He went through a long and arduous training program.
an arduous journey across miles of desert
Traveling for several days by train, stagecoach and horseback, they would reach Mariposa Grove, a stand of some 200 ancient giant sequoias, where they would rest before embarking on an arduous descent via 26 switchbacks into the valley. —Tony Perrottet, Smithsonian, July 2008
As yoga classes go, this is not an arduous one, but the students don't know that. —Richard Corliss, Time, 23 Apr. 2001
Women of middling means had the most to gain from increased consumption, for imported goods often reduced their long and arduous labor, especially in making candles and soap or in spinning and weaving cloth. —Alan Taylor, American Colonies, 2000