Mike O’Hearn trains with fitness author and transformation specialist Kris Gethin for an epic arm day workout

In a recent episode of Generation Iron and Barbend’s The Mike O’Hearn Show, fitness enthusiasts were treated to an exciting session as Mike O’Hearn teamed up with the renowned Kris Gethin to share their expertise on biceps and triceps workouts. Kris Gethin, a fitness transformation specialist originally from Wales, now spends most of his time in the United States, traveling the globe to host seminars and workshops while working with and training the best of the best. Mike O’Hearn and Kris Gethin offer a unique insight into their arm workout strategies, providing valuable tips and tactics they’ve acquired over years of experience.

Mike O’Hearn has always been a firm believer that experience is just as important as science, information, and “textbooks.” That is to say – you can study the rules, guidelines, and science behind how to build the perfect physique, but each individual is different and may react differently.

With that in mind, Mike O’Hearn always urges aspiring bodybuilders and lifters to experiment and listen to their body. Just because a famous coach or bodybuilding influencer states that “x, y, and z” is the best way to build muscle – doesn’t mean that’s the only right way to do it. In fact, sometimes doing things the “wrong way” can be beneficial  to you. It’s all about listening to your body.

Mike O’Hearn and Kris Gethin both swear by certain tactics in the gym or in the kitchen that others would find blasphemy. But the proof is in the pudding – and both individuals are successful athletes.

That’s why on this week’s podcast episode, Mike meets up at the gym to train with Kris Gethin for a biceps and triceps workout. Along the way they share tips and tactics that can be incredibly valuable for those looking to learn something.

Exercises Covered:

  1. Preacher Curls
  2. Reverse Grip Barbell Curls
  3. Concentration Curls

Preacher Curls

The preacher curl is an isolation exercise that is great for your biceps (1). This exercise is particularly effective because the preacher bench isolates your biceps and makes them the primary movers when you lift. Preacher curls are also perfect for the double-front biceps pose as they focus a bit more on the inner head of the biceps. You can do preacher curls with dumbbells, an EZ bar, or a straight barbell. 

  1. Adjust the seat height, sit behind the preacher bench, and grip an EZ bar underhand. 
  2. Put your hands on the padded slant of the preacher bench and ensure that your armpits are in contact with it while gripping the EZ bar with a supinated grip and your arms elongated. Keep your body and legs firmly planted and your spine neutral. This is your starting position.
  3. Next, brace your core, and while squeezing your biceps, bend your elbows slightly to lift the weight.
  4. Pause for a count when it is parallel to your shoulders
  5. Do the motion in reverse to return to the starting position and complete the rep.


Stronger Biceps

Preacher curls keep your upper body and arms immobile, causing your biceps to work harder. It also uses a full range of motion and increases the time your biceps spend under tension, increasing the size and strength of your biceps.

Shoulder Stability

Your biceps connect to your scapular and shoulder joint. As a result, they aid the rotator cuff, which holds your humerus to your shoulder joint. So performing preacher curls improves shoulder stability, which can carry over to all pushing movements, like overhead press

Carryover to Other Compound Exercises

You use your biceps as a secondary muscle group for rows, pull-ups, and chin-ups. Strengthening your biceps will help you do better at these movements, thus improving your overall performance and gains in your posterior chain. 

Reverse Grip Barbell Curls

The reverse grip barbell curl is an exercise that works on your biceps, brachialis, brachioradialis,  and forearm muscles. It’s similar to the barbell curl, except you grab it with a pronated grip — palms facing down. 

  1. Pick up a barbell with a pronated grip and rest it on your thighs.
  2. Stand up straight with your chest up and your shoulders back. This is your starting position.
  3. Bracing your core, lift the weight until you feel your biceps contract. (Keep your elbows by your side to contract your biceps for the curl and prevent momentum.) 
  4. Pause and lower the weight slowly to return to the starting position and complete the rep.


Arm Growth 

Your biceps are only one-half of your upper arm. The reverse grip barbell curl also trains the brachialis and brachioradialis, the other muscles there. This leads to a size increase and promising changes in the total asymmetry of your upper arm.

Stronger Grip & Forearms 

The reverse grip barbell curl also trains your lower arms and the forearm muscles. This strengthens your grip strength, as they play a crucial role. Research also shows that lifting with a reverse grip leads to more muscle activation in the brachoradialis (forearm muscle)(2).

Concentration Curls

Concentration curls are an isolation exercise that targets the short biceps head, which increases the biceps peak when flexing your arms. It’s a unilateral exercise that recruits your brachialis and forearm muscles.

  1. Grab a dumbbell and then sit on a flat bench with your feet flat and your legs forming a “V.”
  2. Using your left hand, grab the dumbbell with a supinated (palms facing up) grip and hinge forward. Then, put your left elbow on the inner thigh of your left leg. Place your free right hand on your right thigh for support. This is your starting position.
  3. Taking a deep breath, curl the dumbbell towards your left shoulder. Pause and squeeze your biceps at the top of your movement.
  4. Lower the dumbbells slowly to return to your starting position and complete your rep.
  5. Repeat for as many reps as you desire, then switch hands and repeat steps 1-5.


