<s>
An	O
ergonomic	B-Device
keyboard	I-Device
is	O
a	O
computer	B-Device
keyboard	I-Device
designed	O
with	O
ergonomic	O
considerations	O
to	O
minimize	O
muscle	O
strain	O
,	O
fatigue	O
,	O
and	O
other	O
problems	O
.	O
</s>
<s>
The	O
common	O
QWERTY	O
keyboard	B-Device
layout	O
is	O
credited	O
to	O
the	O
mechanical	O
typewriter	O
designed	O
by	O
C	O
.	O
Latham	O
Sholes	O
and	O
patented	O
in	O
1878	O
;	O
research	O
indicates	O
the	O
layout	O
may	O
have	O
been	O
influenced	O
by	O
telegraph	O
operators	O
.	O
</s>
<s>
In	O
general	O
,	O
ergonomic	B-Device
keyboards	I-Device
are	O
designed	O
to	O
minimize	O
awkward	O
user	O
wrist	O
positions	O
and	O
finger	O
motions	O
by	O
rearranging	O
and/or	O
repositioning	O
the	O
keys	O
.	O
</s>
<s>
For	O
instance	O
,	O
typing	O
on	O
a	O
conventional	O
keyboard	B-Device
layout	O
can	O
force	O
the	O
user	O
into	O
shoulder	O
elevation	O
,	O
wrist	O
ulnar	O
deviation	O
,	O
and	O
head	O
rotation	O
.	O
</s>
<s>
Consideration	O
of	O
physical	O
ergonomics	O
suggests	O
the	O
most	O
relaxed	O
typing	O
position	O
is	O
one	O
in	O
which	O
the	O
keyboard	B-Device
user	O
's	O
forearms	O
are	O
parallel	O
to	O
the	O
ground	O
,	O
with	O
wrists	O
held	O
straight	O
.	O
</s>
<s>
A	O
more	O
detailed	O
study	O
was	O
published	O
in	O
1972	O
by	O
Kroemer	O
,	O
suggesting	O
that	O
an	O
adjustable	O
split	O
keyboard	B-Device
may	O
reduce	O
user	O
pain	O
.	O
</s>
<s>
Split	O
keyboards	B-Device
group	O
keys	O
into	O
two	O
or	O
more	O
sections	O
.	O
</s>
<s>
By	O
separating	O
the	O
keyboard	B-Device
,	O
split	O
keyboards	B-Device
typically	O
change	O
the	O
angles	O
and	O
the	O
distance	O
between	O
each	O
section	O
to	O
ensure	O
the	O
user	O
's	O
wrists	O
remain	O
straight	O
.	O
</s>
<s>
This	O
can	O
be	O
imagined	O
as	O
the	O
angle	O
of	O
rotation	O
around	O
an	O
imaginary	O
vertical	O
axis	O
drawn	O
through	O
the	O
and	O
keys	O
of	O
a	O
QWERTY	O
keyboard	B-Device
.	O
</s>
<s>
Because	O
most	O
shoulders	O
are	O
wider	O
than	O
the	O
hand	O
position	O
when	O
placed	O
on	O
the	O
home	O
row	O
,	O
when	O
using	O
a	O
conventional	O
keyboard	B-Device
,	O
the	O
resulting	O
slight	O
shoulder	O
adduction	O
points	O
the	O
forearms	O
inwards	O
and	O
requires	O
the	O
wrists	O
to	O
be	O
bent	O
out	O
to	O
position	O
the	O
fingers	O
.	O
</s>
<s>
the	O
slope	O
or	O
tilt	O
angle	O
,	O
which	O
refers	O
to	O
the	O
front-to-back	O
angle	O
made	O
between	O
the	O
plane	O
of	O
the	O
keyboard	B-Device
and	O
the	O
supporting	O
surface	O
.	O
</s>
<s>
This	O
is	O
the	O
angle	O
of	O
rotation	O
around	O
an	O
imaginary	O
horizontal	O
axis	O
drawn	O
through	O
the	O
top	O
of	O
the	O
home	O
row	O
(	O
/	O
keys	O
