Swami Vivekananda meant that a strong body can help you have the frame of mind needed to understand things like the Upanishads and Bhagavad Gita, and thus ultimately attain Jnana.
Here's the quote in its original context: First of all, our young men must be strong.
Religion will come afterwards.
Be strong, my young friends; that is my advice to you.
You will be nearer to Heaven through football than through the study of the Gita.
These are bold words; but I have to say them, for I love you.
I know where the shoe pinches.
I have gained a little experience.
You will understand the Gita better with your biceps, your muscles, a little stronger.
You will understand the mighty genius and the mighty strength of Krishna better with a little of strong blood in you.
You will understand the Upanishads better and the glory of the Atman when your body stands firm upon your feet, and you feel yourselves as men.
Thus we have to apply these to our needs.
Now I'm not a follower of Vivekananda or an Advaitin, but I think this connects with the Advaita notion that certain physical and mental disciplines are a prerequisite for the pursuit of Jnana; that is how Adi Shankaracharya interprets the first Sutra of the Brahma Sutras.
This is in contrast to other schools, including Ramanujacharya's Sri Vaishnava sect, which interpret the prerequisite as the study of the Vedas through the methods of Mimamsa.
hinduism.stackexchange.com/users/36/Keshav Srinivasan
That quote from Vivekananda has a deeper meaning than the plain text.
The entire quote has already been posted.
The key to fully understanding the quote lies in the statement
First of all, our young men must be strong.
Religion will come afterwards.
The key point is 'Religion will come afterwards'.
Vivekananda felt that the people of India of his time did nothing because they were steeped in tamas.
He wanted people of India to graduate to rajas through strength and become active instead of doing nothing.
This is the reason why he wanted the young men to be strong.
The rest of the quote is to make the case that one can graduate to sattva, necessary for spiritual growth, from rajas through strength.
hinduism.stackexchange.com/users/121/Pradip Gangopadhyay
I think we have to understand the words of Swamiji with reference to the famous saying śarīramādyaṃ khalu dharmasādhanam
This body is surely the foremost instrument of doing [good]
deeds Even with a common sense, we can understand that without a body nobody can achieve anything, i.e. studying Gita, Upanishads, etc, pondering over whatever that was studied and finally practicing whatever studied .
Everyone in general, who is in his teens or even in early 30s of his age, will enjoy a fairly good health (I am not quoting exceptions here).
During that age, it does not matter much whether one does exercise to keep himself fit or not.
The body can sustain prolonged study and hard work.
However, in late 30s and even further, the effect of non-doing of exercise will tell upon one's prolonged study and hard work.
One will not be able to sustain for that type of hard work after 40's.
So in order to have a healthy body at old age for all persons in general and even at young age in respect of ill-health bodies, Swamiji adviced exercise.
As playing Football assures building up of strong body, which will sustain the prolonged study and hard work in spirituality
hinduism.stackexchange.com/users/3869/Srimannarayana K V
Thank you Arnav, you kindled our interest in Swamiji's most magical saying..
Its not easy to grasp the meaning of great spiritual person's sayings like Swamiji..
The ultimate aim of human life is to be one with God.
While persuing this aim we are fooled by Kaama(Lust), Krodha(Anger),Lobha(Materialistic temptations),Mada(Ego),Matsara(Hate).
What Swamiji wants to say that life is like a game of 'football' in which while acheiving the 'goal' of self realization we are attacked by these enemies Kaama,Krodha,Mada,Matsara but as with the strategies in the game of 'football'
we win the game
likewise we have to defeat these enemies with our intelligence or 'Viveka'.
Reading BhagvadGeeta will make you only a reader of it
what actually matters is
how much Geeta we live or apply in life.
Thus according to Vivekanandaji it is more useful to apply the tactics of football to acheive the aim of Self Realization than merely reading Geeta!
Swamiji was a naughty son of maa
'Sharda'
so it is difficult to decrypt his sayings without the grace of maa herself!
lol!
hinduism.stackexchange.com/users/4103/Deepeshkumar
Swami Vivekananda meant that playing football needs full devotion towards the game.
While you are at it, you can't think of anything else or can't do anything else.
You have to stay focused, and use your skills to score .
He compares this devotion to that of reading a religious text, and he has a point.
Quoting from Sadhguru Jaggi Vasudev's stories on Swami Vivekananda:
In a soccer game, you have to learn to use your feet like a surgeon’s
scalpel.
This is a game which particularly demands a certain level of involvement because the limbs with which you handle the ball and the limbs with which you transport yourself at full speed are the same, and you have to avoid the ten other people who are trying to do everything that they can do with you.
You have to dodge people, you have to take the ball, you have to be running at full speed; your feet must be as efficient as a surgeon
’s
scalpel because at that speed, at that activity, to direct the ball takes a phenomenal amount of skill.
It takes a certain level of involvement where you are almost mindless.
If you do something with total involvement, you will see, there is just action, the mind is somewhere else.
So in a soccer game, the players reach that kind of a state very often because it is all in one thing.
That is the reason why it grabs half the world when things are being played intensely.
There is a certain kind of transcendence – it is not really a spiritual transcendence,
but there is a certain going beyond one’s limitations which sets fire to everybody else.
hinduism.stackexchange.com/users/10338/Cyclops
That famous line above was uttered by none other than Swami Vivekananda. I admit that I haven't gone through the complete speech yet, but I am curious to know what he meant by that.  Did he mean that being a karmayogi in the path of salvation is more suited to today than any other path or did he speak those lines in some other context?
'Playing football takes us nearer to heaven rather than reading Bhagavad Gita' but how and why?
hinduism.stackexchange.com
<bhagavad-gita><philosophy><karma><vedanta><vivekananda>
hinduism.stackexchange.com/questions/9371
hinduism.stackexchange.com/users/2974/Arnav Das
Swami Vivekananda meant that a strong body can help you have the frame of mind needed to understand things like the Upanishads and Bhagavad Gita, and thus ultimately attain Jnana.    Playing football helps to build a strong body, which will sustain prolonged spiritual study and hard work.  Playing football needs full devotion to the game. Swami Vivekananda meant that a strong body can help you have the frame of mind needed to understand things like the Upanishads and Bhagavad Gita, and thus ultimately attain Jnana. 
 Swami Vivekananda meant that playing football needs full devotion to the game. Playing football helps to build a strong body, which will sustain prolonged spiritual study and hard work. Swami Vivekananda meant that a strong body can help you have the frame of mind needed to understand things like the Upanishads and Bhagavad Gita, and thus ultimately attain Jnana.