Captains of Crush® Grippers FAQ

Choosing, Training, Care, Certification, Ratings

Choosing a Hand Gripper

Captains of Crush (CoC) grippers are the gold standard for building and testing grip strength—and the single most important grip strength tool you can choose. Precise, durable, competition-grade grippers worthy of serious strength athletes, CoC grippers are ready to produce the quickest gains in grip strength and hand health. 

CoC grippers work together as a family. The strength ratings assigned to CoC grippers are backed by premium materials and precision manufacturing so you know that each Trainer, for example, is spot on its rating—and each No. 1, for example, is exactly that much more difficult.

Here is a quick overview; if you have any questions and would like more guidance, please don’t hesitate to contact IronMind.

  • If you are a beginner, a senior or a rehab patient, the Guide might be perfect for you.
  • If you are active, but have not been training your grip and your job does not involve hand strength, then the Sport is the most likely place to start.
  • If you have been doing serious overall strength training, but have not specifically trained your grip, start with the Trainer.
  • If you use the strength of your hands in your job or if you have been training with sporting-goods-store-type hand grippers, start with the No. 1.

Just to keep this in perspective, most people who lift weights cannot close a Captains of Crush No. 1 gripper the first time they try and only rarely do we ever see someone close a Captains of Crush No. 2 gripper on his first attempt.

Training with Captains of Crush Grippers

You can start with one CoC gripper, especially if you’re on a budget. Be sure to warm up with a lighter gripper or by squeezing a rubber ball or an IronMind EGG

However, if grip strength is your goal, you’ll want to have three different grippers to work with:

  • Warm-up gripper: do 1 or 2 fairly easy sets of 10 to 12 reps; these prepare you physically and mentally
  • Working gripper: using a gripper that you can do 5 to 10 reps with, this is where you make progress; depending on your own level, do 1 to 3 sets of 5 to 7 reps to all-out failure
  • Challenge gripper: this is the gripper you are trying to close next; after 6 weeks or so of consistent, progressive training with the working gripper, start doing partial reps, negatives, or holds for time with this gripper, and use a CoC Key to measure your progress, if you like


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We also recommend that you regularly train your extensors, the muscles that open your hand, with Expand-Your-Hand-Bands  to offset all the squeezing you are doing on the grippers. The Expand-Your-Hand Bands promote good hand health and muscle balance, and help prevent or eliminate pain from tennis or golfer’s elbow.

Captains of Crush grippers come with training directions, but our basic philosophy is that low reps plus high effort are the way to build strength. In a nutshell, you might do something like 1 or 2 warm-up sets, followed by 2 or 3 maximum-effort sets of moderate-to-low reps, and do this workout 3 times per week. 

To make the most of your workouts, make sure you:

  • always warm up to prevent injuries
  • avoid overtraining
  • focus on quality effort, not quantity
  • vary your training to keep your mind and body fresh

Remember that the low-intensity–high-volume traditional approach to training with grippers—doing endless easy reps—will do little to improve your grip and a lot to shorten the life of your gripper. Even though you don’t have to change your clothes or go to the gym to train with your hand gripper, we recommend that you take your training as seriously as if you were working on a big power clean, for example, so this is not something to do while you’re driving, sitting at your desk, or watching TV.



   Download Captains of Crush instruction booklet here.

Captains of Crush Booklet PDF

Most people have to be able to do 20 to 25 complete reps on one of our grippers before they can close the next level up. A good rule of thumb is when you can do 10 to 12 full, consecutive reps on one gripper, it is time to start working on the next level.

The key principle is to add a new twist, so try varying your sets, reps, and number of training days, or attack your grip with another training tool. For example, you can do something as simple as training with your CoC gripper held upside down (i.e., with the spring facing down rather than up), or including some negatives or CoC Silver Bullet holds along with your normal training. IMTUGs let you attack your fingers one or two at a time, while the IronMind EGG gives you a different approach to everything from active rest to maximum efforts. If you can’t quite make it to the CoC No. 2, No. 3, or No. 4, give the CoC No. 1.5, No. 2.5, or No. 3.5 a try—it might be the stepping stone you need. Try using a plate-loaded grip machine, such as the Go-Really-Grip Machine

Seek out good training information, starting with:

For a complete listing of the grip-related information we offer, please look at our All-About-It Resource Pages on Grip Training, Hand Grippers, and Hand Strength

Finally, some people just plain overtrain on hand grippers, so sometimes a short break can work wonders for your progress.

