(Strip Number 4650, Original Publication Date, 11 July 1986)
Panel 1: As John overexerts himself doing push-ups, Lizzie asks him if he's exercising.
Panel 2: He says that yes, he is because he's gotta be in some kind of shape to go on this canoe trip.
Panel 3: As we hear an off-camera groan of pain, Elly asks Lizzie what's up with Daddy.
Panel 4: Lizzie says that Daddy just turned into a pretzel.
Summary: Given that Rod took better care of himself than John ever did, I should think that we're looking at Lynn getting her nose out of joint because Rod was better at sticking to exercise plans than she is.