In elite sprinters, the front knee angle at the start is which angle?

• A. 40 degrees
• B. 50 degrees
• C. 60 degrees
• D. 30 degrees

Answer: (A)

In elite sprint starts, the front knee is bent at about 40 degrees. This position hits a sweet spot: it’s flexed enough to store and release elastic energy quickly, yet extended enough to allow a rapid, powerful push off the blocks. With roughly 40 degrees, the body can drive the hip and knee into extension efficiently, producing a favorable force vector that pushes you forward rather than upward. If the knee were more bent (around 50–60 degrees), you’d get more vertical impulse and slower forward acceleration; if it were more extended (around 30 degrees or less), the extension would take longer to develop and the horizontal propulsion would be reduced. So 40 degrees balances speed of transition with effective propulsion, helping the sprinter accelerate optimally from the start.