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PubMed2002

The effect of stepwise increases in vertical dimension of occlusion on isometric strength of cervical flexors and deltoid muscles in nonsymptomatic females.

This mixed, single-double blind study examined the effect of a stepwise increase in vertical dimension of occlusion (VDO) on the isometric strength of cervical flexor and deltoid muscles in 20 asymptomatic females with deep bite (age range 20-40 years). Vertical dimension of occlusion was increased by mandibular acrylic bite plates, 2, 4, 6 and 12 mm. Subjects were instructed to bite while resisting: 1. an increasing horizontal force was applied to the forehead; and 2. an increasing vertical downward force to the wrist of each extended arm. Forces were applied by a hand-held strain gauge until resistance yielded. The force applied at the point of yielding was recorded as isometric peak strength of that trial. The peak strength for each muscle group was measured twice and averaged to produce a mean peak strength measure. This procedure was repeated in the subject's habitual occlusion and for the four increased VDOs. Mean strength of cervical flexors with increased VDO (12.0 kg) was significantly greater than that for existing vertical dimension occlusion (9.6 kg). With the exception of pre-experimental existing VD of occlusion, strength for right and left deltoids did not differ, but mean deltoid strength in the increased condition (8.6 kg) was significantly greater than biting in without a bite plate (6.6 kg). In the peak condition, cervical flexor strength increased 24% and deltoid strength increased an average of 29% from that of biting without an increase. As VDO increased further, strength in all sites was found to diminish. Repeating the strength test without a bite plate, after all trials were administered, did not show differences from pre-experimental levels, indicating that fatigue was not an important factor. The findings demonstrate that isometric strength of the cervical flexors and deltoids increases significantly from habitual occlusion as the VDO is increased, then diminishes as VDO is increased further. The strength of both cervical flexors and deltoids varied in concert with changes of VDO.

Adult↗

PubMed1980

Establishing an industrial strength testing program.

This study was performed to develop and evaluate a scheme for matching the strength of workers to the strength demands of their jobs. Biomechanical analyses were performed on production jobs in an aluminum reduction plant to identify and quantify strength demands. These data were used to design a set of nine strength tests which simulated job activities with the greatest strength requirements. A cross section of plant employees assigned to these jobs was strength tested and monitored for medical incidents for a period of over two years. Significant relationships were found among job strength requirements, worker strengths, and medical incidents. Workers with strength abilities (as determined by the tests) less than job strength requirements suffered a higher rate of medical incidents than workers whose strength abilities matched or exceeded job demands. It was concluded that strength testing can be used to identify workers who would be at increased risk of suffering medical incidents if placed on jobs which exceeded their strength abilities.

Adolescent↗

PubMed1997

Departures from linearity in the relationship between measures of muscular strength and physical performance of the lower extremities: the Women's Health and Aging Study.

BACKGROUND: Sarcopenia, an age-related reduction in muscular mass and strength, may cause a decline in physical functioning and subsequent loss of autonomy. It has been suggested that strength is associated with lower extremity function mainly in the lower portion of the range of strength. Identifying the threshold under which strength is most critical to function may help in targeting groups who may benefit most from exercise interventions. METHODS: The study uses data from the Women's Health and Aging Study. The study population, recruited by screening a population-based sample aged 65 years and older, comprised 1,002 women who represent the one-third most disabled women without severe cognitive impairment living in the community. Knee extensor and hip flexor strength were assessed using a hand-held dynamometer. Lower extremity performance was evaluated using tests of walking, standing balance, and rising from a chair. RESULTS: Among women tested for strength (n = 892), those who could walk (97%), do the side-by-side stand (87%), or complete 5 chair stands (74%) had significantly greater strength. Walking speed was linearly associated with knee extensor strength over the entire range of strength, but its association with hip strength was limited to values below 15 kg. Time for five chair stands was associated with knee extensor and hip flexor strength below 10 and 15 kg, respectively, and no significant association was detected above these values. Stronger women were more likely to hold balance for 10 sec in the side-by-side, semi-tandem, and tandem positions. The percentage of the variance in performance explained by strength alone was always lower than 20%. CONCLUSIONS: In this population, which does not include the strongest older women, there is a departure from linearity in the relationship between muscular strength and some measures of lower extremity performance.