)	O
,	O
i.e.	O
,	O
from	O
the	O
left	O
edge	O
to	O
the	O
right	O
edge	O
of	O
the	O
keyboard	B-Device
.	O
</s>
<s>
Conventional	O
keyboards	B-Device
include	O
feet	O
that	O
can	O
be	O
deployed	O
under	O
the	O
top	O
of	O
the	O
keyboard	B-Device
,	O
which	O
generates	O
a	O
positive	O
slope	O
:	O
the	O
topmost	O
rows	O
(	O
–	O
function	O
keys	O
)	O
are	O
higher	O
than	O
the	O
bottom	O
rows	O
(	O
)	O
,	O
which	O
would	O
require	O
the	O
user	O
to	O
tilt	O
their	O
wrists	O
up	O
.	O
</s>
<s>
Ergonomic	B-Device
keyboards	I-Device
may	O
use	O
a	O
riser	O
under	O
the	O
front	O
to	O
create	O
a	O
neutral	O
or	O
negative	O
slope	O
instead	O
.	O
</s>
<s>
the	O
lateral	O
inclination	O
,	O
also	O
known	O
as	O
the	O
gable	O
or	O
tenting	O
angle	O
,	O
which	O
refers	O
to	O
the	O
left-to-right	O
angle	O
between	O
the	O
plane	O
of	O
each	O
half	O
with	O
the	O
supporting	O
surface	O
;	O
typically	O
this	O
means	O
the	O
center	O
of	O
the	O
keyboard	B-Device
(	O
inside	O
edge	O
of	O
each	O
half	O
)	O
is	O
elevated	O
compared	O
to	O
the	O
outside	O
edge	O
.	O
</s>
<s>
This	O
is	O
the	O
angle	O
of	O
rotation	O
around	O
an	O
imaginary	O
horizontal	O
axis	O
drawn	O
from	O
the	O
top	O
center	O
(	O
between	O
the	O
and	O
keys	O
)	O
to	O
bottom	O
center	O
(	O
middle	O
of	O
the	O
bar	O
)	O
of	O
the	O
keyboard	B-Device
.	O
</s>
<s>
A	O
conventional	O
keyboard	B-Device
requires	O
the	O
wrists	O
to	O
be	O
rotated	O
inwards	O
to	O
bring	O
the	O
hands	O
flat	O
.	O
</s>
<s>
The	O
distance	O
between	O
the	O
sections	O
usually	O
is	O
selected	O
to	O
reduce	O
or	O
eliminate	O
the	O
shoulder	O
adduction	O
that	O
brings	O
the	O
user	O
's	O
hands	O
toward	O
the	O
center	O
of	O
the	O
keyboard	B-Device
,	O
which	O
on	O
conventional	O
keyboards	B-Device
with	O
no	O
opening	O
angle	O
can	O
also	O
result	O
in	O
an	O
awkward	O
wrist	O
angle	O
.	O
</s>
<s>
Ergonomic	O
split	O
keyboards	B-Device
can	O
be	O
fixed	O
,	O
where	O
the	O
user	O
cannot	O
change	O
the	O
relative	O
angles	O
and	O
distance	O
between	O
the	O
sections	O
,	O
or	O
adjustable	O
,	O
which	O
usually	O
has	O
two	O
independent	O
modules	O
that	O
allow	O
these	O
to	O
be	O
tailored	O
exactly	O
to	O
the	O
user	O
.	O
</s>
<s>
Fixed	O
split	O
keyboards	B-Device
are	O
necessarily	O
designed	O
to	O
accommodate	O
a	O
wide	O
range	O
of	O
users	O
,	O
and	O
can	O
be	O
set	O
up	O
rapidly	O
to	O
replicate	O
a	O
similar	O
interface	O
in	O
different	O
settings	O
,	O
but	O
may	O
not	O
fit	O
a	O
specific	O
user	O
exactly	O
.	O
</s>
<s>
For	O
example	O
,	O
people	O
with	O
broad	O
shoulders	O
may	O
benefit	O
from	O
an	O
adjustable	O
split	O
keyboard	B-Device
's	O
ability	O
to	O
customize	O
