Insulin and exercise help muscles take in a type of amino acid even without using the cell's usual sodium-potassium pump, suggesting they use a different route to get nutrients in.

When muscles are resting, they need a specific cellular pump to bring in a type of nutrient, but when they're active—like during exercise or after insulin kicks in—they use a totally different method that doesn’t rely on that same pump.

When you eat, your body releases insulin, which helps muscle cells pull more potassium from your blood by putting more pumps on their surface—this keeps your muscles working smoothly after meals.

When rats are given insulin, a specific part of a pump in their muscle cells moves from inside the cell to the outer membrane, but another similar part stays where it is.

When insulin is present, it tells muscle cells to pump more sodium and potassium around, which creates a better environment for the cell to pull in more creatine — a compound that helps muscles store energy.

When insulin is added to rat leg muscle, it makes the muscle’s sodium-potassium pump work 23% harder, which lowers the sodium inside the cells by 27%—but it doesn’t create more pumps to do this job.