Whether you’re a seasoned endurance runner or new to the half or full marathon, race-day readiness requires a steady, consistent dose of dedication and commitment. But in addition to building stamina through running day in and day out, runners should use training time to focus on one of the most important aspects of racing itself: fueling. After all, what’s all your hard work worth if you bonk when it matters the most?

The same way you test your shoes and race-day apparel, before your big race you need to train your gut to absorb and metabolize fueling under race-day conditions. A long run is the ideal scenario for a race-day dress rehearsal.

 Start this "rehearsal day" with what you plan to eat on race morning, then fuel and hydrate during your run the same way you intend to on race day. Make sure to pack light and easily digestible fuel supplements, like gels, so you’re not carrying more weight than necessary. If your plan goes off the rails, don’t fret. A race-day rehearsal will give you the chance to identify the culprit and try again during your next training session.  

Gels 101

Research shows that supplementing with carbs during exercise improves performance (makes you faster), delays the onset of fatigue (the dreaded bonk!), offsets how quickly you go through the carbs stored in your muscles (go longer!), and promotes muscle recovery (so you can get back to training again more quickly).

Properly formulated sports drinks and gels are the most effective fuel source because of how easy they are to absorb. Gels deliver a boost of energy (ranging from 20-30g CHO/gel) in a small, portable pack. And thanks to handy packaging, gels can fit right in the loops of a race number belt without bouncing or rubbing.

Though gels are a convenient and simple fueling option, some athletes are turned off because of their gooey-thick consistency and sweetness, and because, due to their concentration, most products require a good deal of water to wash them down.

"Gels left me nauseated and bloated, especially after a hard effort," said runner Alissa Coffman, also a Science in Sport ambassador. Before trying SIS isotonic gels, Coffman says she would’ve rather run on an empty stomach than risk GI distress, a common—but avoidable—complaint that can derail race-day performance.

Here’s how to make gels work for you:

  • Caffeinated gels help decrease perceived effort and are most effective if used in the second half of the race. Test-drive them in long runs and before early morning training runs instead of a cup of coffee.
  • Keep in mind that with most gels, you’ll need to drink plenty of water to dilute the gut and enhance gastric emptying. Some products, like Science in Sport gels, are isotonic, so you won’t need water to wash them down.
  • Plan for breakfast 2-3 hours before your event begins, then give yourself a starting-line boost by taking a gel and hydrating 15-20 minutes before you hit the course.
  • Start fueling in the first hour of your run, when absorption rates are the most efficient. Aim for 30-60g CHO/hr from easy-to-digest, simple carb sources like glucose, dextrose, maltodextrin, and fructose mixtures.
  • During the race (if you forego a sports drink), take one gel every 20-30 minutes. If you plan to take in sports drink (2-4 sips/aid station), then one gel/hour is sufficient. "I typically take one gel/hr,” says Coffman, “with no tummy issues and easy to ingest. I’ve tried them with and without water and I don’t see a difference. That is so important because sometimes you need that extra boost while racing, even when a water station is not available.
  • If you have a temperamental tummy, consider nibbling on a gel over the course of a mile or slowly eat only half a gel, and see how you feel.


What should I expect on race day?

The Rock ’n Roll races will offer Science in Sport gels along the course at two fuel stations in the half marathon and three fuel stations on the full marathon course.

On-Course Nutritional Information:

SIS isotonic gels: 22g CHO, <1g sugar, 0mg caffeine