PubMed Health⌕ Search

Biomedical subjects

G Hjertén

Publications and source records attributed to G Hjertén.

6 recordsLinked to original sources
PubMed1994

Semi-quantitative analysis of hoof-strike in the horse.

The initial forelimb loading of a horse trotting at 3.7 ms-1 on a treadmill was studied by use of an instrumented shoe, accelerometers and high-speed cinematography. At the beginning of the stance phase the forelimb was loaded successively from the hoof. This is suggested to be an important factor for effective shock force absorbency in the extremities. Shearing forces may appear in the carpus before the onset of the longitudinal loading of the limb. These forces are proposed to depend on speed, locomotion pattern and the friction and hardness of the surface. It is suggested that shearing forces may be of importance for lameness, especially on surfaces with high friction.

Acceleration↗
PubMed1993

Shortening of the forelimb in the horse during the stance phase.

Compressions in the forelimb of a horse trotting at 3.7 m/s were studied using high-speed cinematography. From a diagram of shortenings it has been concluded that successive loadings in the longitudinal direction from below signify longer impact time and smaller impact forces compared to a theoretically stiff limb. It is proposed that the limb takes up the impact force passively until the onset of loading at the elbow joint, i.e. 30 ms following first contact.

Acceleration↗
PubMed1987

Early development of gait asymmetries in trotting standardbred colts.

Ten trotting Standardbred colts were recorded by high-speed cinematography at the ages of eight, 12 and 18 months. The horses were trotting on a treadmill operating at 4.0 m/secs. Five horses were subjected to a programme of intensified training from eight months of age, whereas the others were not trained and acted as controls. The films were analysed on a semi-automatic film-reading equipment and a number of variables used to demonstrate the gait symmetry were calculated and scaled by computer. Certain differences between left and right diagonal and contralateral pair of limbs, respectively, were noted, suggesting that laterality in horses may be inherited. The most pronounced systematic differences were found in 18-month old horses in the trained group. The results show the importance of careful gait examination and comprehensive coordination training at an early age.

Animals↗
PubMed1983

Treadmill for equine locomotion analysis.

A treadmill for equine locomotion analysis is described and its potential considered for locomotive research and clinical investigation. The treadmill comprised an endless belt driven by a hydraulic motor at various speeds up to 14 m/sec and the direction of belt movement was reversible. The carrying side of the belt ran over a steel-concrete table which acted as a flat support. The belt itself consisted of a steel base on to which was glued a rubber belt and the surface was covered with a layer of coir matting which permitted some forward sliding of the landing hooves simulating the conditions on an ordinary track. The treadway could be inclined up to 10 degree in the longitudinal and 7.5 degrees in the transverse direction. To minimise the risk of injuries a special emergency stop system was installed. Horses adapted well to exercising on the treadmill, even without any previous experience. A good correlation was found between the gait repetitiveness on the racetrack and that displayed on the treadmill. One horse recorded both on the racetrack and on the treadmill showed significantly shorter strides on the treadmill but this did not invalidate the treadmill as a useful research tool in the study of equine locomotion.

Animals↗
PubMed1980

Equine locomotion; 1. The analysis of linear and temporal stride characteristics of trotting standardbreds.

The movements of the individual limbs of 30 clinically sound Standardbred trotters were studied using high-speed cinematography. At a speed of 12 metres per second (m/sec; 1:23.6 min/km) the mean stride length was 545 cm and the mean duration of the stride was 455 milliseconds (msecs). The stance phase in the forelimbs was 100 msecs and 177 msecs in the hindlimbs. This difference was due to a longer restraint period in the hindlimbs and resulted in slightly shorter swing phases for the hindlimbs. The variations in any particular horse for stride length and for the duration of stride, stance, swing and propulsion were very small (variation coefficient: approximately 2 per cent). For the restraint stage, however, the variation coefficient was around 5 per cent. The variations noted between different horses were generally 2 to 3 times greater than those recorded for the same horse. There was a close correlation between stride and swing phase duration, suggesting that the swing phase was the main contributor to the stride-time variations of different horses trotting at the same speed. The restraint and propulsion stages did not seem to play an important role in this respect for this group of animals.

Animals↗