Alpinestars Bionic BNS TECH 2 Benutzerinformationen Seite 8

BIONIC NECK SUPPORT - IMPORTANT USER INFORMATION
Direction of Fall
Force
channeled
through neck
– Direction of Force Illustration
Figure 14
Figure 14– Direction of Force Illustration.
Note also that you can sustain the same injury if you are lofted headfirst into something,
or by sliding quickly along the ground and impacting an obstacle with your head. This is
illustrated in figure 15.
– Horizontal impact with body following
Figure 15
Injury by Hyperflexion and Hyperextension
Figure 15 – Horizontal impact with body following.
The second key fact in off road motorcycling is that hyperflexion (forward bending) and hy-
perextension (backward bending) are NOT likely to be causes of Catastrophic Neck Injury
– despite what many people think. This is because when your head hits the ground the peak
impact force will be transferred to your neck within the first few milliseconds. This compres-
sion will cause a fracture, but your head will have hardly moved from its original position.
It is at this point that the neck is most vulnerable. During the time that the neck is being
hyperextended or flexed (between 150-300 milliseconds) those initial peak forces are dis-
sipated making a neck fracture much less likely. The remaining energy is, however, sufficient
to cause muscular injury. This is illustrated in figures 16, 17 & 18.
– Graph of Force passing through a Cadaver when impacted on a soft surface.
Figure 16
(Source: R W Nightingale – ©1996 Reprinted with permission)
Direction of Fall
Forza non agente sul collo
4 msec - Contact
Figure 17 – Photograph of impact taken at 4 & 18 ms. (Source: Journal of Bone and Joint
Surgery (US) March 1996 Volume 78A – No3. © 1996 Reprinted with Permssion.)
32 msec - Flexion
Figure 18 – Photograph of impact taken at 32 & 90ms showing flexion & extension (NOR-
MAL range). (Source: Journal of Bone and Joint Surgery (US) March 1996 Volume 78A – No3.
© 1996 Reprinted with Permission.)
As part of a university experiment, Figure 16 shows the graph of the compressive force
through the neck when the head and neck of a cadaver (dead person) are impacted with
a simulated torso following. The compression causes the neck to buckle at 18ms which in
turn causes a catastrophic injury. In the photo at figure 17 you can see how distorted the
neck looks when the damage was caused - yet the head itself is completely straight. The
photographs in figure 18 then show the progression of the experiment. The head is moved
into flexion at 32ms and extension at 90ms but note how even though the movement at 90ms
looks substantial it is completely within the normal movement envelope (hence not termed
'hyperextension'). Looking at the Graph it is obvious that the force present is not related to
the angle the head moves because the force present reduces the more the head moves.
Instead it is the energy transferred at the point of impact which causes the damage.
Injury by Whiplash
The third key fact in off road motorcycling is that whiplash practically never happens. Whip-
lash occurs whereby the body is restrained but the head is free to move (like a passenger
in a car with a seatbelt). When you crash the seatbelt stops your body, but your head keeps
going. This can make your head move into hyperflexion – but without the impact spike il-
lustrated in figure 16. Under these circumstances it can be shown that products like the
Bionic Neck Support can reduce the peak torque (or bending) on the neck, and thus reduce
muscular injury – BUT – the risk of sustaining a catastrophic injury in whiplash is negligible
in motorcycling because the body is never restrained.
18 msec - Compression Injury
90 msec - Extension