Lie on your back on the mat with your knees bent about 90 degrees and your feet flat on the ground. Don't fix your feet on the flat ground (for example, your partner presses your ankles with his hands), otherwise the flexors of thighs and buttocks will also join the work, thus reducing the workload of abdominal muscles.
Furthermore, straight leg sit-ups will increase the burden on the back and easily cause damage to the back. Determine the position of your hands according to the strength of your abdominal muscles, because the closer your hands are to your head, the more difficult it will be to do sit-ups. Novices can put their hands on their sides, and when they get used to it or improve their physical fitness, they can cross their hands on their chests.
Finally, try to cross your hands behind your head, but each hand should be placed on the shoulder on the other side of your body. Never cross your fingers behind your head, so as not to strain the neck muscles when exerting force, and this will also reduce the workload of abdominal muscles.
Use a slower speed, just like slow-motion playback. When the abdominal muscles pull you up, you have to exhale, so as to ensure that all the muscles deeper in the abdomen participate in the work at the same time.
After the body is off the ground 10 to 20 cm, tighten the abdominal muscles, pause for a while, and then slowly lower the body back to its original position. When your back touches the ground, you can start the next cycle. In the process of sit-ups, the abdominal muscles actually only participate in the work at the initial stage, and then the hip flexors will replace the task.
Similarly, turn your body in the final stage of sit-ups (right elbow touches your left knee, left elbow touches your right knee, etc.). ) not only will it not help to strengthen the abdominal muscles, but it will even cause trauma to the lower back due to the compression caused by rotation.
Beginners should avoid doing sit-ups too many times at a time. At first, they can try to do it five times, and then add it once in each exercise until it reaches about 15 times. At this time, they can try to do another group until they reach three groups.
Effect of sit-ups on gastrointestinal function
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Lie on your back, the abdomen and thighs are at 90 degrees, the thighs and calves are at 90 degrees, the body is like a flying fish, and things can be put under the calves. This action looks simple, but to really get the best training effect, you need to "compress" the abdominal muscles with the contraction force of the abdominal cluster, and the action is very short. When doing this, the upper back is off the ground, but the lower back is still close to the ground. The action is just to press the abdomen, bend the spine, and make the chest ribs close to the pelvis. It is just to make the abdominal muscles in a "peak contraction" state, pause for a while, then control the tension of the abdominal muscles, slowly stretch and restore the spine.
Note: The position of hands has a direct influence on the pressure of abdominal contraction.
Usually, there are three different placement positions:
1, hands are naturally straight (relaxed) in physical test.
2. Cross your heads and hold them in your chest (middle)
Step 3 put your hands behind your neck (difficult)
1. Accurate method: put your hands gently on the back of your neck and ears to avoid the neck from being pressed inward.
2. inaccurate method: hold the back neck tightly with both hands, bend the back and press the neck column inward with both hands.