a hollow masonry building unit of cement, terra cotta, etc.: a wall made of concrete blocks. one of a set of cube-shaped pieces of wood, plastic, or the like, used as a child's toy in building. a mold or piece on which something is shaped or kept in shape: a hat block.
Neutral powers during World War II. The neutral powers were countries that remained neutral during World War II. Some of these countries had large colonies abroad or had great economic power.
So, in summary, Critical Power represents a very useful physiological parameter, higher than Lactate Threshold but lower than VO2max. Further, it is highly correlated with both of these measures as well as being highly correlated with endurance performance capacity.