During a test in the laboratory, an athlete ran at 10.0 mph for a period of time. At the start of the test, the treadmill speed was set at 10.0 mph and the athlete was standing with legs straddling the moving belt. On a signal, he/she "jumped" onto the moving belt and started running at 10.0 mph. True statements about changes in power at the start of this test include the following:
a. Power output increased abruptly and power input increased gradually over a 1-o 2-minute period.
b. Both power output and power input increased abruptly.
c. Power input increased abruptly and power output increased gradually over a 1-to 2-minute period.
d. Both power output and power input increased gradually over a 1- to 2-minute period.

Power output refers to the power exerted at the time of performing physical activities. Power output is one of the best means of determining athletic performance at the time of exercise or any physical activity. When the athlete jumped over the treadmill, his output power enhanced abruptly, while the power input enhanced slowly over a duration of one to two minutes.