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Muscle Adaptation (muscle + adaptation)

Distribution by Scientific Domains
Life Sciences80%

Selected Abstracts

Arm and leg substrate utilization and muscle adaptation after prolonged low-intensity training

ACTA PHYSIOLOGICA, Issue 4 2010
J. W. Helge
Abstract This review will focus on current data where substrate metabolism in arm and leg muscle is investigated and discuss the presence of higher carbohydrate oxidation and lactate release observed during arm compared with leg exercise. Furthermore, a basis for a possible difference in substrate partitioning between endogenous and exogenous substrate during arm and leg exercise will be debated. Moreover the review will probe if differences between arm and leg muscle are merely a result of different training status rather than a qualitative difference in limb substrate regulation. Along this line the review will address the available studies on low-intensity training performed separately with arm or legs or as whole-body training to evaluate if this leads to different adaptations in arm and leg muscle resulting in different substrate utilization patterns during separate arm or leg exercise at comparable workloads. Finally, the influence and capacity of low-intensity training to influence metabolic fitness in the face of a limited effect on aerobic fitness will be challenged. [source]

Reactive oxygen species are signalling molecules for skeletal muscle adaptation

EXPERIMENTAL PHYSIOLOGY, Issue 1 2010
Scott K. Powers
Increased reactive oxygen species (ROS) production is crucial to the remodelling that occurs in skeletal muscle in response to both exercise training and prolonged periods of disuse. This review discusses the redox-sensitive signalling pathways that are responsible for this ROS-induced skeletal muscle adaptation. We begin with a discussion of the sites of ROS production in skeletal muscle fibres. This is followed by an overview of the putative redox-sensitive signalling pathways that promote skeletal muscle adaptation. Specifically, this discussion highlights redox-sensitive kinases, phosphatases and the transcription factor nuclear factor-,B. We also discuss the evidence that connects redox signalling to skeletal muscle adaptation in response to increased muscular activity (i.e. exercise training) and during prolonged periods of muscular inactivity (i.e. immobilization). In an effort to stimulate further research, we conclude with a discussion of unanswered questions about redox signalling in skeletal muscle. [source]

The training stimulus experienced by the leg muscles during cycling in humans

EXPERIMENTAL PHYSIOLOGY, Issue 6 2009
Jamie S. McPhee
Considerable variability exists between people in their health- and performance-related adaptations to conventional endurance training. We hypothesized that some of this variability might be due to differences in the training stimulus received by the working muscles. In 71 young sedentary women we observed large variations in the ratio of one-leg cycling muscle aerobic capacity to two-leg cycling whole-body maximal oxygen uptake (; Ratio1:2; range 0.58,0.96). The variability in Ratio1:2 was primarily due to differences between people in one-leg (r= 0.71, P < 0.0005) and was not related to two-leg (r= 0.15, P= 0.209). Magnetic resonance imaging (n= 30) and muscle biopsy sampling (n= 20) revealed that one-leg was mainly determined by muscle volume (r= 0.73, P < 0.0005) rather than muscle fibre type or oxidative capacity. A high one-leg was associated with favourable lipoprotein profiles (P= 0.033, n= 24) but this was not the case for two-leg . Calculations based on these data suggest that conventional two-leg exercise at 70% requires subjects with the lowest Ratio1:2 to work their legs at 60% of single-leg , whilst those with the highest Ratio1:2 work their legs at only 36% of maximum. It was concluded that endurance training carried out according to current guidelines will result in highly variable training stimuli for the leg muscles and variable magnitudes of adaptation. These conclusions have implications for the prescription of exercise to improve health and for investigations into the genetic basis of muscle adaptations. [source]

PERSONAL DIGITAL VIDEO: A METHOD TO MONITOR DRUG REGIMEN ADHERENCE DURING HUMAN CLINICAL INVESTIGATIONS

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2006
Chad C Carroll
SUMMARY 1Maintaining patient adherence to a drug regimen has proven to be difficult. Missed doses can impact drug efficacy and disease control, leading to increased health-care costs. 2During clinical drug trials, poor adherence could lead to false conclusions regarding drug efficacy. Therefore, the purpose of the present study was to determine the feasibility of using personal digital video cameras to monitor adherence to a medication regimen during a clinical investigation. 3Older men and women (60,78 years) participated in a double-blind, placebo-controlled trial to determine the effect of ibuprofen or paracetamol on skeletal muscle adaptations to chronic resistance exercise training. Patients took three daily doses of either a placebo or the maximal daily over-the-counter dose of ibuprofen (1.2 g/day) or paracetamol (4.0 g/day) for 12 weeks. Prior to beginning the study, subjects were trained to use a personal digital video camera to record their drug consumption. 4Subjects correctly recorded 4956 of 5375 doses, resulting in an average camera compliance rate of 92% (71,100%). 5We describe a method of monitoring adherence to a prescribed drug regimen during a clinical investigation. Camera compliance rates, which directly confirm drug consumption, were higher than what is typically obtained with other methods of monitoring adherence. This camera compliance method provides the investigator with a simple and convenient means to generate direct evidence of drug consumption. [source]