It is well established that the loss of muscle force and reduction in motor unit survival in 120 d SOD1G93A mice is due to the degeneration of a large number of motor neurons in the lumbar spinal cord.
21 23 Such observations are reported alongside studies reporting a concomitant reduction in muscle force production at the end of matches, for example, reduced hamstring force in response to football specific exercise.
Furthermore, addition of strong synthetic reducing agents or antioxidants such as DTT (2), N-acetylcysteine (29), and DMSO (45, 46) to skeletal muscle in an organ bath resulted in a reduction in skeletal muscle force production.
Given these reported findings, a reduction in joint forces resulting from weaker muscle force production and slower running speeds may explain the diminished chondrogenic response to voluntary running exercise in the proximal femurs of mdx mice.
Long-term CS exposure has a clear potential to contribute to the systemic effects of COPD, as similar findings have been observed in healthy smokers (for example, a decrease in lean muscle mass and force reduction) [ 6].
Dex treated animals showed a significant reduction in fatigable muscle force but only a relatively minor reduction of fatigue-resistant force, which confirms previously published results where type II fibers were significantly more affected by Dex treatment than type I [ 22, 48] and provides support for Dex treatment as a potential animal model to represent muscle aging.
A second reported effect of dopamine on skeletal muscle is an improvement in diaphragm muscle force development and a reduction in diaphragm apoptosis in vitro [ 41].
There was a shorter latency of the reflex loop delay in patients with SCI in this study, which could be due to heightened state of spastic muscles with quicker development of muscle force and/or due to reduction in the presynaptic inhibition between Ia afferent and α-motoneurons under altered upper motor neuron control.
For a femoral component with a smaller distal radius, there was 12% reduction in the quadriceps muscle force and up to 11% reduction in the patello-femoral force from about 100 up to 60° flexion.
As either an increase or a reduction in ROS levels determined a reduction in muscle force, they suggested that there was an optimal redox state for force production [ 40].
