Inactivity is a recognized compounding factor in sarcopenia and muscle weakness in old age. However, while the negative effects of unloading on skeletal muscle in young individuals are well elucidated, only little is known about the consequence of immobilization and the regenerative capacity in elderly individuals. Thus the aim of this study was to examine the effect of aging on changes in musc...

STUDY DESIGN Controlled laboratory study using a cross-sectional design. OBJECTIVES To analyze the relationship of quadriceps-hamstrings and medial-lateral quadriceps anatomical cross-sectional area (ACSA) ratios with knee loads during walking and articular and meniscal cartilage composition in young, healthy subjects. BACKGROUND Muscle forces affect knee loading during walking, but it is n...

BACKGROUND Little is known about limb muscle abnormalities in mild COPD. Inactivity and systemic inflammation could play a role in the development of limb muscle dysfunction in COPD. The objective of the present study was to characterize quadriceps function, enzymatic activities and morphometry, levels of plasma inflammatory markers and physical activity levels in daily life (PAdl) in patients ...

BACKGROUND Although exercise training has beneficial effects on skeletal muscle bioenergetics and exercise performance in patients with severe chronic obstructive pulmonary disease (COPD), it may also be associated with increased quadriceps oxidative and nitrosative stress. The aim of this study was to explore quadriceps oxidative and nitrosative stress in patients with severe COPD, both before...

Being well-established in advanced chronic obstructive pulmonary disease (COPD), skeletal muscle dysfunction and its underlying pathology have been scarcely investigated in patients with mild-to-moderate airflow obstruction. We hypothesized that a loss of oxidative phenotype (oxphen) associated with decreased endurance is present in the skeletal muscle of patients with mild-to-moderate COPD. In...

The purpose of this investigation was to determine the effect of hip position and test velocity on the quadriceps and hamstring reciprocal muscle group ratio. Twelve subjects (7 male, 5 female) were tested for isokinetic peak torque at 60, 180, and 240 degrees /sec from the seated and supine positions. Gravity correction was obtained to determine quadriceps and hamstring peak torque, and to det...

INTRODUCTION Duchenne muscular dystrophy (DMD) is a lethal genetic disease caused by mutations in the dystrophin gene resulting in chronic muscle damage, muscle wasting, and premature death. Utrophin is a dystrophin protein homologue that increases dystrophic muscle function and reduces pathology. Currently, no treatments that increase utrophin protein expression exist. However, exercise increa...

BACKGROUND In the absence of complications, recipients of lung transplants for cystic fibrosis have normal pulmonary function but the impact of the procedure on the strength and bulk of respiratory and limb muscles has not been studied. METHODS Twelve stable patients who had undergone lung transplantation for cystic fibrosis 48 months earlier (range 8-95) and 12 normal subjects matched for ag...

Dynamic one-legged knee extension (DKE) is commonly used to examine physiological responses to "aerobic" exercise. Muscle blood flow during DKE is often expressed relative to quadriceps femoris muscle mass irrespective of work rate. This is contrary to the notion that increased force is achieved by recruitment in large muscles. The purpose of this study, therefore, was to determine muscle use d...

Both vitamin D deficiency and quadriceps muscle weakness are associated with knee osteoarthritis (KOA) and pain. The aim of this study was to determine the restorative effect of vitamin D deficiency on pain and quadriceps muscle strength in knee osteoarthritis. Patients with KOA aged ≥30 years, the presence of knee pain for at least one month or longer and serum 25-hydroxyvitamin (25-OHD) defic...