PubMed Health⌕ Search

Biomedical subjects

M Scheidl

Publications and source records attributed to M Scheidl.

14 recordsLinked to original sources
PubMed2004

Evaluation of pressure distribution under an English saddle at walk, trot and canter.

REASONS FOR PERFORMING STUDY: Basic information about the influence of a rider on the equine back is currently lacking. HYPOTHESIS: That pressure distribution under a saddle is different between the walk, trot and canter. METHODS: Twelve horses without clinical signs of back pain were ridden. At least 6 motion cycles at walk, trot and canter were measured kinematically. Using a saddle pad, the pressure distribution was recorded. The maximum overall force (MOF) and centre of pressure (COP) were calculated. The range of back movement was determined from a marker placed on the withers. RESULTS: MOF and COP showed a consistent time pattern in each gait. MOF was 12.1 +/- 1.2 and 243 +/- 4.6 N/kg at walk and trot, respectively, in the ridden horse. In the unridden horse MOF was 172.7 +/- 11.8 N (walk) and 302.4 +/- 33.9 N (trot). At ridden canter, MOF was 27.2 +/- 4.4 N/kg. The range of motion of the back of the ridden horse was significantly lower compared to the unridden, saddled horse. CONCLUSIONS AND POTENTIAL RELEVANCE: Analyses may help quantitative and objective evaluation of the interaction between rider and horse as mediated through the saddle. The information presented is therefore of importance to riders, saddlers and equine clinicians. With the technique used in this study, style, skill and training level of different riders can be quantified, which would give the opportunity to detect potentially harmful influences and create opportunities for improvement.

Animals↗
PubMed2001

The influence of lameness on equine stride length consistency.

The aim of this study was to assess the influence of orthopaedic pain on the variation of stride length as a kinematic system-parameter in 21 horses with forelimb lameness. Data were collected while the horses were trotting on a treadmill during a minimum of 12 motion cycles, both before and after intra-articular or perineural anaesthesia. Stride length was assessed for each motion cycle, and the mean and standard deviation were calculated for each condition. Forelimb lameness was documented as percentage of asymmetry of vertical head movement. With significant decrease of forelimb lameness after regional anaesthesia, the SD of stride length increased significantly (+0.35%, P< 0.05). Our results show that in the presence of orthopaedic pain horses keep stride variability low, possibly because the lame horse employs an optimum compensatory mechanism to reduce the pain in the affected limb, and every deviation from this pattern increases pain.

Animals↗
PubMed2001

Motion pattern of the toelt of Icelandic horses at different speeds.

The toelt of the Icelandic horse is a symmetric 4-beat gait, with alternating single and double support phases. By definition, the duration of the diagonal and ipsilateral stance phases should be similar. The aim of this study was to investigate the stride characteristics of horses ridden at toelt, and to compare these to previous descriptions of this gait. The kinematics of 23 Icelandic horses was measured using the Expert Vision System. Mature and sound horses, used for pleasure riding and/or competitions, were ridden at toelt at 3 different speeds. For each horse, 10 strides were measured at toelting speeds of 2.9 m/s (s.d. 0.28), 3.7 m/s (s.d. 0.29) and 4.7 m/s (s.d. 0.53). Seven horses showed true toelt pattern at one or 2 speeds. At the highest speed, 60% of all motion cycles showed the pattern of 4-beat pace. This investigation shows that the previously described toelt pattern is present only over a narrow speed range, and toelt at extended speed is, in fact, a 4-beat pace or rarely a 4-beat trot.

Animals↗
PubMed2001

Body centre of mass movement in the lame horse.

The body centre of mass (BCM) is a key factor in the analysis of equine gait, as its position and movement determines the distribution and magnitude of loads on the limbs. Changes in the BCM movement are proposed to be important factors in the lameness management of horses. In this study, changes in the position and the 3-dimensional (3-D) movement of the BCM in horses with induced forelimb lameness were studied using a kinematic, segmental method. The kinematics of 30 markers representing 20 body segments were recorded in 12 horses while trotting (3.9 m/s) on a treadmill using a high speed video system. A transient lameness model, evoking pressure-induced pain on the hoof sole, was used to induce 2 degrees of forelimb lameness. Based on segmental inertial data from Buchner et al, (1997) 3-D segmental centres of mass as well as the BCM were calculated. The changes in BCM movement due to lameness and the influence of selected segments on the total centre of mass were analysed. During moderate forelimb lameness, vertical displacement of the BCM showed a 34% reduced amplitude during the stance phase of the lame limb and a 9% increased amplitude during the stance phase of the sound forelimb. In the sagittal direction, the BCM during midstance moved 9 mm backwards during the stance phase of the lame forelimb. Transversal movements showed a slight, but significant shift of the BCM to the side of the sound forelimb. Head/neck segment movement changed in a sagittal as well as in a vertical direction, but only a small amount, insufficient for considerable BCM position changes. The results show a similar pattern of BCM and trunk movement and only small adaptations of BCM position due to lameness. The influence of the sagittal position of the BCM has to be seen as a minor factor in lameness management compared to the dynamic influences of a changed vertical BCM movement and the moment caused by the typical head and neck movement.

