The key to learning a new motor skill - such as playing the piano or mastering a new sport - isn't necessarily how many hours you spend practising, but the way you practise, according to a 2016 study.

Scientists have found that by subtly varying your training, you can keep your brain more active throughout the learning process, and halve the time it takes to get up to scratch.

The research goes somewhat against the old assumption that simply repeating a motor skill over and over again - for example, practising scales on the piano or playing the same level on your game over and over again - was the best way to master it.

Instead, it turns out there might be a quicker (and more enjoyable) way to level up.

"What we found is if you practise a slightly modified version of a task you want to master, you actually learn more and faster than if you just keep practising the exact same thing multiple times in a row," said lead researcher Pablo Celnik, from Johns Hopkins University.

The researchers figured this out by getting 86 volunteers to learn to a new skill - moving a cursor on a computer screen by squeezing a small device, instead of using a mouse.

The volunteers were split into three groups, and each spent 45 minutes practising this.

Six hours later, one of the groups was asked to repeat the same training exercise again, while another group performed a slightly different version that required different squeezing force to move the cursor.

The third group only completed the first training session, so they could act as a control.

At the end of the training period, everyone was tested on how accurately and quickly they could perform the new skill, and predictably, the control group did the worst after their one training session.

But the surprise was that the group that had repeated the original training session actually did worse on the test compared to those who had mixed things up and trained in new areas - in fact, the group that modified their training did twice as well as those who'd repeated the original skill.

So how does that work?

The researchers believe it's due to something called reconsolidation, which is a process whereby existing memories are recalled and modified with new knowledge. It's long been suggested that reconsolidation could help to strengthen motor skills, but this is one of the first experiments to test that hypothesis.

This is also why the researchers gave the participants a 6-hour gap between training session - earlier neurological research has shown that's how long it takes for our memories to reconsolidate.

"Our results are important because little was known before about how reconsolidation works in relation to motor skill development. This shows how simple manipulations during training can lead to more rapid and larger motor skill gains because of reconsolidation," said Celnik.

"The goal is to develop novel behavioural interventions and training schedules that give people more improvement for the same amount of practise time."

Although there's benefit in mixing things up with your practise, Celnik said the key was adjusting things subtly - for example, adjusting the size or weight of a baseball bat, tennis racket or soccer ball in between practise sessions.

"If you make the altered task too different, people do not get the gain we observed during reconsolidation. The modification between sessions needs to be subtle," he added.

Although these results are pretty exciting, this study has only tested one particular skill-set, and so further research needs to be done to confirm the findings.

But if true, finding an easy way to double the rate at which people can learn new motor skills would be a huge deal.

In addition to helping us all tick off our 2016 resolutions in half the time - hello, finally mastering Debussy's Clair de Lune - there are more altruistic impacts of the research.

The study has "strong implications for rehabilitation", the authors write in Current Biology.

For example, the new information could help amputees learn to use their prostheses faster, or speed up the recover of people who've suffered from spinal injuries or stroke.

We're pretty keen to try it out.