The main problem with a lot of these types of myriad varieties of gel and/or highly cushioned styles of shoes which have become highly coveted and desired for their very typically comfort cushioning characteristics; is that they indirectly cause a joint instability especially when one is running in rugged trail running conditions which is fine if one is a highly physically fit conditioned and trained athlete; but for many weekend warriors who are not quite so physically fit conditioned and trained athlete; one can get into an incredible amount of trouble potentially quite easily;
typically what happens is that one winds up applying very high amount of stresses to ones knees which over time may cause a vertical and/or horizontal miniscus of knee tear which is very painful indeed and that may be serious enough to cause one to even lose their ability to walk normally; so yes one needs to be exceptionally careful and certainly not careless about considering one actual muscle conditioning and fitness especially in consideration of ones all so critical hip flexor muscle actual conditioning and hip flexor muscle strength;
one can actually assess and evaluate ones hip muscle conditioning and strength by actually placing oneself in a typical side plank position(youtube video) and to be able to scissor ones leg upwards and spread outwards while being able to hold that position stably while maintaining the side plank position for about fifteen to twenty seconds; now if one is not able to actually do that one can always look at youtube video on how to specifically strengthen ones hip flexor muscles over time; but their are enough individuals who are not in good enough shape hip flexor muscle wise;
that one could easily potentially get oneself in some considerable trouble by damaging their knees when running and/or even walking when ones knees are not properly muscle strength supported by having sufficiently conditioned and strengthened hip flexor muscles; which is entirely and largely preventable;
now some have even lost their normal ability to walk normally without pain as a result; which is a rather sad and an typically quite important cautionary story to tell those who might be potentially misinformed and/or misguided in terms of having the correct information at hand and having the actual knowledge/ know how to be able to properly utilize the relatively new heavily cushioned gel and/or foam cushioned typical trail running shoes;
now some of the relatively new heavily cushioned gel and/or foam cushioned athletic shoes on the market even have air pockets to add even more cushioning capabilities which is truly great for comfort; but they can also potentially offer still more opportunities and/or possibilities to potentially destabilize ones knees and/or cause a potential horizontal and/or vertical meniscus tear of the knee; which could potentially lead one to be potentially injured to the point that one might not be able to normally walk without pain permanently for life unfortunately; just be careful out their guys as its far to easy to potentially injure oneself in just that kind of way.