Regarding muscles, as an (former) cycling enthusiast, cycling uses a lot fewer muscles than running. The muscles used for cycling are some of the strongest in the body (hamstring, quadriceps). Compared to running which uses almost the whole body, including core muscles for stability, this is a downside for cycling, because it may not be as natural as running. But I wouldn’t say you end up tiring weaker muscles.
2. The speed at which balancing becomes effortless is roughly walking speed. It is actually difficult to ride that slowly (depending on the bike, load, windspeed etc).
I just googled a bit and apparently there are many kinds of “stepper bikes” that you ride standing up and the pedals move up and down, and it looks pretty fun. Not sure if they’re better at climbing than regular bikes, though.
Biking is not always more efficient, as this quora answer points out: https://www.quora.com/Is-it-more-energy-efficient-to-walk-run-or-bike-up-a-hill/answer/Raj-Kumar-855
Regarding muscles, as an (former) cycling enthusiast, cycling uses a lot fewer muscles than running. The muscles used for cycling are some of the strongest in the body (hamstring, quadriceps). Compared to running which uses almost the whole body, including core muscles for stability, this is a downside for cycling, because it may not be as natural as running. But I wouldn’t say you end up tiring weaker muscles.
2. The speed at which balancing becomes effortless is roughly walking speed. It is actually difficult to ride that slowly (depending on the bike, load, windspeed etc).
I just googled a bit and apparently there are many kinds of “stepper bikes” that you ride standing up and the pedals move up and down, and it looks pretty fun. Not sure if they’re better at climbing than regular bikes, though.