Biking 4km isn't very long. Walking 4km would be better. Though running 3km would be even better! Haha. If you wanted to bike, I'd say 10km would be quite good.
then the walking is the better choice for sure, cuz it takes longer walking, meaning ur useing more energy and muscle
walking 4km is probably sumwhat healthier but if your biked around 5km that would be more healthy probably.
I say walking, but if u wud increase the length with the bike I think that wud be healthier
It's just destination to destination so there would not be a longer length on the bike.
It depends on the intensity of walking