the	O
distance	O
between	O
the	O
two	O
halves	O
of	O
the	O
keyboard	B-Device
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
adjustable	O
split	O
keyboards	B-Device
sometimes	O
intimidate	O
potential	O
users	O
,	O
who	O
may	O
fear	O
they	O
may	O
exacerbate	O
or	O
become	O
more	O
susceptible	O
to	O
repetitive	O
strain	O
injuries	O
;	O
fixed	O
split	O
keyboards	B-Device
like	O
the	O
Microsoft	B-Device
Natural	I-Device
have	O
sold	O
well	O
in	O
comparison	O
.	O
</s>
<s>
The	O
angled	O
split	O
keyboard	B-Device
(	O
sometimes	O
referred	O
to	O
as	O
a	O
Klockenburg	O
keyboard	B-Device
)	O
is	O
similar	O
to	O
a	O
split	O
keyboard	B-Device
,	O
but	O
the	O
middle	O
is	O
tented	O
up	O
so	O
that	O
the	O
index	O
fingers	O
are	O
higher	O
than	O
the	O
little	O
fingers	O
while	O
typing	O
.	O
</s>
<s>
Key	O
Ovation	O
makes	O
the	O
Goldtouch	O
ergonomic	B-Device
keyboard	I-Device
which	O
is	O
an	O
adjustable	O
angled	O
split	O
keyboard	B-Device
.	O
</s>
<s>
On	O
some	O
ergonomic	B-Device
keyboards	I-Device
,	O
the	O
tenting	O
angle	O
is	O
increased	O
to	O
90°	O
so	O
the	O
user	O
types	O
with	O
their	O
hands	O
perpendicular	O
to	O
the	O
ground	O
,	O
thumbs-up	O
,	O
similar	O
to	O
the	O
hand	O
position	O
adopted	O
by	O
accordion	O
players	O
.	O
</s>
<s>
Because	O
electric	O
typewriters	O
and	O
computer	B-Device
keyboards	I-Device
no	O
longer	O
need	O
to	O
accommodate	O
a	O
mechanical	O
linkage	O
,	O
the	O
keys	O
can	O
be	O
set	O
in	O
vertical	O
columns	O
without	O
staggering	O
,	O
minimizing	O
lateral	O
finger	O
movements	O
when	O
moving	O
between	O
rows	O
.	O
</s>
<s>
A	O
keyboard	B-Device
with	O
vertical	O
columns	O
can	O
require	O
an	O
adjustment	O
period	O
as	O
the	O
user	O
retrains	O
their	O
finger	O
movements	O
.	O
</s>
<s>
Some	O
keyboards	B-Device
combine	O
a	O
split	O
design	O
with	O
vertical	O
or	O
semi-vertical	O
columns	O
.	O
</s>
<s>
Examples	O
include	O
the	O
"	O
Truly	O
Ergonomic	O
"	O
(	O
fixed	O
split	O
,	O
staggered	O
rows	O
)	O
,	O
ErgoDox	O
(	O
adjustable	O
split	O
,	O
staggered	O
rows	O
)	O
,	O
ZSA	O
Moonlander	O
,	O
and	O
Zergotech	O
Freedom	O
(	O
adjustable	O
split	O
,	O
semi-staggered	O
rows	O
)	O
keyboards	B-Device
.	O
</s>
<s>
The	O
preceding	O
split	O
and	O
vertical	O
column	O
keyboards	B-Device
arranged	O
each	O
key	O
cluster	O
onto	O
a	O
single	O
flat	O
plane	O
.	O
</s>
<s>
Contoured	O
-	O
or	O
dished-surface	O
keyboards	B-Device
like	O
the	O
Maltron	O
(	O
1977	O
)	O
or	O
the	O
newer	O
Kinesis	B-Device
Advantage	O
line	O
(	O
1992+	O
)	O
are	O
fixed	O
split	O
keyboards	B-Device
with	O
tenting	O
that	O
place	O
the	O
keys	O
into	O
two	O
curved	O
depressions	O
set	O
