Determination of isokinetic muscle strength in chronic heart
failure patients and in patients with chronic obstructive pulmonary
disease
Issue title: Selected papers and abstracts of the
"XXXIèmes Entretiens de Médecine Physique et de
Réadaptation", Current Concepts in Isokinetics, Montpellier, France,
5–7 March, 2003
Affiliations: [a] Service d'Explorations Fonctionnelles
Cardio-Respiratoires, Hôpital Nord, CHU de St Etienne, France | [b] Service de Médecine Physique et
Réadaptation PAV 9-11, Hôpital Bellevue, CHU de St Etienne,
France
Abstract: Objective: To evaluate the relationship between isokinetic strength,
and aerobic aptitude in patients with chronic heart failure (CHF) and with
chronic obstructive pulmonary disease (COPD). Methods: Seventeen stable CHF
(n=11) and COPD (n=6) patients aged 51.12 ± 9.95 ys old (15 men, 2
women, CHF patients: NYHA class II: n=8 and III: n=3) underwent a dynamic
isokinetic force evaluation of the quadriceps (IsoK) at an angular velocity of
180°s^{-1}, a symptom-limited cardiopulmonary exercise
test with simultaneous monitoring of respiratory gases, and a 6-min walking
test. Body composition was assessed by electrical bioimpedance. The
relationships between muscle strength, maximal aerobic performance, results of
endurance tests and anthropometric datas were assessed by simple regression
analysis. Results: The isokinetic evaluation has been successfully performed in
all patients. No cardiac arrhythmic event nor abnormal haemodynamic response
was observed in either group of patients. In CHF patients, individual
quadricipital muscle strength was significantly related to fat-free mass
(r=0.862; p<0.01). However, neither peak O_2 (global:
r=0.562, p=NS or weight-adjusted: r=0.083, p=NS) nor endurance capacity
(r=0.068, p=NS) were significantly related to the peripheral muscle strength.
In COPD patients, quadricipital muscle strength was not significantly related
to fat-free mass (r=0.242; p=NS) nor any other measured factor. Conclusion:
Physiopathological mechanisms of exercise limitation in CHF and COPD patients
are complex. Isokinetic strength and O_2 peak are not
related to each other and are therefore independent. Therefore, a systematic
evaluation of isokinetic muscle strength may be of great value. Early
degradations in aerobic capacity are probably followed by an alteration in
muscle strength.