Build Your Biceps Peak

Concentration curls are a great isolation exercise that builds your biceps and increases the size of your bicep peaks. Due to your positioning, you’re less likely to cheat, and this strict form ensures that your biceps and the smaller muscles recruited work. 

Fix Muscle Imbalances

If one arm is stronger than the other, this exercise will help strengthen the lagging side up to par. Doing it unilaterally will help you find and fix any strength and muscle imbalances between both arms.

Inside vs. Outside Grip

Mike O’Hearn and Kris Gethin begin their workout with preacher curls and discuss the significance of grip variation. For example, Kris shares his preference for an inside grip, explaining that it is excellent for thickening the biceps.

Mike appreciates the nuances of different grips, emphasizing how slight modifications can tailor a workout to target specific muscle areas. It’s easy to overcomplicate a workout by trying to find the “best exercises” for ultimate hypertrophy. But sometimes something as simple as changing the grip on the exact same exercise can yield different and powerful results.

Mike also enjoys identifying his body’s weak points and then customizing exercises to address them effectively. To him, that’s part of the fun of bodybuilding. It’s like a puzzle that needs to be solved – and once you start solving it – you start to see results that make you feel empowered.

Starting with the Hardest Position

Kris Gethin reveals his personal approach to maximizing the effectiveness of each exercise. He starts with the more challenging position to push the muscle to fatigue, ensuring that he exhausts the muscle group before transitioning to a less demanding position. This strategy enables him to get the most out of each exercise with the desired weight, without missing reps.

The Importance of Focusing on Weak Muscle Groups

Kris and Mike emphasize the significance of addressing weak muscle groups. Kris points out that a smart bodybuilder prioritizes their weak points, as these are essential for building the strength necessary to sculpt the body to its desired physique.

While strength may not be the primary focus in bodybuilding, it plays a crucial role in achieving the core strength required to shape the body effectively. This is why Kris Gethin recommends that bodybuilders work on their “foundation” so to speak – instead of rushing into the muscle groups that make them look better. In the long run, this will all help build towards achieving the best possible physique on your body.

The Reality Of Training to Failure

Kris Gethin highlights the misconception among many lifters and clients who fail to train to true muscle failure. Kris reveals that many of his clients who send him videos of them training are rarely every truly pushing to failure. But how does an individual know exactly when they’ve actually trained to failure?

True failure occurs when you push your muscles to a point of genuine trauma, prompting them to rebuild stronger. Both Mike and Kris stress the importance of pushing boundaries during workouts to achieve optimal results.

It’s all too common for a bodybuilder or weightlifter to hit a mental limit and think that they have achieved failure. But often times, it’s at this very moment that the athlete must dig down deep and make one final push. Those who have achieved true failure during their workouts will know it. It’s a different feeling and it leads to more optimized strength building.

Concentration Curls and Connective Tissue Strength:

Mike O’Hearn shares his approach to concentration curls, emphasizing the significance of focusing on ligament strength. While he appreciates muscular development, he believes that strong connective tissue is vital. He values the way he feels with robust ligaments, underscoring the importance of balancing muscle and connective tissue strength.

So while performing concentration curls, Mike will often take the weight down, stop, and reengage. While this may be less than typical to traditional concentration curl tactics – Mike uses this moment to recalibrate and make sure that his connective tissue is strong again before performing the next rep.

Fasting and Weight Loss

The conversation takes a detour to discuss fasting, as Mike mentions a four-day fast he undertook to shed approximately 15 pounds. He acknowledges the challenging process of fasting and water weight loss but highlights its necessity for achieving a lean physique, whether for a photoshoot or competition.

Wrap Up

The Mike O’Hearn Show episode featuring Kris Gethin provides a wealth of insights into effective arm workouts, grip variations, training to failure, and the significance of focusing on weak muscle groups. It also delves into the importance of balancing muscle and connective tissue strength and the role of fasting in weight loss. Listeners seeking to enhance their arm workouts and overall fitness strategies will find this episode both informative and inspiring.

You can watch the full episode above. And don’t forget to check back every Friday for new episodes only on the Generation Iron Fitness Network or wherever podcasts are downloaded.


  1. Nunes, J. P., Jacinto, J. L., Ribeiro, A. S., Mayhew, J. L., Nakamura, M., Capel, D. M. G., Santos, L. R., Santos, L., Cyrino, E. S., & Aguiar, A. F. (2020). Placing Greater Torque at Shorter or Longer Muscle Lengths? Effects of Cable vs. Barbell Preacher Curl Training on Muscular Strength and Hypertrophy in Young Adults. International journal of environmental research and public health, 17(16), 5859. https://doi.org/10.3390/ijerph17165859 
  2. Kleiber, T., Kunz, L., & Disselhorst-Klug, C. (2015). Muscular coordination of biceps brachii and brachioradialis in elbow flexion with respect to hand position. Frontiers in physiology, 6, 215. https://doi.org/10.3389/fphys.2015.00215
Derek Dufour has been managing all digital operations on the Generation Iron Network for over six years. He currently manages a team of editors, writers, and designers to provide up-to-date content across the GI Network.