Blocked vs random practice: why varied drills beat repetition

7 min read · Updated 19 August 2026

The two ways to structure a session

Blocked practice repeats one task before moving on: thirty long blacks, then thirty stop shots, then thirty safeties.

Random practice interleaves them: a long black, then a safety, then a stop shot, then a different long black, in an order you cannot anticipate.

Blocked practice produces better performance during the session. Random practice produces better performance later, which is the only kind that counts.

What the research actually found

The classic experiment is Shea and Morgan (1979). Two groups learned the same set of movement patterns, one in blocked order and one in random order. The blocked group performed better in practice. On a retention test days later, the random group performed better — and the gap widened when the test involved a novel variation.

The effect has been replicated across a wide range of motor tasks in the decades since. It is not universal — the size of the effect varies with the learner's experience and how similar the tasks are — but the direction is consistent enough to plan around.

Why it works, in one paragraph

When you repeat a shot, you can reuse the solution you built for the last one. The motor plan stays loaded and you are effectively copying your own homework. When the next shot is different, you have to reconstruct the plan from scratch — read the angle, choose the pace, decide the spin. That reconstruction is the thing that actually gets encoded, and it is why random practice feels harder and sticks better.

What this means at the table

That last point is the hard one. Blocked practice is more enjoyable and more flattering, which is exactly why most people default to it.

• Never play the same shot twice in a row deliberately.
• Cycle three or four drills rather than completing one at a time.
• Randomise which one comes next, rather than rotating in a fixed order — a predictable rotation is still partly blocked.
• Accept a lower success rate in the session. If your practice numbers look worse than they used to, you may be doing it right.

The obvious problem with random practice

It is a nuisance to organise. Genuinely randomising your practice means deciding, before each shot, which of several drills to run and at what difficulty — and doing that honestly, without drifting back to the shots you enjoy.

That is the specific problem CueCards was built to solve: it deals the next drill so you do not get to choose it. But the principle stands whether you use an app, a deck of index cards, or a pen and a scrap of paper.