The relationship between lower body strength and obstructed gait in community-dwelling older adults

OBJECTIVES: To determine the relationship between lower body strength of community-dwelling older adults and the time to negotiate obstructed gait tasks. DESIGN: A correlational study. SETTING: The Biomechanics Laboratory, Deakin University, Australia. PARTICIPANTS: Twenty-nine women and 16 men aged 62 to 88 were recruited using advertisements placed in local newspapers. The participants were independent community dwellers, healthy and functionally mobile. MEASUREMENTS: Maximal isometric strength of the knee extensors and dynamic strength of the hip extensors, hip flexors, hip adductors, hip abductors, knee extensors, knee flexors, and ankle plantar flexors were assessed. The times to negotiate four obstructed gait tasks at three progressively challenging levels on an obstacle course and to complete the course were recorded. The relationship between strength and the crossing times was explored using linear regression models. RESULTS: Significant associations between the seven strength measures and the times to negotiate each gait task and to walk the entire course at each level were obtained (r = -0.38 to -0.55; P < .05). In addition, the percentage of the variance explained by strength (R(2)), consistently increased as a function of the progressively challenging level. This increase was particularly marked for the stepping over task (R(2) = 19.3%, 25.0%, and 27.2%, for levels 1, 2, and 3, respectively) and the raised surface condition (R2 = 17.1%, 21.1%, and 30.8%, for levels 1, 2, and 3, respectively). CONCLUSION: The findings of the study showed that strength is a critical requirement for obstructed locomotion. That the magnitude of the association increased as a function of the challenging levels suggests that intervention programs aimed at improving strength would potentially be effective in helping community-dwelling older adults negotiate environmental gait challenges.     

An investigation of the association between grip strength and hip and knee joint moments in older adults

Grip strength is a predictor of health outcomes but with differing rates of age-related decline in muscle strength, it is unclear whether handgrip is a reliable indicator of lower limb moments. This study investigated the relationship between grip strength and lower extremity moments in community-dwelling older adults. Eighty-two healthy volunteers aged 60-82 years (mean age 73.2 years) performed maximal voluntary contractions of knee and hip extensors and flexors at three positions and at neutral position for hip abductors and adductors using a custom-built dynamometer. Grip strength was measured using an electronic Jamar dynamometer. The relative reduction in muscle strength of 80s age category compared to 60-year-olds ranged from 14% for grip strength to 27% for hip abductors. Peak torque of flexors and extensors of the knee and hip joints were significantly correlated with grip strength and Pearson's correlation coefficients ranged from 0.56 to 0.78 with the highest correlations observed between knee moments and grip strength. "Good" correlation was found but only 31-60% of the variation in grip strength could be related to changes in joint torques. Hence the assumption that grip strength is an indicator of strength in the lower limb would seem unjustified in the healthy older adult.     

MUSCLE STRENGTH IN HEALTHY PEOPLE AND IN PATIENTS SUFFRING FROM RECENT-ONSET INFLAMMATORY ARTHRIRIS

Neuromuscular function was compared among 20 patients with relativelyrecent onset (symptomatic period 17 ± 24 months) rheumatoidarthritis (RA) (experimental group; EG), and 20 age- and sex-matchedhealthy people (control group; CG).The comparison was repeatedafter a period of 6 months, when 16 patients had carried outprogressive strength training. At baseline maximal grip strengthand maximal dynamic unilateral strength of the knee extensorsin the EG were significantly (P < 0.05) lower in comparisonto the CG. The groups did not differ from each other in maximalisometric strength of the trunk flexors and extensors or theknee extensors. The 6-month dynamic strength training in theEG resulted in significant increases in maximal dynamic strengthof 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 thehealthy controls. Only minor changes took place in explosivestrength and maximal isometric strength of the knee extensors.Erythrocyte sedimentation rate (P < 0.001), Ritchie's articularindex (P < 0.01) and modified health assessment questionnaire(P < 0.01) improved significantly during the training period.The results suggest that inflammatory arthritis decreases dynamicand/or isometric muscle strength in selected muscle groups ofthe body already in the early stages of disease. However, progressivedynamic strength training rapidly increases the neuromuscularperformance capacity of the patients even to the level of healthypeople without detrimental effects on disease activity. KEY WORDS: Recent-onset inflammatory arthritis, Muscle strength, Neuromuscular function, Strength training, Disease activity, Healthy people     

