In learning theory and skill acquisition, research supports that several shorter sessions equate to better skill/content retention that one long block of time. So perhaps its not the amount of time, but how you divide that time.
Also, its about the quality of that time. Many people spend many hours at the dojo and on the mat, but not really training (more socializing). So you may also have to qualify the intent and intensity of the quantified clock time and number of days.
As in running, more is not necessarily better. Too much, too fast, too soon often leads to overload, lack of progress, and early burn-out.
Human engineering for skill acquisition is an interesting topic. Please keep us posted on your findings.
There is a lot of 'modern' skill ack. theory in the traditional practice of martial arts, agree with Lynn's points, and there are also some clangers too.
These were some ideas that really changed the way I practice and lead practice.
- Blocked learning - i.e. repetitive drills are great earlier on, but can lead to backward skill development after this
- The variability and stress testing you get through a dynamic uke-nage interaction where uke is pushing nage to the brink is right up there
- The idea of error free learning, where you always get to complete the movement i.e. our aikido kata
The idea of distractor tasks to stop the cognitive brain from impeding a successful action (we might call it ki, moving meditation etc..)