Hello! I am 14 years old and I have been running for almost 3 years now. I haven’t ever experienced leg fatigue before but lately, almost immediately, my legs start to feel so heavy. I often have to quite my run because I can’t move my legs any further. They feel tired and stiff. I do plenty of stretching before. It really messes up my running routine because I plan for 3 or 4 miles and I only end up running. Please help! I don’t know what to do it’s very frustrating.

Hi there, I am sorry to hear about this problem. There could be a few factors involved. First of all, it is really important to fuel up properly before attempting a big run in order to sustain your body through the course of it. Fresh foods like bananas and homemade smoothies contain lots of healthy energy-boosting nutrients so these are the kind of things to focus on. Wholegrains and vegetables are also good choices. 

It is also worth noting that low iron levels can contribute to fatigue. We lose iron during our period and so this can explain why some runs are harder than others. The body also needs iron for growth so many teenagers can get deficient. Foods that contain iron include dried fruit, broccoli, peas and legumes to these are the kind of things to eat a little more of. 

In addition, make sure you incorporate a few rest days a week where you don't do any running to allow you body time to recover. 

If this problem persists, don't be afraid to talk to those around you or your GP for more advice.