Simplest Finger Strength Training: The Limits of the Fingerboard
At first glance, it makes sense why we've used a fingerboard historically. Hanging on our fingers with added weight should equal more available force on the climbing wall. Well, this article will discuss how it isn't that simple, and in some instances, doing too much heavy and slow fingerboarding might reduce performance. And that's never our goal.
How do we use the fingers while climbing?
Loading rate
With few exceptions (mostly wall angle), the speed between holds is rapid when climbing at your limit. Therefore, we don't usually have time to get set up on hand holds during a crux sequence. That's part of why we fail. By comparison, the fingerboard is very slow.
Time under tension
This metric varies significantly by the climb and climber, but average times under tension for climbing are in the 4-7-second range. But, even if that's the average time spent on a handhold, how much rate we use limits the total force output for each move.
Repetition number
The repetition or hand move number is also specific to the discipline. Certainly, bouldering problems have fewer repetitions than rope climbing. But when it comes to strength training research, doing more than three to five repetitions/set is futile unless the goal is to build muscle size. Many climbers using a fingerboard, however, do long repetitions instead of multiple short reps.
Muscle contraction types
We like to think climbing is so different from other sports, but if we slow down the hand moves, the fingers still do plyometric work. It's just a small range of motion. First, you pick your feet off the ground with a concentric-like muscle contraction (overcoming isometric) and then rapidly move to the next hold. This second catch-hold contraction is a rapid eccentric-like (yielding isometric) muscle contraction. But between the two contractions, eccentric to concentric is the true isometric phase, called the amortization phase. We aren't digging into that much here, but the critical point is that we always use rapid eccentric to concentric muscle contractions when climbing. The fingerboard looks nothing like that.
Holds and grip type
There's a lot of variety out there on the climbing wall. Including variations in force direction (side pull, gaston, under cling, pockets), but generally speaking, holds can be straight-up weird (un-level, small granite knobs, narrow, sharp pockets etc.). For example, the forces generated on a sloped granite knob are different than on a flat edge.
Grip type preferences are a function of both hold and hand size. Two hands that aren't the same size aren't going to grab the same hold in the same way. For example, a youth climber with a small pinky won't commonly flex the PIP joints at 90 degrees, and a tall adult regularly hyperflexes the same joint on most edges. This complexity is why the climber (general) will never have a preferred grip type.
In addition, the research on sports performance/injury prevention shows that being too rigid with a technique can reduce movement options and dynamic coordination. This consideration is essential for a sport with quite a variety.
Intensity / force
As mentioned above, moving between two holds has a rate of force component. It's variable, of course, but it can't be more than a quarter of a second on limit moves. This rate limits the climber from latching the hold more than anything. Indeed, body positioning/technique is essential for efficiency, but it doesn't change the fact that the finger flexor muscles need to contract and relax rapidly for a given repetition number. Because of this, it is the coach's responsibility to understand that athletes cannot only strength train (power/speed training is not the topic of this article, though) to increase performance.
Image credit: @sav.cummins
Why should we strength train the fingers?
To improve muscle recruitment.
The title of this section speaks for itself. That is the primary and only thing we should expect to transfer to our sport. To generate more force actively, we need to send a large command from the brain to the finger flexors every rep. To do this, every rep needs to be high intensity and only last around 1-3-seconds in length, if that. Certainly not 4-7-seconds, the average time under tension on the climbing wall.
Improving finger flexor coordination
This response happens before motor unit recruitment. It takes some time (weeks to months) for an athlete to be coordinated enough to increase motor unit recruitment. You can't have one without the other. Even though adding load to the body on a fingerboard seems like an immediate force improvement, it isn't. There's quite a bit of coordination that happens at the start. For example, the forces using a 20mm edge (most commonly used) will not directly transfer to a 10mm edge. It is not the same skill. The mechanics of the hand aren't identical in both positions.
To travel greater distances when climbing.
