BIOMECHANICS APPLICATIONS_1_ by pptfiles

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									  Initiating Rotation while Airborne
1. Reaction Rotation

2. Cat Rotation

3. Twist from a somersault
 Reaction Rotation to Initiate Twist Rotation
 while airborne L is constant and ΣT = 0
  rotation action in one direction causes a rotation
  reaction in the opposite direction
 360° full turn/twist requires 8 series of steps
  alternating I during arm swing/recovery
 HJ clearing trailing body parts [straddle, flop]
Cat Rotation to Initiate Twist Rotation




                       Page 505 FIG 15.8

                    Page 503 FIG 15.6
     Cat Rotation to Initiate Twist Rotation
                         180° half turn/twist requires
                             3 steps as follows:
                    1.    A. place lower & upper
                          axes at an 
                    2.    B. twist upper body, lower
                          body has small reaction
                    3.    C. twist lower body, upper
                          body has small reaction
page 505 FIG 15.8
    Somersault          1.   from symmetrical position,
  to Initiate a Twist        initiate layout back sommie
                             (establish L about ML axis)

                        2.   move to asymmetrical
                             position [drop rt. arm]

                         - this reduces I on rt. side of body
                            about ML axis on that
                         side
page 506 FIG 15.9

                         - nutation (tilt of body) results
                         and a twist begins
Somersault to Initiate Twist Rotation
   most effective of the 3 methods of initiating a
    full twist (360°)

   multiple twists (720° rotation or more),
    performer usually initiates some of the twist
    from the ground (Freaction) in addition to the
    airborne maneuvers

    (symmetrical to asymmetrical during the
    somersault action)
“Kicker” ramp
 places body
in position for
g to apply a T
  to initiate a
back sommie
Left photo

symmetrical




    Right photo
            
asymmetrical
Altering k: radius of gyration
                             page 511
                             FIG 15.13

                                 a
                             tight tuck



                                    e
                                 layout
    Altering    k - radius of gyration
   TABLE 15.1 on page 510
    - read across from left to right

   Example from Table 15.1:

   moving from position a to position e
     diminishes by almost 75 [from 1.00 to 0.28]
Manipulating Rotations in Sport
Manipulating Rotations in Sport
Manipulating Rotations in Sport

                     page 515

                     FIG 15.17
      Manipulating Rotations in Sport




More elongated = Slower Rotation about ML axis
Less elongated body = Faster Rotation
Reaction Rotation to Clear Trailing Body Parts
       Gymnastics Tumbling Skills
 Less Skilled       Highly Skilled
 low vvert due to:          high vvert due to:
   power +  takeoff          power +  takeoff 
  less air time             more air time

 low  due to:              high  due to:
   power +  I @ takeoff      power +  I @ takeoff
 larger k in flight         smaller k in flight
    Sample Tape: Aid in Prep for Test
   1 copy of a sample tape located in each of the 2 video
    viewing booths (VCR in middle booth not working)

   booths located in Thames Hall room 2120A across
    the hall from the Computer Lab

   each booth can hold up to 3 persons
        ABOUT THE VIDEO EXAM
1.   Exam held in Natural Science Room 145

2.   Video Exam is 45 minutes long covering

3.   9 skills, 3 questions per skill (n=27 questions)

4.   5 minutes allowed to answer 3 questions per skill

5.   Exam Value 25% of final course grade

								
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