (T score < -2.5) or osteopenia T (-2.5 to -1) and normal subjects (T > -1) exhibited similar isokinetic hip and trunk muscle strength. Women with osteoporotic distal radii had significantly lower grip strength than subjects who were osteopenic or normal at this site, but the osteoporotic group was also significantly older. In conclusion, our results indicate that the isokinetic strength of hip abductors weakly correlates with femoral BMD in postmenopausal women with and without osteoporosis. Trunk muscle strength did not correlate with lumbar vertebral BMD in either of these groups. The weaker handgrip we observed in the women with osteoporotic radii may be attributed to older age.

Absorptiometry, Photon↗

PubMed2005

Elastic properties of human Achilles tendon are correlated to muscle strength.

The purpose of this study was to investigate whether the mechanical properties of the Achilles tendon were correlated to muscle strength in the triceps surae in humans. Twenty-four men and twelve women exerted maximal voluntary isometric plantar flexion (MVIP) torque. The elongation (DeltaX) and strain of the Achilles tendon (epsilon), the proximal part of which is the composite of the gastrocnemius tendon and the soleus aponeurosis, at MVIP were determined from the displacement of the distal myotendinous junction of the medial gastrocnemius using ultrasonography. The Achilles tendon force at MVIP (F) was calculated from the MVIP torque and the Achilles tendon moment arm. There were no significant differences in either the F-DeltaX or F-epsilon relationships between men and women. DeltaX and epsilon were 9.8 +/- 2.6 mm and 5.3 +/- 1.6%, respectively, and were positively correlated to F (r = 0.39, P < 0.05; r = 0.39, P < 0.05), which meant that subjects with greater muscle strength could store more elastic energy in the tendon. The regression y-intercepts for the F-DeltaX (P < 0.01) and F-epsilon (P < 0.05) relationship were significantly positive. These results might indicate that the Achilles tendon was stiffer in subjects with greater muscle strength, which may play a role in reducing the probability of tendon strain injuries. It was suggested that the Achilles tendon of subjects with greater muscle strength did not impair the potential for storing elastic energy in tendons and may be able to deliver the greater force supplied from a stronger muscle more efficiently. Furthermore, the difference in the Achilles tendon mechanical properties between men and women seemed to be correlated to the difference in muscle strength rather than gender.

Adult↗

PubMed1992

Muscle strength, endurance, and aerobic capacity in rheumatoid arthritis: a comparative study with healthy subjects.

Isometric/isokinetic muscle strength and isokinetic endurance of the lower extremities as well as aerobic capacity were evaluated in 67 patients (43 female, 24 male; mean age 53 years, range 23-65) with classical/definite rheumatoid arthritis (RA) of functional class II. Results obtained were compared with those of a healthy reference group matched for age and sex. Disease characteristics of the group with RA were registered and lifestyle characteristics, such as work load, exercise, diet, smoking, and alcohol habits, were reported by both groups. Generally, results showed that the group with RA had decreased functional capacity. Isometric hip and knee muscle strength of the rheumatoid group was reduced to about 75% of normal function, isokinetic knee muscle strength at the velocities of 60 and 180 degrees/s to about 65% and 75% of normal function respectively, isokinetic endurance of the knee muscle groups to about 45%, and aerobic capacity to about 80% of the results obtained for the healthy reference group. Analyses of variance showed that the rheumatoid group, compared with the healthy group, had significantly reduced function on all isometric and isokinetic tests of the extensors and flexors of the knee. Results for isometric hip muscle strength were similar--all tests but one yielding highly significant differences. To avoid unnecessary functional deficits it seems important to include muscular training in rehabilitation programmes for patients with RA.

Activities of Daily Living↗

PubMed2003

Muscle strength and walking ability after laparoscopic hernioplasty versus conventional repair.

PURPOSE: We examined muscle strength and walking ability after hernia repair to compare the effects of laparoscopic hernioplasty and conventional repair. METHODS: Twenty-seven patients with primary inguinal hernias were randomly divided into two groups according to the surgical procedure: 15 patients were treated with laparoscopic hernioplasty and 12 with conventional repair. Two types of muscle testing around the inguinal region, one by manual examination and one using a musculator, were done preoperatively and 1 week postoperatively. Walking exercise tests were performed at the same time as muscle testing. RESULTS: Manual examination showed that the postoperative muscle strength of the iliopsoas muscle was decreased in six patients from the conventional repair group, but not in any of those from the laparoscopic hernioplasty group. The musculator showed decreased strength of the iliopsoas muscle after conventional repair, but not after laparoscopic hernioplasty. The walking exercise test showed that conventional hernia repair influenced walking. CONCLUSION: A decline in muscle strength of the iliopsoas muscle and walking ability was evident after conventional repair, but not after laparoscopic hernioplasty. Thus, laparoscopic hernioplasty is superior to conventional repair from the perspective of muscle testing and walking ability.

