Why do my legs get tired before I'm out of breath?
Your legs may not be keeping up with your cardio for a variety of reasons. Here are a few, and some options for tweaking your regimen to move faster.
Run less often and with higher quality
When I started running in my 20s, I could train on back-to-back days, teach a step class in between, play a softball game at night, celebrate with the team afterward, and repeat it again and again without much fatigue. If I tried that now, I’d be sore, tired and unable to run at my best for days. If you run by what your body is telling you, you ebb and flow along the way. For instance, I run four times a week, but all of them are high-quality runs. In many cases, runners who are over 40 do really well with fewer runs per week, but higher quality (e.g. a speed workout, tempo run, long run and easy run). This gives your mature running body time to recover before you hit the next run and in doing so, allows you to run harder, faster, and stronger than if you ran on back-to-back days.
Train with the flow of your life
Some runners can suffer in performance if they are training by pace rather than by what their body is telling them on the given day. For instance, you head out to run at your normal easy pace of 10 minutes per mile, but you’re tired from travelling, not eating well, and not sleeping, so your 10 minute pace feels like a moderate effort and it delays your recovery. If you continue to train by pace, it can lead to tired legs - your breathing is fine, but your legs are unable to take you any faster due to fatigue. When you train by effort and feel, you end up running your easy days easy so you can run your hard days harder. Some days your hard days may be at a slower pace because of your life’s flow, while other days it may be faster than you’ve ever imagined. When you let the pace be the outcome of the run, it opens you up to higher quality workouts that allow you to train harder and recover more easily.
Mix up your training efforts
All work and no play make runners’ legs tired and fatigued. Meaning, if you only run in one gear, it’s usually not easy or hard enough and you end up in La La Land, unable to run faster. Mix up your running efforts to include truly easy, moderate and hard effort workouts to focus on all the ingredients for a strong performance. Also remember, the harder the effort, the shorter the workout. A little fast running goes a long way in improving your speed and performance. If you’re looking to get in a lot of miles, get in a lot of miles. But if you’re looking to run faster and without chronic leg fatigue, train by quality and get in a short, hard effort. It’s less about the volume and more about the quality.
Race and fuel yourself wisely
A few other variables that can have a negative effect on your body performance is racing too frequently or not including an off-race season. If we want to race harder and faster, we need to invest in it with racing and recovery seasons. Otherwise, we end up fatigued, burnt out and unable to perform at our best. Nutrition can also wreak havoc on our performance. It may be helpful to evaluate your diet to make sure you’re eating enough calories and in the right amounts for you. Low-calorie diets and nutrient deficiency can lead to tired legs as well.
If your legs are fatigued and aren’t keeping up with your cardiovascular system it may be a sign that something in your regimen is out of balance. Take a look at the big picture, evaluate the flow of your running life, and make a few modifications to ensure your legs are recovering. Nine times out of 10 this is plenty to have a positive effect on your running performance.