they can be somewhat dangerous, i would think. If the child falls and hits their head. My dh won't let my son buy them as he thinks they put to much of a strain on their legs.
here is something from natural health web:
"Unfortunately, the real high risk victims are our little children. They can look forward to the following problems after prolonged use:
1) Neck & Upper Back Injury
2) Lower Back Injury
3) Hip Injury
Neck & Upper Back Injury
The natural skating position of the Heelys forces the neck to push the head outwards to balance a body that is now poised to fall backwards. The neck and shoulder muscles are strained to push the head forward to counteract gravity. However, our neck muscles were not made to hold our head out on a horizontal plane. This is a stop gap measure by our body to prevent us from toppling. Sadly, the damage is not going to be stop gap nor temporary.
The skating position of the Heelys compels the lumbar curve of our backs to flex AGAINST its natural curve, creating a flat lower back instead of a concave one.
To be fair - the skating can be done with a natural curve but it takes great effort; and I certainly do not see children doing it!
Fortunately, in the walking mode, genuine Heelys allow you to take out the wheel but parallel brands usually do not. Remember to always get your child to take out the wheel. Do not allow them to be lazy!
Constant walking on shoes that pivot on rollers (now that wheels have taken the place of the heels) conditions our gait muscles to walk in a manner contrary to natural stride patterns. This leads to knee, shin and foot injuries later in life.
Balancing in a forward motion on one back wheel is no easy task! Hence, our children’s natural sense of balance intervenes by skating with one foot in front of the other. The centre of gravity effectively expands along the diagonal axis, creating a more stable base to balance on.
In other circumstances, this would be a beautiful celebration of the human body’s ability to adapt. Unfortunately, in this case, it is a predisposition to a life of agony.
Modern children spend most of their time seated behind desks and computer. The rare minutes of movement they have in a day will be constrained by the muscular requirements for the precarious Heelys balancing act. Their hips will be locked in an awkward skewed fashion, having to constantly compensate for the imbalance.
The Long Run
Occasional postural stress on our human bodies is not a problem. It only becomes a critical problem when it involves children in their formative years. Prolonged exposure to un-natural stressors on our posture forces our body to evolve by strengthening those incorrect, temporary function, muscles. In the absence of postural rehabilitation, this is the only defence mechanism, albeit temporary. These reinforced muscles become a ticking time bomb waiting to fail.
It is our children’s future that we hold in our hands. This article may not have been written based on a field study but it is definitely based on fundamental anatomic principles. Yes, I may not know what exactly constitutes prolonged use; but let’s try looking at it inversely. What are the unique benefits of wearing Heelys that would justify this lifelong risk?"