weight lifting
Those trying to become stronger by putting in extra hours at the gym may be getting it all wrong, according to new research. Researchers have found that engaging your nerves could be more important to gaining strength than working out your muscles.

In the body, specialised nerves known as motor neurons relay signals from the brain to the muscle tissue, which allows us to choose when we flex our muscles. Scientists have now found that some types of exercise engage the nerves surrounding our muscle tissue more than others.

They discovered that lifting heavy weights engages the nerve cells more than lifting light weights, even if you do far fewer reps. Lifting heavy weights can induce nerves to carry more signals from the brain to the muscles, making muscles stronger, the researchers found.

How was the research carried out?

Researchers discovered that heavy reps can stimulate the nerves after following the activity of frequent gym-goers. They noticed that those who chose to lift many repetitions of light weight could build up muscle mass just as quickly as those who chose to do fewer reps of heavy weights.

But despite this, those who trained with heavier weights made better gains in strength than those who lift lighter loads. To understand why, researchers asked 26 men to train for six weeks on a leg-extensions machine loaded with either 30 or 80 per cent of the maximum weight they could lift.

Researchers monitored the participants three times a week as they did as many reps as they could. They found that those carrying light and heavy weights experienced a similar amount of muscle growth. But participants carrying heavy weights increased their strength by roughly ten pounds more than their counterparts lifting lighter weights.

'If you're trying to increase strength - whether you're Joe Shmoe, a weekend warrior, a gym rat or an athlete - training with high loads is going to result in greater strength adaptations,' said Nathaniel Jenkins, an assistant professor of exercise physiology at Oklahoma State University, who conducted the research.

The role of nerves in building strength

To understand the role that nerves play in building strength, the researchers supplied an electric current to the nerves that stimulate the leg muscles. Supplying the nerves with an electrical stimulant allowed them to work at 100-per cent capacity, which cannot be achieved through exercise alone.

Scientists then compared how hard each participant could kick with and without help from an electrical current. By doing this, scientists were able to determine how close each participant's nerve cells are to achieving 100-percent efficiency. They repeated this test several times over a three-week study period.

Researchers found that over the course of the study period, participants who lifted light weights increased their nerve capacity from 90.07 per cent to 90.22 per cent. But those who carried heavy weights saw the capacity of the nerve cells jump from 90.94 per cent to 93.29 per cent, a rise of 2.35 per cent.

This finding indicated that workouts with heavy weights help to improve how the efficiency of the nerve cells surrounding muscle tissue. More efficient nerves carry more signals between the brain and the muscles, allowing them to become stronger, according to the researchers.

'I don't think anybody would argue (with the idea) that high-load training is more efficient,' Professor Jenkins said. 'It's more time-efficient. We're seeing greater adaptations. And now we're seeing greater neural [nerve cell] adaptations.'