Effect of a strength exercise program on muscle function in children with CF: Preliminary results

Abstract

Introduction Cystic fibrosis is the most lethal autosomal recessive disease with higher prevalence in Caucasian population [1]. More than 1,800 mutations have been identified and can be clustered in six functional groups, therefore, altering the secretion and absorption in different tissues. Recurrent infections result in an increased damage to the lungs that leads to hypoxia in peripheric tissues such as skeletal muscle. Then, skeletal muscle weakness displays very early in patients with CF [2]. Recent studies have shown that CFTR protein is expressed in skeletal muscle, and therefore CF has a direct effect in this tissue [3]. Both respiratory damage and muscular weakness result in a reduced exercise capacity that will lead to exercise intolerance and reduction of expectoration and pulmonary function. Objective: Determine the effect of a strength exercise program on muscle function in children with CF. Methods: 17 pediatric patients with CF participated in a randomized, prospective, controlled design. They were divided in two groups: Control Group (CG) (n=9; Age 12.43 ± 3.78 years; follow standard medical care), and Exercise Group (EG) (n=8; Age 12.75 ± 3.06 years; follow 8 weeks of supervised exercise program). We measured muscle strength by 5RM test of both the upper and lower limbs in pediatric weight training machines. Mean differences between groups and measurements was determined using a mixed multivariate analysis of variance. Results: The EG showed a significant improvement in strength relative to body weight compared to the CG (p=0.015). A large and significant effect size was observed on the leg press strength (p=0.003; η2p =0.514), bench press (p=0.008; η2p=0.428) and seated lateral row (p=0.008; η2p =0.435). Discussion: In this preliminary data it seems that the muscles of the CF pediatric patient can respond to exercise and improve muscle strength despite having CFTR deficit. Practical application: To maintain a correct body composition and physical condition in CF it’s related with better disease prognosis. Strength exercise programs may be a useful and capable tool to maintain and improve the body muscle mass in CF.