Always remember that Captains of Crush grippers warrant the same respect you’d have for a heavy barbell, so treat them the same way. Always warm up, don’t overtrain, focus on quality not quantity, and vary your training to help keep your mind and body fresh. Don’t approach your Captains of Crush grippers any more casually or frequently than you would a barbell loaded to your PR deadlift.

If making progress on Captains of Crush Grippers is your main goal, training on them and doing related work on your crushing grip should be your top priority.

Thus, do pinch gripping or any type of supporting and open-hand grip work after your crushing grip work or on a different day. It’s the same with forearm work: do it either following your CoC gripper training or on a different day. Keep in mind the priority principle: do your most important training first and let everything else follow.

Strap holds, invented by John Brookfield, allow you to “add weight” to your gripper by attaching weight to a strap or belt; you then squeeze the end of the strap between the handles of the gripper, holding the handles shut for time or until failure. If you can’t keep the handles shut tight against the strap, the strap and weight will fall. By adding weight, you can make it tougher to hold the gripper closed.


The CoC Silver Bullet was designed to train doing holds for time and has become a standard event at grip competitions worldwide.

Negatives, first used to great advantage by Joe Kinney in his training to close the No. 4, are used to train on a gripper you can’t close. Close the gripper using an aid (e.g., your other hand, your leg) and then remove the aid and hold the gripper shut only with your training hand for as long as you can, fighting to keep it shut until it finally forces its way open.

Forced reps are just that, continuing to do reps by cheating the gripper closed, pressing with bodyweight, your non-training hand, your leg, etc.

Partials are also just as they sound: doing reps by closing the gripper part way if you cannot fully close the gripper. You are moving from a fully open to a partially closed position; or from a partially closed to a fully closed (or more fully closed) position. Incidentally, don’t confuse training on partials with doing deep-set closes as demonstrations or tests of strength. The former is perfectly legitimate and the latter is not.

These and other methods of training are included in the book Captains of Crush Grippers: What They Are and How to Close Them, Second Edition.

Caring for Your Captains of Crush Grippers

Absolutely, and it is something you should always be prepared for, even though over the years we have had remarkable success boosting the life of our grippers, to the point that breakage is rare these days. If you use them as directed, you probably will never break a Captains of Crush gripper, but because it is a possibility, you should always hold your gripper as if the spring were going to snap on the next rep. 
Remember this, too, when you train with IMTUGs, and be sure to keep your fingers on the handles, without wrapping your hand around the spring itself.

IronMind intentionally uses natural finish steel on Captains of Crush springs, and they will oxidize in a humid environment if left to their own devices—please note that this is cosmetic, not dysfunctional. To remove any oxidation, use a light polishing cream to restore the spring to its natural finish. Then block moisture from the spring by wiping it down occasionally with anything from light oil, like WD-40, to car wax. If you prefer a durable protectant that also has a dry finish (unlike oil), you might want to give the Sentry Tuf-Cloth a try. Clean excess chalk from the knurling of the handles with a stiff toothbrush.

No, absolutely not, but we appreciate that you are being so conscientious about this.

Not to worry: sometimes the edges of the coils on the spring rub against each other in just the perfect way to produce a creaking sound; it’s not indicative of a structural problem, but if you find the sound annoying or distracting, a shot of light oil should dampen or eliminate it.

