Runner cause a runner should keep on running
Swimmer a swimmer should keep on swimming
Cyclist a cyclist should keep on cycling
Flexibility cause it improves that specific muscles at the specific joints.
Specificity means that training must be specific and intended for your sport.
For example: Basketball fitness training should include some distance work with intermittent speed and agility training.
Golfers would require little distance work, but train for power and flexibility.
Basta ayan yon onti lang alam ko po