Final answer:
The correct precaution for pregnant soldiers performing squats is to use proper form, ensuring the knees are over the ankles and not squatting too low. This maintains balance and minimizes stress on the joints.
Step-by-step explanation:
The appropriate precaution for a pregnant soldier performing the knee bender or squats would be c) Use proper form, keeping the knees over the ankles and not going too low. Pregnant women often experience increased back strain late in their pregnancies due to the additional weight they carry, which shifts their center of gravity, causing a backward displacement that places more stress on the lower back. Squats should be performed with correct form to ensure safety, which includes keeping the back straight, knees over the ankles to avoid undue stress on the joints, and not squatting too low to prevent balance issues.
Performing squats with heavy weights (a) or rapidly (d) can increase the risk of injury and should generally be avoided, especially during pregnancy. Meanwhile, option (b) suggests an incorrect posture that can exacerbate lower back strain, contrary to proper ergonomic practices.