If you’re approaching, or well-within your competitive season in your training year, the fitness you’ve built up-to-now should be looked at like an investment. Because it is one.
It is your time and your energy packaged up into a measurable state of potential performance... And if you haven’t been working on it that much- better luck next year.
Either way, there’s nothing you can do overnight to magically boost it. Truthfully, your biggest goal in-season should be to maintain the fitness you’ve built, avoid injury, and recover well between competitions and training sessions.
This doesn’t mean that it’s a good time to be lazy or slack off during training sessions either though. Remember, the goal here is to maintain fitness, so you still need to manage your current ability levels when it comes to the fitness you’ve built.
One of the most effective ways of communicating this in my opinion, has been to tell athletes that during their competitive seasons, they should end their training sessions feeling like they could have done more.
By reducing volumes, increasing inter-set rest times, and maintaining regular intensities rather than trying to push for new heights in every session, athletes recruit muscular strength and utilize energy systems in capacities that encourage fitness levels to stay where they are while working at non-exhaustive, sub-threshold levels.
So... Don’t call it “hitting a plateau”... call it “maintaining fitness”- when you’re in-season, that’s the whole point.