I use the Samsung S-Health app which has a global step challenge with a public leaderboard. To complete the challenge, you need to walk 200,000 steps in the month.
Looking over the leaderboard though, there are some people with ridiculously high step counts:
Fifth place has ~2.5 million steps. 2.5 million / 27 (days so far) = ~92593 steps/day!
As someone who walks ~8k steps a day, and has a record count of 40k steps in one day, 90k steps a day on average seems impossibly high. I filed a report to Samsung noting how the counts seem suspicious, and they replied, assuring me that they take cheating seriously and that the leaderboard is legitimate.
Is it remotely feasible to walk more than 90,000 steps a day, every day for a month? Is this something that someone may do in the course of training or some running sport?