approximately	O
at	O
shoulder	O
width	O
.	O
</s>
<s>
For	O
these	O
keyboards	B-Device
,	O
the	O
resulting	O
bowl-like	O
key	O
surfaces	O
are	O
intended	O
to	O
minimize	O
and	O
make	O
consistent	O
the	O
finger	O
extension	O
required	O
to	O
strike	O
keys	O
away	O
from	O
the	O
home	O
row	O
.	O
</s>
<s>
In	O
general	O
,	O
contoured	O
keyboards	B-Device
also	O
incorporate	O
a	O
vertical	O
column	O
layout	O
with	O
staggered	O
rows	O
for	O
each	O
hand	O
.	O
</s>
<s>
Some	O
keyboards	B-Device
combine	O
vertical	O
key	O
columns	O
and	O
contoured	O
surfaces	O
with	O
fully-adjustable	O
(	O
independent	O
)	O
split	O
key	O
clusters	O
.	O
</s>
<s>
Examples	O
include	O
the	O
Kinesis	B-Device
Advantage	O
360	O
,	O
Dactyl	O
Manuform	O
,	O
and	O
MoErgo	O
Glove80	O
.	O
</s>
<s>
Handheld	O
ergonomic	B-Device
keyboards	I-Device
are	O
designed	O
to	O
be	O
held	O
like	O
a	O
game	O
controller	O
,	O
and	O
can	O
be	O
used	O
as	O
such	O
,	O
instead	O
of	O
laid	O
out	O
flat	O
on	O
top	O
of	O
a	O
table	O
surface	O
.	O
</s>
<s>
Some	O
variations	O
of	O
handheld	O
ergonomic	B-Device
keyboards	I-Device
also	O
include	O
a	O
trackball	O
mouse	O
that	O
allow	O
mouse	O
movement	O
and	O
typing	O
included	O
in	O
one	O
handheld	O
device	O
.	O
</s>
<s>
A	O
few	O
ergonomic	B-Device
keyboards	I-Device
do	O
not	O
have	O
the	O
typical	O
one	O
key	O
per	O
letter	O
,	O
such	O
as	O
a	O
keyer	B-Device
or	O
a	O
keyless	O
ergonomic	B-Device
keyboard	I-Device
.	O
</s>
<s>
Advances	O
in	O
speech	B-Application
recognition	I-Application
have	O
made	O
it	O
possible	O
to	O
eliminate	O
the	O
use	O
of	O
a	O
keyboard	B-Device
altogether	O
,	O
particularly	O
on	O
smaller	O
devices	O
that	O
lack	O
traditional	O
keyboard	B-Device
interfaces	O
.	O
</s>
<s>
It	O
is	O
widely	O
claimed	O
that	O
an	O
ergonomic	B-Device
keyboard	I-Device
may	O
reduce	O
muscle	O
strain	O
and	O
reduce	O
risk	O
of	O
carpal	O
tunnel	O
syndrome	O
or	O
other	O
kinds	O
of	O
repetitive	O
strain	O
injury	O
.	O
</s>
<s>
With	O
respect	O
to	O
"	O
split	O
"	O
keyboards	B-Device
,	O
quality	O
studies	O
that	O
demonstrate	O
injury	O
reductions	O
are	O
lacking	O
,	O
with	O
the	O
exception	O
of	O
physically	O
split	O
keyboards	B-Device
which	O
have	O
"	O
sharply	O
angled	O
keyboard	B-Device
faces	O
"	O
.	O
</s>
<s>
There	O
is	O
evidence	O
,	O
however	O
,	O
that	O
such	O
keyboards	B-Device
are	O
not	O
well	O
tolerated	O
.	O
</s>
<s>
For	O
example	O
,	O
one	O
should	O
be	O
aware	O
that	O
the	O
effect	O
of	O
“	O
ergonomic	O
”	O
keyboards	B-Device
is	O
to	O
change	O
the	O
musculoskeletal	O
region	O
exposed	O
to	O
risk	O
,	O
instead	O
of	O
eliminating	O
hazardous	O
postures	O
.	O
</s>
