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Factors associated with impairment of quadriceps muscle function in Chinese patients with chronic obstructive pulmonary disease.

Ju C, Chen R - PLoS ONE (2014)

Bottom Line: Factors contributing to quadriceps dysfunction have been postulated, while not one alone could fully explain it and there are few reports on it in China.While in COPD, forced expiratory volume in 1 second percentage of predicted value (FEV1% pred), nutritional depletion, gender and physical inactivity were identified as independent factors to quadriceps strength (R(2) = 0.72); FEV1%pred, thigh muscle mass, serum levels of tumor necrosis factor-alpha (TNF-α) and gender were correlated to quadriceps endurance variance, with each p<0.05.For the controls, physical activity is most important for quadriceps function.

View Article: PubMed Central - PubMed

Affiliation: The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.

ABSTRACT

Background: Quadriceps muscle dysfunction is well confirmed in chronic obstructive pulmonary disease (COPD) and reported to be related to a higher risk of mortality. Factors contributing to quadriceps dysfunction have been postulated, while not one alone could fully explain it and there are few reports on it in China. This study was aimed to investigate the severity of quadriceps dysfunction in patients with COPD, and to compare quadriceps muscle function in COPD and the healthy elderly.

Methods: Quadriceps strength and endurance capabilities were investigated in 71 COPD patients and 60 age-matched controls; predicted values for quadriceps strength and endurance were calculated using regression equations (incorporating age, gender, anthropometric measurements and physical activities), based on the data from controls. Potential parameters related to quadriceps dysfunction in COPD were identified by stepwise regression analysis.

Results: Mean values of quadriceps strength was 46% and endurance was 38% lower, in patients with COPD relative to controls. Gender, physical activities and anthropometric measurements were predictors to quadriceps function in the controls. While in COPD, forced expiratory volume in 1 second percentage of predicted value (FEV1% pred), nutritional depletion, gender and physical inactivity were identified as independent factors to quadriceps strength (R(2) = 0.72); FEV1%pred, thigh muscle mass, serum levels of tumor necrosis factor-alpha (TNF-α) and gender were correlated to quadriceps endurance variance, with each p<0.05.

Conclusion: Quadriceps strength and endurance capabilities are both substantially impaired in Chinese COPD patients, with strength most affected. For the controls, physical activity is most important for quadriceps function. While for COPD patients, quadriceps dysfunction is related to multiple factors, with airflow limitation, malnutrition and muscle disuse being the main ones.

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The functional test of quadriceps.
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pone-0084167-g001: The functional test of quadriceps.

Mentions: Quadriceps functional tests included strength and endurance performance. The quadriceps isometric maximal voluntary contraction force (QMVC) test was performed using the technique described by a previous report [10], with a specially designed chair (Figure 1). The chair was designed for the following four functions: first, the chair was immovable with being fixed on the floor, while it was comfortable enough and its armrest was strong enough for subjects to exert their maximal force in a sitting position by wrapping their fingers around the armrest; second, there was a strain gauge and load cell (Strainstall, Cowes, UK) installed under the chair so that the quadriceps force could be measured, and the height of the strain load cell was parallel to the ankle of the subjects; third, the strain load cell could be easily dissembled for everyday calibration; fourth, the back of the chair was movable so it could be changed into a bed by laying the back flat for subjects to lie down if necessary. The tests were performed with the subject in a sitting position at 90° hip flexion and knee flexed at 90° over the end of the chair. An inextensible strap was attached around the subject's right leg just superior to the malleoli of the ankle joint. The strap was connected to the strain load cell that was calibrated after each test with weights of known amounts. Subjects were required to try to extend their dominant leg as hard as possible against the inextensible strap. A computer screen was in front of the subjects in order that the force generated was visible to subjects and investigator, so the computer screen served as a positive feedback to help subjects to perform the test. Repeated efforts were made with vigorous encouragement until there was no improvement in the performance, and each effort was sustained for about 3–5 seconds. If maximal values were reproducible (<10% variability) for a consecutive 3 times, i.e., the generated strength reached a plateau, the highest value of the 3 contractions was considered as QMVC [11]. Surface electromyography (sEMG) was recorded for quadriceps muscles of vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM). The output signals of force and sEMG were recorded via an analogue-digital instrument (Powerlab 8/16SP Instruments, Austin, TX, USA) and a personal computer (Apple Computer Inc., Cupertino, CA, USA) running Chart 5.1 software. The quadriceps sEMG amplitude recordings were quantified by using the root-mean-square (RMS). Typical signals of QMVC and sEMG from a normal male subject are shown in Figure 2.


