Muscle Metabolism and Oxygenation During Localized Fatigue-exercise in COPD

N/AUnknownNCT01909544

Laval University20 enrolled

Overview

The purpose of this study is to investigate whether a localized exercise, in which cardiorespiratory demand is reduced, will result in greater limb muscle fatigue in patients with COPD as a consequence of muscle oxygenation and muscle metabolism disturbances.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Enrollment

Conditions

Pulmonary Disease, Chronic Obstructive

Interventions

Fatiguing exerciseOTHER

All participants (patients and healthy subjects) will perform the exercise both under normoxic (FiO2 = 0.21) and hyperoxic conditions (FiO2 = 100%)

Eligibility

Sex: ALLMin age: 50 YearsMax age: 75 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * COPD (FEV1/FVC \< 0.70 and FEV1 \< 0.80 predicted * Healthy subjects: no evidence of airways obstruction (FEV1/FVC \> 0.70 and FEV1 \> 0.80 predicted) * Smoking history \> 15 pack-years Exclusion Criteria: * Chronic hypoxemia and/or hypercapnia (PaO2 \< 60 mmHg or SpO2 \< 88% at rest and/or PaCO2 \> 45 mmHg) * Recent exacerbation (\< 3 months) * Recent cancer (\< 3 years) * Diabetes * Myopathy, neuromuscular or articular disease * Unstable cardiac disease * Absolute contraindications to exercise testing * Regular physical activity or exercise training program in the last 2 months * Physical activity score \> 9 in the Voorips questionnaire * Thigh skinfold thickness \> 15 mm * BMI \> 30

Locations (1)

Institut universitaire de cardiologie et de pneumologie de Québec

Québec, Quebec, Canada

RECRUITING

Outcomes

Primary Outcomes

Muscle deoxygenation

Changes of deoxyhemoglobin/myoglobin concentrations measured by near-infrared spectroscopy of vastus lateralis muscle.

Time frame: 45 seconds post-exercise (knee-extension repetitions)

Muscle metabolism

Changes in glycolytic and oxidative metabolism pathway markers, energy substrates (glycogen and glucose), end-products of glycolysis (pyruvate, and lactate), intermediate markers of glycolysis and high-energy phosphate compounds obtained from muscle biopsies

Time frame: 45 seconds post-exercise (knee extension repetitions)

Secondary Outcomes

Ventilatory response

Minute ventilation will be monitored during the fatigue-inducing exercise and it will be compared between subjects and conditions (FiO2 = 21% vs. FiO2 = 100%)

Time frame: Baseline, beginning and end of each serie of knee extensions (fatiguing exercise)

Quadriceps muscle fatigue

Quadriceps muscle fatigue will be determined by loss of quadriceps strength measured by magnetic stimulation after the fatigue-inducing exercise. Surface electromyography will also be measured to characterize muscle fatigue.

Time frame: baseline, 15 min and 40 min after the fatigue-inducing exercise

total muscle work

Total muscle work performed during fatigue-inducing exercise that will be composed by subsequent isokinetic knee-extensions repetitions at 40% of maximal peak torque

Time frame: end of fatiguing exercise

Central Contacts

Fernanda Ribeiro, PhD candidate

CONTACT

418-656-8711 fernanda.ribeiro@criucpq.ulaval.ca

Data from ClinicalTrials.gov

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