Avaliação muscular isocinética do quadríceps em indivíduos com doença pulmonar obstrutiva crónica

The phase angle cut-off point capable of discriminating hemodialysis patients with reduced exercise tolerance: a cross-sectional study

BACKGROUND

Phase angle (PhA) is a prognostic marker of all-cause mortality in chronic kidney disease. However, no study has investigated this marker as a predictor of exercise intolerance in hemodialysis (HD) patients. The aim of this study was to determine a cut-off point for the PhA capable of discriminating HD patients with reduced exercise tolerance.

METHODS

Thirty-one patients (80.6% men, median age 69 years) were included. The evaluations were performed on three different days, before the HD session. The outcomes evaluated were: biochemical markers, inflammatory and nutritional status, body composition, peripheral muscle strength and exercise tolerance. Performance ≤50% of the predicted value in the six-minute step test (6MST) was defined as reduced exercise tolerance.

RESULTS

Patients presented an average of 67.6 steps (50.5% of predicted) in the 6MST. Fifteen patients (48.4%) were classified with reduced exercise tolerance. The receiver operating characteristic curve indicated a cut-off point of 3.73° for the PhA (sensitivity = 87%, specificity = 81%, and area under the curve = 0.88 [95% CI: 0.76-1.00]; p < 0.001). Patients with reduced exercise tolerance had worse inflammatory and nutritional status, lower PhA and greater impairment of peripheral muscle strength.

CONCLUSION

The cut-off point of 3.73° for the PhA is sensitive and specific to discriminate HD patients with reduced exercise tolerance.

TRIAL REGISTRATION

This study was registered in the Clinical Trials database (no. NCT03779126, date of first registration 19/12/2018).

[Which physical tests for which objectives in pulmonary rehabilitation?]

Chronic respiratory disease is a major cause of morbidity and mortality worldwide and an important cause of disability including a reduction of exercise, functional and muscle capacity contributing to a decreased quality of life. In the context of pulmonary rehabilitation, a thorough patient-centered outcome assessment, including not only measures of lung function, but also exercise functional and muscle capacity, is imperative for a comprehensive disease management. Assessment of these impairments and dysfunctions with appropriate and change-sensitive procedures is thus necessary for personalizing the physical interventions and assessing the short- and long-term effectiveness of the intervention. The clinician currently has a wide variety of tests and measurements available to assess the physical and functional capacity of people with chronic respiratory disease. The aim of this review is to provide a pragmatic synthesis of the physical, functional and muscle capacity tests most commonly used in pulmonary rehabilitation. Ultimately, it should help the clinician to identify the relevant evaluations according to the objectives of the patients but also according to the available resources, the setting of pulmonary rehabilitation and the specific qualities of each test.

Cognitive and motor performances in dual task in patients with chronic obstructive pulmonary disease: a comparative study

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) may display a motor and/or cognitive disadvantage during dual tasking. However, studies investigating dual task are quite limited in patients with COPD.

AIMS

To compare cognitive and motor performances (i.e., muscle force production and functional balance/mobility together with a cognitive task) in dual task between patients with COPD and healthy controls.

METHODS

Thirty-five clinically stable patients with COPD and 27 age- and sex-matched healthy controls participated in this cross-sectional controlled study. The muscle force production (knee extension muscle strength assessed with an isokinetic strength dynamometer) and functional balance/mobility (Timed Up and Go (TUG) test) were performed with and without a cognitive task. Dual-task interference (DTI) was assessed. Additionally, the rate of correct responses per second (RCR) was calculated to evaluate cognitive performance.

RESULTS

The decrease in RCR_{muscle force production} values was greater in the COPD group compared with the control group (p = 0.045). Similarly, the cognitive DTI in muscle force production test was higher in the control group than in the COPD group (p < 0.001). There was no significant difference in other outcome measures between the two groups (p > 0.05).

CONCLUSION

The study results indicate that in individuals with COPD, cognitive performance deteriorations are more pronounced than motor performance defects during dual tasking. Further studies are needed to investigate the effects of dual task taking into account this disadvantage in patients with COPD rather than focusing solely on motor performance.

