My six-year-old daughter scooters every day for about an hour. She feels very comfortable scootering with her right leg on the scooter and refuses to switch legs.

My question is: If she keeps doing this every day, do I need to worry that one of her leg will become much stronger (and therefore larger) than the other?

  • 2
    One great way to train pushing with both legs is to push uphill : you're slower, so it's less scary to push with the other leg, and it's a great advantage to be able to switch from one side to another when one leg starts to feel numb. Commented Jul 8, 2022 at 17:47
  • 3
    When I started scooting again, I found my “body supporting leg” to be stiffer / more tired than the “propelling” leg the next day. Part of that was when I propelled, I also had to bend my “supporting leg” knee so I could reach. It was constantly going up and down! It may be the same happens to her right leg.
    – Tim
    Commented Jul 8, 2022 at 18:37
  • @Tim that's an answer not a comment - both legs are doing work.
    – Criggie
    Commented Jul 8, 2022 at 22:41
  • 3
    @Criggie it's pretty borderline because I a) don't know if that's how people normally scooter (it's just anecdotal) and b) don't know if it's even enough to balance out any size discrepancies.
    – Tim
    Commented Jul 8, 2022 at 22:42
  • Why would you be worried if one leg is stronger (and therefore a bit larger) than the other? I sincerely intend this only as a helpful observation: you may benefit from speaking with a psychologist regarding your concern. It is normal for people to have one arm/leg stronger (and larger) than the other. Being concerned about it is sometimes indicative of one of several well-documented psychological illnesses. Parents who address their own psychological issues (a substantial percentage of parents have psychological issues) will often be able to be better parents & raise healthier children. Commented Jul 9, 2022 at 16:42

1 Answer 1


Unilateral training does indeed lead to a difference between the size and strength of the muscles on each side. However, most active individuals have discrepancies between their dominant and non-dominant sides. They are measurable but rarely noticeable. Also, the contralateral side receives around half of the strength training effect of the trained side as a consequence of neural development. Hypertrophy appears not to occur on the untrained side.

Activities such as scooting, skating, snowboarding, and surfing inherently encourage us to bias our dominant sides. And the same is true of all racquet and throwing sports. It is worth noting, though, that the non-dominant side often receives a distinct but comparable training effect, too. On a scooter, for example, one leg supports and balances the body while the other drives it. Both are working throughout.

There are valid reasons to train both sides of the body: improved multilateral neurological and brain development, improved multilateral coordination, or for specific skill acquisition. (Raphael Nadal, for example, learnt to play tennis left-handed in order to have an advantage over his opponents who are mostly right-handed. He is naturally right-handed.) And of course for competitive bodybuilding, even subtle imbalances in muscle hypertrophy are disadvantageous.

For your daughter, it should be no cause for concern.

  • 3
    Even playing something like soccer: You mostly manipulate and the ball with one leg. Commented Jul 8, 2022 at 11:46
  • 1
    @ChuckLeButt Not if you want to be any good at it.
    – shoover
    Commented Jul 8, 2022 at 15:43
  • I was an avid bowler in the past. Even then it probably amounted to chucking a 14 pound ball about 35-50 times X 3 times a week. It was enough that my bowling forearm was 1 inch (circumference) larger than the non bowling forearm. I don't seem to recall any difference in size to my upper arm measurement.
    – gns100
    Commented Jul 8, 2022 at 16:44
  • Anecdotal, but I have been skateboarding for 15+ years (goofy footed, so I push with my left foot). I can notice a visible difference in my calves, but nobody else can until I mention it. It's slight, but certainly isn't "overly strong" compared to my right, and again it's barely noticable. As you mention too, with skateboarding and scooting, it's not necessarily easy to just switch stance to "avoid" this rather small issue.
    – BruceWayne
    Commented Jul 10, 2022 at 0:17
  • I have found unilateral differences can definitely be noticeable. I started doing calf raises and found that the right calf is definitely bigger than the left one.
    – Tom
    Commented Jul 14, 2022 at 13:21

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.