Abstract
The isometric muscular strength and endurance of 10 male volunteers were measured four times per day for 15 consecutive days. Eight experimental subjects were inoculated with sandfly fever virus and two double-blind controls were given sterile saline on the seventh day. The muscular performances of the control subjects remained essentially constant throughout. Decrements in muscular strength and endurance occurred with the experimentals during the brief period of illness three or four days after inoculation, then performances improved towards baseline levels. Although the performance decrements occurred in conjunction with changes in certain metabolic indicators of the internal biochemical state of the skeletal muscles, the recovery occurred while these were still abnormal.