By increasing recruitment, the things that were once 90% are now 70% etc. So as strength increases, everything becomes a little bit "easier." This should allow us to travel further at our limit. Or at least that's how the story usually goes. Unfortunately, it's not that simple. Training always has compromises. Strength training is low volume for a reason. To get the highest recruitment levels, we must keep fatigue low. That's the opposite of endurance.
I wouldn't prescribe a capacity phase before a strength phase for this reason. For example, doing a lot of climbing or fingerboard volume makes the largest muscle fibers more aerobic (use oxygen better). This can be good for efficiency but isn't optimal for peak force. It makes little sense to take an athlete off a performance phase and throw a bunch of volume at them. I think that's risky.
Loading the connective tissues for tolerance/health.
Overloading the connective tissues has health benefits. For example, increasing stress regularly with strength training (material sciences definition) allows for more stiff tendons and ligaments. This stress is essential for building capacity or the ability to tolerate more climbing things. The thing I like about the fingerboard for newer climbers is the immediate loads it puts on the connective tissues of the fingers. Experienced climbers, however, don't get the same response.
Image credit: @hannah_smash
Muscle contraction types
The three types of muscle contractions we already mentioned are eccentric (lengthening), isometric (static), and concentric (shortening). However, if we break it down further, there are two types of isometrics. For example, when we hang on a fingerboard, it is called a yielding isometric and is more like an eccentric contraction. Conversely, if we flex our fingers on the board (not hanging), it is called an overcoming isometric and is more like a concentric contraction.
It seems like semantics, I know, but it matters big time when we discuss finger training adaptations. It's important primarily because each contraction type has a maximum load. Notice how I said load and not force. That is because even though the muscular recruitment might be the same (it is in well-trained athletes), the maximal loads are not. This phenomenon is especially true with eccentric muscle contractions, which can be 1.5 times more load than concentric contractions. It is only possible because eccentric contractions rely heavily on passive tension, not because they produce "more" recruitment or force. Unfortunately, that is an outdated idea.
For those who might not be familiar with the mechanism, passive tension is the ability of a muscle to load the connective tissues immediately (through titin filaments) and spread those forces to adjacent muscle fibers (costameres) efficiently. It makes every fiber so efficient that when you do a concentric maximum (let's say a pull-up maximum), the lowering portion (eccentric portion) only uses about 50% of the fibers used during the movement. This is another reason why slowly lowering a load (concentric) is not advantageous for strength gains.
So what's wrong with more passive tension? Are there any downsides? Nothing is "wrong" with it, and it can make a beginner gain recruitment to high levels, but if you recall the term in the previous paragraph, the load is what dictates the outcome. The ability to tolerate those big loads with an eccentric depends on the load itself. Once we remove it, the adaptation, or the ability to resist it, goes away. So, once an athlete is well trained and has high levels of finger recruitment, heavy fingerboarding loads are more about adding passive tension that is not usable on the climbing wall.
How to differentiate the loads
An example is in order, which is easy to demonstrate with finger testing. I'll use myself, but I've seen this on all experienced climbers I've tested. The difference in sustained loads with an eccentric-like and concentric-like load is striking. For the first test numbers, I'll describe pulling against a scale with my upper extremity on a 20mm edge. I have the athlete fixed in place, pulling downward at max intensity for 1-3 seconds. Suppose we include the upper body pulling. In this case, the fingers yield to the pulling muscles strength.
My finger pull numbers:
Right arm: 174 lbs
Left arm: 172 lbs
2-arm sum: 346
These numbers demonstrate that I should be able to yield my bodyweight +16lbs on a 20mm edge with 1-arm, which I can. I recently did a 1-arm hang with +30 lbs even. However, it also means I should be able to 2-arm hang with +185 lbs, which I don't even want to try.
Let's compare those numbers to my isolated concentric numbers (overcoming isometric). For this test, I typically stand with my knees and elbow locked out (straight) on a platform with the scale below. This position eliminates the force from the lat, pec, deltoid, and elbow flexors. It's a more "pure" example of finger flexor force and recruitment. I've also pulled downward with the elbow fixed on a box. Regardless, my forces are as follows.