Adaptation, Physiological↗
PubMed2001

Evaluation of the EMG activity of the long back muscle during induced back movements at stance.

In this study we investigated the activity of the main back muscle (Musculus longissimus) by surface electromyography (EMG) during induced extension and lateral flexion at stance. Measurements were taken of 15 horses (age 5-20 years, 450-700 kg bwt) without signs of back pain. Reflecting markers were placed on the head, spinous processes of T5, T12, T16, L3 and on 2 of the sacral bones. The surface EMG electrodes were situated on the Musculus longissimus on both sides of the dorsal spinous processes of T12, T16 and L3. In all horses and all movements (extension, lateral flexion to the left and right), the EMG on both sides of the dorsal spinous process of T12 had the highest, and the EMG on both sides of the spinous process of L3, the lowest amplitude (30% of T12). At T16 the amplitude of the EMG signal was 60% of that at T12. There was no time shift between the EMG signals at the different locations (T12, T16, L3). There was a very high correlation between motion and amplitude of the EMG signal of extension, with correlation coefficients of 0.78 at L3, 0.80 at T16 and 0.75 at T12. The correlation of the lateral flexion between amplitude of the EMG and motion was lower, with 0.38 at L3, 0.43 at T16 and 0.39 at T12. This investigation showed that the EMG of the Musculus longissimus during spinal reflexes should be derived on both sides of T12, because this is important for the clinical use of surface EMG.

Animals↗
PubMed2001

Evaluation of a signal-adapted filter for processing of periodic electromyography signals in horses walking on a treadmill.

OBJECTIVE: To evaluate an adaptive-filter method for use in analysis of periodic electromyography (EMG) signals in which the transfer function of the filter is matched to characteristics of the signal. ANIMALS: 15 adult horses without clinical signs of back pain. PROCEDURE: Electromyography signals of the left and right longissimus dorsi muscles, middle gluteal muscles, and triceps brachii muscle were recorded from horses walking on a treadmill, using bilaterally placed surface electrodes. A reflective marker was placed on the hoof of the left hind limb for simultaneous kinematic measurement of motion cycles. Absolute value of the measured EMG signal was convoluted by use of a filter signal equivalent to the length of 3 motion cycles. The signal-to-noise ratio (SNR) was calculated from the autocorrelation function and compared with the SNR of the unfiltered and the low-pass filtered signals. RESULTS: The signal-adapted filter significantly increased SNR (by 7.3 dB, compared with the low-pass filter, and by 11.1 dB, compared with the unfiltered EMG signal). CONCLUSIONS AND CLINICAL RELEVANCE: The signal-adapted filter eliminates signal parts that are not correlated to periodic motion. The method reported here improves the applicability of periodic EMG signals as a clinical tool.

Animals↗
PubMed2000

Individual speed dependency of forelimb lameness in trotting horses.

Using a system for motion analysis, linear correlation of speed and forelimb lameness was measured in 16 horses trotting on a treadmill at a minimum of three different trotting speeds. Forelimb lameness was determined as asymmetry of vertical head motion during left and right forelimb stance. In seven horses with a moderate forelimb lameness (head motion asymmetry >40%), lameness increased significantly with trotting speed. In a further seven horses with mild or subclinical forelimb lameness (head motion asymmetry <40%) and in two horses with a moderate forelimb lameness, no significant correlation between speed and motion asymmetry was found. The results indicate that moderate forelimb lameness measured as head motion asymmetry depends on the speed at which the measurements are taken. If head motion asymmetry is measured at two trotting speeds, it can be standardized to any speed within the trotting speed range.

Animals↗
PubMed2000

Body centre of mass movement in the sound horse.

The body centre of mass (BCM) is a key factor in the analysis of equine locomotion, as its position and movement determines the distribution and magnitude of loads on the limbs. In this study, the three-dimensional (3D) movement of the BCM in walking and trotting horses was assessed using a kinematic, segmental method. Thirty markers representing 20 body segments were recorded in 12 sound horses while standing, walking and trotting on a treadmill using a high-speed video system. Based on segmental inertial data, 3D positions of the segmental centres of mass as well as the total BCM were calculated. The position within the trunk during square standing and the movements of the BCM were determined for the three planes. The position of the BCM in the standing horse is presented relative to external reference points. At the trot, vertical displacement amplitude of the BCM amounted to 53 (6) mm as mean (sd), which was 27% smaller than external trunk movement. Medio-lateral displacement amplitude of the BCM was 19 (4) mm, 34% less than trunk amplitude. Sagittal forward-backward oscillations of the BCM independent from general forward movement were 13 (3) mm, being 24% less than trunk movements. At the walk, vertical, medio-lateral and sagittal BCM movements were smaller than trunk movements by 43, 65 and 65% respectively. The results show reduced and efficient BCM movements compared to the trunk and form a basis for the assessment of various clinical conditions such as lameness, the influence of a rider and various dressage performances.

