Sentence:  He started at 9:30 a.m. on Sunday as he began <WSD>rucking</WSD> to church. He changed his clothes, went to church and then began <WSD>rucking</WSD> again. That distance totaled about nine miles. Rucking is hiking with a military style backpack, filled with weight. 
Meaning of the word marked with <WSD> tags:  To carry a backpack while hiking or marching.