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Quadriceps Strength (quadriceps + strength)

Distribution by Scientific Domains

Medical Sciences	63%

Selected Abstracts

Muscle stabilization strategies in people with medial knee osteoarthritis: The effect of instability

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 9 2008
Laura C. Schmitt
Abstract The sensation of knee instability (shifting, buckling. and giving way) is common in people with medial knee osteoarthritis (OA). Its influence on knee stabilization strategies is unknown. This study investigated the influence of knee instability on muscle activation during walking when knee stability was challenged. Twenty people with medial knee OA participated and were grouped as OA Stable (OAS) (n,=,10) and OA Unstable (OAU) (n,=,10) based on self-reported knee instability during daily activities. Quadriceps strength, passive knee laxity, and varus alignment were assessed and related to knee instability and muscle cocontraction during walking when the support surface translated laterally. Few differences in knee joint kinematics between the groups were seen; however, there were pronounced differences in muscle activation. The OAU group used greater medial muscle cocontraction before, during, and following the lateral translation. Self-reported knee instability predicted medial muscle cocontraction, but medial laxity and limb alignment did not. The higher muscle cocontraction used by the OAU subjects appears to be an ineffective strategy to stabilize the knee. Instability and high cocontraction can be detrimental to joint integrity, and should be the focus of future research. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1180,1185, 2008 [source]

Altered loading during walking and sit-to-stand is affected by quadriceps weakness after total knee arthroplasty

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2005
Ryan L. Mizner
Abstract Purpose: Total knee arthroplasty (TKA) successfully reduces pain, but has not achieved comparable improvements in function. We hypothesized that quadriceps strength affects performance by altering loading and movement patterns during functional tasks. Methods: Fourteen subjects with isolated, unilateral TKA were tested three months after surgery. Quadriceps strength was assessed isometrically and kinematics, kinetics, and EMG were collected during level walking and sit-to-stand (STS). Function was assessed using the timed up and go test (TUG), stair climbing test (SCT), and the 6 min walk test (6MW). Results: Functional performance was significantly related to the quadriceps strength of both legs, but was more strongly related to the uninvolved strength (involved rho = ,0.43 with TUG; ,0.65 with SCT; 0.64 with 6MW) (uninvolved rho = ,0.63 with TUG; ,0.68 with SCT; 0.77 with 6MW). During STS, subjects shifted weight away from the operated limb (p <0.01). Quadriceps muscle activity and the extension moments at the knee and hip were smaller in the involved compared to the uninvolved (p <0.05). The amount of asymmetry in knee excursion during weight acceptance in gait, the asymmetry in weight bearing from sit-to-stand, and the uninvolved hip extension moment during STS were related to the amount of asymmetry in quadriceps strength (rho > 0.56, p < 0.05). Conclusions: Quadriceps weakness in patients with TKA has a substantial impact on the movement patterns and performance of the knee during functionally important tasks. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source]

Quadriceps strength and the risk of cartilage loss and symptom progression in knee osteoarthritis

ARTHRITIS & RHEUMATISM, Issue 1 2009
Shreyasee Amin
Objective To determine the effect of quadriceps strength in individuals with knee osteoarthritis (OA) on loss of cartilage at the tibiofemoral and patellofemoral joints (assessed by magnetic resonance imaging [MRI]) and on knee pain and function. Methods We studied 265 subjects (154 men and 111 women, mean ± SD age 67 ± 9 years) who met the American College of Rheumatology criteria for symptomatic knee OA and who were participating in a prospective, 30-month natural history study of knee OA. Quadriceps strength was measured at baseline, isokinetically, during concentric knee extension. MRI of the knee at baseline and at 15 and 30 months was used to assess cartilage loss at the tibiofemoral and patellofemoral joints, with medial and lateral compartments assessed separately. At baseline and at followup visits, knee pain was assessed using a visual analog scale, and physical function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index. Results There was no association between quadriceps strength and cartilage loss at the tibiofemoral joint. Results were similar in malaligned knees. However, greater quadriceps strength was protective against cartilage loss at the lateral compartment of the patellofemoral joint (for highest versus lowest tertile of strength, odds ratio 0.4 [95% confidence interval 0.2, 0.9]). Those with greater quadriceps strength had less knee pain and better physical function over followup (P < 0.001). Conclusion Greater quadriceps strength had no influence on cartilage loss at the tibiofemoral joint, including in malaligned knees. We report for the first time that greater quadriceps strength protected against cartilage loss at the lateral compartment of the patellofemoral joint, a finding that requires confirmation. Subjects with greater quadriceps strength also had less knee pain and better physical function over followup. [source]

