How many hurdles are there in a 100m race

The finishing order is determined on time. The event evolved from wooden barriers being placed along a yard stretch, in England during the s.

The distance was increased to m at the Olympics. The US won Olympic gold in this event in , , and It has provided many dramatic moments in Olympic history such as in when USA's Gail Devers held a clear lead until being knocked off balance at the final hurdle to miss out on a medal.

Her compatriot Lolo Jones suffered a similar fate when leading in the final. The seven elements, expressed in time sequence are: start;. The m hurdles is a sprint event. A good start and maximum acceleration to the first hurdle are necessary in order to maintain the fastest possible rhythm between hurdles. Sprint hurdlers cannot attain their maximum velocity because there are normally only eight strides from the start to the first hurdle. This means that the lead leg is in the back block, except for a few of the tallest, strongest hurdlers who are able to take seven strides with a fast rhythm.

Optimal acceleration is achieved when the greatest amount of force is applied to the track in the shortest amount of time. Force is applied through the foot but it is generated by the summation of forces in other joints working in unified sequence, principally the ankle, knee and hip.

The need for a big force in a short time is an idea of fundamental importance which results in speed, the product of stride length and stride frequency. In this pure acceleration phase, the free leg swing, when the leg is not in contact with the ground, is also a dynamic action. It is brought about by flexion in the same hip, knee and ankle joints which are extended to provide the driving force in the previous stride.

The flexed joints shorten the whole lower limb complex. This enables the hip joint to rotate forward faster by reducing the biomechanical resistance to the rotation, known as the moment of inertia. For these biomechanical reasons, eight shorter strides from the blocks normally permit greater acceleration than seven longer strides.

The distance covered is the same but there is one more opportunity to exert force to the ground. The speed of movement of the joints, that is, their angular velocity, is likely to be greater. Assuming a faultless hurdle clearance in both cases, the eight stride hurdler is likely to be carrying a quicker rhythm over the hurdles.

The distance from the hurdle on takeoff depends on several factors—speed of the approach run, length and speed of the lead leg, height of the athlete, height of the hurdle and the flexibility of the hip, knee and ankle joints. It is rather a continuous four stride pattern with the last stride merely longer and accentuated in its action. The takeoff distance for women before the hurdle will vary between 1. The female hurdler touches down closer to the hurdle than her male counterpart because the hurdle is lower.

The lead leg attacks the hurdle beginning with a high knee action generated from the hip flexor muscles ilio-psoas, rectus femoris and the supporting muscles of the upper leg. These actions decrease the moment of inertia about the hip and therefore permit a high angular velocity in the subsequent movements of the lead leg.

The lead leg action is supported and enhanced by plantar flexion, or foot drive, of the trail leg to lift the body and keep the hips tall as the lead leg attacks the hurdle. The raised center of gravity enables the trajectory over the hurdle, a parabolic curve, to be as flat as possible. This keeps the path of the center of gravity as close as possible to a normal sprinting action.

The rotational force, or torque, of the plantar flexion is generated by the gastrocnemius and soleus and other supporting muscles in the calf. Leading with the foot not cocked has a tendency to lock the knee prior to the heel reaching the hurdle. If this continues throughout the clearance, a delayed landing and greater braking forces will result.

The lead knee should cross the hurdle in a slightly flexed position. We go into far more depth elsewhere. We have many more videos to help you with your hurdling and all aspects of the sport across the website, please have a look around and maybe let us know what you think via our Youtube channel. Check out our Sunday sessions, if you want to just do some technique work weekly or just from time to time Hurdle Sunday training sessions.

Many people want to know how many hurdles are in a race. In most hurdle races m, m and m there are 10 hurdles, there are 8 hurdles in 70m, 75m and 80m hurdles, 7 hurdles in m hurdles and 5 hurdles in the m races. Here is an example of the ways in which we can help athletes with their hurdling.