Relationships between muscle strength and muscle cross-sectional area in male sprinters and endurance runners.
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Adolescent↗
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Cerebral palsy in adults: Independent effects of muscle strength and muscle tone.
OBJECTIVE: To investigate clinical characteristics and their contribution to activities of daily living (ADLs) in adults with cerebral palsy (CP). DESIGN: Descriptions of the clinical features of medical disorders; survey. SETTING: Rehabilitation counseling center in Japan. PATIENTS: A case series of 256 patients (140 men, 116 women; mean age, 31.6yr; range, 17-83yr) admitted to a rehabilitation center from January 1995 to December 1997. MAIN OUTCOME MEASURES: Characteristics investigated included severity of mental retardation, topography of motor deficits, motor power by manual muscle testing, muscle tone rated by using the muscle tone scale, deformity, sensory disturbance, and pain. ADLs were evaluated with the Barthel Index. RESULTS: Patients showed severe impairment in terms of the Ashworth scale for grading spasticity and deformity, and moderate impairment on manual muscle testing. ADLs were influenced significantly by topography of motor deficits, manual muscle test scores, and muscle tone scale assessment (p <.0001). The muscle tone scale findings showed a significant correlation with deformity (p <.0001), but did not correlate with manual muscle testing. ADLs were affected by muscle power and muscle tone independently. CONCLUSION: Adults with CP showed markedly increased muscle tone and moderate muscle weakness. These 2 factors did not correlate with each other, and were independently responsible for worse ADLs.
Activities of Daily Living↗
Relationship between muscle strength and muscle cross-sectional area. Implications for training.
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Biomechanical Phenomena↗
Functional capacity, skeletal muscle strength, and skeletal muscle volume in patients with myocardial infarction.
Previous studies have reported that skeletal muscle strength is closely related to exercise capacity in patients with myocardial infarction (MI). However, none of the previous studies have fully investigated the correlation between exercise capacity and the skeletal muscle volume (MV). Seventy patients with MI underwent symptom-limited cardiopulmonary exercise testing using a treadmill. The MV was evaluated by electrical impedance analysis and the maximal knee extension strength (Peak torque: PT) was measured by a Biodex. The subjects were divided into 2 groups according to the MV (group L, MV < 22 kg; group H, MV > or = 22 kg). The PT was positively and significantly correlated with the peak V(.)O(2) in both the L and H groups (r = 0.70 versus r = 0.71). The MV of the lower limbs was positively correlated with the peak V(.)O(2) in the L group (r = 0.57), but not in the H group. The lower limb MV was positively and significantly correlated with PT in the L group (r = 0.48), but not in the H group. The exercise capacity of patients with MI is thought to depend on both the strength and volume of the skeletal muscle. In MI patients with high muscle volume, exercise capacity was determined by skeletal muscle strength alone.
Electric Impedance↗
A comparison of hand-held isometric strength measurement with isokinetic muscle strength measurement in the elderly.
OBJECTIVE: To compare hand-held isometric muscle strength measurement to an isokinetic muscle strength measurement in a healthy elderly population. DESIGN: Cross-sectional survey. SETTING: Retirement community in Southeastern Arizona. PARTICIPANTS: Thirty-two volunteers (16 men and 16 women) age 60 and over (mean age 70.3 years) who were free of musculoskeletal problems and did not have significant health problems. INTERVENTIONS: None. MEASUREMENTS: Isometric muscle strength was determined using a hand-held isometric strength device (Penny and Giles) for elbow flexion and extension and knee flexion and extension. Isokinetic muscle strength (average peak torque and average work per repetition) was measured on the same individuals using a Lido isokinetic dynamometer. RESULTS: Correlations between the strength measurement techniques were generally favorable with the lowest correlation being .72, (95 percent confidence interval .50-.86) and the highest being .85, (95 percent confidence interval .72-.93). However, there was substantial variability of hand-held strength reading at some levels of isokinetic strength. CONCLUSIONS: Hand-held dynamometry for strength measurement correlates strongly with measurement of strength using isokinetic dynamometry. Despite these high correlations, there is remaining variability of hand-held muscle strength readings when compared with isokinetic strength measurement at some levels of isokinetic muscle strength. Modification of the testing methodology or instrumentation used in this study is needed to improve the consistency of these measurements.
