1. High intensity strength training
If your normal intensity is 10 sprints of 400 meters and you suddenly increase it by 20 or 30 times you are unintentionally damaging yourself.
When you accidentally try too hard, too many strength training sessions, or intense lower body workouts will cause prolonged muscle soreness, swelling of the muscles.
It can make your legs feel heavy in the next run.
2. Skip stretching after running
Try to give yourself 10 minutes at the end of every workout session to focus on a few stretches for your leg muscles.
This will help your leg muscles relax, that’s good for blood circulation, and the cadence will be lighter the next time you run. Try to stretch all the different parts of your body – your quads, hamstrings, glutes, hips and back.
3. Wear wrong or inappropriate shoes
Wearing the wrong shoes can make your feet heavier or may cause running injury. Use running shoes that are suitable for you to be highly effective when exercising. Running shoes usually have a lightweight, resilient soles and should be suitable for the legs because each person’s feet are different, maybe your friend wears that type of shoe to run comfortably and you don’t.
4. Wrong technique
If you regularly run with the wrong technique, it will only put more strain on your body and can make your legs tired and heavy.
In the long run it also causes trauma, potentially bad for yourself. Try to master the basics and simple running techniques first, increasing the difficulty over time.
5. Low carbohydrates (starches) diet
Lack of carbs can lead to a feeling of heaviness in the legs. When you are running, your body will continuously use the mixture of carbs and fats to fuel your muscles. If you cut a significant amount of carbs in your meal, your body will not be able to store much muscle glycogen. This affects the body’s energy production for running.
6. Iron deficiency
If you are iron deficient, your body will have a harder time getting enough oxygen to your muscles while running. The body gets tired when this happens, but some people also experience that fatigue when running and consider this phenomenon as a feeling of heaviness in the legs.
Most dehydration is associated with muscle cramps, but dehydration can also cause general fatigue while running. Similar to iron deficiency, people often feel too tired when the body is not hydrated, meaning running when the body is not fully hydrated will incur extremely uncomfortable feelings of heavy legs.
8. Lack of sleep
Lack of sleep can deteriorate strength in general and in the legs in particular. Getting enough sleep is essential for many types of activities, providing the body and brain with certain necessary energy.