During my first year as a head strength & conditioning coach, I dealt with a football athlete who missed the last game of the season due to knee surgery.
He jumped right back into the weight room as soon as they kicked him out of the hospital and launched into our upper body lifting program.
Three and one-half weeks after the surgery he had moved his supine bench up 25 lbs.
It took me a minute to figure out just what in the wild world of sports was going on until I went to sleep a few times and then it came to me.
He was benefitting in two ways.
*Walking on crutches all day was improving a specific weakness by strengthening his elbow extensors (triceps). This is a common weakness with poor supine bench press performance.
*Related was the passive and subtle additional work he was getting in the form of several small workouts whilst moving about campus on those crutches.
"Small workouts" performed 12 to 24 hours after a regular workout is a tried and true method to increase the volume of work and are sometimes necessary to trigger an improvement.
Typically I would be opposed to multiple daily workouts. Largely because they have a tendency to turn into round two of a glycolytic METCON session. Outside of this practice, I have no opposition to a small workout performed correctly.
These small workouts are generally low resistance continuous in nature and concluded in 20 to 25 minutes. You can find more information on specific examples from BOOK OF METHODS By Louie Simmons