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

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
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