My isolated finger numbers:
Right arm: 111 lbs
Left arm: 112 lbs
2-arm sum: 223 lbs
These numbers demonstrate that I should only be able to 1-arm hang with -54 lbs taken off and hang with 58lbs added, which I did, and it still felt hard enough. There is a 63 and 60lb difference in measure force output per arm and a 122 lb difference in hang load prediction. It should be evident that there is no way my fingers are creating enough force to overcome the load on a fingerboard. It's just not possible. So, in my opinion, It's probably way safer and more practical to use the isolated finger flexor load. For a beginner, maybe not.
The flaw with fingerboard strength training
Finger strength protocols typically have a pre-determined hang time, edge size, and maximum load than can be tolerated to a position loss (falling out of half-crimp). I think this has worked well for the decades when we couldn't measure force, but not anymore. I hope the above numbers demonstrate my point. There is no way I need the tension equivalent of twice my body weight on my fingers when climbing. In addition, the loss of the half-crimp is nothing more than an objective marker to end a test. It is not a direct reflection of force loss. It is only for that grip. But once you change the grip, you change the test and its numbers.
In addition, there isn't much logic in increasing the repetition length (hanging for so long, 5-10 seconds) if we only care about inching up that peak force (high-threshold motor unit recruitment) number. We move slow (think deadlifting) because the load is heavy, not the other way around. We know that doesn't work. So instead, strength training chooses a set:rep scheme that gives them more first reps because those are the highest quality. For example, we could cut a 10-second hang into 3, 3-second hangs at the same load with a 5-second rest between reps. Instead of 1 first rep, you'd get three at the same load.
The problem of placement, proportion, and power when strength training.
The problem with placement is when, the problem with proportion is how much, and the problem with power is trying only to perform. All three can be counterproductive for maximum finger strength gains.
When we train the fingers
I don't think there's a "best time". But we can say it's not after a climbing session. In that context, metabolic waste is still present in the finger flexors. These chemicals send information back to the brain (afferent feedback) and increase the perception of effort. This feedback will reduce subsequent recruitment. So in this context, even though the perception of effort is high, the central command (message from the brain influencing recruitment) will be low, yet the athlete can still perform their max hangs. But it's not because they're producing high levels of recruitment. On the contrary, it's because they're relying on passive tension. I think this is one of the essential points of this article; even though eccentric contractions create metabolic stress, they aren't negatively influenced by it.
Proportion related to climbing volume
A lot of climbing volume (especially low intensity) will stretch the finger flexor muscles at a high dosage. This stretching is the primary mechanism by which we get muscle swelling, breakdown, and inflammation. But this doesn't happen for 24-28 hours after the exercise session. By not recovering between sessions, we elevate the subsequent session perception of effort and reduce total force output once again. Nothing is more counterproductive to finger strength gains than a bunch of climbing volume. If the goal is to strength train the fingers, we have to drop climbing volume. It just won't happen.
Power output with climbing
Remember our initial discussion on how we use the fingers on the wall? Rapid stretch-shortening cycles (ecc-iso-conc) between holds on the wall. This load to the fingers can keep force output high for a time (during a power and performance phase), but becomes risky in the long term. The loading style (performance climbing) has more strain than stress on the fingers. If done too long, slowly, you'll lose the ability to generate the highest levels of recruitment until you slow down the hand movements and increase their time under tension. But not for long. Remember, you're previous strength will return quickly.
One proposed solution, turn off the lights.
I suggest the best solution is to train the fingers on the climbing wall, not the fingerboard. This methodology removes confusion about which protocol works best. The downside is that it requires access to climbing walls with consistently more challenging holds. I prefer a few angles of a spray wall/woody, but any standard board can work (Tension, Grasshopper, etc).
