Sentence 1: My mom was taking out the garbage outside. 
 Sentence 3: She fell on the floor and wasn't able to get up 
 Sentence 4:  I had to take her to the hospital 
 Sentence 5:  Luckily, the doctor said that the injury isn't severe 
 Option 1: As soon as she bent over to pick up the bag, she tripped but didn't hurt herself. 
 Option 2: As soon as she bent over to pick up the bag, her back got sprained.