Aged↗
[Muscle strength in patients with gastrointestinal carcinoma--an important role of muscle strength as a nutritional parameter].
The relationship between nutritional status and muscle strength was examined in 73 patients with gastrointestinal carcinoma preoperatively. Nutritional status was assessed by measuring various nutritional parameters. Muscle strength was determined by measurements of %grip strength and respiratory muscle strength expressed as %maximal expiratory and inspiratory pressure (%MEP and %MIP). The results were as follows: %GS was significantly low in the patients who showed low values in body weight (%ideal body weight: %IBW), mid-arm muscle circumference (%AMC), serum albumin (Alb), serum prealbumin (PA), total peripheral lymphocyte count (TLC), and/or nutritional surgical risk index (NRI). %MEP was significantly low in the patients who showed low values in %IBW, %AMC, triceps skin fold, Alb, PA, retinol binding protein, NRI, and/or nutritional assessment index (NAI). %MIP was significantly low in the patients who showed low values in %IBW, %AMC, creatinine height index, Alb, PA, NRI, and/or NAI. %MEP and %MIP were significantly correlated with %GS. Preoperative %GS value was significantly low in the esophageal cancer patients with postoperative pulmonary complications. It was suggested that %GS was a simple and useful nutritional parameter for detecting depletion of the muscle mass and visceral proteins, for respiratory muscle strength, and for functional capacity of muscle.
Aged↗
Trunk muscle strength and back muscle endurance in construction workers with and without low back disorders.
The aim of this study was to test the hypothesis that male workers exposed to heavy work and with no lifetime history of a low back disorder (group A) have better trunk muscle strength and back muscle endurance compared to male workers with the same work exposure but with a probable (group B) or definite low back disorder (group C). Group A (n = 42) was clinically negative on physical examination. Group B (n = 75) was clinically negative or uncertain and group C (n = 86) was clinically positive, with current or previous low back disorders occurring in both groups. Group A had a significantly higher mean intraindividual extension/flexion ratio, namely 1.29 versus 1.19, in group C. The mean values for maximum isometric trunk extension and flexion strength did not differ between the groups. The isometric trunk extensor endurance was significantly lower in group C than in both group A and group B.
Adult↗
[Physical examination--measurement of muscle strength].
Measuring muscle strength and establishing paretic symptoms are done first of all by having the patient perform actions or movements that require normal muscle strength. Measuring or grading the strength of separate muscle groups is usually done by means of the so-called Medical Research Council (MRC) scale that runs from 0 to 5, with the movement against gravity as an important criterion. This scale is not very valid in tract 4 (more strength than needed to overcome gravity, but still subnormal). Using a manual dynamometer or a fixed dynamometer it is possible to measure the strength of most clinically important muscle groups of the extremities and to compare them with values found in a normal population. For following the individual patient with a neuromuscular disorder, strength measurement with the dynamometer is more reliable than grading using the MRC scale.
Diagnosis, Differential↗
Whistle mouth pressure as test of expiratory muscle strength.