Getting Certified on Captains of Crush Grippers

In 1991, to recognize his exceptional accomplishment in closing our No. 3 gripper, IronMind decided to “certify” Richard Sorin, documenting his feat of grip strength and establishing it as a high water mark for others to shoot for and try to match. We included Richard’s photo and feat of strength in our 1992 IronMind catalog, and when John Brookfield duplicated Richard’s feat in 1992, our gripper certification was off and running . . . although it would be another two years before Tyce Saylor joined the illustrious Richard and John on the world’s most prestigious hand strength list

IronMind’s Rules for Closing and Certification procedures have been honed along the way to reflect the spirit of legitimately closing a Captains of Crush gripper, and over the years, IronMind has been what Richard Sorin calls “the good steward,” guarding the strictness and fairness of this process. Want to get on the list and earn the highest honors in the grip world? First, be prepared to train really hard and really smart, working your way up through the ranks of our benchmark grippers until you close the No. 3, No. 3.5, or No. 4 according to the Rules for Closing. For women, it’s a CoC No. 2 or No. 2.5  gripper. You’ll then need to follow the procedure for certification. 

What will it do for you? As with any goal worth achieving, the reward is in the journey and the knowledge that you did it right. Sure, you’ll have the glory of seeing your name on the list of those having closed a Captains of Crush gripper under certified conditions, but more importantly, you’ll know that you can dig deep inside and with a big dose of dedication and persistence, and a measure of faith, you can climb the mountain.



Read the Rules for Closing and Certification for all the rules. Best of luck!



Meet IronMind's Captains of Crush grippers, IMTUGs and Captains of Crush Compatible Grip Tools.  

 To order Captains of Crush grippers and other Captains of Crush Compatible Grip Tools, please visit our on-line store.

For more information about how to build your grip, wrist and forearm strength, please visit our All-About-It Resource Pages on Grip Training, Hand Grippers, and Hand Strength.

Want even more information on Captains of Crush grippers? Visit the Captains of Crush grippers website for facts, fiction, myths and more about CoC gripper selection, training, certification, FAQs, and highlights—an opportunity you won’t want to miss.

Return to IronMind’s Grip-Tech hub.

Poundage Ratings and Gripper Variability

Ratings on grippers aren’t nearly as straightforward as, say, weighing a barbell, but here’s a quick answer (this topic is covered in some detail in the book Captains of Crush Grippers: What They Are and How To Close Them, Second Edition  if you want to read more about it).

Years ago, IronMind realized what a morass it was trying to evaluate grippers and who had closed what, so we developed a rating system for making sense of Captains of Crush grippers. It worked better than we had ever hoped because not only did we end up with something that helped us make Captains of Crush grippers even more precise, but it also gave our customers a way to understand how much tougher, say, a Trainer was than a Sport. 

IronMind’s Captains of Crush gripper ratings are internally consistent, meaning that they will help you understand the relative difficulty of our CoC grippers (e.g., how tough the Trainer is relative to the No. 1). Plus, they are empirically based; that is, our ratings are actual numbers derived from valid and reliable testing procedures, but we can’t make similar statements about the numbers on other grip devices.

On the other hand, don’t worry too much about the numbers: no matter how good or bad they are, actually training with your gripper is far more productive than analyzing it to death.

No, so don’t worry if your Captains of Crush No. 1 gripper is feeling easier to you now—it’s because you’re getting stronger! What is mistakenly called “seasoning” by some people is actually a weakening with use, and it’s a reflection of an under-designed gripper with a spring that is bending, which is why it’s not uncommon for low-quality grippers to get narrower and easier as they are used. On the other hand, Captains of Crush grippers hold their line for a lifetime of steady training.

Your friend’s gripper may have been derived from a different testing system—or it might simply have a convenient number attached to it, without its really being tied to any specific test or measure. This is why you should not be surprised, for example, if a 195-lb. CoC gripper might be tougher to close than someone else’s “300-lb.” hand gripper, and why Captains of Crush grippers, rather than poundage numbers, are the universal standard for rating grip strength. Incidentally, we would peg an average sporting-goods store hand gripper at about 50 lb.

Meet Captains of Crush Grippers, IMTUGs and Captains of Crush Compatible Grip Tools.  

To order Captains of Crush Grippers and other Captains of Crush Compatible Grip Tools, please visit our on-line store.

Have more gripper-related questions? See IronMind Hand Grippers – Care and Feeding.

For more information about how to build your grip, wrist and forearm strength, please visit IronMind's All-About-It Resource Pages on Grip Training, Hand Grippers, and Hand Strength.

Return to IronMind’s Grip-Tech hub.