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PubMed1990

Strength training and determinants of VO2max in older men.

The effects of strength training on maximal aerobic power (VO2max) and some of its determinants were studied in 12 healthy older men (60-72 yr). They underwent 12 wk of strength conditioning of extensors and flexors of each knee with eight repetitions per set, three sets per session, and three sessions per week at 80% of the one repetition maximum (1 RM). Left knee extensors showed a 107% increase in 1 RM, a 10% increase in isokinetic strength at 60 degrees/s, and a 23% increase in total work performed during 25 contractions on an isokinetic dynamometer. Strength measurements of the untrained left elbow extensors showed no change. Leg cycle ergometer VO2max per unit fat-free mass increased by an average 1.9 ml (P = 0.034) whereas arm cycle VO2max was unchanged. Pulmonary function, hemoglobin concentration, erythrocyte volume, plasma volume, and total blood volume did not change. Biopsies of the vastus lateralis showed a 28% increase in mean fiber area, no change in fiber type distribution, a 15% increase in capillaries per fiber, and a 38% increase in citrate synthase activity. The data suggest that the small increase in leg cycle VO2max in older men may be due to adaptations in oxidative capacity and increased mass of the strength-trained muscles.

Aged↗
PubMed1975

Grip strength and grip endurance in physical therapy students.

A hand-grip dynamometer was used to test the maximal grip strength and endurance index of 15 male and 15 female physical therapy students. The results showed that there was no apparent correlation between maximal grip strength and endurance index in the male subjects, but there was a tendency for endurance index to decrease as maximal grip strength increases in the female subjects. Maximal grip strength and body weight were positively correlated in both the males and the females. There was no significant difference in endurance index between the males and the females.

Adult↗
PubMed1988

An evaluation of the dynamic qualities of isometric grip strength.

A strain gauged torsion dynamometer linked to a microprocessor was used to assess the dynamic qualities of isometric grip strength in patients with rheumatic diseases. Maximum grip strength, time to maximum grip, and percentage fatigue provide independent information on the grip. Time to maximum grip does not appear to be an objective correlate of subjective stiffness. The usefulness of these dynamic variables for the assessment of stiffness appears limited in arthritic disease, where pain may interfere with the maximum voluntary effort of the test.

Arthroplasty↗
PubMedDate not supplied

Strength testing after third-degree acromioclavicular dislocations.

Twenty male patients with a grade III acromioclavicular joint dislocation were evaluated more than 2 years after their injury; the average followup was 4.5 years. Strength testing was performed with a Cybex II dynamometer in three planes evaluating flexion, extension, internal rotation, external rotation, abduction, and adduction at 60 and 120 deg/sec. Subjective complaints were minor and neither daily activities nor athletic participation were impaired. Objectively, only one patient had tenderness over the acromioclavicular joint. All patients had full motion and negative impingement signs. Strength testing with the Cybex II dynamometer showed no significant difference (P less than 0.05) between the injured and uninjured shoulder for strength in internal rotation, external rotation, abduction, adduction, extension, or flexion at speeds of 60 and 120 deg/sec. This study shows that the strength of the shoulder is not significantly affected by conservative treatment of grade III acromioclavicular dislocations. Conservative treatment results in minimal or no functional deficit. The authors recommend that grade III acromioclavicular dislocations be treated nonoperatively.

Acromioclavicular Joint↗
PubMed2003

Hip strength in females with and without patellofemoral pain.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To determine if females with anterior knee pain are more likely to demonstrate hip abduction or external rotation weakness than a similar, asymptomatic, age-matched control group. BACKGROUND: Diminished hip strength has been implicated as being contributory to lower-extremity malalignment and patellofemoral pain. The identification of reliable and consistent patterns of weakness in this population may assist health care professionals establish a more effective treatment plan. METHODS AND MEASURES: Hip abduction and external rotation isometric strength measurements were recorded for the injured side of 15 female subjects with patellofemoral joint pain (mean +/- SD age, 15.7 +/- 2.7 years; age range, 12-21 years). These were compared with strength measurements from the corresponding hip of 15 age-matched female control subjects (mean +/- SD age, 15.7 +/- 2.7 years; age range, 12-21 years). All strength measurements were made using hand-held dynamometers. RESULTS: Subjects with patellofemoral pain demonstrated 26% less hip abduction strength (P<.001) and 36% less hip external rotation strength (P<.001) than similar age-matched controls. CONCLUSIONS: The results indicate that young women with patellofemoral pain are more likely to demonstrate weakness in hip abduction as well as external rotation than age-matched women who are not symptomatic.

