Instead , he was more interested in his physical education career , receiving an honorary PE Masters degree in 1910 , patrolled the Mexican border for four months in 1916 during World War I , traveled to France , published two books ( `` A Modern College '' in 1911 and `` Essence of a Healthy Life '' in 1918 ) and took on American citizenship in 1925 .
Instead , he was more interested in his physical education career , receiving an honorary PE Masters degree in 1910 , patrolled the Mexican border for four months in 1916 during World War I , traveled to France , published two books ( `` A Modern College '' in 1911 and `` Essence of a Healthy Life '' in 1918 ) and became an American citizen in 1925 .