Fear & Loading: Triggers And Fingers

by
posted on June 2, 2015
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
trigger.jpg
Sometimes I research a little too much on subjects, but I ran across something last week I think you’ll find interesting. The paper, titled “Quantifying the Independence of Human Finger Movements: Comparisons of Digits, Hands, and Movement Frequencies,” appeared in The Journal of Neuroscience on Nov. 15, 2000. Charlotte Hager-Ross and Marc H. Schieber conducted the research and composed the article.

Their experiments attempted to determine how well humans could move one digit on their hand without moving the others. It didn’t focus on shooting, but when we move the trigger, our thumb—accustomed to years of working in tweezer-like concert with the index finger—often inadvertently applies point-of-impact-altering pressure to the pistol grip or rifle stock.

The scientists determined the ability to avoid the problem varies considerably and, “To some extent such intersubject variability may reflect differences in the long-term motor experiences of each subject,” they wrote. Those “long-term motor experiences” are what we call practice, range time, tickling the trigger.

As for the wisdom of slowing down and really squeezing, “Negative correlations—lower individuation indexes at higher movement frequencies—were found for all digits except the thumb.” So the faster you pull the trigger, the greater the accuracy-robbing pressure applied by the rest of your hand (with the exception of the thumb).

For the average test subject, the thumb was not immune to movement, however. “We found that even when asked specifically to move one digit without moving any other digits, normal human subjects produced low-amplitude motion in noninstructed digits simultaneous with the large-amplitude motion of the instructed digit.”

Why does it happen? Adjoining and shared muscles, tendons and tissue are part of the explanation, but there’s more at play according to the pair. “…[T]he motoneuron pools innervating different finger muscles receive considerable shared central input.”

None of this is earth-shattering news, and it should come as no surprise they found, “…the thumb and index finger showed the highest degrees of individuation and stationarity, i.e., the greatest independence.” It is, however, nice when science verifies the sage advice to practice and slow down your shots.

And, if you haven’t been practicing with your off-hand regularly, you’re officially out of excuses. “In strongly right-handed subjects, however, we found no evidence of a systematic difference in finger movement independence between the right and left hands in terms of either individuation or stationarity,” the researchers wrote. In fact, there may be a slight advantage in using the weak side for long-distance shooting. “Performing a separate paired comparison of the individuation indexes for each digit of the right versus left hand revealed a significant difference only for the thumb, where the individuation index was higher for the left, nondominant thumb than for the right.”

Latest

Doug Midwayusa Visit 1
Doug Midwayusa Visit 1

A Cathartic Journey Back to Midway Arms & the MidwayUSA Foundation

NRA CEO & EVP Doug Hamlin returned to MidwayUSA, a place he first visited decades ago in the early 1990s as publisher of Guns & Ammo magazine alongside the late, great Robert E. Petersen.

Review: Steiner MPS-C

The new Steiner MPS-C is the compact but rugged, closed-emitter optic we’ve all been waiting for.

The Truth About Bans on Glocks

Gun-control groups are again trying to ban one of the best-selling and most iconic semi-automatic pistols ever—yes, most Glocks.

WOOX Expands Operations in America’s Woodworking Heartland

WOOX, manufacturer of Italian-American made gunstocks, axes and knives, is breaking ground to expand its operations in Hickory, N.C.—where woodworking expertise has been passed on for generations.

Beyond the 1911: Wilson Combat's New Bulwark

The Bulwark is designed as a “hard-use service pistol” that combines the best features of a 1911 with those of a daily-carry duty gun, and Wilson Combat delivers it all at a price point below Wilson’s traditional handgun offerings.

Rifleman Review: Walther Arms PDP Pro-X PMM

Recently, Walther Arms has combined several PDP feature sets with a Parker Mountain Machine compensator to produce the Pro-X PMM.

Interests



Get the best of American Rifleman delivered to your inbox.