Adolescent↗
PubMed1997

The effects of surface anaesthesia on the autonomic dysreflexia response during functional electrical stimulation.

Recently, increases in blood pressure (BP) and concomitant bradycardia, suggestive of autonomic dysreflexia (AD), have been documented during functional electrical stimulation (FES) in individuals with a high spinal cord injury (SCI). If uncontrolled, this response could preclude the safe use of FES among such individuals. FES induced pain is partly related to stimulation of skin nociceptors. Therefore, measures to reduce skin sensitivity may reduce the risk of AD during FES. The purpose of this study was to determine if topical anaesthetic applied over the site of electrical stimulation could minimize the AD cardiovascular and hormonal responses to FES in individuals with SCI above the T6 level. Seven subjects with a SCI above T6 received FES to the quadriceps muscle of each leg under two conditions on two different testing days. The two treatment conditions, topical anaesthetic and placebo creams, were double blinded and randomized. The cream was administered to an area the size of the electrode (10 x 10 cm) 1 h prior to stimulation. Stimulation began at 0 mAmps and increased by 16 mAmps every 2 min until an intensity of 160 mAmps was achieved. HR and BP were measured at each stimulation intensity level. Catecholamines were analyzed three times during the stimulation protocol (pre, mid and post stimulation intensities). At the end of the stimulation protocol, FES induced isometric quadriceps contraction force at 160 mAmps intensity was measured using a hand held dynamometer. As FES stimulation intensity increased, significant rises in systolic and diastolic BP were seen, with a concomitant progressive drop in HR. The AD response to stimulation was not significantly different between the topical anaesthetic and placebo conditions. Serum catecholamine (epinephrine and norepinephrine) levels tended to rise with increasing FES intensity levels but did not reach statistical significance. The two treatment conditions did not significantly affect serum catecholamine levels or FES-induced quadriceps contraction force. In summary, FES application to the quadriceps muscle in high level SCI subjects resulted in significant increases in BP, decreases in HR (AD-like response), a trend towards elevations in catecholamine levels, and no difference in quadriceps muscular strength. However, these responses were unaffected by the use of topical anaesthetic cream on the skin at the stimulation site. This suggests that other mechanisms than skin nociception are operative in FES-induced AD.

Adult↗
PubMed1987

Detecting sincerity of effort when measuring grip strength.

The purpose of the present study was to determine whether sincere and faked grip strength measurements could be distinguished from one another by the patterns of measurements obtained for the five handle (hand size) positions of the Jamar dynamometer. Healthy subjects were instructed on different trials to give a sincere, maximal effort or to fake weakness of grip. Results were that the patterns did differ for sincere and fake trials, but not as strongly as expected. The recommendation is made that further research be done using patients with upper extremity injury.

Deception↗
PubMed2003

Recording the nutrient intake of nursing home residents by food weighing method and measuring the physical activity.

The nutrient intake of 47 female nursing home residents, able to eat without help, and of 20 eating-dependent seniors was measured by weighing method. Hand grip strength was examined by a dynamometer. Furthermore the level of physical activity of the seniors able to eat without help was determined by means of a questionnaire. The results showed that the median energy intake of self-feeding elderly women was 1620 kcal (850-4450 kcal). More than one third of the seniors consumed less than 1700 kcal / d. The intake of vitamins and minerals remained below 40-90% of the recommended level. One important cause for the inadequate micronutrient intake was that 30% of the total energy intake is met by foods of a low nutrient density (cakes, cookies, spreadable fats, soups). The eating-dependent seniors were at high risk for protein-calorie malnutrition, consuming an average of 1130 kcal / d and 34 g protein / d. The level of physical activity was very low. Only 34% of the seniors were active for more than 2 hours per week (walking, gymnastics). 30% of the residents were largely inactive although they were able to walk. It is often ignored that immobility is a major risk factor for the development of malnutrition. Firstly inactivity accelerates the loss of muscle mass. This loss of metabolically active tissue decreases the energy requirements thus leading to a loss of appetite and reduced food intake.

Aged↗
PubMed1986

Importance of correcting isokinetic peak torque for the effect of gravity when calculating knee flexor to extensor muscle ratios.