Animals↗
PubMed1999

Limb locomotion--speed distribution analysis as a new method for stance phase detection.

The stance phase is used for the determination of many parameters in motion analysis. In this technical note the authors present a new kinematical method for determination of stance phase. From the high-speed video data, the speed distribution of the horizontal motion of the distal limb is calculated. The speed with the maximum occurrence within the motion cycle defines the stance phase, and this speed is used as threshold for beginning and end of the stance phase. In seven horses the results obtained with the presented method were compared to synchronous stance phase determination using a force plate integrated in a hard track. The mean difference between the results was 10.8 ms, equalling 1.44% of mean stance phase duration. As a test, the presented method was applied to a horse trotting on the treadmill, and to a human walking on concrete. This article describes an easy and safe method for stance phase determination in continuous kinematic data and proves the reliability of the method by comparing it to kinetic stance phase detection. This method may be applied in several species and all gaits, on the treadmill and on firm ground.

Animals↗
PubMed1999

Supporting forelimb lameness: clinical judgement vs. computerised symmetry measurement.

The aim of this study was to compare supporting forelimb lameness determined by a motion analysis system with the subjective grading of a trained equine orthopaedic surgeon. Trotting on a treadmill, 29 individuals with a supporting forelimb lameness were measured with the SELSPOT II system and judged by the clinician. The vertical motion of the head was measured, analysed using Fourier transform, and the percentages of symmetry determined. The veterinarian evaluated the lameness and graded it according to a clinical routine. Veterinarian and system for motion analysis assigned the lameness to the same leg in all cases, but the grading of the lameness differed in 6 out of 29 cases. The results of this study indicate that motion analysis can be used as an informative tool supporting the subjective veterinary judgement.

Animals↗
PubMed1998

Speed dependency of motion pattern consistency.

Treadmills are widely used in equine motion analysis. For the evaluation of the trot of a horse, a trotting speed with low variation between motion cycles is necessary to make the measurements reproducible. The aim of this study is to show how an individual 'optimum' trotting speed for lameness quantification can be determined. In this study, the stability of a horse's gait pattern was evaluated by calculating the standard deviation (S.D.) of motion-cycle speed (MCS). In trot, eighteen horses were analysed at several speeds. The measurements were taken with the ExpertVision System (Motion Analysis Corporation) every 3 km h(-1) (= 0.83 m s(-1)), from the lowest to the highest individual trotting speed. At the different speeds the S.D. of MCS and the asymmetry of the vertical head motion were compared. At the speed where standard deviation was minimum, motion asymmetry was maximum. In twelve horses this optimum speed was situated in the middle of the individual trotting speed range, and in six horses the optimum speed was the maximum speed. The method presented in this study allows the determination of an optimum trotting speed and so contributes to precision and consistency of equine lameness analysis.

Animals↗
PubMed1997

Compensatory movements of horses with a stance phase lameness.

In order to study the mechanism of lameness transfer from fore- and hindlimb lamenesses 2 hypotheses were investigated. Hypothesis 1: Horses with a true supporting limb lameness in one hindlimb show a false supporting limb lameness in the ipsilateral forelimb. Hypothesis 2: Horses with a true supporting limb lameness in one forelimb show a false supporting limb lameness in the contralateral hindlimb. Fourteen horses with fore- or hindlimb lameness were used for this study. Each horse was measured at the trot on a treadmill with standardised speed, before and after diagnostic blocks (9 horses), or with and without induced lameness (5 horses). The head acceleration asymmetry (HAAS) and the sacrum acceleration asymmetry (SAAS) were used for quantification of fore- and hindlimb lameness respectively. Changes were documented by changes of the HAAS or the SAAS. In all 4 horses with a true hindlimb lameness a synchronous false lameness of the ipsilateral forelimb was documented. In 6 of 10 horses with a forelimb lameness a lameness transfer could be assessed according to hypothesis 2. The results of this study show, that horses with a true severe lameness in the forelimb show a false lameness in the contralateral hindlimb, and horses with a true hindlimb lameness show a false lameness in the ipsilateral forelimb. This indicates that the location of the truly lame limb can be deduced from the distribution of 2 lamenesses on a sagittal or diagonal axis.

Acceleration↗
PubMed1996

A method of signal processing in motion analysis of the trotting horse.

The aim of this paper is to present a method of signal processing necessary for motion analysis in the trotting horse. Motion analysis is widely used to assess lameness in horses. By definition, lameness in trot is present if the movements during the stance phases of both fore or hind limbs differ. The motion of the horse is recorded using a system for motion analysis (Selcom, 1983, SELSPOT II User Manual, Pad Nr. 6710) and the vertical motion of the head during both stance phases is compared. The symmetry is analyzed comparing the values of the Fourier coefficients. Additional head movements are 'single events' and present a problem. In this article we propose a mode of data processing using a system matched filter that neglects the nonperiodic additional movements and allows calculation of the representative Fourier coefficients. In comparison with a filtering method previously used in motion analysis this method is proved to be advantageous, as the precision of symmetry comparison increases.

Animals↗