Correlation between the use of oral contraceptives and sports injury and performance is largely speculative . There are physiological changes from the use of oral contraceptives, but they do not appear to affect performance.
Female soccer players using oral contraceptives reported to have less traumatic injuries may be due to better neuromuscular co-ordination (ref).
Oral contraceptive reduce blood loss during menstrual period higher haemoglobin levels ? better oxygen transport ? better aerobic capacity
Oestrogen component of oral contraceptives beneficial effect on bone mineral density ? decreased risk for stress fractures.