Even the free market regulates store hours sometimes. All the farmers' markets in my area, you have to open shop at exactly 8am and close at exactly 12pm, to be fair to everybody. And that's even if you're sold out at 10--you still have to remain open until 12. Otherwise people would be trying to open shop at 6am to try & increase sales, and soon they're sold out at 8am. Then everybody else feels the pressure to be there at 6am, and you've pretty much screwed up the whole market.
Labor unions curtail the work hours of their members, even if the workers want to work longer hours (again, in an attempt to out-compete). You have to show up to work at 8 and leave at 5.
And then in athletics, the regulatory commissions (like the NCAA) forbid you from holding practice out-of-season. Otherwise coaches would be holding 2-a-days the whole off-season and stress everybody out, in an attempt to be competitive. And the student-athletes wouldn't be getting an education.
Regulating the markets to cut back hours is not automatically a bad thing in this instance. And it's arguable as to what exactly constitutes a "free market" or even if it's a good thing 100% of the time.