Expiratory muscle strength is a determinant of cough function. Mouth pressures during a maximal static expiratory effort (PE,max) are dependent on patient motivation and technique and low values are therefore difficult to interpret. This study hypothesized that a short, sharp and maximal expiration through a narrow aperture, a "whistle", might provide a complementary test of expiratory muscle strength. To obtain a maximal whistle, subjects (27 healthy volunteers and 10 patients with amyotrophic lateral sclerosis) were asked to perform a short, sharp blow as hard as possible, from total lung capacity, through a reversed paediatric inhaler whistle, connected to a flange-type mouthpiece. In both healthy subjects and patients, whistle mouth pressure (Pmo,W) was closely related to the pressure measured in the oesophagus and stomach during the same manoeuvre. In healthy subjects, Pmo,W and PE,max correlated with wide limits of agreement, although Pmo,W values were significantly higher than PE,max (131+/-31 cmH2O versus 101+/-27 cmH2O, p<0.0001). In patients, it was also found that Pmo,w and PE,max values were strongly related (r=0.937, p<0.0001). In healthy subjects, the intraclass correlation coefficient and the variation coefficient for Pmo,W repeated measurements were respectively 0.88 and 7.0%. However Pmo,W and PE,max were always smaller than the gastric pressure generated by a maximal cough. It is concluded that mouth whistle pressure, a noninvasive, reproducible and simple test, provides a reliable measure of expiratory muscle strength in healthy subjects that is acceptable to patients and can be used in a complementary fashion to maximal static expiratory effort.
Adult↗
Skeletal muscle characteristics, muscle strength and thigh muscle area in patients before and after cardiac transplantation.
BACKGROUND: Patients with chronic heart failure demonstrate several skeletal muscle abnormalities. The underlying mechanisms are unclear. After cardiac transplantation, cardiac function is restored, but exercise capacity is still impaired. AIM: To evaluate the influence of cardiac transplantation on skeletal muscle fibre composition, fibre area and capillarization as well as muscle enzymes, lactate, thigh muscle area and strength. METHODS: Ten patients were longitudinally investigated before, 1-3 and 6-9 months after transplantation. Ten healthy individuals served as controls. A biopsy from the lateral vastus muscle was obtained and the thigh muscle area was measured with computed tomography. Muscle strength in the knee extensors and exercise capacity were also evaluated. RESULTS: Muscle lactate was elevated in patients vs. controls (3.6+/-3.0 vs. 1.5+/-0.7 mmol/kg wet wt., P=0.037), and decreased to normal (1.4+/-0.3 mmol/kg wet wt., P=0.038) after transplantation. Citrate synthase activity was decreased in patients (5.6+/-1.5 micromol/g wet wt./min) vs. controls (8.1+/-1.6 micromol/g wet wt./min, P=0.0018), and did not change post transplantation. Patients had decreased number of capillaries in contact with each fibre vs. controls (2.6+/-0.5 vs. 3.5+/-1.0, P=0.039) which persisted post transplantation. Exercise capacity increased after transplantation (74+/-22 vs. 118+/-26 W, P=0.0002), whereas muscle strength did not improve significantly. CONCLUSION: The persisting intrinsic abnormalities in skeletal muscle after cardiac transplantation may contribute to the impaired exercise capacity observed in cardiac transplant recipients.
Case-Control Studies↗
Muscle strength, voluntary activation and cross-sectional muscle area in patients with fibromyalgia.
The objectives were to determine whether the low muscle strength in fibromyalgia is due to lack of exertion and to determine the relation between strength and muscle area. Secondarily we examined the voluntary muscle strength of the different muscles of the leg. The twitch interpolation technique was used to estimate the degree of central activation and the 'true' quadriceps muscle strength. Muscle cross-sectional area was determined with magnetic resonance imaging (MRI). The estimated 'true' muscle strength was 91 Nm (S.D. = 34 Nm) in 15 fibromyalgia patients compared with 125 Nm (28 Nm) in 14 healthy controls (P < 0.02). The 'true' strength divided by the sum of the maximal areas of the four bellies of the quadriceps muscle was lower, being 1.56 Nm/cm2 (0.32 Nm/cm2) in fibromyalgia patients compared with 2.11 Nm/cm2 (0.39 Nm/cm2) in the controls (P < 0.001). The voluntary muscle strength of the flexor muscles of the knee and of the plantar flexors of the ankle was markedly reduced in patients, but no significant differences could be observed in the strength of the dorsal flexors of the ankle. In conclusion, a reduction of the estimated 'true' quadriceps muscle strength per unit area of about 35% was found in fibromyalgia patients.
