The findings provide clue as to how muscles lose mass with age, which can result in weakness that affects mobility and may cause falls.
The study involving researchers from King's College London, Harvard University and Massachusetts General Hospital looked at stem cells found inside muscle - which are responsible for repairing injury - to find out why the ability of muscles to regenerate declines with age.
The study on old mice found the number of dormant stem cells present in the pool reduces with age, which could explain the decline in the muscle's ability to repair and regenerate as it gets older.
When these old muscles were screened the team found high levels of FGF2, a protein that has the ability to stimulate cells to divide.
Researchers found that FGF2 could also awaken the dormant pool of stem cells even when they were not needed.
They attempted to inhibit FGF2 in old muscles to prevent the stem cell pool from being kick-started into action unnecessarily.
By administering a common FGF2 inhibitor drug they were able to inhibit the decline in the number of muscle stem cells in the mice.
"Preventing or reversing muscle wasting in old age in humans is still a way off, but this study has for the first time revealed a process which could be responsible for age-related muscle wasting, which is extremely exciting," Dr Albert Basson, Senior Lecturer at the King's College London Dental Institute, said.
"The finding opens up the possibility that one day we could develop treatments to make old muscles young again. If we could do this, we may be able to enable people to live more mobile, independent lives as they age," Basson said in a statement.
A dormant reservoir of stem cells is present inside every muscle, ready to be activated by exercise and injury to repair any damage.
When needed, these cells divide into hundreds of new muscle fibres that repair the muscle, researchers said.
The study will be published in the journal 'Nature'.