Taiji training improves knee extensor strength and force control in older adults

The purpose of this study was to examine the effects of Taiji training on knee extensor strength and force control in older individuals. Twenty-six healthy older adults (71.9 +/- 1.8 years) participated in the study. Sixteen of the older adults (70.2 +/- 1.8 years) underwent Taiji training for 20 weeks (experimental group), whereas the other 10 (74.6 +/- 1.2 years) served as the control group. For both groups, strength and force control of the knee extensors was assessed twice with an isokinetic dynamometer. Strength was assessed with a maximum voluntary isometric contraction (MVC). Force control was measured as the standard deviation (SD) and coefficient of variation (CV) of force during a constant isometric knee extension task at 2%, 30%, 60%, and 90% MVC. For the experimental group, MVC significantly increased (19.5 +/- 4.9%) and the CV of force decreased (18.9 +/- 3.3%) following Taiji training. Improvements in the CV of force were primarily due to decreases in the SD of force (R(2) =.86) rather than increases in strength (R(2) =.12). Furthermore, decreases in SD of force were independent of improvements in strength. For the control group, strength, SD, and CV of force were not different for the 2 tests. The overall findings suggest that Taiji training improves knee extensor strength and force control in older adults.     

Improved physical performance in older adults undertaking a short-term programme of high-velocity resistance training

BACKGROUND: The age-related loss of muscle power in older adults is greater than that of muscle strength and is associated with a decline in physical performance. OBJECTIVE: To investigate the effects of a short-term high-velocity varied resistance training programme on physical performance in healthy community-dwelling adults aged 60-80 years. METHODS: Subjects undertook exercise (EX; n=15) or maintained customary activity (controls, CON; n=10) for 8 weeks. The EX group trained 2 days/week using machine weights for three sets of eight repetitions at 35, 55, and 75% of their one-repetition maximum (the maximal weight that an individual can lift once with acceptable form) for seven upper- and lower-body exercises using explosive concentric movements. RESULTS: Fourteen EX and 10 CON subjects completed the study. Dynamic muscle strength significantly increased (p=0.001) in the EX group for all exercises (from 21.4 +/- 9.6 to 82.0 +/- 59.2%, mean +/- SD) following training, as did knee extension power (p <0.01). Significant improvement occurred for the EX group in the floor rise to standing (10.4 +/- 11.5%, p=0.004), usual 6-metre walk (6.6 +/- 8.2%, p=0.010), repeated chair rise (10.4 +/- 15.6%, p=0.013), and lift and reach (25.6 +/- 12.1%, p=0.002) performance tasks but not in the CON group. CONCLUSIONS: Progressive resistance training that incorporates rapid rate-of-force development movements may be safely undertaken in healthy older adults and results in significant gains in muscle strength, muscle power, and physical performance. Such improvements could prolong functional independence and improve the quality of life.     

The effect of age and joint angle on the proportionality of extensor and flexor strength at the knee joint

Functional movements require concerted actions of monoarticular and biarticular agonists and antagonists. Understanding age-related changes of muscle function on performance requires insight in the contributions of different muscles to joint moments. Young and elderly participants performed isometric knee extensions and flexions at combinations of knee and hip joint angles. This approach allowed assessing changes in contribution of monoarticular and biarticular knee joint flexors and extensors. Reduced moments were found for elderly persons (flexors: -43%; extensors: -33%). In the flexor group, this reduction was mainly caused by retardation of the biarticular muscles; in the extensors, by reduced strength of the monoarticular muscles. This age-related reduction of joint moments occurred to be joint angle dependent for the extensors. In the flexor group, the reduction was almost invariant. Due to this difference in joint angle dependence, the proportionality between extensors and flexors varied over joint angles and differed with age. It has been discussed how this is related to changes in performances occurring with age.     

