1. Body posture:
When swimming, the body lies flat and prone in the water, the longitudinal axis of the body maintains an angle of 3-5 degrees with the horizontal plane, and the head is raised. A straight posture can narrow the cross section when moving forward and help reduce resistance. The neck naturally bends back to form an angle of 20-30 degrees with the horizontal plane. Look forward and downward, alternate arms to reach forward and paddle backward, and alternate legs up and down. When pumping water, keep your body straight, that is, don't tighten your abdomen and raise your hips, and don't lift your chest or waist. However, your body can rotate rhythmically around the longitudinal axis of your body during swimming. This rotation is generally between 35-45 degrees.
2. Leg movements:
The kick of crawl swimming mainly keeps the body balanced and is conducive to paddling. It plays an important role in the entire crawl swimming coordination technique.
The kick of crawl swimming is that the legs swing up and down alternately. When going down, straighten your legs naturally, use your hip joint to exert force, and your thighs drive your calves to pump water. Generally, the gap between the two legs is about 30-45 cm. When pumping the water downwards, the movements should be fast and powerful, and when lifting the legs upwards, the movements should be relaxed. When pumping water downwards, due to inertia, the lower legs and feet continue to move upward, causing the knee joints to bend somewhat, and the degree of bending is generally between 140-160 degrees. When pumping water, the toes should be straightened naturally. When pumping water downward, the feet should naturally turn inward (inward splay).
The number of strokes is usually a complete arm stroke with six strokes, but some people prefer four strokes and two strokes, which depends on the individual's characteristics.
3. Arm movement:
The arm movement in crawl swimming is the main driving force for generating propulsion. The entire arm movement can be divided into inseparable parts of entering the water, holding the water, paddling, exiting the water and moving in the air. But there is no obvious boundary between them, but a complete movement
1) Entering the water: After completing the arm movement in the air, the hands should move forward and enter the water naturally and relaxedly. The water entry point is generally along the length of the body. and between the front extension line of the shoulder joint. When entering the water, keep your fingers straight and together. Raise the elbow joints by internal rotation of the arm, and bend it to an angle of 130-150 degrees, so that the elbow joint is at the highest point, the palm of the hand is tilted outward and downward, and the fingertips are downward. This position provides the least resistance.
2) Holding the water: After the arm enters the water, the palm of the hand turns from obliquely outward and downward to obliquely inward and backward, and begins to bend the wrist and elbow, and maintain a high elbow-raised posture. When holding the water, the angle between the upper arm and the horizontal plane is about 30 degrees, and the angle between the forearm and the horizontal plane is about 60 degrees. The palm of the hand is vertically facing the water, and the elbow joint is bent at an angle of about 150 degrees. The whole arm is like holding a ball.
When holding water, the angle of elbow flexion is about 150 degrees
3) Stroking: Stroking is the main part of the entire arm movement to generate propulsion force. On the basis of holding the water, the arm and the water surface should be at an angle of about 35-45 degrees when paddling.
Use flexed arms when paddling. The degree of arm flexion can be determined according to your physical condition: those with long arms and weak arm strength can bend their arms to a greater degree, and vice versa. .
When you start paddling, bend your elbow at about 100-120 degrees. At this time, the forward movement is faster than the upper arm. When it reaches the vertical plane under the shoulder, bend the elbow at an angle of 90-120 degrees. Quickly push the water back with your forearm to the side leg to end the stroke. During the stroke, the palm ../.. is concave.
4) Out of the water: After the stroke, the arm uses the speed inertia after pushing through the water, uses the contraction of the shoulder deltoid and shoulder girdle muscles and the rotation of the body along the longitudinal axis to lift the elbow upward. , and quickly lift your arms out of the water. At this time, your arms and wrists should be relaxed gently.
5) Aerial arm movement: It is the rest and relaxation stage of the arm in a stroke cycle. When moving the arm, bend the elbow slightly and keep the position higher than the shoulder and hand. Do not swing the straight arm sideways, and do not use the hand to drive the arm into bending the elbow to move the arm. This action is tense and incorrect, and will not achieve the goal. Relaxation purpose.
6) Cooperation of the two arms: Whether the two arms of crawl swimming are coordinated is an important condition for the uniformity of forward speed. There are usually three ways to coordinate the two arms.
Front cross: means that when one arm enters the water, the other arm is in the sliding stage. This is a technique with a sliding stage.
Middle cross: refers to the middle part of the stroke when one arm enters the water and the other arm has entered the stroke.
Rear crossover: means that when one arm enters the water, the other arm has already entered the second half of the stroke phase.
Generally, for swimming enthusiasts, it is advisable to learn the front cross, because the front cross can better maintain body balance, it is easier to master breathing techniques, and it can also save energy and reduce fatigue.
Paddle practice method
4. Coordination of breathing and arm movements:
The breathing of crawl swimming is to use the rotation of the head to the left or right , breathing through the mouth. Take breathing to the right as an example. After your right hand enters the water, slowly start to exhale through your mouth and nose. Sweep your arms under your shoulders and turn your head to the right. The amount of exhalation begins to decrease. When you push the water with your right arm, the amount of exhalation further increases. Increase. When your right arm comes out of the water, immediately open your mouth and inhale. When the arm is moved halfway, the inhalation ends and the head rotation recovery begins. At this time, hold your breath again, continue to turn your head and move your arms, and turn your face forward and downward. When the head position is stable, the right arm enters the water again to start the next breath. Repeat this cycle for breathing.
5. Coordination of breathing and complete movements:
The coordination of crawling swimming legs, arms, and breathing generally uses one stroke with each hand, one breath and six kicks with both legs. In order to give full play to the hands and increase the swimming speed, there is also a coordination method of one stroke with each arm, one breath and four kicks.