Sentence 1: Derrick loved the monkey bars. 
 Sentence 3: It was really cold today and the bar was impossible to hold 
 Sentence 4:  He didn't realize because of the callouses on his hand 
 Sentence 5:  He slipped off instantly and fractured both arms 
 Option 1: His hands were so calloused from hanging on them, he stayed home for two weeks. 
 Option 2: His hands were so calloused from hanging on them for so long.