One ironclad prediction for the coming year: 12 months from now, we'll still be debating the ingredients of the ideal workout, diet and lifestyle. But even if the final answers remain elusive, we'll keep learning more about how our bodies work. Here are six fitness science topics I expect to make a splash.
Better than average
Most health advice suffers from the tyranny of the average. Studies with thousands of subjects might tell us that a certain type of exercise or diet produces an average improvement of 20 per cent – which is great, except that the individual results may range from 0 to 40 per cent.
What we know: Many researchers have begun publishing data showing the full range of individual responses to health interventions, and identifying "responders" and "non-responders."
What we'll learn in 2014: The biggest challenge is to identify the underlying factors that determine why individuals do or don't respond to a given intervention. The answers will be different for every study, which makes this an incredibly challenging proposition. But reporting only the average is no longer good enough.
But how hard?
The biggest question about exercise used to be "How long?" But over the last few years, "How hard?" has emerged as an equally important query.
What we know: Short bouts of high-intensity exercise seem to offer many of the same benefits as longer bouts of moderate effort. Debates over which is better have become heated.
What we'll learn in 2014: Instead of fixating on the "right" intensity for a single workout, researchers will broaden the discussion to encompass the full range of intensities used in workouts over the course of weeks and months. For example, polarized training models incorporating a mix of short, hard intervals and longer moderate efforts show promise.
The neuroscience of sports
Sports are 90-per-cent mental (the other half, by former Major League Baseball great Yogi Berra's math, being physical). You'd be hard-pressed to find a pro sports team or a Sochi-bound Olympian who doesn't work on their mental game.
What we know: Experience shows us that the tools of sports psychology – mental imagery, self-talk, goal setting, mindfulness – help athletes excel. But figuring out exactly what, when and how much an athlete needs remains an uncertain art.
What we'll learn in 2014: Neuroscientists are turning their attention to elite athletes, using advanced imaging tools such as fMRI and high-resolution EEG to see how their brains respond to stress and challenges. The results will begin to reveal exactly how various sports-psych tools work, and enable more personalized prescription.
How much is too much?
Nothing makes a better man-bites-dog headline than the suggestion that exercise might actually be bad for you. So it's no surprise that recent studies claiming that too much aerobic exercise might damage your heart have received plenty of attention.
What we know: Just like any drug, exercise must follow a U-shaped dose-response curve, with a sweet spot for optimal health somewhere between "too little" and "too much." But where exactly is the line?
What we'll learn in 2014: It would be too optimistic to hope that we'll nail down exactly where that "too much" threshold lies, but we should see progress. My bet is that it will be much, much higher than expected.
All in the genes
The success of David Epstein's bestselling book The Sports Gene inserted the topic into public conversation last year, but interest has been growing since groundbreaking experiments at Laval University and elsewhere in the 1990s showed that genes affect exercise response.
What we know: There's no single fitness program that is "right" for everybody, because we all respond differently even if we do exactly the same exercises. Researchers have already developed simple genetic tests to determine how strongly you'll respond to aerobic or strength training.
What we'll learn in 2014: The big question now is what we'll do with this new-found genetic information. Will it empower us to find our own best fit for exercise, or discourage us from even trying? Or will we just ignore it?
Personal fitness trackers are collecting ever more comprehensive information about how much we move and how hard we push. But are we taking full advantage of this flood of data?
What we know: The simple act of tracking your exercise encourages you to be more consistent about pursuing your fitness goals, much like keeping a food diary often results in weight loss.
What we'll learn in 2014: Modern tracking and computing technology offers the possibility of sifting through vast reams of data and unearthing more subtle connections. For example, which specific workouts have the biggest impact on your blood pressure, energy levels or mood?
Alex Hutchinson blogs about exercise research at sweatscience.runnersworld.com.