This variation really increases the load on the biceps during the eccentric (lowering) phase of the movement. While it'll overload every arm flexor, it'll target the short head of the biceps (the inner portion) a bit more. Interestingly, this head is involved in shoulder flexion. You'll see why this is relevant in a second.

Here are three key facts to remember about the curl:

1. We're stronger eccentrically – like when lowering the bar or dumbbell back down in a curl – than concentrically. So the eccentric phase will always be easier than the concentric phase.
2. The eccentric phase is where you have the potential to stimulate the most growth. It's the part of the movement where you cause the most muscle damage and mTOR activation.
3. The more tension you can get during the eccentric phase, the more damage and mTOR activation you can create in the muscle. And if you accomplish that, the more growth you'll get.

If you can make the eccentric phase harder, you'll increase the growth potential of the exercise. This is why most experts recommend doing the eccentric phase a bit slower than the concentric phase.

Another way of increasing muscle tension during the eccentric phase is to put your body position at more of a mechanical disadvantage. This just forces you to work harder during the eccentric portion.

A typical example of this is the Zottman curl. You do the concentric phase with a supinated grip (palms-up) which is stronger, then you do the eccentric with a pronated grip (palms-down) which is weaker. Obviously you'd have to do this with dumbbells.

Another way of doing it on curls is to have the dumbbells move further away from your body during the eccentric. Once you've curled the weight up, you lower it back down by pushing away under control.

The simple change in leverage dramatically increases the load on the biceps. And since you're now overloading the shoulder flexion pattern (think of a front raise), which involves the short head of the biceps, you're putting even more tension on the biceps.

You can do this exercise with a bar, dumbbells, or a pulley station. You can use a supinated (normal curl), pronated (reverse curl), or neutral (hammer curl) position.

You can make it even more effective by leaning forward slightly during the concentric (this will increase tension at the peak contraction portion) and then leaning back slightly during the eccentric, keeping the tension more constant in the lower portion of the movement.

I learned this from powerlifting coach Alex Babin who puts a premium on developing the whole forearm to increase performance on the big basic movements.

It's a regular hammer curl with three twists:

1. You hold the dumbbells with an offset grip. The outside of your thumb and index finger are touching the weights on the front side, leaving a greater distance from your pinkie finger to the back side of the dumbbell.
2. At the start of the movement (bottom position) you fully extend your arms by contracting the triceps.
3. While you're flexing the triceps in the bottom position, you execute an ulnar deviation. Imagine trying to move the back portion of the dumbbell upward.

When you curl the weight up, you also do a radial deviation as you flex the elbow (opposite movement as the ulnar deviation).

The full extension at the bottom stretches out your brachialis and biceps a bit more and increases elbow stability. This allows you to recruit the elbow flexors more.

The exercise will strengthen a function of the wrist and forearm that's pretty much never trained and is under-developed compared to its opposing radial deviation. The latter is heavily trained in the hammer curl, so starting the movement with an ulnar deviation and an offset grip will allow you to better balance your strength to help prevent injuries.

Furthermore, that ulnar deviation will have the same effect on the hammer curl as the triceps contraction at the start of the movement. It'll allow you to better recruit the brachioradialis during the ensuing curling motion. All of that makes for a more effective hammer curl.

This is the way Chuck Ahrens used to overhead press back in the 50s. Instead of pressing the dumbbells straight overhead, he'd press them up and out. At the top, his arms and head would form a "W" shape. This is why some coaches often call it the W-press.

The reason he did overhead presses this way was simply because he used special dumbbells to accommodate the amount of weight he was lifting. Those dumbbells were wider than normal, so he had to press out to avoid them colliding against each other.

Ahrens is likely among the strongest men in history when it comes to pressing overhead, using 170-200 pound dumbbells for standing strict dumbbell presses. And he did that for reps. Keep in mind this was in the mid 1950s; steroids weren't used back then.

I recently started having my athletes use the Ahrens press. For them, it's meant to specifically improve the catch position of a snatch, but as a by-product it's had a positive impact on delt strength and size.

This pressing variation is great at improving shoulder stability and medial delt development leading to more width. It also takes some of the load away from the triceps and upper pecs, so it's more delt-dominant than regular overhead pressing.

You can do it seated or standing. In both cases, focus on trying to reach "out and up" at the top to maximize contraction and muscle growth.

I recently started playing around with clubbells. If you don't already know, they're heavy clubs that look a little like short baseball bats. They weigh between 5 and 45 pounds. While they're used mostly for swings and other dynamic motions, you can also use them for slower hypertrophy movements.

Don't worry, you won't have to buy clubbells to do the exercise below. It can be done with a dumbbell or even a weight plate.

With the clubbell chest press, start with the 'bell held in both hands (close to you) at around mid-abdomen height. Then press forward in a slight upward arc so that the arms end up fully extended with your hands around mouth level.

Another key: squeeze in with both arms. The mental image I have is to try and push my pecs up with my arms.

If you do the squeeze-in action, it'll properly engage the pecs. And by nature, this exercise already hits the delts, arms, and forearms (with the clubbell).

Try it with a dumbbell. Hold the handle so it's parallel to the floor and hold the dumbbell by pressing on the outer portion of the plates, trying to crush it with both hands.

This isn't a heavily loaded exercise. It's more important to focus on squeezing in with your arms than lifting more weight. Try doing this for more reps, even up to 30. Try using a timer and do a set over 45-60 seconds, going for smooth, controlled movements.

Use this as an assistance movement or as an activation movement prior to a chest hypertrophy workout.

This is the Zercher squat of the upper body – it's a great core strengthener on top of its main purpose.

The Z-press is when you do an overhead press while seated on the floor with extended legs. The purpose of sitting like this with no back support is to make the core work a lot harder to stabilize the upper body.

It also teaches you proper overhead pressing technique. If you push too far forward or lean back (the two cardinal sins of overhead pressing), you simply won't be able to use a lot of weight and your core will tell you that you're off-line.

You can get a lot out of the single-arm version. Most people get a better mind-muscle connection when they only use one arm at a time. And it also increases the need for the core to stabilize – a significant benefit, especially with the athletes I'm training.

I normally use this exercise either in the first phase of training, to prepare the body for the heavier barbell overhead work, or during deload weeks.

As a big basics guy, the squat, press, pull, hinge, and carry have been the cornerstone of my programs for more than 20 years. However, I do like to include variation in the assistance work.

It's best to stick to the big basics for longer – not changing them too much or too often – and using progressive overload on these lifts. But you can vary the assistance work much more often and include metabolic factors (longer time under tension, more focus on mind-muscle connection) to stimulate growth.

Progressive overload requires you to stick to a movement for longer because you want to gradually add weight (or reps) to a certain lift. But metabolic factors (accumulation of growth factors and lactate) don't require the same: you don't have the burden of gradually increasing the weight. You just want to get that "burn." As such, you can rotate these exercises pretty much at will.