Picture this: One woman is doing bicep curls with 12-pound dumbbells.
Three slow sets of 12 reps, resting for about a minute between each set.
These exercises not only work different muscles; they work them in different ways.
In fact,Healthlineclaims there are more than 650 skeletal muscles in the human body.
Within these muscles are two types of fibers, as theNational Academy of Sports Medicine(NASM) explains.
Slow-twitch muscle fibers support cardio exercises
The aforementioned slow bicepweightliftingexercises are supported by slow-twitch muscle fibers.
As the name implies, these fibers contract slowly slower than fast-twitch muscle fibers.
This is how you know you’re using slow-twitch muscles.
They fatigue faster and typically require longer recovery periods, asMen’s Journalexplains.
Unlike slow-twitch muscles, fast-twitch muscles use what’s called “anaerobic metabolism” to produce energy.
They rely on glucose for fuel, asPhysiopediaexplains.
In comparison, marathon runners can possess that same percentage, but in slow-twitch fibers.
