Physical activity	Any bodily movement produced by the skeletal muscles that results in a substantial increase over resting energy expenditure.
Exercise	Physical activity that is usually performed on a repeated basis over an extended period of time (exercise training) with a specific external objective such as improvement of fitness, physical performance or health.
Mode	Type of exercise (running, swimming, etc) AND temporal pattern of activity (continuous or intermittent activity).
Intensity	Absolute or relative (eg, percentage of one repetition maximum or maximum oxygen consumption: VO2max/heart rate (HR) reserve).
Frequency	Number of sessions undertaken in a typical week.
Duration	Minutes or hours of one session or the whole exercise period (3 months, 1 year).
Fitness	A set of attributes (qualities) relating to the ability to perform physical activity/exercise.
Performance-related fitness	Those components of fitness that are necessary for optimal work or sport performance; the individual's ability in athletic competition, performance or occupational work.
Health-related fitness	A state characterised by (1) an ability to perform daily activities with vigour and (2) demonstration of traits and capacities that are associated with low risk of premature development of hypokinetic diseases and conditions.
Exerciser	A person who performs regular strenuous exercise both for fitness and competition, but not representing any national team.
Elite athlete	A person who is a member of any national team or other high-level representative team in any sport organised by a National Sports Federation.
Postpartum	In general, the period from childbirth until 6 weeks postpartum. For this review, we have extended this period to 12 months after childbirth.