Knee strength maintained despite loss of lean body mass during weight loss in older obese adults with knee osteoarthritis

BACKGROUND: The effects of weight loss on muscle function in older adults have not been well studied. This study determined the effects of a 6-month weight-loss intervention on muscle strength and quality in older obese adults with knee osteoarthritis. METHODS: Participants were randomized to a weight loss (WL) (n = 44, 70 +/- 6 years) or weight stable (WS) (n = 43, 69 +/- 6 years) group. The WL intervention consisted of weekly educational meetings, a meal replacement diet, and a three-session-per-week structured exercise program to achieve 10%-12% weight loss. The WS intervention included bimonthly group meetings and newsletters. Body composition and knee extensor strength were measured at baseline and after intervention. RESULTS: The WL group decreased body weight, lean body mass, fat mass, and percent body fat (p <.001 for all). Concentric extension strength increased 25% in WL (p >.05), whereas eccentric extension decreased 6% in WS (p =.028). Concentric muscle quality (strength per kg body weight or lean body mass) increased in WL (p <.05), whereas eccentric muscle quality decreased in WS (p <.05). Changes in lean body mass and fat mass were inversely associated with changes in most muscle strength and quality measures (p <.05). Men and women did not differ in response to the intervention in knee strength outcomes. CONCLUSIONS: Hypocaloric dieting in combination with exercise training had beneficial effects on muscle strength/quality, despite loss of lean body mass in this sample of older men and women. Greater fat loss was associated with greater gains in muscle strength and quality. More studies are needed regarding the mechanisms by which loss of fat mass increases muscle strength and quality.     

Can neuromuscular strength and function in people with dementia be rehabilitated using resistance-exercise training? Results from a preliminary intervention study

BACKGROUND: Neuromuscular weakness is a prominent symptom among people with central nervous system disorders, such as dementia, typically leading to disability in activities of daily life. We sought to evaluate the potential of resistance exercise to improve neuromuscular strength and function in the lower extremities among community-dwelling people with dementia. METHODS: Twenty-eight subjects, aged 70-88 years and with an average Mini-Mental State Examination score of 17.8 +/- 7.2, were recruited from a population of adult daycare facility users. Subjects underwent pre- and postintervention assessment of strength and physical function consisting of determination of bilateral maximum strength of the knee extensor, hip flexor, dorsiflexor muscles, and handgrip; and evaluation of lower-extremity function based on repeated chair stands and gait speed. The intervention consisted of moderate-intensity progressive resistance training of the hip extensors, abductors, knee extensors and flexors, and dorsiflexors using the Theraband resistance system for up to 3 days weekly over a 6-week period. RESULTS: Subjects completed an average of 11.4 +/- 2.5 exercise sessions. Among those who exercised at least twice per week (> or = 12), they improved an average of 15.6% in quadriceps strength, 10.1% in handgrip strength, 22.2% in sit-to-stand (STS) time, 9.9% in usual gait time, 5.4% in fast gait time (p =.03), and 14.0% in the timed-up-and-go (TUG) test. CONCLUSIONS: Subjects demonstrated improvements in some areas of muscular capacity (quadriceps and handgrip) and most tests of lower-extremity function (STS, gait, TUG), yet declines in other areas (dorsiflexion and iliopsoas strength). Although strength or functional deficits in all domains were not remediable, these results suggest the potential of a resistance-exercise intervention of longer duration and/or greater intensity to produce beneficial effects on the neuromuscular functioning of people with dementia.     

Age-related differences in the force generation capabilities and tendon extensibilities of knee extensors and plantar flexors in men

