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Young Runners: Training Load and Energy Balance

As cross-country season is getting into full swing, we have been seeing more runners with injuries and issues arising from training. This is common during training season and is to be expected, but I wanted to draw attention to an issue that is becoming more common. Young runners in particular are going through growth spurts, hormonal changes, and bodily adjustments that make the balance of training load and energy a tough bit to manage. Let’s define some terms to help clarify this issue:

- Training Load: “output” via exercise or activity

o Running workouts for the team

o Strength workouts with team or alone

o Yoga, Pilates, power stretch sessions

o Playing games with friends/family (ex: basketball in the driveway, frisbee at school)

o Short social media workouts for “accessory work”

- Energy Balance: “input” back into your body via food, rest

o Total calories consumed (meals, snacks, protein shakes)

o Amount of sleep (actual hours, not just ‘planned’ hours)

Now that we have identified these two terms, we can discuss why managing these two aspects is so important. In order to maintain proper balance, an athlete must be putting enough energy into the body that is taken out via exercise or activity. If this does not occur, weight loss and/or injury will result. If input is equal to or greater than output level, this will allow an athlete to continue training at the current level or increase training volume or intensity with less risk for overuse injury due to caloric deficit.

There are two main areas where this can be challenging. First is energy input, meaning caloric intake and sleep. These two factors recharge the body and provide fuel for exercise. Think of in this way: you wouldn’t be surprised if you went on a road trip and got stranded because you didn’t put any gas in the car! This is often what happens when caloric input is not equal to energy expenditure. There are many reasons for reduced caloric intake, some of which have serious implications regarding preoccupation with weight loss, food shaming, or even eating disorder. These cases are serious and should be handled by a medical professional who can help. However, the majority of cases of lacking caloric intake merely comes down to unintentionally not consuming enough. Teen athletes in particular are susceptible to this because metabolic rates can fluctuate significantly with growth, hormonal changes, and puberty. Many athletes don’t realize their body needs significantly more calories, because they have just consumed what they always have!

The next area of challenge for maintaining balance is energy expenditure via output. This encompasses all forms of exercise and activity, including the small spurts of activity like playing basketball in the driveway for 30 minutes, trying a new short exercise routine you saw on Instagram, or working out with both the team and alone. Often, this energy expenditure increases drastically within season due to increased weekly mileage, increased demand from school/social calendar, and a well-meaning intention to stay strong via lifting throughout the season. By themselves, none of these things are bad! However, when added to the overall load of activity, overuse can occur subtly.

So, what happens when this energy balance gets out of whack? Chronic overuse injuries, sudden exhaustion or fatigue, slower race times, reduced capacity for exercise, and overall malaise. This can be a signal from your body that it is wanting more gas in the tank!

But, you may say, how am I to calculate all of this and know I am on track? Aren’t calorie trackers and activity trackers mostly inaccurate? Unfortunately, yes. Most activity trackers and calorie trackers are inaccurate and can provide a hurdle for proper estimation of energy input and output. However, we do not need to track each and every minute of exercise or calorie consumed. An easy way to track this is to monitor your body weight. (I will take a moment here to acknowledge that there are many psychological implications that arise from weighing and scale usage, and if there is a history of problem here – tread carefully. My intention is NOT to cause a triggering of anxiety or previous trauma.) Tracking weight will provide a concrete way of tracking energy balance – BUT with a caveat! Your weight should be monitored over the week and NOT day to day. Day to day fluctuations in weight are absolutely normal and you should look at the big picture when tracking body weight. If your weight is decreasing as activity increases, that is a clue that you are not getting enough fuel.

If you are looking for a more measurable approach to energy balance, you can get metabolic testing which will tell you your resting metabolic rate, which can then be used to create a plan for enough calorie consumption.

My intention with this blog was to create an awareness to make sure our teen athletes are eating enough. In my experience, endurance athletes in particular struggle to eat enough to maintain their high activity levels. Hopefully this has encouraged some thought on putting enough gas in your tank to go the distance!

If you are dealing with a stubborn chronic injury or overuse, please do not hesitate to reach out to me at

Thanks for reading!



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