The purpose of our investigation was to compare, for the hamstring and quadriceps femoris muscles, peak torque values uncorrected for gravity with the peak torque values corrected for gravity and to determine the effect of making this correction on the hamstring to quadriceps femoris muscle peak torque ratio at slow and fast isokinetic speeds. We measured peak torques isokinetically at 60 degrees/sec (slow) and 240 degrees/sec (fast) in 25 female university soccer players. The gravity effect torque (GET) is the torque resulting from the effect of gravity on the combined weight of the leg and dynamometer arm at the precise angle of extension and flexion peak torque. The GET was added to the measured quadriceps femoris muscle peak torque and subtracted from the hamstring muscle peak torque to yield gravity corrected values. Failure to consider GET greatly underestimated quadriceps femoris muscle torque and overestimated hamstring muscle torque and the ratio between these torques at both speeds. Whereas the uncorrected hamstring to quadriceps femoris muscle peak torque ratio increased as speeds went from 60 degrees/sec to 240 degrees/sec, the gravity corrected ratio significantly decreased. Clinicians must remember the importance of making the gravity correction in patients with reduced torque output where the gravitational torque is a greater percentage of the measured torque to ascertain correctly the relative strength of antagonists inversely affected by gravity.

Adolescent↗
PubMed1982

The response of plasma immunoreactive adrenocorticotropin, beta-endorphin/beta-lipotropin, gamma-lipotropin and cortisol to experimentally induced pain in normal subjects.

1. We examined the effect of ischaemic pain and sustained isometric muscle contraction on plasma immunoreactive gamma-lipotropin (gamma LPH), beta-endorphin/beta-lipotropin (beta END/beta LPH) and corticotropin (ACTH), which are all synthesized from a common precursor (pro-opiocortin), and plasma cortisol in 10 normal subjects. 2. Experimental pain was produced by inflation to 250 mmHg of a sphygmomanometer cuff, placed above the elbow of the 'dominant' arm, after which the subject squeezed a hand dynamometer, loaded to 12 kg, 20 times at 2 s intervals. Blood was drawn before, after 5 and 10 min of pain, and 30 min after release of the cuff. In a control session, the subjects were asked to squeeze the handgrip alone for 5 min at 30% of their maximum strength, a procedure which elevates the blood pressure without causing pain. 3. One subject had unexplained high (30--71 pmol/l) baseline peptide concentrations. Baseline values for the nine other subjects were: ACTH, 7.3 +/- 1.9 pmol/l (mean +/- SEM); gamma LPH, 18.6 +/- 1.0 pmol/l; beta END/beta LPH, 10.0 +/- 1.1 pmol/l; cortisol, 599 +/- 55 nmol/l. Neither procedure significantly increased the plasma concentration of ACTH or any other peptide, whereas plasma cortisol was significantly increased at both 5 min and 10 min. Plasma ACTH was positively correlated with plasma gamma LPH (r = 0.701; P less than 0.001), beta END/beta LPH (r = 0.970; P less than 0.001) and plasma cortisol (r = 0.758; P less than 0.05). 4. The present study demonstrates that, in normal man, plasma endorphins do not change with experimental ischaemic pain. The rise in plasma cortisol without concomitant rise in ACTH is not explained, but suggests the action of some other agent at the level of the adrenal cortex.

Adrenocorticotropic Hormone↗
PubMed1983

Quantitative testing of handgrip strength, myotonia, and fatigue in myotonic dystrophy.

An electrically calibrated, isometric hand dynamometer was used to quantitate maximum voluntary contraction (MVC(, relaxation time and fatigue time (at 50% MVC) in 18 normal and 10 myotonic dystrophy subjects. Precise measurements of MVC and fatigue time were obtained in normals and myotonic dystrophy patients. Relaxation times were markedly prolonged and were quite variable in all patients with myotonic dystrophy in contrast to the highly reproducible times in normals. Neither "warm-up" activity nor acetazolamide treatment altered relaxation time.

Acetazolamide↗
PubMed2000

Pyridostigmine bromide intake during the Persian Gulf War is not associated with postwar handgrip strength.

Many Persian Gulf War veterans took pyridostigmine bromide (PB) during the Persian Gulf War. Previous research suggests that PB intake and insecticide exposure may reduce muscular strength. During 1994 and 1995, we examined the relationships between self-reported PB intake, self-reported exposures, and handgrip strength among 527 Gulf War veterans (GWVs) and 969 nondeployed veterans of that era (NDVs). We found that 25.4% and 6.7% of the GWVs and NDVs, respectively, reported generalized musucle weakness (for 1 month or longer) since the Gulf War (July 1990). Many veterans also reported exposure to insecticide during the war. Dominant handgrip strength was measured three times with a hand-held dynamometer in subjects standing with the elbow bent at a right angle. Multiple linear regression revealed that handgrip strength was negatively associated with age (p = 0.001) and female gender (p < 0.001). Handgrip strength was also found to be positively associated with height (p < 0.001), but it was not associated with PB intake (p = 0.558). Exposure to insecticides had no major effect on handgrip strength. These data suggest no association between PB intake and postwar handgrip strength.

