How 'Muscle Memory' Helps People Stay in Shape

A man lifts weights made of rusty car parts in a handmade gym
made with construction bars, cement and other recycled materials in
Caracas, Venezuela on Sept. 3, 2019. Carlos Jasso, Reuters
A man lifts weights made of rusty car parts in a handmade gym made with construction bars, cement and other recycled materials in Caracas, Venezuela on Sept. 3, 2019. Carlos Jasso, Reuters
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How 'Muscle Memory' Helps People Stay in Shape

A man lifts weights made of rusty car parts in a handmade gym
made with construction bars, cement and other recycled materials in
Caracas, Venezuela on Sept. 3, 2019. Carlos Jasso, Reuters
A man lifts weights made of rusty car parts in a handmade gym made with construction bars, cement and other recycled materials in Caracas, Venezuela on Sept. 3, 2019. Carlos Jasso, Reuters

Muscles may "remember" in ways that will allow us to regain fitness once gyms reopen and we start working out again.

For those of us sheltering at home because of coronavirus and unable to visit the gym or otherwise weight train — which, right now, is most of us — a new study of the inner workings of our muscles should be heartening.

It said that if muscles have been trained in the past, they seem to develop a molecular memory of working out that lingers through a prolonged period of inactivity, and once we start training again, this "muscle memory" could speed the process by which we regain our former muscular strength and size, the New York Times reported.

The findings suggest that skipping workouts now need not guarantee enfeeblement later, and if we forget what fitness once felt like, our muscles recollect.

Many of us probably think that muscle memory refers to our well-documented ability to retain physical skills even without practice. Learn to ride a bicycle can never be forgotten, as well as skiing a mogul or starting to walk as a child.

Scientists believe that repeated movements apparently burn themselves into our motor neurons, and remain available for later retrieval from our brains and nervous systems, whenever needed. But it has been less clear whether trace memories of past exercise reside within our muscles themselves and affect how well we respond to future workouts.

Past studies in animals and people suggest that they might. In a recent study, for instance, sedentary older men who completed 12 weeks of weight training gained muscle strength and size, much of which they lost during a subsequent 12-week layoff, but all of which returned within only eight weeks of returning to the gym.



Jellyfish Force French Nuclear Plant Shutdown

This photograph shows jellyfish lying on the shore near the Gravelines nuclear power plant in Gravelines, northern France on August 12, 2025. (Photo by Sameer AL-DOUMY / AFP)
This photograph shows jellyfish lying on the shore near the Gravelines nuclear power plant in Gravelines, northern France on August 12, 2025. (Photo by Sameer AL-DOUMY / AFP)
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Jellyfish Force French Nuclear Plant Shutdown

This photograph shows jellyfish lying on the shore near the Gravelines nuclear power plant in Gravelines, northern France on August 12, 2025. (Photo by Sameer AL-DOUMY / AFP)
This photograph shows jellyfish lying on the shore near the Gravelines nuclear power plant in Gravelines, northern France on August 12, 2025. (Photo by Sameer AL-DOUMY / AFP)

A nuclear plant in northern France was temporarily shut down on Monday after a swarm of jellyfish clogged pumps used to cool the reactors, energy group EDF said.

The automatic shutdowns of four units "had no impact on the safety of the facilities, the safety of personnel, or the environment", EDF said on its website.

"These shutdowns are the result of the massive and unpredictable presence of jellyfish in the filter drums of the pumping stations," the Gravelines plant operator said.

The site was fully shut after the incident, with its two other units already offline for maintenance.

Teams were carrying out inspections to restart the production units "in complete safety", EDF said, adding the units were expected to restart on Thursday, AFP reported.

"There is no risk of a power shortage," the company added, saying other energy sources, including solar power, were operational.

Gravelines is Western Europe's largest nuclear power plant with six reactors, each with the capacity to produce 900 megawatts.

The site is due to open two next-generation reactors, each with a capacity of 1,600 megawatts, by 2040.

This is not the first time jellyfish have shut down a nuclear facility, though EDF said such incidents were "quite rare", adding the last impact on its operations was in the 1990s.

There have been cases of plants in other countries shutting down due to jellyfish invasions, notably a three-day closure in Sweden in 2013 and a 1999 incident in Japan that caused a major drop in output.

Experts say overfishing, plastic pollution and climate change have created conditions allowing jellyfish to thrive and reproduce.