A "personal record", or "PR", is when you accomplish a feat in the gym that you've never done before.

The concentric phase of a movement is the section of a movement where we are flexing our muscles to shorten a joint angle.

The eccentric phase of a movement is the lengthening of muscles to increase a joint angle.

An isolation exercise isolates one muscle group, these are also generally known as single joint exercises.

Compound exercises use multiple joints & multiple muscle groups to complete a movement.

Reps in reserve refer to the number of reps you feel like you could do after you complete an exercise.

Isometrics are exercises, or variations of exercises where you contract your muscles without moving your joints.

Static stretching is stretching by holding the stretch position for a specified amount of time.

Dynamic stretching is stretching with movement.

CARS are Controlled Articular Rotations.

Active recovery is a catch-all term to indicate movement meant to aid in recovery on a rest day.

LISS stands for Low Intensity Steady State Cardio.

Plyometrics are high force, high impact movements, like jumping and bounding, used to improve power and speed.

Warm-up sets are done prior to your working sets to let your body get acclimated to more challenging weights.

Body Composition refers to the percentage of body fat and lean mass that your body has.

AMRAP stands for as many rounds as possible.

EMOM stands for Every Minute On the Minute.

Tabata is a specific timing period of 20 seconds of work followed by 10 seconds of rest.

HIIT stands for High Intensity Interval Training.

Non-Exercise Activity Thermogenesis (NEAT) accounts for daily movement outside of "working out".