Movement Analysis of the Back handspring

1. Movement Analysis of the Back handspring December 8, 2005 Catie O’Reilly Kurstin Meenan Andrea Maillett Bob Kniffen Lisa Stuart

2. Background and Goals • Gymnastics • Introduced to the United States in 1830’s • 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. “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 Muscles and Joints of Phase 1

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

6. 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 Muscles and Joints of Phase 2 Muscles Joint movements

7. 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)

8. Concentric Wrist extensors Triceps Latissimus dorsi Trapezius Deltoids Levator scapula Hip Flexors Stabilization Abdominal muscles Erector spinae group Extension Wrists Elbows Flexion Hips Muscles and Joints of Phase 3 Muscles Joint movements

9. 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

10. Eccentric Quadriceps Hamstrings Gastrocnemius Gluteals Stabilization Core muscles Flexion Hip Knee Ankle Muscles and Joints of Phase 4 Muscles Joint movements

11. 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 back 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

12. Angular Momentum • 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 Phase 1 Phase 2 Phase 3 Phase 4

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

14. 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

16. 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

17. Video

18. Video (cont…)

19. References • http://www.ausport.gov.au/fulltext/2000/vic/gymnastics.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 Women’s 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-Feb;20(1):61-6. • Hay, James G; The Biomechanics of Sports Techniques. Benjamin Cummings; 1993. • Sands, Bill et al. Scientific Aspects of Women’s Gymnastics, S. Karger Publishers, 2004

20. 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 • What’s the most important part of a back handspring • Arching the back • Snapping the legs down • Take off from the floor • Ability to hold a handstand • None of the above • If a gymnast doesn’t have enough force during the takeoff phase of a back handspring, which of the following would decrease the moment of inertia allowing them to complete the exercise • Bending the elbows • Bending legs • Straddling legs • Keeping head forward