Spartan culture and society laid a lot of emphasis on physical fitness and military might after the reforms introduced by the legislator Lycurgus. All citizens were expected to be physically strong – both men and women.
Spartans did workouts such as running, swimming, wrestling, discus and javelin throwing, hunting, and weapons training. They also performed endurance events and choral dancing to improve their physical fitness. All these were performed barefoot for improved agility.
Spartan men entered military service at thirty and remained soldiers till sixty. They were expected to maintain their physical fitness the entire time. Spartan men and women would continue their endurance and weapons training for their entire lives.

What Training Did Spartans Do?
The foundation of education in Sparta was centered around physical discipline and military training and proficiency. The ancient Spartan training is called Agoge, which trained young boys into soldiers through endurance events and athletic competitions like wrestling and gymnastics.
While both men and women trained physically in Sparta, only boys entered Agoge at the age of seven as the ultimate aim of the Agoge training was to produce soldiers.
In Agoge, boys were deliberately underfed and encouraged to steal food, which was considered an important survival skill. They were also taught to be economical with their words.
These elements of food and speech complimented the intense physical training program that comprised Agoge and its aim to produce loyal and physically tough soldiers. The intensity only increased as the boys grew older and stronger.
Agoge training started with young boys trained physically through gymnastics, endurance events, wrestling, and running. The boys would perform these activities barefoot and often naked, as the Spartans believed that this improved the overall agility and strength of the body. [1]
Apart from wrestling and gymnastics, the boys would participate in swimming, boxing, hunting, javelin, and discus throwing. All of these were traditional athletic activities across Greece during the Hellenic periods. The boy also took up weapons training as part of Agoge as they grew older.
Choral dancing was also a part of the Agoge training, as well as some amount of music, reading, and writing. Agoge taught reading and writing to ensure that all soldiers could read military maps. Apart from improving endurance and agility, the music training aimed to make these young boys and men good citizens of Sparta.
Strengthening the body and preparing for war were the primary goals of the Agoge training in Sparta. The boys would engage in mock fights and games to build camaraderie and train their bodies.
All young men had to enter Agoge at the age of seven and continue training until they completed the training when they turned thirty. The men would continue to serve in the army until sixty.
This long service meant that Spartan men’s military and endurance training continued throughout their lives, only ending when they retired from the military after crossing sixty.

How Did Spartans Get Physically Fit?
Spartans were physically fit as the culture emphasized physical training for both men and women. Young children would be trained at home by their parents. When the boys turned seven, they would be taken away for intensive training called Agoge while the girls would continue to be trained at home.
The training for boys would involve everything from competitive athletic events like wrestling, running, discus throwing, and participating in drills and mock fights with each other. They were underfed and were only allowed to wear a tunic during their training, regardless of the weather.
The harshness of the training was deliberate to ensure that all the boys who left Agoge at the age of thirty would be physically capable soldiers who could serve in the army till they died or retired at the age of sixty.
The emphasis on physical training was also extended to women even though they did not serve in the army. Childbirth was given an enormous amount of respect in Spartan culture. Spartans believed that strong women would produce strong children.
Parents educated their young girls in gymnastics, wrestling, and other athletics just like the young boys were trained in Agoge. The girls also participated in calisthenics and weapons training. Women were also expected to defend themselves and the city if all the men were away at war.
All Spartans abided by the core virtues espoused by the Spartan legislator Lycurgus who established the militaristic culture and founded Sparta’s iconic army.
Lycurgus believed that the core virtues for all Spartan citizens were austerity, strength, and fitness. Therefore Spartan society was set up to ensure that all men and women would be trained and physically fit to serve the state.

How Did Spartans Become So Muscular?
All Spartan citizens were muscular due to their lifetime of intense endurance and weapons training, as well as the compulsory military service that all male citizens had to perform. The training incorporated athletics and choral dancing as well for agility and strength.
In Ancient Greece, playing sports and wrestling was essential for all men as it was believed to beautify the body. The Spartans, in particular, laid great emphasis on the physical fitness of all their citizens. The state of Sparta trained its men intensely to ensure that it had a powerful army to defend its interests.
All children started their training young. They would first be trained at home, after which the boys would enter Agoge, the Spartan military training, while the girls would train at home with their mothers or other trainers.
All Spartan citizens would continue their physical training throughout their lives, as long as they were physically able. Men would stay in Agoge until they were thirty and continue being a part of the military until sixty.
The intensity of training that Spartan citizens performed would increase as they grew stronger. Effectively, Spartans continued training their bodies to be stronger and physically fit for their entire lives, which is why they were so muscular.
Conclusion
Spartans worked out by wrestling, discus and javelin throwing, swimming, and other athletics. They also performed endurance and military training their entire lives.
References:
[1] Source