Activities of Daily Living↗
Isometric strength measurement for muscle weakness in cancer patients: reproducibility of isometric muscle strength measurements with a hand-held pull-gauge dynamometer in cancer patients.
Our aim was to determine several indexes of reproducibility for strength measurements with a hand-held pull-gauge dynamometer (MFB50K) in cancer patients. Two independent testers performed repeated measurements of maximal isometric elbow and knee strength. The measurements were gathered in a convenience sample of 40 patients (27 men, age 20-72 years) with various types and stages of cancer. These patients were recruited from the medical oncology clinic of a university hospital. The Pearson product moment correlation coefficient, the intraclass correlation coefficient (ICC), the standard error of measurement (SEM) and its associated 95% confidence interval, the smallest detectable difference (SDD) and the limits of agreement were determined as outcome measures for reproducibility. The results for the Pearson product moment correlation and the ICC were 0.90 for elbow and 0.96 for knee extension strength. The results in terms of the SDDs were 29.4 newton (N) for elbow and 54.8 N for knee strength. The limits of agreement for elbow strength were -21.7 N and 38.5 N (mean 8.4 N). For knee strength the limits of agreement were -49.8 N and 59.8 N (mean 5 N). The Pearson product moment correlation and the ICC suggested good reproducibility. However, the more informative indices of reproducibility, i.e. the SEM and the SDD, showed relatively large measurement error between the testers. Therefore, the current use of the MFB50K for the measurement of muscle strength is not supported in cancer patients.
Adult↗
Human jaw muscle strength and size in relation to limb muscle strength and size.
The aim of the present study was to investigate to what extent general factors (e.g. genotype, hormones) and factors at the craniofacial level (e.g. craniofacial size, jaw muscle architecture) contribute to the size and strength of the jaw muscles. A strong relationship of jaw muscle size and strength with that of other muscles would argue for general influences, whereas a weak relationship would argue for craniofacial influences. In 121 adult individuals, moments of maximal bite force, arm flexion force and leg extension force were measured. In addition, thicknesses of jaw muscles, arm flexor muscles and leg extensor muscles were measured using ultrasound. Relationships were assessed by using a principal component analysis. In females, one component was found in which all force moments were represented. Bite force moment, however, loaded very low. In males, two components were found. One component loaded for arm flexion and leg extension moments, the other loaded for bite force moments. In both females and males, only one component was found for the muscle thicknesses in which all muscle groups loaded similarly. It was concluded that the size of the jaw muscles was significantly related to the size of the limb muscles, suggesting that they were both subject to the same general influences. Maximal voluntary bite force moments were not significantly related to the moments of the arm flexion and leg extension forces, suggesting that besides the general influence on the muscle size, variation in bite force moment was also influenced by local variables, such as craniofacial morphology.
Adolescent↗
Associations of isometric and isoinertial trunk muscle strength measurements and lumbar paraspinal muscle cross-sectional areas.
The relationships of dynamic and static trunk muscle strength measurements and muscle geometry are studied. Physiologically, isometric muscle strength is directly related to muscle cross-sectional area. We measured isometric and isoinertial trunk muscle strength of 111 former elite male athletes, aged 45-68, by Isostation B-200. Paraspinal muscle cross-sectional areas were measured from axial magnetic resonance images at the L3-L4 level. Isometric and isoinertial torques were closely related, but angular velocities were not predicted by isometric maximal torque. The area of the psoas muscles correlated with isometric maximal flexion, as well as with isoinertial maximal torque. angular velocity, and power in flexion (r = 0.24-0.27). The area of the extensor group correlated with isometric maximal extension and with isoinertial maximal torque and power in extension (r = 0.24-0.25). We conclude that dynamic and static strength measurements are closely related, with angular velocity giving additional information on muscle function. Paraspinal muscle cross-sectional area is one determinant of isometric and isoinertial trunk muscle strength.