Correlation between Limb Muscle Endurance, Strength, and Functional Capacity in People with Chronic Obstructive Pulmonary Disease

PURPOSE

To examine the correlation between limb muscle function (endurance and strength) and functional capacity in upper limbs (ULs) and lower limbs (LLs) of people with chronic obstructive pulmonary disease (COPD).

METHOD

This article describes a secondary analysis of data from a randomized controlled trial. A stationary dynamometer was used to measure isokinetic muscle strength and endurance; the 6-minute walk test, the 6-minute pegboard and ring test, and the unsupported UL exercise test were used to measure functional capacity.

RESULTS

Participants were 44 adults with COPD. Muscle strength and endurance in ULs and LLs demonstrated a moderate to strong correlation with functional capacity. When controlling for muscle strength, muscle endurance was moderately correlated with functional capacity in ULs and LLs, but when controlling for muscle endurance, there was no positive and significant correlation between muscle strength and functional capacity for the ULs or LLs.

CONCLUSIONS

Functional capacity seems to be more closely related to limb muscle endurance than to limb muscle strength in people with COPD.

Why and How Limb Muscle Mass and Function Should Be Measured in Patients with Chronic Obstructive Pulmonary Disease

Impaired limb muscle function is a common occurrence in patients with chronic obstructive pulmonary disease (COPD), and it negatively influences exercise tolerance, quality of life, and even survival. Assessment of limb muscle mass and function in COPD is highly encouraged; it should include the quadriceps muscle, but other lower and upper limb muscles may also be evaluated to provide valuable information. Quantification of muscle mass as well as assessment of muscle strength and endurance are suggested. Bioelectrical impedance and dual-energy X-ray absorption can be realistically used in the clinical environment to monitor body composition. Although sophisticated computerized dynamometers provide the most accurate assessment, simple exercise and testing equipment are valid alternatives and they should help in implementing limb muscle function assessment in clinical settings. Isometric measurements, using strain-gauges or hand-held dynamometers, should be favored for their simplicity, availability, and quality of information provided. This perspective provides a rationale for the evaluation of limb muscle mass and function in COPD in routine clinical practice. In addition, measurement techniques used to assess limb muscle mass, strength, endurance, and fatigue in various clinical settings are discussed.

Muscular and functional effects of partitioning exercising muscle mass in patients with chronic obstructive pulmonary disease - a study protocol for a randomized controlled trial

BACKGROUND

Low-load, high-repetitive single-limb resistance training may increase limb muscle function and functional exercise capacity in patients with chronic obstructive pulmonary disease (COPD) while minimizing the occurrence of limiting exertional symptoms. Whether high-repetitive single-limb resistance training would perform better than high-repetitive two-limb resistance training is unknown. In addition, the mechanisms underlying possible benefits of high-repetitive resistance training has not been investigated. The aims of this study are to compare single versus two-limb high-repetitive resistance training in patients with COPD and to investigate mechanisms of action of these training modalities.

METHODS/DESIGN

This trial is a prospective, assessor-blind, randomized controlled trial. The participants are patients with stable severe to very severe COPD who are older than 40 years of age and healthy controls. The intervention is single-limb, high-repetitive, resistance training with elastic bands, three times/week for 8 weeks. The control is two-limb high-repetitive resistance training with elastic bands, three times/week for 8 weeks. The primary outcomes is change in the 6-min walking distance after 8 weeks of single-limb or two-limb high-repetitive resistance training. The secondary outcomes are changes in limb muscle strength and endurance capacity, key protein involved in quadriceps anabolic/catabolic signalization, fiber-type distribution and capillarization, subjective dyspnea and muscle fatigue, muscle oxygenation, cardiorespiratory demand and health-related quality-of-life after 8 weeks of single-limb or two-limb high-repetitive resistance training. The acute effects of single-limb versus two-limb high-repetitive resistance training on contractile fatigue, exercise stimulus (the product of number of repetition and load), subjective dyspnea and muscle fatigue, muscle oxygenation, and cardiorespiratory demand during upper and lower limb exercises will also be investigated in patients with COPD and healthy controls. Randomization will be performed using a random number generator by a person independent of the recruitment process, using 1:1 allocation to the intervention and the control group using random block sizes.

