Movement Analysis of the Back handspring

1
Movement Analysis of the Back handspring
December 8, 2005

• Catie OReilly
• Kurstin Meenan
• Andrea Maillett
• Bob Kniffen
• Lisa Stuart

2
Background and Goals

• Gymnastics
• Introduced to the United States in 1830s
• First large scale competition was held in 1896 in
  Athens, Greece
  
• There are many levels of gymnastics activity
  including recreational, non-elite competitive
  (levels 1-7), high level competitive (levels
  8-10) and elite.
• The Back handspring
• Part of progression to more difficult skills
• Performed numerous times in training and
  competition
  
• From a stand, a backward jump in an arched
  position to the hands (passing through a
  handstand) followed by a quick snap-down of the
  legs, finishing in a standing position
• Goals
• Perform skill in controlled and graceful manner
• Perform skill according to standards set by the
  sport of gymnastics (body alignment etc)

3
Phase 1 sit and swing

• Most important part of the back handspring
• Stand with arms above head
• Bend at hip and knee joints to lower buttocks
  down and back (shifts the center of gravity)
  
• Knees should not bend past 90o
• While bending, arms swing down and then up
  overhead in a continuous motion
  
• Lean backward and push forcefully with legs
  projecting the gymnast upwards and backwards

4
Muscles and Joints of Phase 1

• Sit
• Muscle
• Eccentric
• Quadriceps
• Hamstrings
• Gastrocnemius
• Gluteus Maximus
• Concentric
• Rear deltoids
• Stabilization
• Abdominal muscles
• Joint Movements
• Flexion of hips, knees, ankles
• Extension of shoulders

• Swing
• Muscles
• Concentric
• Quadriceps
• Hamstrings
• Gastrocnemius
• Anterior Deltoids
• Gluteus Maximus
• Trapezius
• Joint Movements
• Extension of hips, knees, ankles, back
• Shoulder flexion

5
Phase 2 passing through the handstand position

• Arch back and reach for the floor
• Body is still very tight
• Hands touch floor
• Large compressive forces at wrist and hand
• Elbows flex slightly to absorb shock (compression
  forces are an average of 2.37 times the body
  weight)
  
• Angular momentum created in phase 1 keeps the
  body rotating backwards

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Muscles and Joints of Phase 2
Muscles
Joint movements

• Eccentric
• Triceps
• Wrist extensors
• Concentric
• Gluteus maximus
• Erector spinae group
• Deltoids
• Trapezius
• Quadriceps
• Stabilization
• Biceps
• Abdominal muscles

• Vertebrae extend
• Shoulders keep extending
• Hips, knees and ankles remain extended

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Phase 3 Push off and snap down

• Angular momentum generated during phase 1 allows
  passage through handstand position
  
• Hands press on floor (push off)
• Helps the body maintain adequate angular momentum
  to continue the movement
  
• Flight path of the body was determined by the
  velocity and height of the center of gravity at
  the time of takeoff (Phase 1)

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Muscles and Joints of Phase 3
Muscles
Joint movements

• Concentric
• Wrist extensors
• Triceps
• Latissimus dorsi
• Trapezius
• Deltoids
• Levator scapula
• Hip Flexors
• Stabilization
• Abdominal muscles
• Erector spinae group

• Extension
• Wrists
• Elbows
• Flexion
• Hips

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Phase 4 Landing

• Feet touch floor, head and torso come up
• Joint flexion
• Hip (32o), knee (22.4o), ankle (-0.5o)
• Eccentric forces during landing provide a
  rotating effect in the opposite direction of BHS
  movement
  
• Angular momentum and linear translation are
  decreased to zero

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Muscles and Joints of Phase 4
Muscles
Joint movements

• Eccentric
• Quadriceps
• Hamstrings
• Gastrocnemius
• Gluteals
• Stabilization
• Core muscles

• Flexion
• Hip
• Knee
• Ankle

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Center of gravity
Phase 1
Phase 2
Phase 3
Phase 4
Phase 1 Center of gravity is moved to behind
the body Phase 2 Center of gravity is thrown ba
ck into an arch Phase 3 Angular momentum allows
center of gravity to pass over head/hands
Phase 4 Center of gravity is returned to
starting position
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Angular Momentum
Phase 1
Phase 2
Phase 3
Phase 4

• Center of gravity is behind the body during the
  sit and swing (Phase 1)
  
• An explosive push at this point generates the
  angular momentum needed to project the gymnast
  upwards and backwards
  
• Angular momentum generated during phase 1 is
  enough to allow the gymnast to pass through the
  handstand position
  
• A push with the arms and shoulders while passing
  through the handstand position generates slightly
  more angular momentum to make the landing sharp
  
• Angular momentum is returned to zero during the
  landing (when feet hit the floor)
  
• The landing is controlled by flexing at the
  knees, hips and ankles this slows down the body
  and dissipates the energy
  

13
Mass Moment of Inertia

• Defined as the resistance to change in angular
  velocity
  
• How this concept applies to the back handspring
• Not enough power generated during phase 1 of the
  exercise
  
• Cannot complete exercise in the desired extended
  position
  
• Bend knees to decrease moment arm

Moment arm
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Limitations

• Flexibility
• Back, shoulder, hips
• Strength
• Ability to generate enough angular momentum
• Ability to support bodyweight on hands
• Balance
• Ability to get past mental fear

15
Specific exercises

• Handstand
• With snap down
• Squat jumps
• Core strengthening
• Pushups
• Bridge
• Shoulder stretches
• General stretching

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Common Injuries

• Floor exercises are the most common cause of
  injury, due to the large number of bends, twists,
  and landings required in those routines
  
• The ankle and foot are the most common site of
  injury in both males and females.
  
• Injuries also occur to the lower back, knee and
  wrist/hand.
  
• Muscle pulls (strains)
• Stress fractures
• Tendonitis
• Lumbar spine injuries are common in gymnastics
  because of the repetitive hyperextension and
  excessive training

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Video
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Video (cont)
19
References

• http//www.ausport.gov.au/fulltext/2000/vic/gymnas
  tics.asp
  
• http//www.safeusa.org/sports/gymnasti.htm
• http//www.medscape.com/viewarticle/408524_5
• http//www.coachesinfo.com/category/gymnastics/65
  3
  
• Tonry, Don Sports Illustrated Womens Gymnastic,
  Harper Row, publishers, New York, 1980
  
• Koh TJ, Grabiner MD, Weiker GG. Technique and
  ground reaction forces in the back handspring.
  American Journal of Sports Medicine. 1992
  Jan-Feb20(1)61-6.
• Hay, James G The Biomechanics of Sports
  Techniques. Benjamin Cummings 1993.
  
• Sands, Bill et al. Scientific Aspects of Womens
  Gymnastics, S. Karger Publishers, 2004

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Questions for final exam

• During phase 1 of a back handspring (sit and
  swing) what begins the backward rotation of the
  body
  
• Keeping the head lifted
• Leaning forward
• Transfer of the center of gravity behind the
  body
  
• A running start
• Bending your legs past 90o
•  
•  2. During phase 1 of the back handspring you
  extend which of the following
  
• ankle
• hip
• knee
• All of the above
•  
• When passing through the handstand position of a
  back handspring elbows should be completely
  straight to absorb shock
  
• True
• False
•  
• Whats the most important part of a back
  handspring
  
• Arching the back