Love in the time of lumbago

Isadora was the most beautiful woman that Captain Amellio had ever seen.  Her curvature of the spine was far less pronounced than was commonly found, and she could almost pass as walking upright.  She often managed short journeys on foot without wincing, staggering, or supporting herself on either passers-by or street-furniture.  Her eyes twinkled occasionally without the liquidity of tears behind them, and this alone would have been enough for Amellio to adore her.  That she also played the piano, hockey and could peel a crab with a set-square just added to her appeal.
He approached her in the street one day, his good leg striding proudly forward, and his bad leg, his right leg, assisted by a powered exo-brace.  He whined slightly when he walked, but he appeared an imposing figure of a man.  Isadora could not help but be impressed.
"Perhaps I might be of assistance," he said, his tone suggesting that this wasn't a question.  "You have many heavy bags to carry."
"Oh, they're not all mine," said Isadora sweetly.  "My sister is shopping with me, and she is momentarily in the butchers.  When she returns she will carry the majority of them."
"Your sister must be very strong, for there are bags enough here to tax a donkey!"
"Oh, but she is so bent-over that she could easily pass for a donkey in the evening.  I shall drape these bags over her back like so many saddle-bags and we shall return home together.  She is truly cursed with disease."
Captain Amellio was impressed with the practicality that Isadora showed, but was not so easily deterred.  "Then I shall assist you and your sister nonetheless," he said.  "Permit me to lighten your burdens equally."
"Well, if you insist," said Isadora.  'Oh look, here comes Hayley now!"  And from the butchers walked a woman so stooped over as to be almost shaped like a lower case n, her face so close to the ground that the walk home through long grass must have been a real trial for her.
"Are you sure she's your sister?" asked Amellio, unable to reconcile how bent one sister was and how unbent the other.
"Oh yes.  When we were little girls I used to ride her like a horse.  Now though, I know better."
"You just treat her like a mule?"
"Well, Captain, what would you do with someone who is unemployable for normal labour and yet still desires to eat and reside and be kept warm?"
It was Captain Amellio's opinion that exactly that kind of person was sent to him to become part of the army, but he decided to keep that quiet.  "I concede your point," he said, attempting to be humble.
"Oh hurrah!"  Isadora cheered.  "I have always wanted to beat a soldier, and today I have succeeded!"
"Have you ever wanted to be beaten by a soldier?" he asked, and then dismissed the question with a wave of his hand when her face indicated her puzzlement.  "Is there nothing I can help you with, Mistress...?"
"Isadora," said Isadora quickly.  "There may be one thing, but I'll need to think about it first.