Kinematic information was obtained at 350Hz via an eight camera gesture analysis system as participants ran at 4.0ms-1+5 % , angles were created utilizing the coiling method and about XYZ, ZXY, XZY, YXZ, YZX and YXZ rotary motion cardan sequences.
The consequences indicate that important scope of gesture chief effects were observed for the coronal and cross plane. Furthermore, it was besides observed that extremum angle chief effects were found for the coronal and cross planes. Post-hoc analyses revealed that ROM and extremum values utilizing the YXZ sequence and extremum values utilizing the ZXY sequence were significantly greater than the others.
A popular method of quantifying the angular place of a stiff dynamic frame with regard to a mention frame is via the use of independent angles known normally as cardan or Euler angles ( Schace et al. , 2001 ) . Cardan/Euler rotary motions are obtained by agencies of an order sequence of rotary motions ( Schace et al. , 2001 ) . Rotations are considered to happen about the axis of the section co-ordniate system. For illustration during an XYZ cardan sequence of rotary motions, the section is rotated about the X axes by an angle A, so rotates about a revolved Y ' by an angle B and so eventually rotated about a twice rotated Z '' axes by an angle C ( Scahce et al. , 2001 ) .
For a given gesture, different cardan sequences can act upon the angular computations ( Cole et al. , 1993 ) . The International Society of Biomechanics ( ISB ) recommends that joint angles be calculated utilizing an XYZ sequence of rotary motions ( Wu and Cavanagh 1995 ) . However, the big sum of sagittal plane gesture during pace can encroach on the representation of motions outside the sagittal plane ( transverse talk ) , ensuing in greater than expected coronal/transverse plane articulation profiles ( Thewlis et al. , 2008 ) . As such it has been proposed that the XYZ sequence when applied to rotary motions outside the sagittal plane may non be the most appropriate method.
A choice figure of probes have examined the influence that changing the sequence of rotary motions has on the representation of segmental kinematics ( Schace et al. , 2001, Kavaduna et al. , 2000, Tupling and Pierrynowski 1987 and Thewlis et al. , 2008 ) . However none of these probes have focused on the consequence that changing the sequence may hold on ankle joint kinematics.
In add-on to the normally used method of Cardan angles, coiling angles ( Woltring et al. , 1985 ) can besides be used to depict joint gesture when projected on to a plane. The coiling method from a mention place is described in footings of rotary motion about and interlingual rendition along a individual line or axis in infinite ( Robertson et al. , 2004 ) .
The ankle articulation plays a cardinal function in the stance stage pace rhythm. In combination with the hip and articulatio genus articulations the mortise joint facilitates motive power and transmits forces and minutes during the stance stage when the pes is regarded as the interface of the human locomotor system with the environment. Therefore, motion of the mortise joint is an of import constituent of pace mechanics and as such the right reading of its motion is indispensable in kinematic analyses. This survey investigated the influence of the coiling method every bit good as the 6 available cardan sequences on ankle joint kinematics in the sagittal, coronal and cross planes.
Method
Participants
Eleven male participants volunteered to take portion in this probe ( age 19 + 1 old ages ; Height 176.5 + 5.2 centimeter ; Mass 78.4 + 9.0 kilogram ) . All were injury free at the clip of informations aggregation and completed an informed consent signifier. Ethical blessing for this undertaking was obtained from the School of Psychology moralss commission, University of Central Lancashire and each participant provided verbal consent. A statistical power analysis of pilot informations was conducted in order to cut down the likeliness of a type II mistake and find the minimal figure participants needed for this probe. It was found that the sample size was sufficient to supply more than 70 % statistical power in the experimental step.
Procedure
An eight camera gesture analysis system ( Qualisys Medical AB, Goteburg, Sweden ) captured kinematic informations at 350Hz from each participant running at 4.0ms-1. Velocity was controlled utilizing infrared photoelectric cells Newtest 300 ( Newtest, Oy Koulukatu 31 B 11 90100 Oulu Finland ) , a maximal divergence of + 5 % from the in agreement speed was allowed. Participants ran over a force platform ( Kistler, Kistler Instruments Ltd. , Alton, Hampshire, UK ; Model 9281CA ) , stance clip was determined as the clip over which 20N or greater of perpendicular force was applied to the force platform.
The marker set used for the survey was based on the CAST technique ( Cappozo et al. , ( 1995 ) . Retro-reflective markers were attached to the 1st and 5th metatarsal caputs, median and sidelong maleoli, median and sidelong epicondyle of the thighbone, with a tracking bunch positioned on the right shank. A inactive test was captured to specify the pes and tibial sections. Kinematic parametric quantities were quantified utilizing Ocular 3-D ( C-Motion Inc, Gaithersburg, USA ) and filtered utilizing at 6 Hz utilizing a zero-lag low base on balls Butterworth 4th order filter following insertion with a maximal spread fill of 10 frames. Five tests of ankle joint rotary motion during stance were averaged for each participant. Angles were created about an XYZ, ZXY, XZY, YXZ, YZX and YXZ rotary motion cardan sequence referenced to organize systems about the proximal terminal of the section, where Ten is flexion-extension ; Y is ab-adduction and is Z is internal-external rotary motion.