BACKGROUND: Recently, the number of elderly individuals who participate in sports has increased, thus injuries from overuse are now becoming recognized in the elderly population. Therefore, it is important to determine which muscle groups and tendons are most affected with aging to plan appropriate exercise interventions for elderly individuals. In particular, muscles and tendons in knee extensors and plantar flexors play an important role during locomotion. The purpose of this study was to compare the knee extensor and plantar flexor muscles and tendons. METHODS: Young (n = 19) and elderly (n = 17) men performed isometric voluntary knee extension and plantar flexion contractions. Muscle thickness and elongation of tendon structures in knee extensors and plantar flexors were measured by ultrasonography. RESULTS: Relative muscle thickness (to limb length) in the elderly group was significantly lower than that in the young group in knee extensors (p <.001), although no significant difference was found between the two groups in plantar flexors (p =.063). Relative muscle strength (to body mass) in the elderly group was significantly lower than that in the young group in both sites (all p <.001). Ratio of muscle strength to muscle thickness in the elderly group was significantly lower than that in the young group in plantar flexors, but not in knee extensors. The elderly group had significantly lower maximal elongation and strain of tendon structures in both sites than the young group had. CONCLUSION: These results suggest that the age-related weakness in knee extensors may be attributed to muscle atrophy, whereas that in plantar flexors is not, and that elderly persons have less extensible tendon structures in both sites.     

Differential increases in average isokinetic power by specific muscle groups of older women due to variations in training and testing

BACKGROUND: As a person ages, leg speed and power decrease. These changes are associated with increased falls and reduced gait speed. It has been shown that upper leg training in younger persons results in increased strength and power at the specific speed at which resistance training is applied, although there are only limited data concerning speed-specific training effects on lower leg activity. However, because both upper and lower leg speed and power influence gait and balance, it is important to determine the training speeds that selectively improve these variables in older persons. METHODS: No studies have examined selective speed-specific changes in performance for the upper and lower leg muscles in older individuals. Therefore, we compared shifts in the power-velocity relationship after high-speed (HS) and low-speed (LS) isokinetic training of knee extensors (KE) and flexors (KF), dorsiflexors (DF), and plantar flexors (PF) in community-dwelling women (ages 61 to 75). Subjects were randomly assigned to a HS training, LS training, or control (C) group. Training occurred three times a week for 12 weeks. HS training occurred at 4.73 rad.s(-1) (knee) and 3.14 rad.s(-1) (ankle); LS training for both joint actions was at 1.05 rad.s(-1). RESULTS: HS training improved KE power at intermediate (3.14 rad.s(-1); p =.0007) and high (5.24 rad.s(-1); p =.0004) testing speeds. Neither the HS nor LS group showed any change in KF as a result of the training. Both LS and HS training improved DF power at all testing speeds; however, PF power improved only with LS training and only at 1.05 rad.s(-1) (p =.0132) and 3.14 rad.s(-1) (p =.0310). CONCLUSIONS: Our results suggest that, in older women, lower leg training should occur at lower training speeds than upper leg training. Additionally, attention to differential speed-specific training of knee and ankle actions could improve power production, mobility, balance, and other functional measures in older persons.     

A community-based fitness and mobility exercise program for older adults with chronic stroke: a randomized, controlled trial

OBJECTIVES: To examine the effects of a community-based group exercise program for older individuals with chronic stroke. DESIGN: Prospective, single-blind, randomized, controlled intervention trial. SETTING: Intervention was community-based. Data collection was performed in a research laboratory located in a rehabilitation hospital. PARTICIPANTS: Sixty-three older individuals (aged > or = 50) with chronic stroke (poststroke duration > or = 1 year) who were living in the community. INTERVENTION: Participants were randomized into intervention group (n=32) or control group (n=31). The intervention group underwent a fitness and mobility exercise (FAME) program designed to improve cardiorespiratory fitness, mobility, leg muscle strength, balance, and hip bone mineral density (BMD) (1-hour sessions, three sessions/week, for 19 weeks). The control group underwent a seated upper extremity program. MEASUREMENTS: Cardiorespiratory fitness (maximal oxygen consumption), mobility (6-minute walk test), leg muscle strength (isometric knee extension), balance (Berg Balance Scale), activity and participation (Physical Activity Scale for Individuals with Physical Disabilities), and femoral neck BMD (using dual-energy x-ray absorptiometry). RESULTS: The intervention group had significantly more gains in cardiorespiratory fitness, mobility, and paretic leg muscle strength than controls. Femoral neck BMD of the paretic leg was maintained in the intervention group, whereas a significant decline of the same occurred in controls. There was no significant time-by-group interaction for balance, activity and participation, nonparetic leg muscle strength, or nonparetic femoral neck BMD. CONCLUSION: The FAME program is feasible and beneficial for improving some of the secondary complications resulting from physical inactivity in older adults living with stroke. It may serve as a good model of a community-based fitness program for preventing secondary diseases in older adults living with chronic conditions.     