Factors associated with impairment of quadriceps muscle function in Chinese patients with chronic obstructive pulmonary disease.

Ju C, Chen R - PLoS ONE (2014)

The functional test of quadriceps.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3928035&req=5

pone-0084167-g001: The functional test of quadriceps.
Mentions: Quadriceps functional tests included strength and endurance performance. The quadriceps isometric maximal voluntary contraction force (QMVC) test was performed using the technique described by a previous report [10], with a specially designed chair (Figure 1). The chair was designed for the following four functions: first, the chair was immovable with being fixed on the floor, while it was comfortable enough and its armrest was strong enough for subjects to exert their maximal force in a sitting position by wrapping their fingers around the armrest; second, there was a strain gauge and load cell (Strainstall, Cowes, UK) installed under the chair so that the quadriceps force could be measured, and the height of the strain load cell was parallel to the ankle of the subjects; third, the strain load cell could be easily dissembled for everyday calibration; fourth, the back of the chair was movable so it could be changed into a bed by laying the back flat for subjects to lie down if necessary. The tests were performed with the subject in a sitting position at 90° hip flexion and knee flexed at 90° over the end of the chair. An inextensible strap was attached around the subject's right leg just superior to the malleoli of the ankle joint. The strap was connected to the strain load cell that was calibrated after each test with weights of known amounts. Subjects were required to try to extend their dominant leg as hard as possible against the inextensible strap. A computer screen was in front of the subjects in order that the force generated was visible to subjects and investigator, so the computer screen served as a positive feedback to help subjects to perform the test. Repeated efforts were made with vigorous encouragement until there was no improvement in the performance, and each effort was sustained for about 3–5 seconds. If maximal values were reproducible (<10% variability) for a consecutive 3 times, i.e., the generated strength reached a plateau, the highest value of the 3 contractions was considered as QMVC [11]. Surface electromyography (sEMG) was recorded for quadriceps muscles of vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM). The output signals of force and sEMG were recorded via an analogue-digital instrument (Powerlab 8/16SP Instruments, Austin, TX, USA) and a personal computer (Apple Computer Inc., Cupertino, CA, USA) running Chart 5.1 software. The quadriceps sEMG amplitude recordings were quantified by using the root-mean-square (RMS). Typical signals of QMVC and sEMG from a normal male subject are shown in Figure 2.

Bottom Line: Factors contributing to quadriceps dysfunction have been postulated, while not one alone could fully explain it and there are few reports on it in China.While in COPD, forced expiratory volume in 1 second percentage of predicted value (FEV1% pred), nutritional depletion, gender and physical inactivity were identified as independent factors to quadriceps strength (R(2) = 0.72); FEV1%pred, thigh muscle mass, serum levels of tumor necrosis factor-alpha (TNF-α) and gender were correlated to quadriceps endurance variance, with each p<0.05.For the controls, physical activity is most important for quadriceps function.

View Article: PubMed Central - PubMed

Affiliation: The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.

ABSTRACT

Background: Quadriceps muscle dysfunction is well confirmed in chronic obstructive pulmonary disease (COPD) and reported to be related to a higher risk of mortality. Factors contributing to quadriceps dysfunction have been postulated, while not one alone could fully explain it and there are few reports on it in China. This study was aimed to investigate the severity of quadriceps dysfunction in patients with COPD, and to compare quadriceps muscle function in COPD and the healthy elderly.

Methods: Quadriceps strength and endurance capabilities were investigated in 71 COPD patients and 60 age-matched controls; predicted values for quadriceps strength and endurance were calculated using regression equations (incorporating age, gender, anthropometric measurements and physical activities), based on the data from controls. Potential parameters related to quadriceps dysfunction in COPD were identified by stepwise regression analysis.

Results: Mean values of quadriceps strength was 46% and endurance was 38% lower, in patients with COPD relative to controls. Gender, physical activities and anthropometric measurements were predictors to quadriceps function in the controls. While in COPD, forced expiratory volume in 1 second percentage of predicted value (FEV1% pred), nutritional depletion, gender and physical inactivity were identified as independent factors to quadriceps strength (R(2) = 0.72); FEV1%pred, thigh muscle mass, serum levels of tumor necrosis factor-alpha (TNF-α) and gender were correlated to quadriceps endurance variance, with each p<0.05.

Conclusion: Quadriceps strength and endurance capabilities are both substantially impaired in Chinese COPD patients, with strength most affected. For the controls, physical activity is most important for quadriceps function. While for COPD patients, quadriceps dysfunction is related to multiple factors, with airflow limitation, malnutrition and muscle disuse being the main ones.

Show MeSH
Related in: MedlinePlus