Hormonal and Biochemical Parameters and Osteoporotic Fractures in Elderly Men

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2000
Dr. Jacqueline R. Center
Abstract Low testosterone has been associated with hip fracture in men in some studies. However, data on other hormonal parameters and fracture outcome in men is minimal. This study examined the association between free testosterone (free T) estradiol (E2), sex hormone-binding globulin (SHBG), 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), insulin-like growth factor I (IGF-I), and fracture in 437 elderly community-dwelling men. Age, height, weight, quadriceps strength, femoral neck bone mineral density (FN BMD), and fracture data (1989,1997) also were obtained. Fractures were classified as major (hip, pelvis, proximal tibia, multiple rib, vertebral, and proximal humerus) or minor (remaining distal upper and lower limb fractures). Fifty-four subjects had a fracture (24 major and 30 minor). There was no association between minor fractures and any hormonal parameter. Risk of major fracture was increased 2-fold for each SD increase in age, decrease in weight and height, and increase in SHBG, and risk of major fracture was increased 3-fold for each SD decrease in quadriceps strength, FN BMD, and 25(OH)D (univariate logistic regression). Independent predictors of major fracture were FN BMD, 2.7 (1.5,4.7; odds ratio [OR]) and 95% confidence interval [CI]); 25(OH)D, 2.8 (1.5,5.3); and SHBG, 1.7 (1.2,2.4). An abnormal value for three factors resulted in a 30-fold increase in risk but only affected 2% of the population. It is not immediately apparent how 25(OH)D and SHBG, largely independently of BMD, may contribute to fracture risk. They may be markers for biological age or health status not measured by methods that are more traditional and as such may be useful in identifying those at high risk of fracture. [source]

Altered loading during walking and sit-to-stand is affected by quadriceps weakness after total knee arthroplasty

A prospective analysis of incidence and severity of quadriceps inhibition in a consecutive sample of 100 patients with complete acute anterior cruciate ligament rupture

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2004
Terese L. Chmielewski
Background: Weakness of the quadriceps femoris muscle after anterior cruciate ligament injury and reconstruction has been attributed to incomplete voluntary activation of the muscle. The literature is conflicting on the incidence of incomplete voluntary quadriceps activation after anterior cruciate ligament injury because of differences in testing methods and population biases. The purpose of this study was to systematically examine the incidence and severity of quadriceps voluntary activation failure in both lower extremities after acute anterior cruciate ligament injury. We hypothesized that the incidence of quadriceps inhibition would be higher in the anterior cruciate ligament injured limbs than the uninvolved limbs, that the incidence of inhibition in the anterior cruciate ligament deficient limbs would be larger than in our historical sample of healthy young individuals tested in the same manner and that there would be no difference in inhibition by gender. Study design: Prospective, descriptive. Methods: One hundred consecutive patients with acute anterior cruciate ligament rupture (39 women and 61 men) were tested when range of motion was restored and effusion resolved, an average of 6 weeks after injury. A burst superimposition technique was used to assess quadriceps muscle activation and strength in all patients. Dependent t -tests were used to compare side-to-side differences in quadriceps strength. Independent t -tests were used to compare incidence of activation failure by gender and make comparisons to historical data on young, active individuals. Results: The average involved side quadriceps activation was 0.92, and ranged from 0.60 to 1.00. The incidence of incomplete activation in the involved side quadriceps was 33 per cent and uninvolved side quadriceps was 31 per cent after acute anterior cruciate ligament rupture. The incidence of incomplete activation bilaterally was 21 per cent. There was no difference in incidence of quadriceps inhibition by gender. Conclusion: The incidence of voluntary quadriceps inhibition on the involved side was three times that of uninjured, active young subjects, but the magnitude was not large. The incidence of quadriceps inhibition on the uninjured side was similar to the injured side. Clinical relevance: Both the incidence and magnitude of quadriceps inhibition after ACL rupture are lower than have previously been reported. The conventional wisdom, therefore, that quadriceps inhibition is a significant problem in this population is challenged by the results of this study. Differences between this study and others include sufficient practice to ensure a maximal effort contraction and rigorous inclusion criteria. The findings have implications for strength testing as well as rehabilitation. The quadriceps index, an assessment of the injured side quadriceps strength deficit may be affected by the presence of voluntary activation failure in the uninvolved side. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source]

The effectiveness of a pre-operative home-based physiotherapy programme for chronic anterior cruciate ligament deficiency

PHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 4 2006
SL Keays
Abstract Background and Purpose.,Little evidence supports the prescription of pre-operative rehabilitation in the treatment of chronic anterior cruciate ligament-deficient (ACLD) subjects. The aim of the present study was to assess the effectiveness of a specific six-week pre-operative exercise programme on ACLD knees.,Method.,A single, masked, controlled study was designed. This comprised two matched groups of 12 chronically ACLD patients awaiting reconstruction and a group of 12 matched uninjured control subjects. Only one ACLD group received a home-based exercise and educational programme. Assessment before and after the exercise intervention included: knee joint stability (clinical and KT1000 evaluation); muscle strength (Cybex II); standing balance and functional performance (agility, hop and subjective tests).,Results.,At the time of initial assessment there were no statistically significant differences in any measures for the two ACLD groups but both ACLD groups were significantly different from the uninjured control group as regards quadriceps strength and function. Measures taken after six weeks showed no significant improvement in the untreated ACLD group or in the uninjured control group The treated ACLD group showed significant improvement in the following measures: quadriceps strength measured at 60° and 120° per second (p < 0.001); single leg standing balance with eyes closed (p < 0.001); instrumented passive stability at 20,lb (89N) force (p = 0.003); agility and subjective performance (p < 0.001). The incidence of unstable episodes had decreased in the treated ACLD group, reducing further damage to the joint.,Conclusion.,This study leaves little doubt that pre-operative physiotherapy had a positive effect on motor function in ACLD subjects and should be prescribed routinely to maximize muscle stabilizing potential prior to reconstruction. Patients report improved stability and, in certain cases, may avoid surgery. The finding that exercise increased the passive stability of the joint was unexpected and requires further investigation. Copyright © 2006 John Wiley & Sons, Ltd. [source]