“This sport that young Jews play in Eretz Yisroel in order to strengthen their bodies to be strong young men for the Nation, completes the spiritual strength of the Tzadikim above … playing sports to strengthen the body and the spirit for the strength of the entire Nation is a holy service to Hashem, and raises the Shechinah higher and higher, like the 80 songs and praises sung by Dovid HaMelech in Tehillim (Oros M’Ofel 34).
(Not my translation, nor have I seen it inside.)