Freestyle-the most basic freestyle of arms and shoulders. Hand movements are alternating strokes with both hands. As the legs alternately pump water up and down, the arm pushing water under water resistance can effectively exercise biceps brachii (upper arm), triceps brachii (butterfly sleeve) and shoulders. Lying on your back-latissimus dorsi (back muscle) doesn't squeeze out fat from your back when you want to wear a halter top or bikini? By leaning back and clamping the back, you can stretch and stretch the muscles of the back and arms, exercise the latissimus dorsi, and make the back muscles strong; Backstroke is a movement from thigh to toe, similar to the foot movement of splashing water upwards, which can also exercise the hips and front thighs. The frog leg movement of quadriceps femoris (front thigh) and adductor hip (inner thigh) is that the legs are centered on the knees, adducted and clamped outward, and then combined with hands to draw a circle for ventilation, emphasizing the coordination of the body. Because leg movements are different from freestyle and supine vector, it can effectively strengthen the butterfly stroke of the front thigh (kicking) and the inner thigh (clamping)-the butterfly stroke of pectoralis major, latissimus dorsi and rectus abdominis (abdominal heart) mainly emphasizes the muscle training of the upper body, the arm pushes forward by expanding the chest and paddling outward, and the foot drives the lower body to swing with the abdominal heart. However, due to the resistance of water, female students need strong muscle strength, endurance and good coordination in swimming butterfly, which is an advanced event in swimming training. Reminder: Girls are different from boys because of their innate physiological conditions, and will not become crouching or player-like inverted triangle figures because of the intensity of self-training, but will be stronger and more linear; If you want to make the fitness effect more obvious, remember to combine diet control (not dieting), retraining, and cross-training with other sports such as jogging or flywheel.