Adult↗
PubMed1996

Effects of unilateral strength training and detraining on bone mineral mass and estimated mechanical characteristics of the upper limb bones in young women.

The aims of this study were to examine the effects of 12 months unilateral high-resistance strength training and 8-month detraining on bone mineral content (BMC), density (BMD) and estimated mechanical characteristics of upper limb bones, and also to estimate consequent loading induced strains on forearm bone shafts. Thirteen female physiotherapy students (mean 23.8 +/- 5.0 yrs, 166 +/- 7 cm, 64.4 +/- 7 cm, 64.4 +/- 13.3 kg) trained their left upper limbs with dumbbells on average 2.8 times per week for 12 months, followed by eight months detraining. Nineteen students served as controls (mean 25.7 +/- 5.2 yrs, 165 +/- 4 cm, 62.1 +/- 7.0 kg). BMC, BMD, and bone width and estimated cortical wall thickness (CWT) were measured at five different sites in both upper extremities (proximal humerus, humeral shaft, radial shaft, ulnar shaft, and distal forearm) using dual energy x-ray absorptiometry (DXA) scanner. In addition, cross-sectional moment of inertia (CSMI) was estimated from DXA data. The maximal isometric strength of the upper extremities was measured with an arm flexion-extension dynamometer. The training increased significantly the flexion strength by 14% (p = 0.001). During the detraining period, all measured strength values in the training group decreased in both limbs with respect to values after training. Despite the clear effect on muscular strength, no significant intergroup differences were observed in BMC, BMD, bone width, CWT, or CSMI values at any measured site after the training or detraining period. The estimated loading-induced strains remained within customary loading, and the change in strain level was only 15%. In conclusion, this study indicated that using high-resistance strength training may not provide an effective osteogenic stimulus for bone formation and geometric changes in upper limb bones of young, healthy, adult women. The interaction of bones and muscles may play an important and relatively unrecognized role in the development of bone strength, suggesting that the entire biomechanical environment should be carefully considered when evaluating the osteogenic efficiency of physical loading.

Absorptiometry, Photon↗
PubMed2005

Strength and endurance of knee extensors in subjects after paralytic poliomyelitis.

PURPOSE: To compare the strength and endurance of knee extensors in subjects after paralytic poliomyelitis as well as to extend the comparison to healthy subjects. METHOD: Twenty subjects after poliomyelitis with new symptoms (SYM group), 10 without new symptoms (ASYM group) and 15 healthy controls were included. To determine strength, isometric maximal voluntary contraction (MVC) torque of knee extensors in both legs was determined by Biodex dynamometer at 60 degrees knee angle. To determine endurance, the subjects were asked to maintain force in the knee extensors in the same position, in the range between 40-45% of MVC torque, as long as possible. The 'tensiomyography' method was applied to measure the radial displacement of m. rectus femoris during submaximal continuous electrical stimulation until recording a flat response. RESULTS: No significant difference in MVC torque and endurance was found between SYM and ASYM group, as well between the duration of m. rectus femoris response of both groups to submaximal electrical stimulation. MVC torque and endurance of knee extensors with 'normal' strength was significantly lower in post-polio subjects compared to healthy controls. CONCLUSION: Endurance of knee extensor muscles in post-polio subjects is generally and significantly lower than that of knee extensors in healthy subjects, regardless of the implication of normal strength and subjective observations of post-polio subjects.

Adult↗
PubMed1985

Isometric torque of the quadriceps femoris after concentric, eccentric and isometric training.

Twenty-seven normal, healthy women participated in this study, which investigated three methods of increasing the isometric strength of the quadriceps femoris through a six-week training program. Three experimental exercise groups were formed: A, eccentric, B, concentric, and C, isometric. The peak isometric torque of the quadriceps femoris was determined on the Cybex II Isokinetic Dynamometer before and after training. A total of 18 exercise sessions per subject were held. A two-way ANOVA with repeated measures revealed that while all three experimental groups significantly increased in isometric strength, no one method of training was superior. No interaction occurred in the population between the effects of pre- and posttraining scores and the type of training. The relationship between the experimental design and knee joint biomechanics may have precluded significant differences in strength gain among the experimental groups.

Adult↗
PubMed1996

Detecting submaximal grip exertions of variable effort by electromyography.

