What does Islam say regarding playing dangerous games in some parks? What does it also say about skydiving? Some people play games that are very high and scary just for fun. They also jump from airplanes using parachutes for fun too. Can a Muslim look to jumping from airplane using parachute as training and making his heart stronger.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

The games that subject a person to destruction are forbidden as Allaah says (which means): {...and do not throw yourselves into destruction.}[Quran 2:195]. Moreover, the Prophet said: "It is forbidden to afflict harm on oneself or others (whether directly or indirectly)." [Ahmad] Therefore, if the harm of a specific game is confirmed or that it is most likely that it will cause harm, then it is forbidden; this is indeed one of the great rules of religion.

There is no confirmed harm for jumping from airplanes, and it is unlikely that this will cause harm because those who practise this kind of game take all the safety measures. So we do not see any religious obstacle for practising this kind of game especially if the purpose is good, like physical exercise and preparing the power that Allaah has ordered us to prepare against the enemy, as long as this game does not lead to leaving a religious obligation, like the prayer, or neglecting a right.

However, a Muslim should know that time is the most precious thing that he possesses so he should not waste it in useless things. 

Allaah knows best.