Why Is Your Non-Dominant Hand Weaker?
Contrary to popular belief, hand dominance does not necessarily dictate which hand is stronger than the other. Hand strength relies on hand use, and while hand dominance can be a major contributing factor to hand strength, it is by no means an absolute determinant. In fact, the tools of modern society, which are constructed based on the fact that most people are right-handed, has more to do with hand strength than does hand dominance.
1 Right Handed Strength
Most studies on hand strength show that right-handed people have 10 percent stronger right hands than left hands. As most tools in a person's life are either usable by either hand or are designed to be used by the right hand, this 10 percent difference is fairly straightforward. Right-handed people use their right hand by both choice and necessity, and therefore it gets significantly more exercise. That exercise translates into a higher hand strength.
2 Left Handed Strength
Earlier hand strength studies made no distinction between left- and right-handed individuals, so it was assumed that the 10 percent hand strength difference in favor of the dominant hand found in right-handed individuals was true regardless of hand dominance. Later studies segregated the results of left- and right-handed test groups, leading to the discovery that left-handed people may fall into either of two categories. The first category, making up about half of left-handed people, are those that have no considerable strength difference between hands. The second category (and second rough half of left-handed individuals) consisted of left-handed people whose right hand was slightly stronger than their left. Generally, the fact that many tools are designed for right hand use only is attributed to the fact that left-handed people do not usually have stronger dominant hands.
3 Right Handed Bias
The majority of people are right-handed. The direct result of that fact is that many everyday items are designed for only right-hand use. Consider some common items: can openers, scissors, computer mice, etc. While left-handed variants of these items exist, they are not always readily available or convenient. Some left-handed people simply do not bother with the left-handed variants, as well, choosing instead to simply adapt to the right-handed bias.
4 Hobbies & Occupations
One notable fact about hand strength, regardless of hand dominance, is the effect of hobbies and occupations on hand strength. Certain activities focus on hand strength more than others, resulting in greater hand strength. Depending on an individual's handedness, their difference in hand strength can likely be traced to their habits. For example, left-handed people who commonly engage in activities that required right-handed tools likely have slightly stronger right hands, while left-handed people who engage in activities that prefer neither hand likely have little or no difference in hand strength.