Skeletal muscle contributions to reduced fitness in cystic fibrosis youth.

Background: Increased maximal oxygen uptake (V̇O) is beneficial in children with cystic fibrosis (CF) but remains lower compared to healthy peers. Intrinsic metabolic deficiencies within skeletal muscle (muscle "quality") and skeletal muscle size (muscle "quantity") are both proposed as potential causes for the lower V̇O, although exact mechanisms remain unknown. This study utilises gold-standard methodologies to control for the residual effects of muscle size from V̇O to address this "quality" vs.

Quantification of thigh muscle volume in children and adolescents using magnetic resonance imaging.

Estimating muscle volume (MV) using variable numbers of cross-sectional area (CSA) slices obtained from magnetic resonance imaging (MRI) introduces an error that is known in adults, but not in children and adolescents, whereby body sizes differ due to growth and maturation. Therefore, 15 children and adolescents (11 males, 14.8 ± 2.

Scaling the Oxygen Uptake Efficiency Slope for Body Size in Cystic Fibrosis.

Purpose: The aim of this study was to describe the relationship between body size and oxygen uptake efficiency slope (OUES) in pediatric patients with cystic fibrosis (CF) and healthy controls (CON), to identify appropriate scaling procedures to adjust the influence of body size upon OUES.

Methods: The OUES was derived using maximal and submaximal points from cardiopulmonary exercise testing in 72 children (36 CF and 36 CON). OUES was subsequently scaled for stature, body mass (BM), and body surface area (BSA) using ratio-standard (Y/X) and allometric (Y/X) methods.

Is cardiac autonomic function associated with cardiorespiratory fitness and physical activity in children and adolescents? A systematic review of cross-sectional studies.

Background: Heart rate variability (HRV) is considered to explain improvements in cardiovascular health accrued by physical activity (PA) and cardiorespiratory fitness (CRF) over and above traditional cardiovascular risk factors.

Objective: To systematically address associations between HRV, PA and CRF in children and adolescents.

Data Sources: Medline, EMBASE, SportDISCUS and CINAHL Plus were searched on 5th September 2015 and updated on 4th August 2016.

Impaired Pulmonary V˙O2 Kinetics in Cystic Fibrosis Depend on Exercise Intensity.

Purpose: This study aimed to investigate the effects of mild-to-moderate cystic fibrosis (CF) on the pulmonary oxygen uptake (V˙O2) kinetics of seven pediatric patients (13.5 ± 2.8 yr) versus seven healthy matched controls (CON; 13.

The effect of ivacaftor in adolescents with cystic fibrosis (G551D mutation): an exercise physiology perspective.

Purpose: The purpose of this report was to evaluate the influence of 12 weeks of ivacaftor treatment on the aerobic function of 2 teenage patients with cystic fibrosis (CF; ΔF508/G551D) using a maximal cardiopulmonary exercise test.

Summary Of Key Points: One patient, with relatively mild disease, demonstrated no clinically meaningful changes in maximal oxygen uptake ((Equation is included in full-text article.)O2max).

Two protocols to measure mitochondrial capacity in women and adolescent girls: a 31P-MRS preliminary study.

The phosphocreatine (PCr) recovery time constant (τ) following exercise provides a measure of mitochondrial oxidative capacity. The purpose of this investigation was to use 2 different protocols to determine τ in adolescent females. 31P-MR spectra were collected during 2 exercise tests in 6 adolescent girls (13.

Impaired aerobic function in patients with cystic fibrosis during ramp exercise.

Purpose: This study aimed to document the matching of muscle O2 delivery to O2 use in young patients with cystic fibrosis (CF) from muscle deoxygenation (HHb) dynamics during ramp exercise.

Methods: Ten patients with stable, mild-to-moderate CF (12.7 ± 2.