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