“Rocket Start” Decides the Bobsleigh Time

©1993 NAOC TM NAOC 7-056

Three Factors to Determine Bobsleigh Time

What decides the bobsleigh results?

The competition results of a bobsleigh are decided by the following 3 factors.

  1. Powerful push to the sleigh at the start. (It's similar to launching a rocket and is called a “rocket start”.)
  2. Driving skill of the pilot (driver)
  3. Mechanical performance of the sleigh

Among the factors the most important is the dash power of the athletes at the start.
Why does “Rocket Start ”decides the results? How can we examin the reason? Here we introduce a Japanese research of time analysis using the speed mesurement equipment.

What Shall We Do To Aim the Gold Medal?

Relation between the start time and the goal results

Why does “ rocket start ” influence the results in the bobsleigh?

See the graph below indicating the start time and the goal time of the bobsleigh of 4 men.
The x-axis indicates the start time, The team plotted to the left has a short start time, that is to say the “rocket start” is excellent. Vertical axis indicates the goal time and the team plotted near to the bottom has the short goal time.
How is it?
The team with the short start time would result in short goal time and a good result. Therefore it is necessary for the Japanese bobsleigh team of 4 men to shorten the start time to 4.9 seconds if they aim at the gold medal.

Speeding up for 0.2 seconds is needed for them.

Good Speed Curve

Checking the speed of the bobsleigh

Then what should be done to shorten the start time?

The sleigh for 2 person weighs about 200 kilogram. The distance to run and push the sleigh is about 50 meters. While pushing the sleigh the runners can not swing their arms like track and field runners (See the form of a pilot pushing a sleigh in the picture). The course they run goes steep downhill.

In Japan we find fast runners in the other fields of sports and invite them in bobsleigh.
To check the starting skill of the runners, a speedometer was installed in the sleigh and several experiments were done.

In bobsleigh start 2 or 4 people push the sleigh together(A).
The results of the experiment show that when they push the sleigh and start to run(B), and when the pilot gets on the sleigh, there is decreasing speed.
Especially when the people pushing behind jump into the sleigh, great decrease of the speed was seen.

After finding those things, the bobsleigh team members started a skill up training of pushing the sleigh so that thy can produce a good speed curve of the sleigh.

Roller Bobsleigh to Practice

To improve the skill of “ rocket start”, many countries such as United States, Canada, and Japan, are using the roller bobsleigh which has wheels under the actual sleigh.

With this roller bob sleigh the athetes are training even during the summer season.