Grip for the snatch and clean is a topic very important to me personally as someone with relatively small hands. For most lifters my size, grip is not an issue because they tend to have fairly large hands and easily get better coverage on the bar. Even my lovely wife Aimee's fingers are almost as long as mine, and she gets to lift on a bar 3 mm smaller.
There are a million ways to train grip strength and related abilities and quite an array of movements and positions. However, if we're talking about grip strength for weightlifting, there are a limited number of applicable exercises because the type of gripping is limited to two slight variations on a barbell - the snatch grip and the clean grip. The only difference between the two is that the snatch grip will allow less purchase of the ring and pinkie fingers because of the wider hand placement.
A few considerations: One, you will be using the hook grip
when you pull a snatch or clean. Two, there is need for very little grip stamina - the amount of time you're pulling the bar is very brief. Three, the force the grip must resist will change during the course of the pull because of the rapid acceleration of the second pull and the transition under the bar.
This being the case, we can eliminate many typical grip exercises because they won't contribute much if anything to our specific task. This is not to say that a variety of hand and wrist work isn't useful, at least for general ability and hand health, but that if our problem is an inability to hold onto the bar during heavy lifts, we need to focus accordingly.
One of the most common problems with programming is trying to do everything out there at once. If you addressed every single possibility, you'd be training 10 hours/day. It's important to both prioritize and to make your training efficient without making it less effective.
One of the simplest ways to start improving your grip without adding work to your training is to reduce the use of straps. The best place to start on this is in slow lifts like stiff-legged deadlifts, RDLs and rows. The slow speed means any lack of grip strength will not have a huge effect on your ability to hold onto the bar.
Don't use a hook grip and force your fingers to do the work. Be sure to wrap your hands just as you would for a snatch or clean with respect to the ring and pinkie fingers; that is, make sure those fingers are hitting the bar in the same place, rather than placing the bar deeper in the palm than you would normally. Squeeze the bar more tightly than is necessary to get even more work into it.
The next step is reducing strap
use in the classic lifts and variations. It's typical to use straps for power snatches, muscle snatches, hang or block snatches and snatches for reps. Usually this isn't an issue, but for someone with a relatively weak grip, it can exacerbate the problem. If you fall into this category and have been using straps for a long time, you will need to work your way into this gradually or you'll end up limiting what you can lift, which won't help anything. Start with the above step regarding slow lifts; once you've made some progress there, start reducing strap use with the classic lifts by putting them off on your warm-up sets longer and longer until you don't need them on your work sets. This can take quite a while, so be patient.
You can also start doing as many of your warm-up snatches and cleans without the hook grip. Once you start feeling unable to control the bar, return to the hook grip to finish your sets. A way to make this even tough is to not only not use the hook grip, but to remove the use of the thumbs completely - this was taught to me by Bob Morris. In the snatch, you won't be able to use a false grip overhead because of the strain on the wrists, but you can do the entire lift holding the thumbs straight out and making sure they're not contributing to the grip on the bar.
If you have time, to this you can add some actual grip training if necessary. If you have to choose only only exercise, I would suggest grippers. Use these less for reps, and more for intensity. That is, work on reps of 5 or fewer with heavier grippers for most of the volume you do. Use a level that you can close completely and hold closed at least momentarily. Eventually work up to holding it close for 2-5 seconds.
You can emphasize the ring and pinkie fingers when using grippers as well. Get them into position as they would be on the bar - this may take using your other hand to help partially close the gripper to set the starting grip. Focus on using these two fingers more than your first and index fingers to close and hold the gripper. Do a couple sets of 5 reps with a light gripper to warm up your hands before doing your heaviest work. With your heaviest gripper, work reps between 2-5 and build up to a 3-5 sec hold in the closed position, with the tightest squeeze you can manage. Once you can hit 5 reps with a 5 second hold for 3 sets, it's time to move up to the next weight. If the jump to the next gripper is too big - that is, you can't close it completely - try adding 1-2 more sets with the previous level before trying to move up.
Remember, this advice is specifically for improving your grip for lifting. If you're interested in grip strength for other tasks or its own sake, you can get more grip specialty training grip specialists.
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