Hartpury University Repository

Middlecote, Lucy

Chandler, Sharon

Cooper, Barbara

Mullineaux, Elizabeth

Turner, Lynn

Greet, Tim

Principles of General Nursing

Longhurst, Kelly

McDonald, Kirsty

RESULTS: 
Absolute angles of the upper arm expressed larger tendencies on the right (p≤0.001) indicating a more vertical upper arm position  
leading to a subsequent retraction of the hand. During motion the lower legs demonstrated significant asymmetries with larger  
angles on the left (p≤0.05) indicating a straighter limb. Significant differences were also seen between the two points of motion for  
the absolute angles on the right side for the trunk (p≤0.001) and thigh (p≤0.05), whereby angles increased during the highest point                                         
in the cycle. Together, these results suggest a rotational movement of the rider within which the left lower leg was positioned further forwards in relation to the 
right and the rider’s right shoulder and hip were posteriorly rotated in relation to the left. No significant correlations were observed between the asymmetry of 
joint angles and LLD (P≥0.05), however conclusions suggest that lateral dominance of the rider may be an influencing factor. absolute angle.  
  
  
Angle 
Frame 1  Frame 2 Frame 3 
P value 
Distribution  
P value 
Distribution  
P value 
Distribution  
L R L R L R 
Absolute Angles 
Upper arm 0.000 0 14 0.005 2 12 0.000 1 13 
Trunk 0.218 8 6 0.007 3 11 0.716 6 8 
Thigh 0.808 5 9 0.098 2 12 0.180 4 10 
Lower Leg 0.012 11 3 0.015 10 4 0.077 7 7 
Relative Angles 
Shoulder 0.234 11 3 0.022 12 2 0.069 5 9 
Elbow 0.920 7 7 0.856 6 8 0.117 11 3 
Hip 0.816 7 7 0.684 6 8 0.141 5 9 
Knee 0.136 8 6 0.515 7 7 0.603 6 8 
Contact author:  Kirsty.Lesniak@hartpury.ac.uk 
Centre for Performance in Equestrian Sports 
CONCLUSIONS: 
The present study suggests some commonly asymmetrical 
postures may be adopted by riders; the degree and type of 
asymmetry  observed appears to be exaggerated during motion of 
the mechanical horse. Typically, alterations in posture occur within 
the upper limbs of the rider through a greater retraction of the 
dominant upper limb. However, despite the theoretical basis, LLD’s 
did not show any significant correlation with the postural 
asymmetry observed, therefore the underlying cause of  the rider 
asymmetry requires further research. Potentially, as suggested by 
the results of this study, laterality factors should be considered as 
a predisposing factor. 
REFERENCES: 
Cocq, P., Clayton, H.M., Terada, K., Muller, M. and Leeuwen, J.L. (2009). Usability of normal 
force distribution measurements to evaluate asymmetrical loading of the back of the horse 
and different rider positions on a standing horse. The Veterinary Journal. 181, 266-273.   
Symes, D. and Ellis, R. (2009). A preliminary study into rider asymmetry within equitation. 
The Veterinary Journal. 181, 34-37.   
INDUSTRY APPLICATIONS:  
The study suggests that there are commonalities in rider posture faults. 
Awareness of these, and identification of predisposing factors could assist 
riders and trainers in developing compensatory strategies within training to 
enhance rider performance.  
Postural asymmetry of the rider  
whilst static and in sitting trot 
Longhurst, K. & McDonald, K.  
University of the West of England, Hartpury College, Gloucester, UK 
METHOD: 
Fifteen female riders, aged 18 to 22 years (21.5±0.71, mean body mass 67kg± 9.42kg, mean height 169.9cm± 5.5cm) all with a 
competitive record within a range of disciplines, and riding at least five times a week took part in the study. Although not a 
variable for this study, the handedness of the riders were recorded; all were right handed. Video analysis was used to measure 
eight joint angles of the upper limbs, lower limbs and trunk of the rider during the lowest (frame 1) and highest (frame 2) point of 
the simulated trot stride cycle within sitting trot, and also within the static position (frame 3) to quantify the effect of motion on 
the degree of asymmetry observed. Reflective markers were placed on the approximate instantaneous centre of rotation of the 
joint (Figure 1), to enable accurate calculation of the joint angles. Leg length discrepancies (LLD) were measured to identify 
correlations between LLD and angle discrepancies. Marker placement and LLD measurements were undertaken by a qualified 
physiotherapist to ensure accuracy. Two cameras situated perpendicularly to the axis of the mechanical horse captured the static 
and dynamic data. Dartfish Connect 5.5 was used to analyse the films. Related samples T-tests were used to established bilateral 
differences in joint angles and for differences between the angles in each of the three frames. Spearman rank correlation 
coefficient was used to determine if a relationship existed between LLD and the calculated difference of the left and right angles.  
Figure 1: Marker position 
INTRODUCTION: 
Results from a preliminary study by Symes and Ellis (2009) quantified asymmetry of the riders (n=17) and evaluated leg length 
discrepancies as a possible predisposing factor. However the study used a range of horses and the affect of the horses motion on 
the asymmetry observed was not established and a number of significant variables within the study were not controlled. The aims 
of this study were therefore to identify rider asymmetry, with fewer influencing variables, within a static position and during sitting 
trot and to establish any correlations with leg length discrepancies.  
Postural asymmetry is commonly seen in horse riders and can be associated with poor performance, however, the prevalence and 
manifestation of asymmetry has received minimal attention within literature and has yet to be quantified sufficiently. Kinetic 
research demonstrates that asymmetric positioning of the rider can significantly alter the forces acting on the horses back (Cocq et 
al 2009); however the affect on the horses kinematics has also yet to be quantified. Consequently, establishing both the 
manifestation and cause of rider asymmetry could act as a forerunner to understanding the influence on the horses kinematics and 
aid in improving rider performance. 
Figure 2: Mean left & right values for the absolute upper arm angle in frame 1 (lowest point of cycle (p=0.000) 
Table 1: Distribution of sides showing largest absolute & relative angles  