Adult↗

PubMed1996

The effects of lumbosacral support belts and abdominal muscle strength on functional lifting ability in healthy women.

STUDY DESIGN: This study focused on lumbosacral support belts, abdominal muscle strength, and lifting ability in healthy women. Subjects underwent manual muscle testing to determine muscle strength and performed lifting procedures to determine lifting capacity. OBJECTIVES: The purpose of this study is threefold: 1) to determine the effectiveness of lumbosacral support belts in improving lifting ability in healthy women, 2) to determine if lumbosacral support belts are more effective for those with weak abdominals than those with strong abdominals, and 3) to determine if the maximum amount of weight varies with abdominal muscle strength. SUMMARY OF BACKGROUND DATA: In a review of published literature, one study has addressed the relationship of lumbosacral support belts and lifting capacity. However, no study has examined the use of lumbosacral support belts and lifting capacity in a female population. METHODS: A convenient sample of 69 healthy women, aged 20 to 40 years, participated in this study. Subjects were categorized into one of three groups based on lower and upper abdominal muscle strength. Each subject then performed two lifting procedures, one with a lumbosacral support belt and one without, to determine two maximum lifts. RESULTS: Women between the ages of 20 and 40 years could lift approximately 1.0 kg more weight from the floor to waist height with the lumbosacral support belt. The maximum weight lifted varied with abdominal strength. Lumbosacral support belts were not more effective for those with weak abdominals than those with strong abdominals. CONCLUSIONS: When applied properly and used in conjunction with proper lifting technique, lumbosacral support belts slightly improved lifting ability in healthy women. The magnitude of the increase, although statistically significant, is not sufficient to advocate the use of lumbosacral support belts to increase lifting capacity.

Abdominal Muscles↗

PubMed1999

A comparison of bone mineral density and muscle strength in young male adults with different exercise level.

The aim of this study was to investigate any differences in bone mass at different sites between young adults subjected to a high physical activity and a group of young adults with a low level of physical activity. In addition, we compared the relationship among bone mass, muscle strength, and body constitution in these two groups. The reference group consisted of 20 men, age 24.6 +/- 2.3 years, not training for more than 3 hours per week. The ice hockey players consisted of 20 players, age 23.4 +/- 4.9 years, from an ice hockey team in the second highest national Swedish league, training for about 10 hours per week. The groups were matched according to age, height, and weight. Areal bone mineral density (BMD) was measured in total body, head, humerus, spine, pelvis, femur, femoral neck, Ward's triangle, trochanter, femur diaphysis, proximal tibia, and tibia diaphysis using dual energy X-ray absorptiometry. BMD was significantly higher in the total body (8.1%), humerus (11.4%), spine (12.7%), pelvis (12.4%), femoral neck (10.3%), femur (7.4%), proximal tibia (9.8%), and tibia diaphysis (7.5%) in the high activity group. Fat mass was significantly lower in the high activity group (18.7%). The high activity group also had a significantly higher lean body mass (5.4%) and a significantly higher isokinetic muscle strength of the quadriceps muscle compared with the reference group. In the reference group, there was a general strong independent relationship between muscle strength of the thigh and all BMD sites, except for the head, tibia diaphysis, and proximal tibia. Furthermore, in the same group, body mass index (BMI) independently predicted pelvis BMD. On the contrary, in the high activity group, muscle strength did not predict any BMD site at all. In the same group, body constitutional parameters (weight, height, and fat mass) independently predicted pelvis BMD, and BMI was shown to be an independent predictor of humerus BMD. The differences in BMD between the groups seem to be site-specific and may be associated with the type and magnitude of loading during off season training and preferentially during ice hockey. High physical activity seems to weaken the relationship between BMD and muscle strength. Hence, impact forces may be of greater importance in regulating bone mass than muscle strength in itself in highly trained athletes.

Absorptiometry, Photon↗

PubMed1998

Isokinetic muscle strength after anterior cruciate ligament reconstruction.

The purpose of the present study was to investigate the isokinetic muscle strength 6 months after reconstruction of the anterior cruciate ligament (ACL). In order to recommend full-load come-back in sport, sufficient muscle strength may be important. Ninety female elite team handball players (mean 24.1 years) were postoperatively tested with Biodex. The operated limb was compared with the contralateral limb: 82.2% had a hamstring strength of a minimum of 49.6 Nm, corresponding to at least 90% of the non-operated limb, while only 12.2% fulfilled the recommended strength of 117.7 Nm for quadriceps femoris. Patients over 26 years showed significantly lower muscle strength in the operated limb than their younger counterparts. Increased focus on quadriceps femoris muscle strength during rehabilitation may improve the knee function faster after ACL reconstruction.

Acceleration↗