Aged↗
Trunk muscle strength in and effect of trunk muscle exercises for patients with chronic low back pain. The differences in patients with and without organic lumbar lesions.
STUDY DESIGN: Trunk muscle strength and the effect of trunk muscle exercises on chronic low back pain were investigated in patients with chronic low back pain. OBJECTIVE: Patients with chronic low back pain include those with organic lumbar lesions and those without such lesions. This study analyzed the differences in trunk muscle strength and effect of trunk muscle exercises between these two groups of patients. SUMMARY OF BACKGROUND DATA: Previous studies have reported lower trunk muscle strength in patients with chronic low back pain and higher efficacy of trunk muscle exercises for treating chronic low back pain. However, no analysis have yet been done of differences in these parameters between patients with chronic low back pain with and without organic lumbar lesions. METHODS: One-hundred-twenty-three patients with chronic low back pain and 126 healthy individuals without low back pain (control group) underwent trunk muscle strength evaluation. The patients were further divided into two groups-- those in group 1 had detectable organic lumbar lesions and those in group 2 had no detectable organic lesions. Seventy-two of these patients performed trunk muscle exercises and the correlation between improvement in low back pain and increase in trunk muscle strength was analyzed. RESULTS: Trunk flexor and extensor strengths were significantly lower in both groups. However, the flexor/extensor ratio of maximum torque was significantly higher in group 1 than in the control group, but was not significantly different between group 2 and the control group. Trunk muscle exercises reduced low back pain in both groups, but were more effective in group 2 than in group 1. The degree of correlation between increase in trunk muscle strength and improvement of low back pain also was higher in group 2 than in group 1. CONCLUSION: This difference in flexor/extensor ratio may have been due to reduced extensor strength resulting from neurogenic muscle weakness induced by the organic lumbar lesions in group 1. The exercise-associated increase in trunk muscle strength did not completely eliminate the low back pain induced by the organic lumbar lesions in group 1. However, increasing trunk muscle strength was extremely effective in patients of Group 2, in which decreased trunk muscle strength was a major factor in chronic low back pain.
Adolescent↗
Impact of Muscle Quality on Muscle Strength and Physical Performance Beyond Muscle Mass or Diabetes Status.
BACKGROUND: Muscle quality, represented by myosteatosis, is recognized as an important factor in sarcopenia. In this study, we aimed to determine the associations between myosteatosis, muscle strength and physical performance among the elderly South Korean population. METHODS: We included 1440 participants (mean age 62.7 ± 6.2 years) from the Korean Genome and Epidemiology Study (KoGES). Based on the computed tomography attenuation of mid-thigh imaging, the total muscle area (TMA), normal-attenuation muscle area (NAMA), low-attenuation muscle area (LAMA) and inter-intramuscular adipose tissue (IMAT) and its indices were used to evaluate myosteatosis. Muscle strength was evaluated using hand grip strength, whereas physical performance was evaluated through 4-m gait speed, a 30-s sit-to-stand test and 2-min walking test. RESULTS: Of the 1440 patients, 51.5% were women, and 37.2% had diabetes. With aging, the LAMA index gradually increased, and the NAMA index gradually decreased in both men and women (p for trend < 0.001). The NAMA index was positively associated, whereas the LAMA and IMAT indices were negatively associated with muscle strength and physical performance after adjusting for age and sex. Higher tertiles of the NAMA index were consistently associated with improved physical performance across all appendicular skeletal muscle tertiles. The relationship between the NAMA index or LAMA index and muscle strength and physical performance did not differ according to diabetic status. Regular exercise was associated with a higher NAMA index and a lower LAMA index in the non-diabetic group; however, no significant difference in muscle quality was observed in the diabetic group in relation to exercise. CONCLUSIONS: Reduced myosteatosis was positively associated with greater muscle strength and better physical performance in both men and women, regardless of muscle mass or diabetes status; improving myosteatosis may be a therapeutic target for the prevention of sarcopenia.