The methodology is simple. Spend more time moving on the wall while only using the small and/or hard holds. The difficulty is relative to the individual and requires using open (any) feet. Thinking about why you aren't using these holds when climbing a board problem is because of the power output. Board problems have a ton of velocity and technical skill. But if the goal of the phase is to train strength on harder holds, turn off the lights. It might not be as sexy, but it will transfer better than a fingerboard protocol.
There are a few important considerations why using the wall to train makes sense. The most important is to keep the session volume low. The session is automatically shorter if we only use the hardest (relative to our strength) holds. The session is over as soon as you note a force loss (inability to travel up the wall). There is no going to other parts of the gym and hoarding a bunch of volume. That's a mistake.
The next thing this has is more variety. Because we pull on holds from all directions (side pull, under cling, claw grip etc.), we probably want to strength train all those directions. Not just hanging below the fingers on a board. I suggest open feet for this drill so athletes can adjust their bodies for optimal force on every hold. For example, if you're grabbing a small side pull with your right hand, putting your feet more towards the right allows you to "own" that hold better.
This methodology isn't maxing out the intensity of every rep like a heavy hang or an overcoming isometric but has the skill component they both lack. We all know how important climbing skill development is, but forget grabbing holds is an important skill. If we don't learn to generate high forces on smaller/harder holds slowly, we shouldn't expect to be able to do it rapidly. That doesn't make much sense.
Example finger strength training session on the wall
-45-60-seconds up/around the climbing wall each set.
-Hard/small hand holds with open feet.
-Control each hold for 4-7 seconds while searching for feet.
-Minimize desperate moves and power by keeping hand moves close together.
-Rest 3-4-minutes between sets, and perform 8-12 sets per session.
-Wall angle depends on the terrain you're climbing outside.
-2-3 times per week during a three-week strength block. As a default, I think 35-45 degrees work great, but 20-degree holds condition the skin more.
Non-climbing isolated finger recruitment protocol
Let's assume you don't have access to the climbing walls discussed above, or maybe you mostly climb outside. In that context, keeping your strength block volume low is critical. In this scenario, the non-climbing recruitment protocol might be a better option. This protocol could also be used in combination with the finger training session above.
The great thing about this protocol above is its recovery need. It does not take long to recover from a strength training session like this. In many cases, I'll do it twice on the same day. I'm not suggesting that for everyone, but it should be fine if you have a decent history of finger training. -Isolate the finger flexors most conveniently (standing, sitting, etc.) for you.
-Close the system by using 100% resistance. That could be with a scale (more engaging and productive for feedback) or without.
-Perform 5 sets of 3-4 reps/set. Each rep is a max effort pull of 1-3 seconds in duration separated by 5-seconds. I like measuring force on every rep to track fatigue and guide set length. But it isn't necessary.
-Rest 3-4 minutes between sets on the same hand.
-2-3 times per week during a three-week strength block. I'd suggest 4-6 hours later than a climbing session or another non-climbing strength training workout.
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The takeaway
Please don't hear what I'm not saying. I am not suggesting that a heavy fingerboard protocol won't increase high-threshold motor unit recruitment and strength because it can. What I am suggesting is that it does not reflect it very well. At some point, your recruitment levels will plateau, and loads beyond that represent the addition of passive tension, not more recruitment. The most important thing to consider is that your supramaximal strength goes away with those heavy loads. That's the whole point.
One last consideration. No strength training protocol is specific to rock climbing. Once an athlete has attained peak recruitment again (2-3-weeks with the protocol of choice), they need to transition into a power phase, focusing on more rapid eccentric loads. Rapid eccentric training (limit moves, velocity hangs, redpoint climbing etc.) will keep these new recruitment levels high until we need to start doing more climbing volume in our performance phase. Then, at some point (6 weeks?), we need to circle back and do a little finger strength training.
If you're interested in learning more from Dr Tyler, you can find him @c4hp on Instagram or through his website at https://www.camp4humanperformance.com
He offers many online education options and customized rehabilitation and training programs for climbers. https://c4hpschedule.as.me/