Please Define the Following Terms or Concepts in No More

Please define the following terms or concepts in no more than two sentences, and give an example to support your definition.
A. Adenosine-triphosphate-creatine (ATP-PC)
B. Aerobic exercise
C. Agility
D. Anaerobic exercise
E. All-or-none conditioning principle
F. Balance
G. Cardiovascular endurance
H. Chondromalacia
I. Cool-down period
J. Duration of exercise
K. Fat-soluble vitamins
L. Flexibility
M. Frequency of exercise
N. Intensity of exercise
O. Karvonen's heart rate equation
P. Lactic acid
Q. Mode of exercise
R. Muscular endurance
S. Muscular strength
T. Parasympathetic rebound
U. Phases of a workout
V. Pilates
W. Power
X. Progressive overload principle
Y. Runner's high
Z. Stimulus period
AA. Target heart rate
AB. Warm-up period