Fitt has four principles, Frequency, Intensity, Time, and Type. These are meanings of each of them.
Frequency: Frequency is how many times you do your workout each week because if you do it around once a week you are not going to make much of a difference
Intensity: Intensity is how hard you work out like if you do like one push up and you're done that's not good intensity you have to do an amount that you can do every time you workout like you can't just do 200 and say i'm never doing push ups again
Time: Time is how long you do your workout each time you do it, a good amount of time for working out is 20-30 mins and time can also be how long you are going to keep working out like if you are going to keep working out for a month or up to a year.
Type: Type is what kind of workout you do like Cardio or leg day or triceps or biceps you can a bit of those each day or have a cycle like one day you do cardio and the other day leg and so on.
Said stands for Specific Adaptation to Imposed Demand. Said's principle is basic concepts in sports science, but it is one of the most important basic concepts. These are the meanings of them.
Specific: Specific is the stress that your body gets and starts to make adaptations to the specific stress.
Adaptation: Adaptation is when your body adapts to stress when your body get under stress. When your body adapts, your body gets a better withstanding of the specific stress in the future.
Imposed: Imposed is when the stress gets imposed on something. Like if you are playing baseball and the person hit and the ball comes at you and whatever hand you had the glove, the stress would get imposed on that hand.
Demand: Demand is the area where the stress gets imposed on your body like either one of your arms and either one of your legs.