Aged↗

PubMed1995

Human trunk strength profile in flexion and extension.

STUDY DESIGN: Isometric and isokinetic trunk flexion-extension strengths were studied among 73 subjects (41 males and 32 females) and 10 patients (9 males and 1 female). The isometric strengths were measured in four postures of trunk flexion. The isokinetic trunk strengths were measured through the range of these postures. OBJECTIVES: The study had two objectives: to develop a database for isometric flexion-extension strength at different levels of trunk flexion and isokinetic strength at corresponding angles and to determine the decrement in strength characteristics among patients of idiopathic low back pain. SUMMARY OF BACKGROUND DATA: Though flexion-extension strength among normal subjects and patients has been studied, its variation due to standardized postural change has not been reported extensively. The influence of postural deviation on flexion-extension ratios are also largely unknown. METHODS: To achieve the objectives of the study, a device flexion-extension-lateral flexion tester (FELT) was designed and fabricated. The male and female subjects performed isometric flexion and extension at 0 degree, 20 degrees, 40 degrees and 60 degrees of trunk flexion; and isokinetic flexion starting at neutral posture, and isokinetic extension starting at 60 degrees of trunk flexion. The patients performed isometric flexion and extension in neutral posture only; and isokinetic flexion-extension similar to normal sample. RESULTS: The average strength in each activity was between 70 and 80% of the corresponding peak strength. The isokinetic activity strengths ranged between 60 and 70% of the corresponding isometric activities in each group. The strength of females ranged between 60 and 70% of males. The ANOVA revealed that posture had a significant effect on strength. The multiple regression explained 73% of variance in isometric and 34% in isokinetic modes. CONCLUSIONS: A patient's strength profile should be determined in a posture that simulates activities of daily living to determine impairment and plan rehabilitation.

Adult↗

PubMed2001

Muscle strength, pain and disability in patients with osteoarthritis.

OBJECTIVE: Reduced muscle strength is regarded as a risk factor for pain and disability in osteoarthritis (OA). Currently, various indices for muscle strength are used when assessing determinants of pain and disability. The goal of the present study was to evaluate these indices of muscle strength. DESIGN: Isometric muscle strength was measured for 16 muscle actions around the knees and hips in 52 patients with OA of the hip and 70 patients with OA of the knee. Various indices of muscle strength were derived from these measurements, applying five alternative approaches. These approaches ranged from a single overall index to a set of 16 separate indices. The internal consistency of these indices was determined (Cronbach's alpha), and it was determined to what extent they could reveal the association between reduced muscle strength on the one hand and pain and disability on the other hand. RESULTS: Internal consistency was satisfactory for all indices (Cronbach's alpha >0.74). As expected, reduced muscle strength was associated with increased disability, but no clear relationship could be established between muscle weakness and pain. The strength of these associations did not depend on the approach used to derive the indices for muscle strength. CONCLUSIONS: The indices did not show major differences with regard to internal consistency or the extent to which the association with pain and disability could be revealed. For reasons of parsimony, approaches resulting in few indices appear to be most useful. However, muscle strength was found to be significantly reduced around affected joints, compared with muscle strength around unaffected joints. Therefore, the most suitable approach for reducing muscle strength data into indices is one that results in as few indices as possible, but with separate indices for muscle strength around affected and unaffected joints.

Aged↗

PubMed1994

Effect of recombinant human growth hormone on the muscle strength response to resistance exercise in elderly men.