Once-weekly resistance exercise improves muscle strength and neuromuscular performance in older adults.

OBJECTIVE: To determine the effect of frequency of resistive training on gain in muscle strength and neuromuscular performance in healthy older adults. DESIGN: A randomized controlled trial with subjects assigned either to high-intensity resistance training 1 (EX1), 2 (EX2), or 3 (EX3) days per week for 24 weeks or to a control group (CO). SETTING: An exercise facility at an academic medical center. SUBJECTS: Forty-six community-dwelling healthy men (n = 29) and women (n = 17) aged 65 to 79 years. INTERVENTION: Progressive resistance training consisting of three sets of eight exercises targeting major muscle groups of the upper and lower body, at 80% of one-repetition maximum (1-RM) for eight repetitions, either 1, 2, or 3 days per week. MEASURES: Dynamic muscle strength (1-RM) using isotonic equipment every 4 weeks, bone mineral density and body composition by dual energy X-ray absorptiometry (DXA), and neuromuscular performance by timed chair rise and 6-meter backward tandem walk. RESULTS: For each of the eight exercises, muscle strength increased in the exercise groups relative to CO (P < .01), with no difference among EX1, EX2 and EX3 groups at any measurement interval. Percent change averaged 3.9 +/- 2.4 (CO), 37.0 +/- 15.2 (EX1), 41.9 +/- 18.2 (EX2), and 39.7 +/- 9.8 (EX3). The time to rise successfully from the chair 5 times decreased significantly (P < .01) at 24 weeks, whereas improvement in the 6-meter backward tandem walk approached significance (P = .10) in the three exercise groups compared with CO. Changes in chair rise ability were correlated to percent changes in quadriceps strength (r = -0.40, P < .01) and lean mass (r = -0.40, P < .01). CONCLUSIONS: A program of once or twice weekly resistance exercise achieves muscle strength gains similar to 3 days per week training in older adults and is associated with improved neuromuscular performance. Such improvement could potentially reduce the risk of falls and fracture in older adults.     

A randomized two-year study of the effects of dynamic strength training on muscle strength, disease activity, functional capacity, and bone mineral density in early rheumatoid arthritis

OBJECTIVE: To evaluate the impact of a 2-year program of strength training on muscle strength, bone mineral density (BMD), physical function, joint damage, and disease activity in patients with recent-onset (<2 years) rheumatoid arthritis (RA). METHODS: In this prospective trial, 70 RA patients were randomly assigned to perform either strength training (all major muscle groups of the lower and upper extremities and trunk, with loads of 50-70% of repetition maximum) or range of motion exercises (without resistance) twice a week; all were encouraged to engage in recreational activities 2-3 times a week. All patients completed training diaries (evaluated bi-monthly) and were examined at 6-month intervals. All were treated with medications to achieve disease remission. Maximum strength of the knee extensors, trunk flexors and extensors, and grip strength was measured with dynamometers. BMD was measured at the femoral neck and lumbar spine by dual x-ray densitometry. Disease activity was determined by the Disease Activity Score, the extent of joint damage by the Larsen score, and functional capacity by the Health Assessment Questionnaire (HAQ); walking speed was also measured. RESULTS: Sixty-two patients (31 per group) completed the study. Strength training compliance averaged 1.4-1.5 times/week. The maximum strength of all muscle groups examined increased significantly (19-59%) in the strength-training group, with statistically significant improvements in clinical disease activity parameters, HAQ scores, and walking speed. While muscle strength, disease activity parameters, and physical function also improved significantly in the control group, the changes were not as great as those in the strength-training group. BMD in the femoral neck and spine increased by a mean +/- SD of 0.51 +/- 1.64% and by 1.17 +/- 5.34%, respectively, in the strength-training group, but decreased by 0.70 +/- 2.25% and 0.91 +/- 4.07% in the controls. Femoral neck BMD in the 17 patients with high initial disease activity (and subsequent use of oral glucocorticoids) remained constantly at a statistically significantly lower level than that in the other 45 patients. CONCLUSION: Regular dynamic strength training combined with endurance-type physical activities improves muscle strength and physical function, but not BMD, in patients with early RA, without detrimental effects on disease activity.     

