In a previous post, I defined and introduced the idea of a rep. (I suggest reading that post before continuing on with this post, there are some concepts and terminology that are needed to understand this post.) Towards the end of that post, I mentioned that I will at some point go over in detail the listed types of repetitions. Well, this post will cover that. Here goes...
Let's begin with the positive rep. A positive rep applies resistance to a muscle as the muscle shortens. In other words, a force is applied to the muscle from its stretched position to its contracted position. Take for example a barbell curl. A positive rep starts when the barbell is down at your thighs and ends when the barbell is up at your shoulders.
A negative rep can be thought of as the opposite of a positive rep. Instead of applying resistance to a muscle as it shortens, the force is applied to the muscle as it is lengthened, i.e., from the contracted position to the stretched position. Expanding on the barbell example, a negative repetition starts when the barbell is up at your shoulders and ends when the barbell is down at your sides.
A static-hold rep applies resistance to a muscle at a fixed point in its range of motion. There is no movement during a static-hold rep. Static-hold reps can be done in the contracted position of the muscle where the muscle is shortest in length, in the stretched position of the muscle where the muscle is longest in length or in some midrange position.
Almost all other types of reps are some variation or combination of a positive, negative and static-hold rep. The most common type of rep is the full (or complete) rep. It is safe to assume that when I say rep, I am referring to the full rep. This rep consists of a positive rep followed by a static-hold rep and finishes with a negative rep.
A partial rep consists of a positive rep followed by a negative rep so that there is little or no pause between these reps and the range of motion for both the positive rep and negative rep is less than a full range of motion. Partial reps can be used to pump a muscle or simply to work a muscle more intensely at a specific point in its range of motion.
A forced rep consists of a positive rep where a partner helps you apply a small amount of force as the muscle's length shortens from its stretched position to its contracted position, followed by a slight pause in the contracted position and then followed by a negative rep which you perform without the help of your partner.
A negative-accentuated rep consists of a positive rep that you perform with two limbs, followed by a slight pause and then followed by a negative rep that you perform with only one limb. For example, when you perform a negative-accentuated rep on a leg extension machine, you use both legs to move from the stretched position to the contracted position, pause and then use only one leg to move from the contracted position back to the stretched position.
These types of reps are incorporated into my workouts to add effectiveness, efficiency and intensity. Of course, these are not the only types of reps that you can perform, but this will provide a good starting point and a diverse selection to construct a good workout.