Concentration bonds mind with object; sensation bonds heart with mind.
Without concentration one's mind is not in sync with reality; without sensation one's heart is not in sync with one's mind.
Concentration and sensation are inseparable: concentrating on something inevitably yields some degree of sensation, and sensing something brings one to concentrate on it. However, there are varying degrees of emphasis. For example, when watching a compelling film, sensation is typically the dominant quality, and concentration on the film follows after it. (Or in other words, if the film wasn't stimulating, one would cease paying attention to it.) In contrast, when studying a subject which one finds rather boring, willed concentration becomes the dominant quality and sensation depends upon it. (In other words, if one stops willing himself to concentrate on his studies, he wouldn't be stimulated by it.)
Ideally, concentration should prevail over sensation. There are at least two reasons for this:
a. mental stability: one who's able to will himself to pay attention to whatever he believes is required of him at any moment, rather than being compelled to attend to what offers more excitement and stimulation, is more mentally stable.
b. Deeper perception: People are naturally inclined to focus on the more colourful, large, dangerous, tasty, rich, etc objects in the environment - those which speak directly to lower Da'at - and to ignore subtler patterns or aspects. The ability to will oneself to concentrate on objects of choice allows one to become aware of and appreciate more elusive aspects of reality.
Many people, including myself, claim that skateboarding is enthralling, bringing one to temporarily forget about everything, including (thank G-d) personal problems and woes. Some people even identify this state of consciousness as a highly focused and meditative one. I beg to differ.
In general, meditation involves the attainment of mental stability, self-control, self transcendence, or an enriched and expanded awareness of reality. Meditation, in all its forms, involves the strengthening of upper Da'at. When skateboarding, however, one's mind is completely absorbed in the activity because of its appeal to lower Da'at. One concentrates fully on skateboarding because the mind is drawn by the powerful magnetism of lower Da'at. In short: skating is very exciting.
However, skateboarding offers a good opportunity to meditate: to practice upper Da'at. Since skating grips lower Da'at so strongly - for one naturally pays attention to aspects of a trick which are more obvious, be it in terms of danger levels, trick technique, self image when performing the trick (do I look cool?), etc - it challenges one to transcend the magnetism by intentionally concentrating on the dimensions of skating which are more subtle and sophisticated, and to develop general mind over heart rule.