English

Postural asymmetry of the rider whilst static and in sitting trot

Kelly.longhurst@hartpury.ac.uk
Static and Dynamic Postural Asymmetry of the Rider
Kelly Longhurst  and Kirsty McDonald
Department of Equine Science, Hartpury College, University of the West of England, Gloucestershire.  
Introduction
Postural asymmetry is commonly seen in horse riders and can be associated with poor performance, however, the prevalence and manifestation of asymmetry has received minimal attention within literature and has 
yet to be quantified sufficiently. Kinetic research demonstrates that asymmetric positioning of the rider can significantly alter the forces acting on the horses back (Cocq et al 2009); however the affect on the horses 
kinematics has yet to be quantified. Consequently establishing both the manifestation and cause of rider asymmetry could act as a forerunner to understanding the influence on the horses kinematics and aid in 
improving rider performance. Preliminary results by Symes and Ellis (2009) quantified asymmetry of the riders (n=17) within their study and evaluated leg length discrepancies as a possible predisposing factor. 
However the affect of the horses motion on the asymmetry observed was not established and a number of variables within their study were not controlled. The aims of this study were therefore to evaluate 
asymmetry of the rider  within a static position and during sitting trot and to establish any correlations with leg length discrepancies.
Method
Fifteen female riders, aged 18 to 22 years (21.5±0.71, mean body mass 67kg± 9.42kg, mean height 169.9cm± 5.5cm) all with a competitive record within a range of disciplines, and riding 
at least five times a week took part in the study. Although not a variable for this study, the handedness of the riders were recorded; all subjects were right hand dominant. Video analysis 
was used to measure eight joint angles of the upper limbs, lower limbs and trunk of the rider during the highest and lowest point of the simulated stride cycle and also within the static 
position to quantify the effect of motion on the degree of asymmetry observed. Reflective markers were placed on the approximate instantaneous centre of rotation of the joint (Figure 1), to 
enable accurate calculation of the joint angles. Two cameras situated perpendicularly to the axis of the mechanical horse were used to capture both the static and dynamic data and leg 
length discrepancies (LLD) were also measured to identify correlations between LLD and angle discrepancies. Dartfish connect 5.5 was used to analyse the films and statistical analysis 
was carried out using SPSS Version 18.0. Related samples T-tests were used to established bilateral differences in joint angles and for differences between the angles in each of the three 
frames. A Spearman rank correlation coefficient was used to determine if a correlation existed between LLD and the calculated difference of the left and right angles. 
Results
Related samples T-tests performed for bilateral discrepancies identified very highly significant differences (p≤0.001) in 
the absolute angle of the upper arm, for all of the frames measured. Upper arm angles (angle 1) expressed larger 
tendencies on the right (as shown by figure 2) through a more vertical upper arm position and retraction of the hand. 
During motion the lower leg absolute angle was significantly different (p≤0.05) with larger left leg angles (angle 4) 
indicating a straighter limb. Significant differences were also seen between the two points of motion for the absolute 
angles on the right side for the trunk (p≤0.001) and thigh (p≤0.05), whereby angles increased during the highest point 
in the cycle. These results indicated rotational movement of the rider, within which the rider’s right shoulder and hip 
were posteriorly rotated in relation to the left. No significant correlations were observed between the asymmetry of 
joint angles and LLD (P≥0.05), however conclusions suggest that lateral dominance of the rider may be an influencing 
factor.   
Figure 2:  The mean left and right values for angle 1 in frame 1 (p = 0.000).
Conclusion
The present study suggests some commonly asymmetrical postures may be adopted by riders; the degree and type of asymmetry  
observed appears to be exaggerated during motion of the horse. Typically, alterations in posture occur within the upper limbs of the 
rider through a greater retraction of the dominant limb. However, as despite the theoretical basis, leg length discrepancies did not 
show any significant correlation with the postural asymmetry observed, therefore the underlying cause of  the rider asymmetry
requires further research. Potentially, as suggested by the results of this study lateral dominance should be considered as a potential    
predisposing factor.
Angle
Frame 1 (down) Frame 2 (up) Frame 3 (static)
P value
Angle  
greater
P value
Angle 
greater
P value
Angle 
greater
L R L R L R
1 0.000 0 14 0.005 2 12 0.000 1
1
3
2 0.218 8 6 0.007 3 11 0.716 6 8
3 0.808 5 9 0.098 2 12 0.180 4
1
0
4 0.012 11 3 0.015 10 4 0.077 7 7
5 0.234 11 3 0.022 12 2 0.069 5 9
6 0.920 7 7 0.856 6 8 0.117
1
1
3
7 0.816 7 7 0.684 6 8 0.141 5 9
8 0.136 8 6 0.515 7 7 0.603 6 8
Figure 1: Marker 
position
Table 1: Angle asymmetry P values 
References
Cocq, P., Clayton, H.M., Terada, K., Muller, M. and Leeuwen, J.L. (2009). Usability of normal force distribution measurements to
evaluate asymmetrical loading of the back of the horse and different rider positions on a standing horse. The Veterinary Journal. 181, 
266-273.  
Symes, D. and Ellis, R. (2009). A preliminary study into rider asymmetry within equitation. The Veterinary Journal. 181, 34-37.  


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