Table 1.

Cell and molecular targets of exercise. A summary of known effects of exercise in the injured spinal cord demonstrates a wide range of action, including local and distant increase in neurotrophic factors, upregulation of cFosexpression in multiple neuron cell types, expression of downstream molecules of the AKT/mTOR pathway that may reflect a strong regenerative potential and retention of muscle size and motoneuron membrane properties and reflex activity. In future experiments, exercise will be employed to attempt to increase the growth of regenerating axons into and then out of a PNG.

Cell and molecular plasticity with exercise
Outcome	Location	Effects	What’s next
Increased expression of neurotrophic factors	Below and above injury site	Neuroprotective  Reduce axon dieback  Rescue injured neurons	Examine the potential of exercise to promote axon growth into and out of a PNG.
Upregulation of cFos expression	Multiple neuronal cell types below injury site	Neuroplasticity  Enhanced neuronal activity
Increased expression of phosphorylated S6	Interneurons below injury site	Neuroregenerative  S6 is a molecule downstream of AKT/mTOR, suggests a strong regenerative potential
Retention of MN properties, muscle size and modulation of H-reflex	Below injury site	Neurorehabilitative  Promote interneuronplasticity  Modulate MN excitability  Reduce muscle atrophy