When running long distance it is up to you. As of now there is no conclusive evidence supporting any one form as better than another. Some people like to use a heel foot strike as they run because it allows them to run with a longer stride. Personally I advocate a front foot strike, landing between your frontfoot (the All Beauty Comes From Within shirt Apart from…,I will love this toes and ball of your foot) and midfoot (the arch). Most of us have shoes with thick pads on the heel. This encourages a heel foot strike. Imagine you were running without shoes, you wouldn’t land on your heel that would hurt very badly. It is much more ergonomically correct to land forefoot rather than heel foot. Running with a heel foot strike may cause pain to manifest in the knees or hips. When you run with the fore foot strike you absorb the impact of each step with the muscles throughout your foot and leg, rather than taking it on your bones and joints. So yes it may be a little more tiring, but it does lower the risk of knee pain or injury.