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Biomechanics of the Butterfly Stroke

a biomechanical analysis of the butterfly stoke

Kirtley Caldwell

on 13 December 2012

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Transcript of Biomechanics of the Butterfly Stroke

The Biomechanics of the Butterfly Stroke Abstract The butterfly stroke is a swim stroke that is both difficult and tiring. It is categorized as the second fastest stroke and originated from the breast stroke in 1933, making it the newest swim stroke as well. This movement consists of four phases that complete a cycle. This cycle is then repeated to continuously swim the butterfly. Kirt Caldwell Anatomy and Physiology Mr. Robert Ladeur The four phases of the butterfly include the catch, the front sweep, the back sweep, and the recovery. PHASES Phase 1
"The Catch"

The catch phase of the butterfly stroke includes the hands entry into the water. The body begins from the initial position in the water: prone position, head flexed downward and facing down, hands extended above head at shoulder length, legs extended, feet planterflexed, trunk extended. The hands penetrate the water pronated with thumbs first. The arms the depress simultaneously into the water. The arms then horizontally abduct, forming a "Y" shape. The hips flex while the legs remain extended, projecting the gluteal region out of the water. Hands should enter soft and the trunk should undergo natural flexion. Muscles:
erector spinae
rectes abdominis
iliacus, psoas major and psoas minor
semitendinosus, semimembranosus, and biceps femoris muscles
gastrocnemius and soleus
deltoid and trapezius
pronator teres and pronator quadratus
adductor magnus, adductor brevis and adductor longus
gracilis and pectineus
extensor digitorum
vastus intermedius, medialis, and lateralis, and rectus femoris muscles Biomechanics of the Butterfly Stroke Phase 2
"The Frontsweep" This phase begins propulsion through water. To start this phase, the arms circumduct symmetrically outward. The right arm moves clockwise and the left counterclockwise. The arms protract down into the water as the body is submerged naturally. The arms continue to abduct horizontally until they are at a 90 degree angle with the body. As they are abducting, the forearm flexes at the elbow to create a 120 degree angle. This keeps the elbow superior to the forearm. The trunk goes from a flexed position to an extended position, straightening the body out. Also the knees now begin to flex, and the hips remain flexed as well. Muscles:
trapezius, rhomboid major and rhomboid minor muscles
biceps brachii, brachialis, and brachioradialis
serratus anterior and pectoralis minor
pectoralis major
gluteus maximus,minimus, and medius
rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius
iliacus, psoas major/minor, biceps brachii, semitendinosus, and semimembranosus
gastrocnemius and soleus Phase 3
"The Backsweep"

This phase generates the most drive through water. It is essentially when the athlete pushes back and propels forward swiftly. From the angle created in phase 2, the arms begin to extend at the shoulder and horizontally adduct. The forearms flexes at the same time even more until the hand are almost touching and under the abdomen. This makes the arms circumduct backwards. Once the arms and hands pass under the body the forearms quickly extend and the arms abduct and hyperextend at the shoulder. This movement is synchronized with a second leg kick, in which the hips and knees go from being flexed, to extending rapidly. The second kick should ALWAYS be stronger than the first. This propels the body forward as the body undulates. The hips sink into the water and the head naturally pops out. This is the small window in which a breath should be taken. Muscles:
erector spinae
vastus intermedius, vastus lateralis, vastus medialis, and rectus femoris
iliopsoasic muscles.
trapezoid, rhomboid major, rhomboid minor
supraspinatis muscle
triceps brachii
biceps brachii, brachialis, and brachioradialis
pectoralis major, latissimus dorsi, and coracobrachialis
Deltoid, upper fibers of trapezius Phase 4

The recovery phase is basically a quick transition back to the initial potition and first phase. The arms should be hyperextended behind the body from the last phase. The arms now circumduct symmetrically forward.The right arm is now moving counter-clockwise and the left is moving clockwise. The arms are abducting with thumbs facing forward unti the arms are perpendicular to the body. Then they continue to the fron of the body with lateral flexion of the shoulder. The forearms should be slightly flexed in order to keep the elbow above the arm and water. As the arms move forward they pronate again, facing the thumbs downward towards the water. When the arms circumduct forward, the head and trunk flex downward, making them parallel with the water. The hip follows as it slightly flexes. The knees flex as well, getting ready for the first kick. Muscles:
posterior deltoid, trapezius, rhomboid major, and rhomboid minor
pectoralis minor
biceps brachii, brachialis, brachioradialis
psoas major and psoas minor
biceps femoris, semitendinosus, semimembranosus
gastrocnemeus, soles
pectineus Phase 1 Phase 2 Phase 3 Phase 4 Common Injuries Although swimming is a low risk non-contact sport, many injuries are prevalent in swimmers: Impingement syndrome aka Swimmers shoulder

inflammation of the tendons around the rotator cuff
caused by over use of shoulders and improper technique
can be prevented by resting at least one day a week, stretching before workouts, and fixing form flaws
treatment includes rest, ice, physical therapy, and pain medication Butterfly back

