All perfect praise be to Allah, The Lord of the Worlds. I testify that none is worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
There is no doubt that fasting Ramadan is obligatory for everyone who is competent for religious assignments and has the ability to carry them out. It is impermissible to give up fasting in Ramadan unless there is a sharia-approved excuse, such as travel, illness, disability, etc., or due to other impediments, such as menstruation or post-partum bleeding for women. Allah Almighty Says (what means): {So whoever among you is ill or on a journey [during them]—then an equal number of days [are to be made up]. And upon those who are able [to fast, but with hardship]—a ransom [as substitute] of feeding a poor person [each day].}[Quran 2: 184]
Thus, it is impermissible to abandon fasting because of sport training sessions, as it is not one of the Sharee'ah-approved excuses in this respect. Moreover, fasting is to be observed for one month only and you can delay the training to the evening, as many sportsmen do. We would like to remind sportsmen that fasting has many spiritual and physical benefits too. It is a kind of sport for them as well. The Prophet, sallallaahu ‘alayhi wa sallam, said: “Fast and you will be in a good health.” [At-Tabaraani and Abu Nu‘aym; Al-‘Iraaqi: Dha‘eef (inauthentic) and As-Siyooti: Hasan]
We ask Allah to grant us all success to do what He likes and causes His pleasure.
Allah Knows best.