Moderate-intensity resistance exercise training in patients with chronic heart failure improves strength, endurance, heart rate variability, and forearm blood flow

BACKGROUND: Resistance exercise training was applied to patients with chronic heart failure (CHF) on the basis that it may partly reverse deficiencies in skeletal muscle strength and endurance, aerobic power (VO(2peak)), heart rate variability (HRV), and forearm blood flow (FBF) that are all putative factors in the syndrome. METHODS AND RESULTS: Thirty-nine CHF patients (New York Heart Association Functional Class=2.3+/-0.5; left ventricular ejection fraction 28%+/-7%; age 65+/-11 years; 33:6 male:female) underwent 2 identical series of tests, 1 week apart, for strength and endurance of the knee and elbow extensors and flexors, VO(2peak), HRV, FBF at rest, and FBF activated by forearm exercise or limb ischemia. Patients were then randomized to 3 months of resistance training (EX, n=19), consisting of mainly isokinetic (hydraulic) ergometry, interspersed with rest intervals, or continuance with usual care (CON, n=20), after which they underwent repeat endpoint testing. Combining all 4 movement patterns, strength increased for EX by 21+/-30% (mean+/-SD, P<.01) after training, whereas endurance improved 21+/-21% (P<.01). Corresponding data for CON remained almost unchanged (strength P<.005, endurance P<.003 EX versus CON). VO(2peak) improved in EX by 11+/-15% (P<.01), whereas it decreased by 10+/-18% (P<.05) in CON (P<.001 EX versus CON). The ratio of low-frequency to high-frequency spectral power fell after resistance training in EX by 44+/-53% (P<.01), but was unchanged in CON (P<.05 EX versus CON). FBF increased at rest by 20+/-32% (P<.01), and when stimulated by submaximal exercise (24+/-32%, P<.01) or limb ischemia (26+/-45%, P<.01) in EX, but not in CON (P<.01 EX versus CON). CONCLUSIONS: Moderate-intensity resistance exercise training in CHF patients produced favorable changes to skeletal muscle strength and endurance, VO(2peak), FBF, and HRV.     

Pilates and Proprioceptive Neuromuscular Facilitation Methods Induce Similar Strength Gains but Different Neuromuscular Adaptations in Elderly Women

Background/Study Context: The aging process is associated with a decline in muscle mass, strength, and conditioning. Two training methods that may be useful to improve muscle function are Pilates and proprioceptive neuromuscular facilitation (PNF). Thus, the present study aimed to compare the influence of training programs using Pilates and PNF methods with elderly women.

Methods: Sixty healthy elderly women were randomly divided into three groups: Pilates group, PNF group, and control group. Pilates and PNF groups underwent 1-month training programs with Pilates and PNF methods, respectively. The control group received no intervention during the 1 month. The maximal isometric force levels from knee extension and flexion, as well as the electromyography (EMG) signals from quadriceps and biceps femoris, were recorded before and after the 1-month intervention period.

Results: A two-way analysis of variance revealed that the Pilates and PNF methods induced similar strength gains from knee flexors and extensors, but Pilates exhibited greater low-gamma drive (i.e., oscillations in 30–60 Hz) in the EMG power spectrum after the training period.

Conclusions: These results support use of both Pilates and PNF methods to enhance lower limb muscle strength in older groups, which is very important for gait, postural stability, and performance of daily life activities.     

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.     