Humans↗
Local bone mineral density, muscle strength, and exercise in adolescent boys: a comparative study of two groups with different muscle strength and exercise levels.
The primary objective of the present study was to evaluate the impact of physical activity and muscle strength on bone mineral density (BMD) of the tuberositas tibiae in adolescent boys. Two groups with different exercise levels were compared. The high activity group consisted of 20 subjects (age 15.9 +/- 0.3) from a junior ice hockey team. The reference group consisted of 24 volunteers (age 15.9 +/- 0.3) not training for more than 3 hours per week. The groups were matched for age, weight, and pubertal stage. BMDs (g/cm2) of the tuberositas tibiae and proximal tibia were measured using dual energy X-ray absorptiometry. Quadriceps strength was significantly higher in the high activity group (P < 0.01). Univariate correlations were measured between tuberositas tibiae BMD and pubertal stage, weight, height, BMI, fat mass, lean body mass, quadriceps strength, and hamstrings strength in the high activity group and the reference group, respectively. Quadriceps strength was estimated to be the best significant predictor of BMD of the tuberositas tibiae in the reference group. A multivariate analysis confirmed this result. In the high activity group, there was no significant predictor of BMD of the tuberositas tibiae. There was no significant difference in BMD at this site when comparing the two groups. However, five of the boys in the high activity group had a former history of Mb Osgood-Schlatter with a significantly lower BMD of the tuberositas tibiae than the rest of the boys in that group. After exclusion of these boys, the remaining 15 boys were matched against 20 boys from the reference group using the previous criteria. These 15 boys then showed a significantly higher BMD of the tuberositas tibiae (P < 0.05) but not of the proximal tibia than the 20 boys in the reference group. In conclusion, this study demonstrates site-specific increments of tuberositas tibiae BMD in adolescent ice hockey players unless they are affected by the negative effects on BMD by Mb Osgood-Schlatter. These increments seem primarily to be associated with forceful muscle contractions related to high quadriceps strength and not greater weight-bearing loading. Muscle strength seems to positively affect BMD of the tuberositas tibiae in adolescents, but only up to a certain level, above which additional muscle strength has no effect.
Adolescent↗
Normal trunk muscle strength and endurance in women and the effect of exercises and electrical stimulation. Part 2: Comparative analysis of electrical stimulation and exercises to increase trunk muscle strength and endurance.
Several studies have shown positive correlations between muscle strength, flexibility, and the frequency of low-back pain. Weak trunk musculature and decreased endurance have thereby come to be identified as significant risk factors in the development of occupational back problems. Because it is widely accepted that exercise plays an important role in the conservative treatment and prevention of low-back pain, the goals of most rehabilitative programs involves improving the strength and endurance of the low-back pain patient. Whereas electrical stimulation has been shown to increase the muscle strength of the lower extremities, this effect has not been demonstrated for the trunk muscles. Part 2 is a prospective controlled study designed to document and to compare objectively the effects of electrical stimulation and exercise on trunk muscle strength. A total of 117 healthy women were divided randomly into four groups. Two groups received electrical stimulation with different electrical parameters, one group received exercises, and one group acted as a control group. The results showed that low-frequency electrical stimulation and exercises significantly (P less than .05) increased isokinetic back-muscle strength compared to the control and medium-high-frequency electrical stimulation groups. Both types of electrical stimulation, however, significantly increased (P less than .05) the endurance in the back muscles compared with the control and the exercise groups. This study showed that electrical stimulation may be a valuable treatment in the early care of low-back pain patients in maintaining and increasing strength and endurance of back muscles when a more active exercise program is too painful to perform.
Adolescent↗