Kines Analysis

Kinesiological Analysis of the Breaststroke Arm Pull

Introduction: The breaststroke is one of four recognized competitive swimming strokes in United States

swimming and internationally. Breaststroke competition typically occurs in two distances. The

distances are 100 yards in American swimming or 100 meters in international swimming, and 200 yards

during American competition or 200 meters when competing internationally. United States and

international swimming varies as a result of difference venue (pool) structure. American swimming,

which is defined more specifically as college or high school swimming, occurs in pools that are 25 yards

in length. International swimming, including the Olympics, occurs in pools that are 50 meters in length.

Besides the differences in absolute distances swum, American swimming requires more turns than

international swimming. For instance, during a 200-yard American swim, the swimmer will make seven

turns. During an international 200-meter event, in a 50-meter pool, only three turns will occur.

During the breaststroke, the upper extremities (arm-stroke) move simultaneously and separately from

the lower extremities (leg-kick), which also move simultaneously. The stroke pattern consists of

repetitive arm-strokes and leg-kicks that are initiated by the arm-stroke and then followed by the leg-

kick. There is a pause between each segment of the stroke which allows the swimmer to glide using the

energy generated in the previous arm-stroke or leg-kick. The length of the pause/glide phases depends

upon the distance of the race. The gliding phases are shorter in in the 100 yard/meter events due to the

sprint nature of the event.

This analysis is limited to the arm-stroke phase of the complete breaststroke. For this presentation, the

arm stroke will be broken into three temporal phases: 1) Catch; 2) Down-sweep 3) recovery. The

temporal phases are presented in the figures below. The starting phases is presented as an initial

reference point.

Starting Position Catch Down-Sweep Recovery

The Catch Analysis: From the starting position, the swimmer begins the catch phase of the with the

shoulders fully flexed and outwardly rotated to approximately 45 degrees. The wrists are slightly flexed

and abducted. After the pause associated with the stroke, the shoulders begin to adduct and the hands

move away from each other. The movement during the initial part of this phase is passive and occurs as

a result of the propulsion from the previous stroke. Concentric muscle contractions begin when the

elbows flex toward the end of the catch phase. This movement is the result of concentric contraction of

the biceps brachii, brachialis, and briachioradialis. The biceps brachii is a two-headed, extrinsic, bi-

articular muscle that crosses both the shoulder and the elbow with the muscle belly located on the

anterior aspect of the humerus. Its distal tendon crosses the anterior aspect of the elbow joint. The

brachialis is an intrinsic muscle on the anterior aspect of the elbow deep to the biceps brachii. It is a

powerful elbow flexor when the forearms are pronated. The brachioradialis muscle belly lies

predominately on the lateral forearm and supports elbow flexion when the forearm is in the neutral

position. All of these muscles are supplied by the musculocutaneous nerve. This phase ends with

powerful shoulder adduction which occurs due to forceful contraction of the pectoralis major and

latissimus dorsi. These muscles are large muscles located on either side of the torso. The pectoralis

major is found on the anterior aspect of the torso and attaches on the upper humerus. The latissimus

dorsi is located on the posterior aspect of the torso and also attaches to the upper humerus. The

pectoralis major is innervated by the medial and lateral pectoral nerves. The latissimus dorsi is

innervated by the thoracodorsal nerve. Movement in this phase occurs in the frontal plane and

horizontal planes.

The Down-sweep Analysis: During this phase, the hands approach each other as a result of shoulder

horizontal adduction and inward rotation. This is the primary propulsion phase of the stroke and

requires powerful concentric contraction of the pectoralis major supplied by the medial and lateral

pectoral nerves and the anterior deltoid innervated by the axillary nerve. These muscle contract to

create shoulder horizontal adduction. Shoulder inward rotation also occurs and is primarily supported

by the subscapularis, a rotator cuff muscle. Other muscles contributing to the movement include the

anterior deltoid, pectoralis major, teres major, and latissimus dorsi. As the shoulders are horizontally

adducting, the elbows flex to approximately 90 degrees and the forearms supinate to approximately 90

degrees. The elbow flexors and neural supply have been mentioned previously. Supination of the

forearm is caused by contraction of the supinator and biceps brachii. Most of the movement in the

phase occurs in the horizontal plane. This phase is completed when the hands, forearm, and elbows

meet each other directly underneath the upper torso of the swimmer.

Recovery Analysis: The purpose of this phase is to reposition the hands to begin the next arm-stroke.

Once the hands and forearms meet under the upper torso, they are thrust forward by fully extending

the elbows and flexing the shoulders to 180 degrees from the anatomical reference position. Also

during this phase, the forearms pronate approximately 300 degrees from the anatomical reference

position. Elbow extension occurs due to powerful concentric contraction of the triceps brachii and

ancoeus which are located on the anterior aspect of the elbow joint. The muscles are innervated by the

radial nerve. Shoulder flexion occurs due primarily to concentric contraction of the anterior deltoid

which is which is located on the anterior aspect of the shoulder joint and supplied by the axially nerve.

Forearm pronation is caused by the pronator teres, which is located on the proximal anterior aspect of

the forearm, and the pronator quadratus, which is located on the anterior distal aspect of the forearm.

Strength and Flexibility Training: Strength training to support the arm-stroke portion of the

breaststroke would heavily emphasize exercises to support shoulder horizontal adduction, because this

is the primary propulsive segment of the stroke. Training should include exercises for the pectoralis

major and anterior deltoid. Also due to the shoulder inward rotation involvement during the stroke,

strength training should include exercises to strengthen the rotator cuff and other muscles involved with

shoulder inward rotation. This would primarily include the subscapularis, anterior deltoid and teres

major. Flexibility training should focus on allowing as much forward extension of the upper extremities

as possible. This would primarily target increasing the range of motion of the shoulders by increasing

the flexibility of the pectoralis major and latissimus dorsi.