Normal aging is characterized by detrimental changes in body composition, muscle strength, and somatotropic function. Reduction in muscle strength contributes to frailty and risk for fracture in the elderly. Although older adults increase muscle strength as a result of resistance exercise training, the strength gains quickly level off, with only modest increases thereafter despite continued training. To investigate whether age-related deficits in the somatotropic axis limit the degree to which muscle strength can improve with resistance training in older individuals, we conducted a double blind, placebo-controlled exercise trial. Eighteen healthy elderly men (65-82 yr) initially underwent progressive weight training for 14 weeks to invoke a trained state. Subjects were then randomized to receive either 0.02 mg/kg BW.day recombinant human GH (rhGH) or placebo, given sc, while undertaking a further 10 weeks of strength training. Sequential measurements were made of muscle strength (one repetition maximum), body composition (dual energy x-ray absorptiometry), and circulating levels of insulin-like growth factor-I (IGF-I) and IGF-binding protein-3. For each exercise, strength increased for both groups (P = 0.0001) through 14 weeks of training, with little improvement thereafter. Increases in muscle strength ranged from 24-62% depending on the muscle group. Baseline plasma IGF-I concentrations were similar in both groups (mean +/- SEM, 106 +/- 9 micrograms/L), approximately half that observed in healthy young adults. In the rhGH group, IGF-I levels increased to 255 +/- 32 micrograms/L at week 15 and 218 +/- 21 micrograms/L at week 24 (P < 0.001). In the placebo group, IGF-I increased slightly to 119 +/- 6 micrograms/L at 24 weeks. IGF-binding protein-3 also increased in the rhGH group (P < 0.05). rhGH had no effect on muscle strength at any time, and no systematic difference in muscle strength was observed between groups throughout the study. Body weight did not change in either group, but lean body mass increased, and fat mass decreased (P < 0.05) in the rhGH group. Supplementation with rhGH does not augment the response to strength training in elderly men. These results suggest that deficits in GH secretion do not underlie the time-dependent leveling off of muscle strength seen with training in the elderly and provide no support for the popular view of GH as an ergogenic aid.

Aged↗

PubMed2006

Trends in strength training--United States, 1998-2004.

Strength training is physical activity intended to increase muscle strength and mass. Adults who engage in strength training are less likely to experience loss of muscle mass, functional decline, and fall-related injuries than adults who do not strength train. Studies on strength-training interventions have indicated that inactive older adults who begin regular strength training achieve substantial strength gains within a few months. Because certain health benefits are linked to strength training, a national health objective for 2010 is to increase to 30% the proportion of adults who perform physical activities that enhance and maintain muscular strength and endurance on > or =2 days per week (objective 22-4). This objective is also recommended by the American College of Sports Medicine. CDC analyzed 1998-2004 data from the National Health Interview Survey (NHIS) to determine the annual prevalence of strength training among U.S. adults by age group and race/ethnicity. This report describes the results of that analysis, which demonstrated that although the national prevalence of strength training for U.S. adults increased slightly during 1998-2004, only 21.9% of men and 17.5% of women (age adjusted) in 2004 reported strength training two or more times per week. This is substantially lower than the national 2010 objective of 30% and underscores the need for additional programs to increase strength training among adults.

Adult↗

PubMed1981

[Studies of dental methacrylic resin. (Part 8) Flexural and impact adhesive strength of self-curing methacrylic resin to cross-linked polymethyl methacrylate resins (author's transl)].

Heat-curing methacylic resins cross-linked with three kinds of dimethacrylates, i.e. EDMA, tri-EDMA and nona-EDMA, were prepared, and the flexural and the impact adhesive strength of the dough moulding type and the pour type self-curing methacrylic resins to them were examined. The results obtained were as follows. (1) The flexural and the impact adhesive strength of the pour type self-curing resin were higher and more stable than those of the dough moulding type one. (2) The flexural and the impact adhesive strength of self-curing resins to cross-linked adherent resins rised in order of nona-EDMA greater than tri-EDMA greater than EDMA in the range of higher concentration of cross-linking agents. This tendency was marked for the pour type resin. (3) When the dough moulding type resin was used as adhesive resin, to adherent resin cross-linked with EDMA or tri-EDMA which had relatively short chain, the respective adhesive strength of that decreased with increasing the concentration of cross-linking agent. While, to adherent resin cross-linked with nona-EDMA, which had relatively long and more flexible chain, the respective adhesive strength of the dough moulding type resin increased with increasing the concentration of cross-linking agent. (4) When the pour type resin was used as adhesive resin, to adherent resin cross-linked with EDMA or tri-EDMA, the respective adhesive strength of that showed the maximum at the concentration near 2 to 5 mole% and decreased with increasing the concentration. While, to adherent resin cross-linked with nona-EDMA, the flexural adhesive strength of the pour type resin was approximately constant without the effect of the concentration, but the impact adhesive strength of that increased with increasing the concentration. (5) The flexural adhesive strength of the dough moulding and the pour type resin under the wet condition decreased about 30 to 60% compared with under the dry condition, but the percentage of the falling for the impact adhesive strength was about 15 to 30% and relatively small. (6) The flexural adhesive strength showed a similar adhesive tendency to the tensile adhesive strength, but the impact adhesive strength showed a different adhesive tendency from those.

