Islamic athletics is an athletics organisation governed by Sharia and formed through the Islamic history. In Islam, athletics is perceived as important to gain a healthy body. Sports like swimming and horseback riding are especially encouraged by Hadith. There are, however, some other sports that are banned in Islam. Any sports that involve killing (i.e. hunting) are strictly forbidden according to Islamic Law Sharia.
The Islamic law, or Sharia, sets several bounds that indirectly impact Muslim athletes. This includes rules regarding the awrah, those parts of the body not to be exposed in public. The hijab or Burqas required by strict divisions of Islam can make it difficult for women to engage in many sports. Also, men are not allowed to have clothing that shows the area between the knees and navel, prohibiting them from engaging in, for example, Sumo wrestling. For some time, Iranian women at the Olympics only competed in shooting because it was the one area unaffected by their dress codes. To solve this, many sports companies have begun creating Muslim-friendly sportswear.
Salafi Fatwa 
Salafi scholar Sheikh Muhammed Salih Al-Munajjid  has made the following statement in response to this question: "What is the ruling on our body building in Islam? Are we allowed to put our bodies in structures like the wrestlers so long as we don't show it out and it's to our own good?"
- "Praise be to Allaah.
- Bodybuilding aims to make the body strong and sound, which is an important and desirable goal.
- Islam is concerned with man’s well-being in both body and soul, and it encourages all kinds of sport that will strengthen the body and maintain good health as well as providing relaxation and leisure, such as swimming, shooting, horse-riding, sword-fighting and wrestling.
- But when Islam accepts sports and encourages us to engage in them, it does not make them a goal in and of themselves, rather sport is considered to be a means of protecting the sacred limits of Islam and the dignity and rights of the Muslims, in the belief that strength is one of the most important means of achieving victory and prevailing in the face of challenges and warding off the threats that face Islam.
- If the purpose of sport is to prepare the body to be fit to carry out the duty of jihad so as to make the word of Allaah supreme, then sport is essential. Allaah says (interpretation of the meaning):
- “And make ready against them all you can of power, including steeds of war…”
- [al-Anfaal 8:60]
- And the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “The strong believer is better and more beloved to Allaah than the weak believer.” Narrated by Muslim, 6774.
- If the aim is relaxation and maintaining good health, then sport is permissible. If it involves something haraam, such as missing prayers, uncovering any part of the ‘awrah or mixing with women and so on, then it is haraam.
- Those who engage in bodybuilding uncover their ‘awrah when practicing this sport, which is undoubtedly haraam. The ‘awrah of a man extends from the navel to the knee, and it is not permissible for him to uncover it in front of anyone other than his wife. It is also not permissible for him to look at the ‘awrah of anyone else.
- The basic principle concerning this matter is the hadeeth of the Prophet (peace and blessings of Allaah be upon him): “What is between the navel and the knee is ‘awrah.” Al-Albaani said in Irwa’ al-Ghaleel, 281; (it is) a hasan hadeeth.
- If the sport is free of these haraam things, then there is nothing wrong with engaging in it.
- But two points should be noted:
- Some of those who engage in this sport are motivated by self-admiration and love of pride and showing off before others because of their beautiful bodies and strong muscles… and other bad motives, some of which are worse than others. The believer should shun such things and seek the adornment of good attitude, humility and fairness.
- Going to extremes in making the body look good and being concerned with that is not a good thing. What is good in this regard is that which helps the Muslim to maintain good health, to practise Islam, to engage in jihad for the sake of Allaah and to do the acts of worship which require physical strength such as Hajj.
- But doing more than that and going to extremes usually distracts the Muslim from doing things that are more important, as happens in the case of those who practise many kinds of sports nowadays, so you see them training for many hours each day.
- What benefit can a Muslim gain if his body is as strong as a bull, but his heart is devoid of faith and all virtue?
- We ask Allaah to help us to do that which is good for us and will bring us happiness in this world and in the Hereafter.
- See also question no. 11963.
- May Allaah send blessings upon our Prophet Muhammad.
- Islam Q&A source: Islam Q&A
This ruling however only seem to address male bodybuilding ('mixing with women' description of only male 'awra'). It does not address whether it is acceptable for a women to do so too even if making the body strong and sound is desirable for men and women. Competitive bodybuilding which include revealing awvra would most probably be considered haram for both sexes.
Salafi fatwa on boxing: 
Prophet Muhammad's era 
In early Islam, athletics existed in the form of military preparations. Most men were encouraged to learn to ride a horse or shoot with arrows.
As stated in Sunan Abi Da'ud:
- Narrated Uqbah ibn Amir:
- I heard the Apostle of Allah say: Allah, Most High, will cause three persons to enter Paradise for one arrow: the maker when he has a good motive in making it, the one who shoots it, and the one who hands it; so shoot and ride, but your shooting is dearer to me than your riding. Everything with which a man amuses himself is vain except three (things): a man's training of his horse, his playing with his wife, and his shooting with his bow and arrow. If anyone abandons archery after becoming an adept through distaste for it, it is a blessing he has abandoned; or he said: for which he has been ungrateful.
Some scholars believe that polo originated among the Iranian tribes sometime before the 6th century BC. Once played by groups of soldiers and nomads, polo became the "sport of kings" and the wealthy during the Middle Ages. 
Twentieth Century 
Throughout the twentieth century, Muslim countries have been involved in international athletics events like the Olympics and have achieved some success. The Organisation of the Islamic Conference established the Islamic Solidarity Games as a means of encouraging cooperation among Muslim states. The first Games were held in 1980 in İzmir, Turkey and included both men's and women's track-and-field events with participation from nine countries and one unofficial country (Algeria, Bahrain, Libya, Malaysia, Morocco, Pakistan, Saudi Arabia, Turkey and the Turkish Republic of Northern Cyprus). The next Games were due to be held in Saudi Arabia in 1983 but no details are available on whether they took place. However, an Islamic Women's Games were held in 1993, 1997, and 2001 in Tehran, Iran.
From the Qu'ran (Surah Al-Ahzab:59):
- "O Prophet! Tell your wives and your daughters and the women of the believers to draw their cloaks all over their bodies. That will be better, that they should be known so as not to be annoyed. And Allâh is Ever Oft Forgiving, Most Merciful."
Hadith recorded by Tabrani (RA), narrated by Hadhrat Jabir (Radhiallaahu Anhu) who reports of Nabi (Sallallaahu Alayhi Wasallam) to have said, 'Everything devoid of the remembrance of Allah Ta'ala is Lahw save four actions; a) Walking between 2 targets (while practicing archery), b) Training or disciplining of one's horse, c) Amusing oneself with the company of one's wife, d) Learning of the art of swimming. (Targheeb Wa Tarheeb vol.2 pg.389; Dar Ihya al-Turaath)
Omar ibn Al-Khattab (2nd Caliphate):
- “Teach your children swimming, archery and horse-riding.”
Among the achievements made by Islamic athletics are the men's Super Heavyweight Class in weightlifting (at present, the 105+ kg category). A perennial favorite among spectators, it is currently dominated by Iranian Hossein Reza Zadeh who first set a world record at the world championships and another on the road to a gold medal at the 2000 Summer Olympics. Reza Zadeh has since broken his own records on a number of occasions, including at the 2004 Athens Games, where he captured his second Olympic gold medal. While lifting, he shouted "Ya Abul-Fazl!", supplicating in the name of Abbas ibn Ali.
- ^ The OIC resolution establishing the Islamic Solidarity Games
- ^ Results for the 1980 Games from GBRAthletics.com
- ^ Results for the 2005 Games from GBRAthletics.com