Single Finger Training – Hand Injury Risk vs Reward
I’ve often been asked about single finger training, and whether I ever do it. My answer is ALWAYS a resounding NO!
This came up a lot a few weeks ago when Dmitry Klokov posted the Grip Challenge lift below:
There are two reasons why I don’t suggest people do single finger lifts.
First off, there is very little reward for doing them, compared to the extremely high risk of injury, especially for those who have never done this type of training before. Most people who ask me, are just now getting into grip training, so their hands are not yet conditioned for the stresses of whole-hand grip training yet. Many of the others have been doing grip training for a while, and think single-finger work might be good for them to get an edge.
The second reason why I do not suggest single-finger lifting is because I have felt the pain of finger injuries, and I know what it’s like to have to stop training due to finger injuries. In February of 2011, I hurt both of my middle fingers so severely, both in the same workout, that I had to miss Mighty Mitts that year because of it, and wasn’t even able to train my hands at full intensity until May, just weeks before Nationals that year.
To add insult to the injury, I wasn’t even doing a single-finger lift that time. I was demonstrating how to do the Rim Topz lift to some friends. I wasn’t warmed up, and just reached down and tried to pull a light weight, and first my right middle finger popped, and then my left. BOOM – on the shelf for about 3 months due to 12 seconds of stupidity. I can only imagine how much worse the injury could have been, if it were just the middle finger working alone.
Obviously, Klokov is an exceptional strength athlete with years of training under his belt. And for all I know, he could have been doing that sort of training for a long time, before putting up that video. Either way, since single digit force production is not something he needs, it DOES surprise me he would take that risk, given his outstanding weightlifting career and how much is always riding on his hand health.
And when guys like Andrew Durniat post videos trying the lift, I don’t worry as much. Andrew does a significant amount of rock climbing and climbing-specific grip training, so his finger are more conditioned than most peoples, and his risk is more calculated.
But, when it comes to my training, and the training programs I set up for my clients, single-finger lifts DO NOT have a place in the program.
Recently I was lucky enough to come in contact with Stan Hunter, the man behind the Hunter Push-up Spikes. Stan runs a sports medicine fellowship at Summa Health System and provides team medical coverage for everything from high school to NCAA D1 to professional level athletics in the Akron, OH, area. So he knows a thing or two about hand injuries.
Actually, his understanding of the hands is quite impressive, and we were emailing recently about the risks of single-finger training, and he was nice enough to put together a nice article on the risks of this sort of training from a more medically-based perspective. I really want to thank Stan Hunter for putting this together. I know he is extremely busy in his studies and practice, so it means a lot to me that he would put something like this together for us here at DieselCrew.com. Now, I turn it over to Stan Hunter…
The Risks and Injury Potential of Single Finger Training
by Stan Hunter
Sometimes in sports we do odd and unnatural things that tax our body. For instance, as with a climber trying to hang from a small hold, a sports pursuit may require a substantial load to only one finger. In general, however, single-finger loading is something our bodies did not evolve to do. Several anatomic features of our hands and forearms demonstrate this as they limit our ability to perform strenuous one-finger tasks, and one-finger loading is associated with a variety of classic injury patterns.
One anatomic feature that limits our ability to perform challenging single-finger tasks is the juncturae tendinum. This is a group of thin bands of tissue that run between and interconnect the extensor tendons of our fingers. They function to distribute loads between the extensor tendons, assist in the alignment and tracking of the extensor tendons, and provide some collateral finger extension even if an extensor tendon ruptures. They also, however, couple the fingers so that extending each individually is difficult. To illustrate by example, “flipping the bird” with any finger other than the index, and sometimes even with the index, is not possible with full extension. Try it and you will find that the metacarpophalangeal joint – the joint at the base of each finger – will not extend as far as it will when you extend all fingers simultaneously. To do this experiment properly, remember to keep the fingers you are not extending in a fully closed fist. The limited range of motion you experience, as well as some of the tension and discomfort you may feel in the back of your hand, is due to the juncturae tendinum.
The structure of one of the two main finger flexors is also poorly adapted for single-finger feats. The tendons of the flexor digitorum profundus (FDP) that go to the middle finger, ring finger, and little finger, and sometimes also the tendon to the index finger, share a common muscle belly. This makes it difficult to flex the joints nearest the fingertips individually, particularly if approaching the limit of muscle contraction. The FDP tendons attach at the bones of the fingertips (the distal phalanges), and although the FDP tendons can help flex the bases of the fingers (metacarpophalangeal joints) and the middle joints (proximal interphalangeal joints), they are the only tendons that can flex the last joints of the fingers (distal interphalangeal joints). This is why we cannot flex, say, our ring finger into the same position it is in when we make a fist while leaving our other fingers straight. If you start with an open hand and try to flex your middle, ring, or little finger at all three joints, you will find the last joint just will not flex. That is because these tendons arise from the same muscle and cannot be flexed individually.
More evidence that the FDP functions poorly for individual finger tasks is the quadriga effect. If a single tendon of the FDP ruptures and is surgically repaired at slightly the wrong length, or if it develops an adhesion that limits its motion, the motion of the other three fingers is affected. If the FDP to one finger ruptures and is surgically repaired slightly too short, that finger will reach full flexion before the other fingers, and the other fingers will never be able to flex fully. They will stop when the repaired finger reaches full flexion. A related phenomenon occurs if the FDP to one finger is too long. The involved finger will never be able to flex fully, always stopping when the other fingers reach full flexion. The four fingers are connected by four tendons to one muscle belly, like four horses connected by four yokes to the same chariot. If one yoke is shorter, all four horses cannot run side-by-side, as the shorter yoke will always hold one horse closer to the chariot. The quadriga effect derives its name from this metaphor, as quadriga is a term for a Roman four-horse chariot.
As for safety, plenty of injuries happen with one-finger loading, particularly with sudden or eccentric loading. (In eccentric loading, the muscle is getting longer despite attempting to contract, such as when doing a “negative” rep.) Jersey finger, or avulsion/rupture of an FDP tendon, classically happens when an athlete tries to make a tackle by grabbing someone’s jersey but manages to hook only one finger. This either ruptures or tears from the bone (avulses) the FDP tendon of the unlucky finger. Despite the name jersey finger, this injury also happens with single-finger loads not involving jerseys.
Another injury common with single-finger loading is pulley rupture. To keep the flexor tendons against the bones and prevent them from “bow-stringing” when the fingers flex, the tendons run through a series of straps that hold them down. These straps are called pulleys. With heavy isometric (muscle staying the same length – neither elongating nor contracting) or eccentric one-finger loading, particularly if the finger is in a position of proximal interphalangeal joint flexion, these pulleys can rupture. The second annular pulley, or A2 pulley, is the most commonly ruptured pulley. Sometimes called “climber’s finger,” this often results from a crimp grip, especially with a single-finger, eccentric, or sudden loading component.
In general, single-finger maximal efforts are high risk and non-natural ways to use the hands. Single-finger deadlift, for instance, involves a maximal effort on a single finger and is isometric if the lift is successful and eccentric if not. Any high-speed or explosive training makes the lift sudden and almost surely eccentric. Participation in many sports comes with substantial risk, sometimes well beyond hand injury, but for many people the pursuit is worth the risk. Athletes should understand the risks and think deliberately before participating in such sports or competitions. If risky motions, such as described above, are not required in a sport, athletes should deliberate even more seriously on whether the risks are worthwhile simply for training.
Stan Hunter
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