Adhesiveness↗

PubMed1999

Analysis of strength properties of light-cured resin composites.

OBJECTIVES: To determine and correlate the compressive and tensile strengths of resin composites, to scale their failure probability and to analyze their failure mode under combined state of stresses. METHODS: Ten brands of composites were tested for compressive and diametral tensile strengths. A recently introduced device for testing of pure shear stresses was modified to adapt to smaller specimens. Uniformity of pure shear stress distribution in the significant section was verified by a photoelastic model. Loading specimens in pure shear up to failure determined their mode of fracture under combined state of stresses. RESULTS: Diametral tensile strength yielded values that were 20% of their respective compressive strength. Multiple comparison test indicated that strength properties of the tensile strength test were much more sensitive in predicting differences between resin composites when compared to a compressive strength test. Pertac (Espe) had the highest compressive strength, Graft LC (GC) and Z-100 (3M) had the highest diametral tensile strength. No correlation was found between tensile and compressive strengths. The Weibull modulus disclosed differences in the liability of the materials to fracture. When combined state of stresses were applied through the pure shear test, failure of each specimen occurred at the principal tensile planes. SIGNIFICANCE: Compressive strength cannot predict the ability of the resin composite to withstand tensile stresses. The importance of compressive strength is limited as failure of a brittle material occurs in tension.

Analysis of Variance↗

PubMed2005

Relationship of radiographic and clinical variables to pinch and grip strength among individuals with osteoarthritis.

OBJECTIVE: Little is known about how specific radiographic features are related to hand strength in osteoarthritis (OA). This study examined associations of radiographic variables with pinch and grip strength among individuals with radiographic hand OA. METHODS: Participants (n = 700, 80% female, mean age 69 years) were part of a study on the genetics of generalized OA. All had bilateral radiographic hand OA. Linear models were used to examine associations of grip and pinch strength with 1) OA in joint groups (proximal interphalangeal, metacarpophalangeal [MCP], carpometacarpal [CMC]), 2) OA in rays (first through fifth), and 3) summed Kellgren/Lawrence (K/L) grades for severity of OA in all joints. Adjusted models controlled for age, sex, hand pain, chondrocalcinosis, and hand hypermobility. Mixed models accounted for clustering within families. RESULTS: In bivariate analyses, all joint groups, all rays, and total summed K/L grades were significantly negatively associated with grip and pinch strength (P < 0.05). In adjusted models, the only joint group significantly associated with grip strength was the CMCs, and only OA in the MCP joint was significantly associated with pinch strength (P < 0.05). The only ray significantly associated with grip strength (P < 0.05) was ray 1, and no individual rays were significantly associated with pinch strength. A higher summed K/L grade was significantly associated with both lower grip strength and lower pinch strength. CONCLUSION: Among individuals with radiographic hand OA, increasing radiographic severity is associated with reduced grip and pinch strength, even when controlling for self-reported pain. Individuals with radiographic OA in specific locations (CMC joints, MCP joints, and ray 1) may be at particular risk for reduced hand strength.

Aged↗

PubMed2002

The impact of gender, body dimension and body composition on hand-grip strength in healthy children.

