求翻译：身体仰卧于运动机上，膝部屈曲成90度左右，脚部平放在地上。平地上切勿把脚部固定，否则大腿和髋部的屈肌便会加入工作，从而降低了腹部肌肉的工作量。是什么意思？

Body lying on the campaign plane, knee flexion 90 degrees, feet flat on the ground. Do not put feet on the ground fixed, or the thigh and hip flexor is added, thus reducing the workload of the abdominal muscles.

ABS machine, the body movement of the knees bent about 90 degrees, feet on the floor. Flat feet do not leave your thighs and hip fixed, otherwise the aggrieved, will join the working, thereby reducing the workload of your abdominal muscles.

The body lies supine in transporting in the motive, the knee department flexure becomes about 90 degrees, the foot department places evenly ground.On the flat land is sure not the foot department to be fixed, otherwise the thigh and the hip department flexor then can join the work, thus reduced the

Bodies lay on the sports machine, knee buckled as about 90 degrees, feet flat on the ground. Do not put your feet on the level fixed, or thigh and hip flexor muscles will be joining the work, thus reducing the workload of the abdominal muscles.

The body lies supine on the sport plane, it is about 90 degrees that the knee flexes, the foot is kept flat on the ground. Make sure not to fix the foot on the level land, otherwise the thigh and hip one will join work when crooking the skin, thus has reduced the work load of belly muscles.