Sentence 1: Matt began his exercise routine by stretching. 
 Sentence 3: She smiled and handed him a jump rope 
 Sentence 4:  Time for their weekly challenge, he thought, beginning to jump 
 Sentence 5:  He jumped fifty times before stopping 
 Option 1: He was excited already, but he was anxious when Mia joined him. 
 Option 2: Despite this, he pulled a muscle while working out.