Maximum hand-grip (HG) strength, body composition and main anthropometric variables were evaluated in 278 children with normal weight and growth, aged 5-15 yr divided into 3 age groups: group 1, age+/-SD: 7.6+/-0.9 yr 7.6+/-0.9 SD (Tanner stage 1); group 2, age: 10.8+/-0.7 yr (Tanner stage: 2-3); group 3, age: 13.2+/-0.9 yr (Tanner stage: 4-5). Weight, height, body surface area (BSA), BMI, percent body fat (BF) and fat free mass (FFM) increased progressively and significantly from the younger to the older age group. A significant difference between genders was detected only for BF and FFM, females having a higher fat mass and a lower FFM compared to males. Most children were right-handed (91%). In either genders, a curvilinear relation was detected between HG strength and age, with best fit for the dominant (d) hand given by the equations: dHG=5.891 *10(0.051) age, r2=0.986, p<0.001 in males and dHG=6.163 *10(0.045) age r2=0.973, p<0.001 in females. The increase in HG strength after 11 yr appears to be steeper in males as compared with that found in females. In both d and non-dominant (nd) hand, a significant difference in HG strength was detected between males and females, the average difference being about 10% at all ages. For both genders, nd hand was significantly weaker than d hand in the older age groups (2 and 3), but not in the younger group 1. Age and gender-dependent differences in HG strength (but not differences between d and nd hand) disappear if HG strength is normalized for FFM. Thus, in general, dHG strength normalized for FFM resulted on average to be 0.67+/-0.11 kg/kg. A multiple linear regression analysis indicated that HG was positively correlated with BMI, BSA, stature, stature2 and FFM (p<0.001 for all correlations) without differences between genders, while a negative correlation was found between HG strength and %BF. The most significant correlation was found between HG strength and FFM, without any significant difference between genders, so that the overall equation describing the line for the d hand was: dHG strength= 2.32+0.63 FFM, r2=0.72, p<0.001. In conclusion, the present study indicates that the age-dependent increase of HG strength as well as the between-gender differences are strongly related to changes of FFM values occurring during childhood. Moreover, the study provides a standard normative value of maximal HG strength for the healthy children population in Northern Italy.

Adolescent↗

PubMed2003

Handgrip strength and cause-specific and total mortality in older disabled women: exploring the mechanism.

OBJECTIVES: To examine the association between muscle strength and total and cause-specific mortality and the plausible contributing factors to this association, such as presence of diseases commonly underlying mortality, inflammation, nutritional deficiency, physical inactivity, smoking, and depression. DESIGN: Prospective population-based cohort study with mortality surveillance over 5 years. SETTING: Elderly women residing in the eastern half of Baltimore, Maryland, and part of Baltimore County. PARTICIPANTS: Nine hundred nineteen moderately to severely disabled women aged 65 to 101 who participated in handgrip strength testing at baseline as part of the Women's Health and Aging Study. MEASUREMENTS: Cardiovascular disease (CVD), cancer, respiratory disease, other measures (not CVD, respiratory, or cancer), total mortality, handgrip strength, and interleukin-6. RESULTS: Over the 5-year follow-up, 336 deaths occurred: 149 due to CVD, 59 due to cancer, 38 due to respiratory disease, and 90 due to other diseases. The unadjusted relative risk (RR) of CVD mortality was 3.21 (95% confidence interval (CI) = 2.00-5.14) in the lowest and 1.88 (95% CI = 1.11-3.21) in the middle compared with the highest tertile of handgrip strength. The unadjusted RR of respiratory mortality was 2.38 (95% CI = 1.09-5.20) and other mortality 2.59 (95% CI = 1.59-4.20) in the lowest versus the highest grip-strength tertile. Cancer mortality was not associated with grip strength. After adjusting for age, race, body height, and weight, the RR of CVD mortality decreased to 2.17 (95% CI = 1.26-3.73) in the lowest and 1.56 (95% CI = 0.89-2.71) in the middle, with the highest grip-strength tertile as the reference. Further adjustments for multiple diseases, physical inactivity, smoking, interleukin-6, C-reactive protein, serum albumin, unintentional weight loss, and depressive symptoms did not materially change the risk estimates. Similar results were observed for all-cause mortality. CONCLUSION: In older disabled women, handgrip strength was a powerful predictor of cause-specific and total mortality. Presence of chronic diseases commonly underlying death or the mechanisms behind decline in muscle strength in chronic disease, such as inflammation, poor nutritional status, disuse, and depression, all of which are independent predictors of mortality, did not explain the association. Handgrip strength, an indicator of overall muscle strength, may predict mortality through mechanisms other than those leading from disease to muscle impairment. Grip strength tests may help identify patients at increased risk of deterioration of health.