Effects of dynamic strength training on physical function,Valpar 9 work sample test,and working capacity in patients with recent-onset rheumatoid arthritis

OBJECTIVE: To study the impact of 24 months of strength training on the physical function of patients with early rheumatoid arthritis (RA). METHODS: Seventy patients were assigned to either the strength training (experimental) group (n = 35) or the control group (n = 35). Patients in the experimental group performed strength training for 24 months, and control patients were instructed to perform range of motion exercises. Maximal strength of the knee extensors, trunk flexors, and extensors, as well as grip strength were recorded with dynamometers. Disease activity was assessed by the erythrocyte sedimentation rate and Ritchie's articular index, joint damage was determined by the Larsen x-ray index, and functional capacity was assessed using the Valpar 9 test and the Stanford Health Assessment Questionnaire (HAQ). The employment status of each patient was recorded. RESULTS: In the experimental group, strength training led to significant increases (19-59%) in maximal strength of the trained muscles. Such increases in the control group varied from 1% to 31%. There was a clear training effect on muscular strength in favor of the experimental group, but significant improvements in the HAQ indices as well as in the Valpar 9 test were seen also in control patients. Results of the Valpar 9 and the HAQ were statistically significantly better in patients who remained gainfully employed compared with patients who retired preterm during followup. However, compared with patients who remained in the work force, patients who retired were older, and their work was physically more demanding. CONCLUSION: As expected, strength training led to increased muscle strength, but this increase did not correlate with improved physical function as assessed by the Valpar 9 work sample test. The increased muscle performance did not prevent a substantial proportion of patients from retiring preterm. The 2 items from the Valpar 9 test that were applied were not sensitive enough to differentiate the patients according to their working status.     

A home-based protocol of electrical muscle stimulation for quadriceps muscle strength in older adults with osteoarthritis of the knee

OBJECTIVE: To determine whether home-based neuromuscular electrical stimulation (NMES) applied to the quadriceps femoris (QF) muscle increases strength, physical activity, and physical performance in older adults with knee osteoarthritis (OA). METHODS: Thirty-four adults (> 60 yrs) with radiographically confirmed symptomatic knee OA were randomized to NMES plus education or education only (EDU). The primary outcome was isometric QF peak torque (PTIso), with secondary outcomes of daily step counts, total activity vector magnitude, 100-foot walk-turn-walk, timed stair climb, chair rise, and pain. The NMES group used a portable electrical muscle stimulator 3 days a week for unilateral QF training with incremental increases in the intensity of isometric contraction to 30-40% of maximum over 12 weeks. Both groups received the 12-week Arthritis Self-Management course and were followed an additional 12 weeks. RESULTS: The stimulated knee-extensor showed a 9.1% increase in 120 degrees PTIso compared to a 7% loss in the EDU group (time x group interaction for 120 degrees PTIso; p = 0.04). The chair rise time decreased by 11% in the NMES group, whereas the EDU group saw a 7% reduction (p = 0.01, time; p = 0.9, group). Similarly, both groups improved their walk time by approximately 7% (p = 0.02, time; p = 0.61 group). Severity of pain reported following intervention did not differ between groups. CONCLUSION: In older adults with knee OA, a home-based NMES protocol appears to be a promising therapy for increasing QF strength in adults with knee OA without exacerbating painful symptoms.     

Knee extensor and knee flexor strength: cross-sectional area ratios in young and elderly men.

The relationships between isometric and isokinetic-concentric knee extensor and knee flexor strength, and quadriceps and hamstring cross-sectional area (CSA) were determined in young (n = 13, M = 24.5y) and elderly (n = 12, M = 70.7y) men. Quadriceps and hamstring CSA was determined by computed tomography. Knee extensor and flexor strength at 0 degree/s and 120 degree/s was determined on a Kin-Com isokinetic dynamometer. Compared to the young men, elderly men had significantly smaller quadriceps muscles and were weaker (22-32%) in knee flexion and knee extension at both angular velocities. Strength:CSA ratios were similar at 0 degree/s, but elderly men had decreased ratios for both extensors and flexors at 120 degree/s. Correlations of knee extensor and flexor strength with muscle CSA were significant at both velocities in elderly men, but not at either velocity for the knee flexors in young men. The decrease in isometric strength in elderly men can be accounted for by their decrease in muscle CSA, but their decrease in isokinetic-concentric strength was greater than their loss of CSA. Further study is required to determine the reason for this nonproportional loss of isokinetic-concentric strength.