Commentary
The misplaced faith in repetition training and the benefits of interleaving
- by John O'Sullivan , Feb 4, 2021
Peter Brown (Make It Stick: The Science of Successful Learning) calls this the myth of massed practice. “Most of us believe that learning is better when you go at something with a singleminded purpose,” says Brown. “Faith in focused, repetitive practice of one thing at a time until we’ve got it nailed is pervasive among classroom teachers, athletes, corporate trainers, and students. Despite what our eyes tell us, this faith is misplaced.” The faith is misplaced because, in the short term, we can see and feel ourselves improving. But those gains are short-lived.
“If learning can be defined as picking up new knowledge or skills and being able to apply them later,” writes Brown, “then how quickly you pick something up is only part of the story. Is it still there when you need to use it out in the everyday world? The rapid gains produced by massed practice are often evident, but the rapid forgetting that follows is not.”
Massed or blocked training is repeating the same exact technique over and over—think hitting fifty reps in a row with your seven-iron or practicing the same soccer move without opposition fifty times in a row. The science tells us that when we block our training, with each subsequent repetition, our brain devotes less energy to going through the process of solving the problem before us.
For example, I saw Dr. Tim Lee, a leading researcher in this space, demonstrate this to a crowd of golf coaches with a simple math problem. He asked them to come up with the answer to the following multiplication problem: what is 21 x 14? Coaches went through the problem in their heads and slowly hands came up as they came up with the answer. Finally he called on a raised hand. “294!” shouted the coach. “Correct,” said Lee. “How did you come up with that?” The coach went on to explain how he went through the process of multiplying 21 x 10 and then 21 x 4 and then adding them together.
“Ok, next problem,” said Lee as he advanced his slide. The next problem came up: what is 21 x 14?
The audience chuckled, and someone shouted triumphantly, “294!” We all laughed, and Lee asked us about the process we went through to come up with that answer the second time around. We didn’t. We already knew the answer. “This is similar to what the brain does when we block our practices,” said Lee. Every time we repeat the same exact motion, we devote less time to going through the process. We shout out the answer, and this slows down learning as it allows the brain to divert its attention away from the skill you are trying to develop.
Research demonstrates that interleaved training—solving different math problems instead of the same ones repeatedly—promotes mastery and long-term retention when compared to massed practice. Interleaved training mixes and matches various techniques and skills, usually in a game-conditioned setting. Many practitioners call it “repetition without repetition.”
The main reason is that interleaved learning engages different parts of the brain. Neuroimaging has shown that motor skills learned from massed practice seem to be consolidated in areas of the brain used for cognitively simple and less challenging motor skills, what we might call factual knowledge. Interleaved learning is consolidated in areas associated with learning higher-order motor skills and provides conceptual knowledge, an understanding of when and how to deploy a skill in relation to its environment.
Writes Brown, “The varied and more challenging practice demands more brain power and encodes the learning in a more flexible representation that can be applied more broadly.” In other words, if you want to be able to call upon it more readily, it needs to be learned with more struggle.
If you are an ice hockey coach, for example, instead of doing an entire practice on skating or passing, you would incorporate multiple elements into your session. USA Hockey’s ADM is excellent at this, setting up six stations on a sheet of ice and having players learn something new at each one. In the short term, athletes may experience a feeling of frustration and think, I was just getting good at that, and we moved on. But in reality, the interleaving of these skills trades short-term satisfaction for long-term learning, and next week the hockey player will retain more of the previous week’s session than if he had only worked on one aspect of his game.
(John O'Sullivan is the founder of the Changing the Game Project and the host of the Way of Champions Podcast. His latest book, Every Moment Matters: How the World's Best Coaches Inspire Their Athletes and Build Championship Teams, from which this article was excerpted, came out in December of 2019. It is available in paperback and Kindle. His previous books are, Is It Wise to Specialize?: What Every Parent Needs to Know About Early Sports Specialization and its Effect Upon Your Child’s Athletic and Changing the Game: The Parent's Guide to Raising Happy, High Performing Athletes, and Giving Youth Sports Back to our Kids.)
The problem is, as stated, many repetitions without opposition. However, once the skill is comfortable without any opposition, if easy or even moderate opposition is added, the learning has a new element with which to deal. Now, the repetitions involve solving a new problem using the acquired skill. After that situation is more easily solved,, make the situation game condition. I never forget John Stockton of the Utah Jazz, after being questioned about his 20 ft shot to win the Western Division championship in the last second, saying "I knew I would make that shot, I've dine it a thousand times in practice.
The easiest way to explain it is:
Practicing a skill in isolation benefits short term learning.
Practicing a skill in a context of multiple actions benefits long term learning.
In youth sports the primary objective is usually long term learning.
There is an old saying at Ajax, " Repeat, repeat, repeat,repeat ,repeat" ....
This discussion would reflect a philosophical issue the U.S. Soccer Coaching courses had in the 1980s, when Education Direcrots Karl-Heinz Heddergott always wanted some defensive resistance, even if very low intensity (I think the motor learning specialist would call this "contextual interference"). Without it, Heddergott said "drills kill skills". When he left, the coaching methodology returned to include more time in a passive/fundamental stage.
While I understand some of what Tim Lee was trying to convey with his example of the math problem in repetition, there is a significant difference between muscle memory and intellectual memory. When your body is learning a new skill, you do have to do a number of repetitions of something correctly to build the neural pathways (myelin sheath!) to be able to do it correctly under pressure without thinking about it--in a game context, for example. That doesn't mean that as you learn new skills you should only practice them in repetition in a vacuum--they do have to be woven in with the other plays/skills that would flow into that one--or challenged by the variety of challenges you might face in a game setting. But, a player that is struggling with a technical aspect of their game is likely going to still need to isolate it and practice it correctly with some repetition to improve to the next level. As a piano and voice teacher, I have to teach students to practice towards this kind of muscle memory, which often involves repetition of one thing, but then be able to combine it with intellectual knowledge and the challege of several different moving parts to make a whole piece of music. When talking to my students who are also soccer players, we discuss the similarity in this process for learning better soccer skills. It requires a combination of repetition, variety, challenge and flow to perfect the game.