Vibration load of the rider during exercise on hors ebackHeipertz-Hengst,C. 1, Fischer, S.2, Göres, B.2, Sayn, D.2, Homuth, H.P.3

1 IAS Institut für angewandte Sportwissenschaften, Mozartstr. 18 D 65779 Kelkheim2 BIA Berufsgenossenschaftliches Institut für Arbeitssicherheit, D St, Augustin

3 VBG Verwaltungsberufsgenossenschaft D Mainz

ReferencesDIN EN 30 326: Mechanische Schwingungen, Laborverfahren zu r Bewertung der Schwingungen von Fahrzeugsitzen. Teil 1: Gr undlegende Anforderungen. Juni 1994ISO 2631-1: Mechanical Vibration and Shock – Evaluation of H uman Exposure to Whole-Body Vibration – Part 1: General Requ irements, 1997Fischer S., Göres B., Heipertz-Hengst C., Homuth H.-P., Say n D.: Schwingungsbelastung beim Reiten von Pferden. Arbeit smedizin 1/2000, 35. Genter Verlag Stuttgart, 5-9Heipertz-Hengst C.: Die Wirbelsäule im Reitsport – Reaktio nen und Repairmechanismen. In: Liesen et al. (Hrsg.): Regul ations- und Repairmechanismen. DeutscherÄrzteverlag, Köln, 1994, 89-901Heipertz-Hengst C.: The Horserider´s Spine during Exercis e. In: Steinacker J.M., Ward S.A. (ed.): The Physiology and P athophysiology of Exercise Tolerance. PlenumPress, New York, London. 1994, 233-238

IntroductionAn increasing amount of professional or top class riders com plain of back pain after long-term exercise on horseback. Th eGerman Berufsgenossenschaften deal with "diseases due to w ork load" (Occupational desease No. 2110 "vertical disc-related diseases of the lumber spine") and provide an assess ment system for the evaluation of whole-body vibration to th espine of mechanical origin, such as from operating mobile ma chinery. No investigations for evaluation of these paramet ersfor riders have been published so far.

Materials and MethodsWe used accelerometers to measure acceleration forces at th e characteristic points of their initiation into the body du ring riding: underand on the saddle on three axes: x = fore- and backward, y = left - and right-hand, z = up- and downwards (direction of spinal m ovement).The effective dimension of the oscillating input and its dur ation were indicated via cable transmission. We monitored a ll gaits - walk, trotand canter - of one horse (standard bred, female, 165 cm, 9 yea rs) under one rider (female, experienced, 63 kg, 168 cm, 50 ye ars). Due tothe weight and size of the measurement equipment we initiall y installed it beside a treadmill on which the horse (very wel l adapted tothis kind of exercise) run under the rider. Subsequently, we set the equipment up on a turning table which allowed measure ments during

exercise on a circle ( ∅∅∅∅ 8m) with sandy soil.ResultsThe values for acceleration by vibration during walk are 0,8 5 - 1,25 m/s2; for trot and canter 6,3 - 7,65 m/s 2 on treadmill and5,75 m/s2 on sand. Trot and canter show a high range of energy equivalen t mean values in the z-axis (rider's spine), the nexthighest range was measuered for the x-axis (rider's back and trunk).The results were evaluated with regard to the above mentione d occupational disease accordung to the shock definition ofthe standard ISO 2631-1:1997 and taken into consideration t he material fatigue of the spine.

DiscussionThe values of a mechanical load are approximate and possibly cannot be transferred and off-hand compared to the situatio n of ariding exercise. Risk assessment based on the values recomm ended for vehicles and mobile machinery is not possible. Sho cks asdefined by the ISO-standard do not occur. Risks due to materi al fatigue of the spine cannot be excluded after long-term ri ding in trotand galopp. Compared to the references for stochastic oscil lation by vehicles, the values for shock and vibration cause d by ridinghave a very high range (the direct use of technical limit valu es would allow galopp for no more than six minutes!) but the na turalprocess is rhythmically defined and predictable.

ConclusionThe rider´s exposition to the vibration load during exercis e can cause strain to his locomoterapparatus. It is obviously possible to match the high load wi th sufficient musclestatus and agood condition of training and co-ordination. Thus it canno t be said that the vibration load ofriding means direct danger for the health of the rider. Furth er epidemiological studies areneeded.

Ausschnitte aus dem unbewerteten zeitlichen Schwingu ngsverlauf(Amplituden nicht maßstabgerecht!)

Meßpunkt: Satteloberseite, Satteladapter

Meßpunkt: Sattelunterseite

Measuring device: accelerometer typ 7265A-HS, ENDEVECO 1) under the saddle2) in a half elastic disk, installed in rider’s trouser3) in a half elastic adapter on the saddle4) Measuring situation on treadmill (Mustang 2200, KAGRA AG , CH)

Obere Zahl (fett ): bewertete Schwingstärke Keq (dimensionslos)Untere Zahl (kursiv): bewertete Schwingbeschleunigung aw (m/s2)

Obere Zahl (fett ): bewertete Schwingstärke Keq (dimensionslos)Untere Zahl (kursiv): bewertete Schwingbeschleunigung aw (m/s2)

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Schritt auf dem Laufband Trab auf dem Laufband Schritt auf dem Laufband Trab auf dem Laufband Links-Galopp auf dem Laufband

Schritt im Zirkel rechtsherum Trab im Zirkel rechtsherum Rechts-Galopp im Zirkel rechtsherum

Schritt im Zirkel linksherum Trab im Zirkel linksherum Links-Galopp im Zirkel linksherum

Rechts-Galopp auf dem Laufband