Cellular mechanisms of muscle fatigue.
- R. Fitts
- BiologyPhysiological Reviews
It appears likely that this condition is associated with and likely caused by muscle injury, such that the SR releases less Ca2+ at low frequencies of activation, and LFF could result from a reduced membrane excitability,such that the sarcolemma action potential frequency is considerably less than the stimulation frequency.
The cross-bridge cycle and skeletal muscle fatigue.
- R. Fitts
- BiologyJournal of applied physiology
- 1 February 2008
The functional correlates of fatigue observed in both animals and humans during exercise include a decline in peak force (P0), maximal velocity, and peak power. Establishing the extent to which these…
Physiology of a microgravity environment invited review: microgravity and skeletal muscle.
Evidence in rats indicates that SF increases fatigability and reduces the capacity for fat oxidation in skeletal muscles, and the microgravity-induced decline in peak power is partially offset by the increased fiber velocity.
Exercise in space: human skeletal muscle after 6 months aboard the International Space Station.
Data show a reduction in calf muscle mass and performance along with a slow-to-fast fiber type transition in the gastrocnemius and soleus muscles, which are all qualities associated with unloading in humans, as well as a redistribution among the faster phenotypes.
Effect of a 17 day spaceflight on contractile properties of human soleus muscle fibres
The results support the idea that ground‐based bed rest can serve as a model of human spaceflight and the increase in shortening velocity greatly reduced the impact that impaired force production had on absolute peak power.
Functional and structural adaptations of skeletal muscle to microgravity.
The major effects of space travel on skeletal muscle with particular emphasis on factors that alter function are muscle atrophy and the associated decline in peak force and power, and weightlessness reduces the ability of the slow soleus to oxidize fats and increases the utilization of muscle glycogen, at least in rats.
Skeletal muscle fatigue.
Evaluation of muscle fatigue in a wide range of disease states builds on the understanding of basic function by revealing the sources of dysfunction in response to disease.
Muscle Mechanics: Adaptations with Exercise‐Training
A positive correlation exists between the percentage of fast fibers and peak torque output at moderate-to-high angular isokinetic velocities and, consequently, peak power output is substantially greater in subjects possessing a predominance of fast fiber types.
Effect of 17 days of bed rest on peak isometric force and unloaded shortening velocity of human soleus fibers.
- J. Widrick, J. Romatowski, R. Fitts
- BiologyAmerican Journal of Physiology - Cell Physiology
- 1 November 1997
Results raise the possibility that alterations in the geometric relationships between thin and thick filaments may be at least partially responsible for the elevated V o of the post-BR type I fibers.
Models of disuse: a comparison of hindlimb suspension and immobilization.
A major difference existed in the effects of HS and HI on the maximal speed of soleus muscle shortening (Vmax), and one plausible explanation is that the apparent HS-mediated modification in muscle fiber type is dependent on the elimination of loadbearing or isometric contractions, a condition that does not exist during HI.