A few questions about the workouts, and you, to help frame the issue:
Leggings might help reduce blood pooling, but they would not be legit in a meet, and it would be better if you could locate and correct the root causes of the cramping.
- How often do you practice?
- How much kicking alone do you do in an average practice, and is it early or late in the practice?
- Do your practices mix speed and endurance work, or just focus on one or the other?
- Are you maintaining hydration levels before and during your workout?
- Is your diet balanced?