Statistical Analysis
Descriptive statistics including agencies and standard divergences were calculated for each status. Differences in stance stage kinematic variables were examined utilizing perennial steps ANOVA 's with significance accepted at the P & A ; lt ; 0.05 degree. The Mauchly 's sphericalness premise was violated in all instances and as such the grades of freedom of the F statistic were adjusted via the Greenhouse Geisser rectification. The Shapiro-wilk statistic for each status confirmed that the informations were usually distributed. Appropriate post-hoc analyses were conducted utilizing a Bonferroni rectification to command for type I error. Effect sizes were calculated utilizing an Eta2. Cohen 's suggestion sing effects sizes was observed ( little R & A ; lt ; 0.3 ; medium R & A ; gt ; 0.3 and & A ; lt ; 0.5 ; big & A ; gt ; 0.5. All statistical processs were conducted utilizing SPSS 17.0.
Consequence
Tables 1 and 2 present scopes of gesture and peak angles observed in all three planes of rotary motion as a map of cardan sequence.
Table1: Mean ( and standard divergence ) scope of gesture ( deg ) for each rotary motion as a map of cardan sequence ( * = important chief consequence ) n=11.
Ten
Yttrium
Omega
XYZ
27.94 + 10.34
5.62 + 3.86
4.67 + 3,21
XZY
26.75 + 11.35
5.29 + 5.13
5.88 + 4.52
YXZ
25.67 + 11.45
17.04 + 11.95
15.22 + 10.45
YZX
26.51 + 11.37
6.86 + 5.83
4.08 + 2.04
ZXY
26.38 + 10.12
15.96 + 27.51
28.78 + 11.73
ZYX
24.52 + 12.17
6.16 + 6.47
4.09 + 2.17
Coiling
25.45+8.64
5.26 + 6233
5.08 + 2.72
Main Effect
*
*
Table 2: Mean ( and standard divergence extremum values ) ( deg ) for each rotary motion as a map of cardan sequence ( * = important chief consequence ) n=11.
Ten
Yttrium
Omega
XYZ
-87.65 + 3.83
-11.04 + 5.48
-2.14 + 4.53
XZY
-87.70 + 3.57
-11.15 + 5.46
0.21 + 4.78
YXZ
-84.07 + 5.05
-68.25 + 24.29
-71.01 + 20.91
YZX
-87.64 + 3.68
1.00 + 4.97
-11.71 + 4.80
ZXY
-87.7 + 3.66
1.07 + 20.47
-1.42 + 13.41
ZYX
-84.6 + 3.75
-3.18 + 4.88
-11.78 + 4.81
Coiling
-87.75 + 2.40
-7.40 + 7.68
-11.91 + 3.27
Main Effect
*
*
The consequences indicate that important scope of gesture chief effects were observed for the coronal F ( 1.85, 16.66 ) = 10.04, P & A ; lt ; 0.05, eta2= 0.53 and cross plane F ( 2.04, 18.39 ) =21.91, P & A ; lt ; 0.05, eta2=0.71. Post-hoc analyses revealed that both coronal and cross plane ROM utilizing the YXZ and ZXY sequences was significantly greater than the others. Furthermore, it was besides observed that extremum angle chief effects were found for the coronal F ( 2.28, 20.48 ) = 82.99, P & A ; lt ; 0.05, eta2=0.90 and transverse planes F ( 2.08, 18.72 ) = 80.49, P & A ; lt ; 0.05, eta2= 0.90. Post-hoc analyses revealed that peak coronal and cross plane angles utilizing the YXZ sequence were significantly greater than the others.
Figure 1: Ankle joint kinematics in the sagittal, coronal and cross planes as a map of cardan sequence ( XYZ= black, XZY= red, YXZ=yellow, YZX=blue, ZXY= cyan, ZYX=green and Helical =purple.
Discussion
Euler/Cardan angles are used extensively within the Fieldss of clinical and sport biomechanics. However, the consequence of changing the sequence of rotary motions has yet to be investigated with regard to the ankle articulation composite.
The consequences indicate that changing the sequence of rotary motions when detecting kinematics in the sagittal plane has no important affect on joint scope of gesture parametric quantities. This is unsurprising given the laterality of sagittal plane gesture at the mortise joint during pace. Leading to the decision that choosing the appropriate sequence of rotary motions is non an issue when look intoing kinematics in the sagittal plane.
However, for the coronal and cross planes a important consequence was found in footings of both the scope of gesture and peak angle observed during the stance stage. The consequences of this survey with regard to the mortise joint articulation found that the ZXY and YXZ sequences significantly affected ankle joint kinematics bring forthing highly big values for both scope of gesture and peak angles. The mistake associated with these sequences is such that the kinematic estimations are anatomically unrealistic. It is interesting to observe that the two combinations which were observed to be significantly different from the others ( YXZ and ZXY ) each had X 2nd in the order of rotary motions. This was the instance even when the principal axis under probe is placed foremost ( i.e. ZXY when detecting transverse plane rotary motion and YXZ when detecting coronal plane rotary motion ) , where one would presume that the comparative orientation could non be affected by the grade of sagittal plane gesture holding been placed after it in the sequence.
It appears based on these consequences that the ISB recommendations are appropriate for the representation of ankle joint kinematics and as such its usage is encouraged, as it will let comparing of future research trying to quantify ankle joint gesture performed by different research workers. In add-on the consequences suggest that the YXZ and ZXY sequences produce the greatest mistake and therefore the use of these sequences to quantify ankle gesture outside the sagittal plane is strongly discouraged. This survey emphasizes the demand for methods leting joint kinematics to be measured accurately. Therefore, guaranting joint map is represented right.