Aged↗

PubMed2001

The effect on leg strength of tourniquet use during anterior cruciate ligament reconstruction: A prospective randomized study.

PURPOSE: The purpose of this study was to prospectively evaluate the effect of tourniquet use during endoscopic anterior cruciate ligament (ACL) reconstruction surgery on dorsiflexion strength, plantarflexion strength, quadriceps strength, and calf and thigh girth. TYPE OF STUDY: The study was a prospective, double-blind, randomized clinical trial. METHODS: Forty-eight patients were prospectively randomized into 2 groups: (1) tourniquet use during surgery (T) and, (2) no tourniquet use during surgery (NT). Within 1 week before ACL reconstruction, all patients were evaluated for isometric plantarflexion and dorsiflexion strength, thigh strength, and thigh and calf girth. These same measurements were repeated 3 weeks postoperatively. At 6 months, isokinetic quadriceps strength was evaluated at 60 degrees per second. All patients underwent ACL reconstruction using a patella-tendon autograft and a tourniquet was placed on the affected extremity. In all 25 T patients, the tourniquet was inflated to 300 mm Hg. The average tourniquet time was 85 +/- 7 minutes (range, 51 to 114 minutes). RESULTS: ACL reconstruction resulted in a significant decrease in thigh girth (P <.01), calf girth (P <.01), dorsiflexion strength (P <.01), and plantarflexion strength (P <.05) at 3 weeks postoperatively in both groups. The T group had a greater decrease in thigh girth than the NT group (P <.05). Tourniquet use did not have an effect on calf girth (P =.53), dorsiflexion strength (P =.17), or plantarflexion strength (P =.32) at 3 weeks postoperatively. Tourniquet use also had no effect on quadriceps strength at 6 months postoperatively (P =.78). CONCLUSIONS: Tourniquet use of less than 114 minutes during ACL reconstruction had no effect on the strength of the lower extremity after surgery.

Adult↗

PubMed1996

Anthropometric, strength, endurance and flexibility characteristics of elite and recreational climbers.

There has been remarkable development in the scope and quality of rock climbing in recent years. However, there are scant data on the anthropometry, strength, endurance and flexibility of rock climbers. The aim of this study was to compare these characteristics in three groups of subjects-elite rock climbers, recreational climbers and non-climbers. The 30 male subjects were aged 28.8 +/- 8.1 (mean +/- S.D.) years. Group 1 (n = 10) comprised elite rock climbers who had led a climb of a minimum standard of 'E1' (E1-E9 are the highest climbing grades) within the previous 12 months; Group 2 (n = 10) comprised rock climbers who had achieved a standard no better than leading a climb considered 'severe' (a low climbing grade category); and Group 3 (n = 10) comprised physically active individuals who had not previously done any rock climbing. The test battery included tests of finger strength [grip strength, pincer (i.e. thumb and forefinger) strength, finger strength measured on climbing-specific apparatus], body dimensions, body composition, flexibility, arm strength and endurance, and abdominal endurance. The tests which resulted in significant differences (P < 0.05) between the three groups included the bent arm hang (elite 53.1 +/- 1.32 s; recreational 31.4 +/- 9.0 s; non-climbers 32.6 +/- 15.0 s) and pull-ups (elite 16.2 +/- 7.2 repetitions; recreational 3.0 +/- 4.0 reps; non-climbers 3.0 +/- 3.9 reps); for both tests, the elite climbers performed significantly better than the recreational climbers and non-climbers. Regression procedures (i.e. analysis of covariance) were used to examine the influence of body mass and length. Using adjusted means (i.e. for body mass and leg length), significant differences were obtained for the following: (1) finger strength, grip 1, four fingers (right hand) (elite 447 +/- 30 N; recreational 359 +/- 29 N; non-climbers 309 +/- 30 N), (2) grip strength (left hand) (elite 526 +/- 21 N; recreational 445 +/- 21 N; non-climbers 440 +/- 21 N), (3) pincer strength (right hand) (elite 95 +/- 5 N; recreational 69 +/- 5 N; non-climbers 70 +/- 5 N) and (4) leg span (elite 139 +/- 4 cm; recreational 122 +/- 4 cm; non-climbers 124 +/- 4 cm). For tests 3 and 4, the elite climbers performed significantly better than the recreational climbers and non-climbers for any variable. These results demonstrate that elite climbers have greater shoulder girdle endurance, finger strength and hip flexibility than recreational climbers and non-climbers. Those who aspire to lead 'E1' standard climbs or above should consider training programmes to enhance their finger strength, shoulder girdle strength and endurance, and hip flexibility.

