There is no way around it. The National Hockey League is changing. The way that players train today is totally different than how they did just a decade or so ago. Regimens for health and durability make players more fit and built for the strain that an 82-game schedule provides.
For a coach, it is extremely hard to adjust to this shift. Because of all of these changes, they still need to find a way to develop players in their rookie stages, or the deeper stages of their NHL careers.
How they find successful methods to develop those players has an answer that no one really knows the answer to, unless you’re part of an NHL coaching staff.