Researchers studied healthy adults by asking them to perform various tasks using both arms.
Among other tasks, participants were asked to reach for targets under normal conditions, while carrying extra weight, and while using a tool that required a high level of precision.
Their movements were measured using specialized equipment, according to the study published in the Proceedings of the National Academy of Sciences.
The results showed that there was almost no difference between the arms during the easier tasks.
Only when the tasks became more demanding did the preferred arm perform better, according to HealthDay.
Another test
The researchers also asked participants to write using both their hands and their elbows.
In this test, there was no difference between the right and left elbows because neither had performed the task before.
After a short period of practice, both elbows improved at the same rate.
According to the University of California, Los Angeles (UCLA), this suggests that practice plays a major role in determining how skilled an arm becomes at performing specific movements.
The dominant hand
For many years, researchers have believed that a dominant hemisphere of the brain was the primary explanation for whether a person becomes right- or left-handed.
Previous research has also shown that hand preference may develop before birth.
However, the new study suggests that the difference between the right and left hand is mainly shaped through many years of practice and use.
The researchers believe that this knowledge could help improve rehabilitation for people who need to relearn motor skills after, for example, a stroke or a brain injury.