Abdominal Muscles↗

PubMed2003

Hand strength in juvenile chronic arthritis: a two-year follow-up.

AIM: To describe changes in muscle strength in the hands of children with juvenile chronic arthritis (JCA) and to examine the relationship between muscle strength, presence of local arthritis and disease subtype. METHODS: Twenty children (10 girls and 10 boys) with JCA aged 7 to 18 y were followed for two years. Isometric muscle strength in wrist dorsiflexors and handgrip strength were measured repeatedly. The results were compared with reference values for the same methods. Arthritis severity in the hand was scored every third month. Nerve conduction velocities were measured twice. RESULTS: Seven out of 20 patients had initially low or decreasing strength in one or both of the two tests. Five out of 20 children had reduced strength (more than two standard deviations below the mean of the reference group) in at least one test. Four children showed a significant reduction in muscle strength in at least one test during the observation time. The greatest reduction in strength was measured in four children with polyarticular disease. These children also had local arthritis in the hand. A greater proportion of children with polyarthritis had low or decreasing strength compared with children with oligoarthritis. The same was true for children with active arthritis in the hand. Nerve conduction velocities were normal in all cases and did not change. CONCLUSION: The majority of children with JCA have normal strength in the hand. Some children, especially those with polyarthritis and hand arthritis, have reduced muscle strength in the hand. Risk factors for low or decreasing strength are polyarthritis and/or active arthritis in the hand.

Adolescent↗

PubMed2000

Muscle strength and body mass index as long-term predictors of mortality in initially healthy men.

BACKGROUND: Muscle weakness, low body weight, and chronic diseases are often observed in the same people; however, the association of muscle strength with mortality, independent of disease status and body weight, has not been elucidated. The aim was to assess hand grip strength as a predictor of all-cause mortality within different levels of body mass index (BMI) in initially disease-free men. METHODS: Mortality was followed prospectively over 30 years. Maximal hand grip strength tests and BMI assessments were done at baseline in 1965 to 1970. The participants were 6040 healthy men aged 45 to 68 years at baseline living on Oahu, Hawaii. RESULTS: The death rates per 1000 person years were 24.6 in those with BMI <20, 18.5 in the middle BMI category, and 18.0 in those with BMI > or = 25. For grip strength tertiles, the mortality rates were 24.8 in the lowest, 18.5 in the middle, and 14.0 in the highest third. In Cox regression models, within each tertile of grip strength, BMI showed only minimal effect on mortality. In contrast, in each category of BMI there was a gradient of decreasing mortality risk with increasing grip strength. Among those with BMI <20, the adjusted relative risks (RRs) of mortality over 30 years were 1.36 (95% confidence interval 1.14-1.63) for those in the lowest third of strength at baseline, 1.27 (1.02-1.58) in the middle, and 0.92 (0.66-1.29) in the highest third. Correspondingly, for those with BMI 20-24.99, the RRs of death were 1.25 (1.08-1.45), 1.14 (1.00-1.32), and 1.0 (reference) in the lowest, middle, and highest third of grip strength, respectively. In those with BMI > or =25, the RRs were 1.39 (1.16-1.65) in the lowest, 1.27 (1.08-1.49) in the middle, and 1.14 (0.98-1.32) in the highest third of grip strength. Models were adjusted for age, education, occupation, smoking, physical activity, and body height. CONCLUSIONS: In healthy middle-aged men, long-term mortality risk was associated with grip strength at baseline, independent of BMI. The possible interpretation of the finding is that early life influences on muscle strength may have long-term implications for mortality. Additionally, higher strength itself may provide greater physiologic and functional reserve that protects against mortality.

