Considering we use our dominant arm for lifting, most tasks, holding things, etc.
In: Biology
The advent of the interwebs.
(I suppose it’s simply because we use our dominant arm more.)
Because you use the muscles in your forearm more than your biceps, check your forearms one should be noticeably more defined than the other
[Your forearm muscles pull tendons to move the fingers](https://assets.answersingenesis.org/img/articles/am/v5/n3/index-finger-muscles-large.gif); this way you can have a lot of muscles to grip strongly, without them needing to be located IN your hand / IN your fingers. So for something like a sword-and-shield medieval fighter, where they grip the sword tightly with their right hand but “lift” the shield with the entire left arm, you would see a thicker right forearm.
Otherwise, with day to day activities we use our dominant hand for “precision” stuff like writing and fine manipulation of objects, and precision doesn’t require muscles.
Heavy things that do require muscles, we tend to lift with both hands, so your biceps tend to develop evenly.
Because it doesn’t take a lot of bulk to do everyday tasks. Your dominant arm does a lot, but doesn’t have to be that big. As such, it probably is bigger, but not enough to be noticeable.
Now, if you have a dominant arm and do lots of strength work with it, it will be noticeably larger. Take Rafael Nadal, for instance, who is famous for having one huge (tennis) dominant arm and a nicely built but much smaller (tennis) non-dominant arm. https://www.reddit.com/r/tennis/s/nUIJfI5Cl6
Edit: put in some parentheticals for the pedantic because Nadal is a righty but plays tennis lefty, so his left arm is huge
Muscles grow due to volume of challenging work. High volume but no challenge = no growth, very low volume but high challenge = no growth, so squeezing a piece of paper 100 times won’t make you grow, but lifting something really heavy once a week won’t make you grow. It’s why body builders are often recommended to work out a muscle twice a week for 6-10 sets each time for 8-12 reps, and to usually work to near failure in each set. However, most things you do with your dominant hand aren’t difficult at all, like holding a pen, steering a car, or opening a door handle. Plus, your hand is controlled by muscles in your forearm, not your bicep, and your bicep usually doesn’t get fully stressed in daily movements, even if you are highly active.
It Don’t explain anything but my left hand is actually stronger than my right because it is holding stuff while I do stuff with my dominant hand
Ye ol 4.20, 4 muscles in the upper arm and 20 in the forearm.
We are rarely actually flexing the arm and holding weight in day to day life so bicep is not that overworked compared to the other.
All of our grabbing, squeezing, typing ect. Is done in the forearm and there’s a lot of good muscle to distribute tension and the muscle belly’s are much much smaller so even when strengthened regularly they done look as “bulked”
People often do have more developed dominant sides, but the difference is typically slight enough that you cannot easily tell without measuring tape. That’s because your body wants to conserve resources and avoid starvation, therefore it will not commit resources to growing bigger or stronger unless it experiences taxing stimulus that convinces the body that it is worth it to get stronger and be less vulnerable/avoid getting overloaded in the future. The result is that serious hypertrophy (muscle growth) is reserved for draining movements that typically employ multiple muscle groups rather than repetitive tasks like brushing your teeth or writing your name which are unilateral but are experienced at too low of an intensity to trigger a hypertrophic adaptive response. People who do engage in strenuous activities that only engage one limb or side of the body actually can develop disproportionately sized musculature such as in the case of baseball pitchers who train until they can throw 90+ mile per hour fastballs or experienced archers who train to use bows with heavy draw weights.
Muscles grow when they’re broken down. In order to break down a muscle you need to push it beyond what it’s used to. You might use your dominant hand for more daily tasks but 99% of them aren’t creating enough resistance to break down the muscle, and for the few that do you most likely end up using both hands.
People are only about 5-10% stronger on their dominant side, unless you do an activity which significantly alters this ratio, most day to day things aren’t gonna build your muscles very much, and that’s not generally a noticeable amount unless you’re specifically measuring
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