Whether you run outside or on the treadmill, it may be a good idea to do it uphill.
When we run uphill, it gives a better training effect. For most of us, a five percent incline will improve our working economy - we are not as dependent on a good running technique.
However, it is not necessary to run with a five percent incline to have a good training effect - we can also walk with a steeper incline. What is important is that we work with the same relative intensity - that we work equally intensively and reach the right heart rate zone (85-95% of maximum heart rate). Our heart does not know if we are running a little faster up a gentler hill, or walking fast on a steeper hill. We get the same training effect. However, there are two reasons for doing the intervals uphill.
Gentle on your joints
When running uphill, the mechanical load is much less than when running on flat ground, and this is particularly important when you train a lot. If, for example, you struggle with your back or knees, you will notice that the incline is gentle on your joints.
Optimal Heart Exercise
When running uphill, the heart, not the technique, becomes the limiting factor. When training for maximum oxygen uptake, the heart is optimally filled. Active breaks make it possible to keep going for longer, quite simply. You'll get more minutes with a high heart rate and a full heart, and your workout will be more effective.