Aged↗

PubMed1995

Muscle strength in healthy people and in patients suffering from recent-onset inflammatory arthritis.

Neuromuscular function was compared among 20 patients with relatively recent onset (symptomatic period 17 +/- 24 months) rheumatoid arthritis (RA) (experimental group; EG), and 20 age- and sex-matched healthy people (control group; CG). The comparison was repeated after a period of 6 months, when 16 patients had carried out progressive strength training. At baseline maximal grip strength and maximal dynamic unilateral strength of the knee extensors in the EG were significantly (P < 0.05) lower in comparison to the CG. The groups did not differ from each other in maximal isometric strength of the trunk flexors and extensors or the knee extensors. The 6-month dynamic strength training in the EG resulted in significant increases in maximal dynamic strength of the knee extensors (P < 0.001), in isometric grip strength (P < 0.001) and in isometric strength of the trunk flexors (P < 0.05) and extensors (P < 0.05) to the level of the healthy controls. Only minor changes took place in explosive strength and maximal isometric strength of the knee extensors. Erythrocyte sedimentation rate (P < 0.001), Ritchie's articular index (P < 0.01) and modified health assessment questionnaire (P < 0.01) improved significantly during the training period. The results suggest that inflammatory arthritis decreases dynamic and/or isometric muscle strength in selected muscle groups of the body already in the early stages of disease. However, progressive dynamic strength training rapidly increases the neuromuscular performance capacity of the patients even to the level of healthy people without detrimental effects on disease activity.

Adult↗

PubMed1999

Predicting 'normal' grip strength for rheumatoid arthritis patients.

OBJECTIVE: An ability to predict accurately 'normal' grip strength in rheumatoid arthritis (RA) patients would facilitate a more accurate assessment of the degree of their functional loss. This, in turn, would allow the setting of more meaningful treatment goals aimed at restoring hand function towards normal. This study carefully measures three modalities of hand grip strength and their correlation with multiple simple anthropometric parameters in normal subjects. We aim to determine which of these parameters are best correlated to grip strength, and whether this correlation is strong enough to allow the accurate prediction of what normal grip strength should be in RA patients. METHODS: In 81 normal subjects (67 female), power, pinch and tripod grip strength measurements were made using an MIE digital pinch grip analyser. These strength data were correlated with specific local forearm anthropometric measurements: forearm circumference, forearm length, forearm volume, hand circumference, hand length, hand volume, hand and forearm volume, and various general anthropometric parameters (weight, height and age). These normal subjects had been chosen so as to be age and sex matched with 83 RA patients (67 female) in whom the same strength and anthropometric parameters were assessed and correlated. In patients, the grip strength results were additionally correlated with two markers of disease activity: a modified Ritchie Articular Index local to the hand and forearm (mRAI) and a visual analogue scale (VAS) assessing subjective pain severity. RESULTS: In normal subjects, clear correlations were demonstrated between hand grip strengths and all specific anthropometric variables, the strongest correlation being with forearm and hand volume (r = 0.729 and 0.638 for dominant and non-dominant hands, respectively; P < 0.01 for both). The patients were considerably weaker than normal subjects. Markers of disease activity showed a negative correlation with grip strength. In normal subjects, the dominant hand was significantly stronger than the non-dominant hand, and on average by 8%, while the opposite was true in patients, who were 20% weaker on the dominant side. CONCLUSION: Simple anthropometric measurements, and forearm and hand volume in particular, would be useful at baseline for predicting 'normal' hand grip strength in RA patients, both in the clinical setting and in research trials aimed at improving grip strength and hand function.

Aged↗