Question

Which of the following would cause your legs to buckle during a jump?

Option 1: Insufficient muscle strength
Option 2: Excessive joint flexibility
Option 3: Proper biomechanical alignment
Option 4: Controlled breathing

Answer 1

Insufficient muscle strength can cause legs to buckle during a jump because without enough strength, legs can't absorb the landing impact effectively, leading to a sharp force that can overwhelm the leg structure. Option 1 is correct.

Step-by-step explanation:

When jumping, if a person's legs buckle, it is usually due to insufficient muscle strength to absorb the impact of the landing. When an 80.0-kg person jumps from a height and lands stiffly, a very large force is exerted on the joints.

If the jumper lands without bending the knees, the impact causes a high force in a short time frame, which could result in bone fractures due to the lack of cushioning, as bones will fracture when the force on them is too immense.

Conversely, bending the knees or rolling on landing significantly decreases the force by extending the time over which the force acts, like the hopping of a kangaroo that uses the bending of its hind legs to cushion the landing. The force when bending the legs can be 100 times smaller than landing stiffly, preventing the legs from buckling.