This is a broad term used to explain back problems and pains associated with the butterfly stroke. This discomfort usually occurs in the lumbar spine. The most frequent cause of this injury is over use and improper form, causing strains in the erector spinae.
prevention includes practicing undulation and giving the back time to rest
treatments for this include rest, physical therapy, anti inflammatory medication, and icing Vertebral column fractures
on rare occasion the inferior spine of the swimmer will undergo a stress fracture due to the intense amount of stress placed upon this region.
this is usually a result of ignoring existing back pain caused by the swimming as well as poor form and over use.
In order to stop this from happening, it is important to always lay off the physical activity if the back is in pain. Also, maintaining good form is important
Treatment for this type of injury includes ice, a lot of rest, medication for pain, physical therapy, and possibly a back brace. Spondylolisthesis
this is when one of the vertebral columns of the spine slips forward onto another one causing spinal deformities (lordosis).
When a swimmer does the butterfly incorrectly long enough, or over works their lumbar spine, this injury may occur.
Stretching, swimming correctly, and taking it easy on the back are several precautionary steps to avoid spondylolisthesis.
Treatment for spondylolisthesis includes rest, anti-inflammatory medication, physical therapy, steroid injection, and possibly a back brace Medial and Lateral Epicondylitis
also known as golfers or tennis elbow, this is the inflammation of the tendons surrounding both the medial and lateral epicondyles.
When a swimmer is performing the butterfly stroke, there is a pulling of the arms under water. This strenuous movement causes stress on the elbow and if an athlete is not careful, inflammation will occur leading to this injury.
As a result, proper form, days off, and stretching and engaging the elbow before workouts will help prevent this inflammation.
Treatment for this condition includes physical therapy, rest, ice, compression, elevation of the elbow, elbow braces, and sometimes surgery. Workout Plan This workout plan includes multiple exercises and drills that prevent injury and maximize performance when doing the butterfly stroke. Stretching
Shoulder stretches- to build flexibility and durability:
Simple across the body (horizontal addution of arm), over the head, and arm circles are good to begin with.
Back stretches:
Horizontal trunk flexion can be held at each side for one stretch.
Hollywood stretch, which is where the athelete sits upright with one leg extended flat on the ground and the other crossed over it. Then he or she proceeds to take the hand on the side of the body with the extended leg and extend it to the other side, across the body, on the outside of the flexed leg. Then a twisting motion occurs.
Lock one elbow straight, keeping it extended, and, with the other hand, pull back on the fingers of the extended arm, which should extend the wrist and the forearm muscles. One can also flex the same wrist to stretch the other side of the forearm. Do this for both arms.
Leg :
Quadriceps stretches
Hamstrings also need to be stretched, so easy stretches such as keeping the legs extended standing up and reaching down and touching the toes would work. Drills
There is no better way to prepare for the butterfly than to get into the water and practice the movement. Not all at once, though, drills for this stroke include isolating some of the movements that are key to the butterfly.
Body Dolphins
Practice the kick by undulating through the water (without initiating the hands) and focusing on the natural, wave like movement that is used when swimming the butterfly. The legs are kept close together with the arms fully extended to the side or in front. The body is face down in the water. The head and chest are the first to go down, and initiate this drill. Then they bob up and the hips go down, creating a wave like motion with great form.
“Stone Skippers”
Body dolphins with the arms extended out in front, except this time, every 2 body waves or so, the arms go through the “keyhole” motion, propelling the body forward. This also helps become more familiar with the breathing technique.
Working on technique will help prevent injuries as well as speed. It also increases endurance just as running helps a runner. It is common sense. Isometrics
Multiple beneficial training exercises can be done outside of the pool as well. Core is a very important aspect of swimming the butterfly.
To strengthen the abdomen, crunches can be performed. This exercise is done by laying down flat on the back, with knees and hips extended. Then the trunk and head is brought up to the knees using the abdominal muscles. Also, planks are a good form of core strengthening exercises. A plank is basically holding a push up stance on the elbows. Therefore, a strong core is key to having a fast and efficient butterfly stroke.
Band exercises allow high reps with low risk.
Simple band exercises for the shoulder like horizontal adduction, vertical adduction/abduction, and arm extension are good for the ligaments, tendons, and muscles of the arm.
Dry land:
There are multiple other workouts that isolate body parts while minimizing the risk of over use. Bench dips are one of these exercises. A bench dip is basically holding oneself up on a bench with the hands on the bench and the feet on the floor, facing up, with the body linear, then slowly flexing the arms and dipping down, then back up.
Bench pushups can be done. These are like normal pushups, but elevated with the hands on a bench and the body at an angle with the ground. References Samuel James Freas, S.(2010).Swimming. In The World Book __Encyclopedia (2010ed., Vol 18, p. 1044). Chicago, IL: World Book Inc Osborough, C., & Peyrebrune, M. (n.d.). Coaches info. Retrieved from http://www.coachesinfo.com/index.php?option=com_content&view=article&id=75:swimming-butterfly-tired&catid=49:swimming-coaching&Itemid=86 Richards, D. R. (n.d.). The mechanics of modern butterfly swimming. Retrieved from http://www.teamunify.com/cseksc/__doc__/Butterfly mechanics.pdf Butterfly back : Swimming injuries. (n.d.). Retrieved from http://www.medic8.com/healthguide/sports-medicine/swimming/butterfly-back.html Swimming injuries. (2009). Retrieved from http://www.nsmi.org.uk/articles/swimming-injuries.html Mardhika, A. (2012). Swim butterfly (no flip turn) [Web]. Retrieved from MscMncVideo. (2010). Butterfly stroke comparison [Web]. Retrieved from SamuraiK7. (2012). Michael phelps - butterfly 01 [Web]. Retrieved from
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