BLINDING

All outcome assessors will be blinded to group assignment.

DISCUSSION

The results of this project will provide important information to help developing and implementing customized exercise training programs for patients with COPD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02283580 Registration date: 4 November 2014. First participant randomized: 10 November 2014.

An official American Thoracic Society/European Respiratory Society statement: update on limb muscle dysfunction in chronic obstructive pulmonary disease

BACKGROUND

Limb muscle dysfunction is prevalent in chronic obstructive pulmonary disease (COPD) and it has important clinical implications, such as reduced exercise tolerance, quality of life, and even survival. Since the previous American Thoracic Society/European Respiratory Society (ATS/ERS) statement on limb muscle dysfunction, important progress has been made on the characterization of this problem and on our understanding of its pathophysiology and clinical implications.

PURPOSE

The purpose of this document is to update the 1999 ATS/ERS statement on limb muscle dysfunction in COPD.

METHODS

An interdisciplinary committee of experts from the ATS and ERS Pulmonary Rehabilitation and Clinical Problems assemblies determined that the scope of this document should be limited to limb muscles. Committee members conducted focused reviews of the literature on several topics. A librarian also performed a literature search. An ATS methodologist provided advice to the committee, ensuring that the methodological approach was consistent with ATS standards.

RESULTS

We identified important advances in our understanding of the extent and nature of the structural alterations in limb muscles in patients with COPD. Since the last update, landmark studies were published on the mechanisms of development of limb muscle dysfunction in COPD and on the treatment of this condition. We now have a better understanding of the clinical implications of limb muscle dysfunction. Although exercise training is the most potent intervention to address this condition, other therapies, such as neuromuscular electrical stimulation, are emerging. Assessment of limb muscle function can identify patients who are at increased risk of poor clinical outcomes, such as exercise intolerance and premature mortality.

CONCLUSIONS

Limb muscle dysfunction is a key systemic consequence of COPD. However, there are still important gaps in our knowledge about the mechanisms of development of this problem. Strategies for early detection and specific treatments for this condition are also needed.

Assessing the effect of high-repetitive single limb exercises (HRSLE) on exercise capacity and quality of life in patients with chronic obstructive pulmonary disease (COPD): study protocol for randomized controlled trial

Background

Single-limb knee extension exercises have been found to be effective at improving lower extremity exercise capacity in patients with chronic obstructive pulmonary disease (COPD). Since the positive local physiological effects of exercise training only occur in the engaged muscle(s), should upper extremity muscles also be included to determine the effect of single limb exercises in COPD patients.

Methods/design

Trial design: a prospective, assessor-blind, block randomized controlled, parallel-group multicenter trial. Participants: stage II-IV COPD patients, > 40 years of age, ex-smokers, with stable medical treatment will be included starting May 2011. Recruitment at three locations in Sweden. Interventions: 1) high-repetitive single limb exercise (HRSLE) training with elastic bands, 60 minutes, three times/week for 8 weeks combined with four sessions of 60 minutes patient education, or 2) the same patient education alone. Outcomes: Primary: determine the effects of HRSLE on local muscle endurance capacity (measured as meters walked during 6-minute walk test and rings moved on 6-minute ring and pegboard test) and quality of life (measured as change on the Swedish version of the Chronic Respiratory Disease Questionnaire). Secondary: effects on maximal strength, muscular endurance, dyspnea, self-efficacy, anxiety and depression. The relationship between changes in health-related variables and changes in exercise capacity, sex-related differences in training effects, feasibility of the program, strategies to determine adequate starting resistance and provide accurate resistance for each involved movement and the relationship between muscle fatigue and dyspnea in the different exercise tests will also be analyzed. Randomization: performed by a person independent of the recruitment process and using a computer random number generator. Stratification by center and gender with a 1:1 allocation to the intervention or control using random block sizes. Blinding: all outcome assessors will be blinded to group assignment.

Discussion

The results of this project will contribute to increase the body of knowledge regarding COPD and HRSLE.

Trial registration

ClinicalTrials.gov Identifier: NCT01354067. Registration date: 2011-05-11. First participant randomized: 2011-09-02