A fitness scientist at San Diego State University tested the effectiveness of the most popular 13 abdominal exercise, and finally summed up four most effective "abdominal fat killers". In order to achieve the best results, three groups should be selected for these four exercises every day, and each group should last 15 minutes. The goal of exercise is until you sweat.

Pedaling exercise: Lie on the floor, press the floor with your back down, put your hands behind your head, raise your knees at a 45-degree angle, and pedal with both feet. Your left ankle should touch your right knee, and then touch your left knee with your right ankle.

Sit on the edge of the chair with your knees up, your feet naturally droop to the ground, tighten your abdomen, lean back slightly, and your feet are a few centimeters off the ground. Pull your knees to your chest and bend your upper body forward to maintain stability. Then put your feet back in place. Repeat.

Sit-ups lie flat and bend your knees, hook your feet together at the head of the bed, put a towel around your neck, pull one end of each hand, tuck in your abdomen and lift your body, slightly leave the bed surface and stay still.

Lift the ball to your back, hold the tennis ball in your hand, extend your arms to the sky, keep your legs together and straighten, and hook your feet. Embrace your knees in your abdomen and lift your shoulders and head slightly off the bed, keeping still.