Medical and Biological Sciences XXVI/2 - Collegium Medicum ...

Intrarater repeatability of manual testing of first muscle movement resistance 29
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0
Mean and maximal values for Standard Error for measurement
0,31
0,55
Ankle Flexion (º)
0,33
0,75
Muscle lenght (mm)
Mean SE
Maximal SE
Fig. 4. Standard error for angular and linear movement –
average and maximal values
Another possibility of evaluation of the
examination method is standard error of mean. In this
case, because every test was conducted on different
sample, each could have had a different actual result,
there was no possibility to calculate standard error of
mean (SE) for whole methodology of measurement. So
in this paper, standard error was assessed for every test
separately, and then average and maximal outcome has
been calculated. These results of SE for both linear and
angular measurement are shown in Fig. 4.
It must be noted that results observed in Fig. 4,
actually very good, far below one millimeter and one
degree respectively for linear and angular movement,
could be considered only in discussion about
repeatability, not accuracy. The reason is the fact that
actual true values of spatial position of ankle or muscle
length while first mechanical resistance occurs were
unknown.
DISCUSSION
Manual testing of the muscles and joints is
considered as a major skill in testing and treating
musculoskeletal patients in many methods of manual
therapy [3, 5, 10, 12]. Ability to feel and differentiate
quality of movement, especially from its first
resistance to the end of passive range of movement is
considered crucial for testing in manual therapy [1, 2,
11]. In fact, this is what makes the difference between
manual therapy and physiotherapy in general.
Supporting the idea, the general assumption is made
that a therapist is able to gain ability to feel in recurrent
manner both first mechanical resistance and quality of
changes in elasticity of the movement. It is called end
feel or joint play examination, respectively for
physiological and additional movements [1, 3, 11].
Nevertheless, there is visible lack of research works
that confirm or deny that possibility among manual
therapist. One of the reason of the small amount of
research works in that subject is that described
phenomenon itself is very subtle and dependent on
many factors. It is very hard to assess in objective
manner when this first mechanical resistance occurs in
a living human being. Theoretically, first mechanical
resistance (or tissue resistance) of muscle occurs when
during passive movement myofibrils, fascia, tendon
and other part of muscle as a whole, reach its resting
length [8, 13, 14]. It is the moment from which
stretching of the muscle-tendon unit could occur. So,
physically, from that moment force needed to increase
muscle length and range of movement rises, dependent
on parameter called muscle stiffness [13, 18]. But it is
not easy to perform objective evaluation of that
moment on a living person, due to both technical
problems and great amount of factors influencing that
parameter. One of the technical problems is that
passive movement does not produce electric activity of
the muscles, so EMG is not valid for such examination
[13, 18].
The moment in which first resistance occurs is
dependent mainly on muscle tonus, so the first group
of factors influencing tissue resistance are
neurophysiologic factors, such as mood, emotions,
apprehension or reliance to therapist, but also spatial
position of other part of the body causing stress to the
nervous system – i.e. rotation in cervical spine
[2,8,10,19,20].
Other group of influencing factors is of mechanical
nature. The most prominent in this group seems to be
velocity of movement and number of repetition –
especially if a test movement exceeds moment of first
resistance [13, 14]. The importance of velocity is
associated with viscoelasticity, mechanical
characteristic of human soft tissues that is responsible
for different reactions of forces acting with different
speed, but also with physiologic protective reaction of
a muscle [8, 13, 18]. The high amount of repetition
could lead to a change of mechanical characteristic of
the muscles, moving point of first resistance further in
the range of movement [8, 10, 13]
Third group of factors could be named technical.
Inappropriate, uncomfortable position of both patient
and therapist could affect both muscle tonus and make
patient relaxation impossible. We also must not forget
that movement in which tissue resistance is assessed
must be passive. In clinical test, it is impossible to