The Anatomy of a Rep

Legendary UCLA basketball coach John Wooden, winner of 10 National Championships in 12 seasons, famously started his first practice each year by teaching college-age kids how to properly put on socks.

As the fitness world continues to move towards trying to come up with more sophisticated exercises and routines, one thing that is getting overlooked today is a focus on the fundamentals.

Just like Coach Wooden spent valuable practice time on a seemingly trivial topic, this article will break down how to execute a single repetition for greater success.

In strength training every repetition of an exercise has 3 phases - eccentric, isometric, and concentric.  

The eccentric is the lowering portion, the isometric is the 'stop' phase where you transition from down to up, and the eccentric phase is the lift itself.

Although most of us focus exclusively on the concentric phase, each of the three holds benefits in developing greater strength and overall athletic ability.   Let's look at how to best execute each phase.

Eccentric Phase

Lowering weights in any exercise, especially when first learning how to strength train, should be relatively slow and controlled.   This should take roughly 2-3 seconds per repetition.


First, a controlled descent makes it easier to keep the weights on the proper path, a critical aspect of the lift as any drifting forward, backward or laterally can immediately lead to injury.   Over time, the ability to control the descent of a weight will allow you to safely use heavier weights.   

Second, the controlled descent makes it easier to execute the isometric phase without having to bounce at the bottom (more on this coming up).

There are variations of how to use the eccentric phase to enhance development.  A longer descent of 5 to 8 seconds may enhance strength development in experienced lifters.  Forced negatives, where you use more weight than you can lift with a slow descent, are not necessary for younger lifters and are potentially dangerous.  

With a focus on the fundamentals, the lesson here is to always use a controlled descent for all your lifts, on every single repetition to get the most out of your workout.

Isometric Phase

Unless you picked more weight than you could handle, this is the fastest of the three phases.

From a fundamentals standpoint, you only want the isometric phase to avoid bouncing at the bottom and to keep the weights in line with the overall movement.

Bouncing weights at the bottom portion can cause damage to ligaments and tendons because they are the fibers that create the rebound effect for you.   This would be a great concept if the bounce actually strengthened those fibers, but all it does is potentially stretch them to the point they make the joint (shoulder and knee usually) less stable.

A quick pause at the bottom would also help to keep the weights from shifting out of alignment.  Even a 1 centimeter or so deviation to the side can make that initial lift far harder.  In fact, this is an under appreciated reason why you may struggle to lift a weight you know you can handle on a particular rep.   This happens very often with less experienced lifters, limiting their ability to gain strength.

Once again, there are all sorts of isometric variations that can be applied, including a full one second pause on every rep right up to a full set of just the isometric hold for longer periods.

Fundamentally, however, coming to a brief but full stop will lower injury risk and increase your chances of raising the weight in the concentric phase.

Concentric Phase

Assuming you've executed the eccentric and isometric phases properly, in most cases for the concentric phase you want to move the resistance as fast as possible.  Even novice lifters should be doing this if they are training for a sport.

Lifting at maximum velocity in the concentric phase develops not just strength, but also power (strength x speed).   This is the foundation of speed development, and the skill you need to throw, kick, jump, swing and shoot more explosively.  

This is safe provided that you've lowered the weight properly, and have stopped at the bottom to avoid any bouncing movement.

There is a second way to look at the concentric phase, however.

Many studies have linked the 'time under tension' variable to increased muscle building.   This says that by raising and lowering weights slower you can build muscle mass more rapidly.   This has never been 100% proven, but there is a lot of evidence to support its accuracy.

My advice would be to first learn how to explode through the concentric phase, because this not only builds greater power but also teaches you how to successfully lift heavier weights in time.   If you need to build muscle mass, after at least one year of weight lifting experience you can phase in some time under tension lifts into your training as well.


To summarize, the breakdown of a proper weight lifting repetition should be:

1. Lower slowly

2. Come to a brief, complete stop at the bottom without a bounce

3. Raise explosively

Boring as it may seem, consistently executing the fundamentals in every aspect of athletics leads to greater success.  

Every single repetition in your workout, just like putting on your socks, is no different.





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