The purpose was to determine if the surface electromyogram (EMG) would allow detection of submaximal grip exertions of variable effort. Fifteen healthy subjects were instructed on different trials to give maximal 100% efforts, fixed 50% submaximal efforts, or submaximal efforts of variable amount (30, 40, 50 or 70%) with the right hand. The subjects were tested at each of the five handle positions of the Jamar dynamometer. Surface EMG was obtained for the right palmaris longus/flexor carpi radialis muscles. Consistent with previous research was the finding that the variable effort condition yielded a bell-shaped force curve, similar to that produced by patients with true injuries. The key finding was that 100% and 50% exertions yielded linear EMG amplitude curves whereas the variable-effort exertion yielded a bell-shaped or quadratic curve. Thus, the EMG did allow for detection of the variable submaximal effort. However, the 100% and 50% exertions could not be distinguished by the average sustained force/peak force ratio. The EMG has the potential of being a valuable adjunct for the clinician needing to determine if a patient is feigning loss of grip strength.

Adult↗
PubMed1993

Quantification of trunk muscle performance in standing, semistanding and sitting postures in healthy men.

The purpose of this study was to determine trunk muscle performance in the sitting, semistanding, and standing postures during isometric and dynamic extension and flexion movements. Twenty-five male subject volunteers, with no previous history of back pain participated in the study. A triaxial dynamometer that measures torque, angular position, and velocity was used to measure isometric and dynamic motor output. The dynamometer allows testing in the sitting and standing postures. A custom-designed module also allowed testing in the semistanding posture. Each subject was tested in two sessions. The first session included the physical examination and three trials of isometric maximum voluntary contractions in the three postures. The second session included the dynamic performance against a resistance equal to 50% of the effort, as measured in the first session. Subjects were instructed to perform five repetitive flexion and extension cycles as fast and accurately as possible with maximum effort. An analysis of variance with repeated measures design was used to investigate the effects of the postures (standing, semistanding and sitting), the direction of exertion (flexion and extension), and the interaction effects of the isometric and dynamic parameters (maximum and average torque, velocity, power, and range of motion). The effects of direction (F = 98, P < 0.0001) and the interaction of posture and direction (F = 7.9, P < 0.001) were significant. The maximum isometric flexion strength was significantly higher in the standing posture than in semistanding and sitting. The maximum isometric extension was not affected by the posture (sitting, semistanding and standing).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1999

Grip strength and the risk of developing radiographic hand osteoarthritis: results from the Framingham Study.

OBJECTIVE: In knees, quadriceps strength may protect against osteoarthritis (OA). Muscle activity is a major determinant of forces at the hand joints, and grip is a common task during which high muscle forces are sustained, especially at the proximal hand joints (metacarpophalangeal [MCP] joints and thumb base). This longitudinal study of radiographic hand OA examined the association between incident OA at different hand joints and maximal grip strength. METHODS: Four hand joint groups were studied: distal interphalangeal (DIP), proximal interphalangeal (PIP), MCP, and the base of the thumb (carpometacarpal and scaphotrapezial combined). Subjects were members of the Framingham OA Study who had a baseline radiograph in 1967-1969 and a followup radiograph in 1992-1993 (mean followup 24 years) and had no prevalent radiographic OA in any hand joint at baseline. Incident disease was defined as development of OA defined as a modified Kellgren/Lawrence grade of > or =2. Grip strength was measured in kilograms by dynamometer in 1958-1961 and again in 1960-1963, and the 2 measures were averaged and divided into sex-specific tertiles. Joint-based analysis was performed by adjusting for age, physical activity, and occupational category using the lowest grip strength tertile as the referent. RESULTS: Baseline and followup radiographs were obtained from 746 subjects. Of these, 453 subjects with no prevalent OA at baseline were eligible for analysis. In men, higher maximal grip strength was associated with an increased risk of OA in the PIP (highest tertile odds ratio [OR] 2.8 compared with lowest tertile, 95% confidence interval [95% CI] 1.2-6.7), MCP (highest tertile OR 2.9, 95% CI 1.1-7.4), and thumb base joints (highest tertile OR 2.8, 95% CI 1.1-7.4). In women, there was increased risk of OA in the MCP joints (highest tertile OR 2.7, 95% CI 1.1-6.4). CONCLUSION: Men with high maximal grip strength are at increased risk for the development of OA in the PIP, MCP, and thumb base joints, and women, in the MCP joints. No association was found between maximal grip strength and incident OA in the DIP joints of men or women.

Female↗