40
stimulation, normal muscle fatigue, ischemic fatigue and
partial neuromuscular transmission block with curare.
During all of these treatments, the relationship between
O2 uptake and developed tension has been unaltered.
The data also show that although resting metabolic
rate following fatigue approaches pre-fatigue levels after
30 minutes, developed tension is still quite low.
Phosphorylcreatine and ATP levels should be fully
recovered following 30 minutes of rest (38, 51). Edwards
and coworkers (23) have also identified a long lasting
element of fatigue in humans that is not due to
depletion of high-energy phosphates. Further study
is warranted to determine whether or not there really
is a causative relationship between phosphorylcreatine
depletion and fatigue, as suggested by Spande and
Schottelius (56).