Propulsive Drag Propulsive Lift

1
Propulsive Drag Propulsive Lift

• FLIFT always ? to segment direction
• hand shaped like wing moves laterally in water
• FLIFT pushes forward on palm
• FIGs 14.10,14.11,14.12

• FDRAG always opposite to segment direction
• FDRAG is propulsive when hand/foot moves backward
  in water
• FDRAG on hand/foot provides handle/wall
• FIG 14.9 page 467

2
pg 467FIG 14.9FDRAG on handopposesthe
directionof pull
3
Page 468 FIG 14.10Blading/Sculling Hand to
generate FLIFT
4
page 469 FIG 14.11FLIFT on Hand using ? of
ATTACK
5
page 470 FIG 14.12FLIFT on hand in ? direction
(forward)due to lateral motion of the hand
(sculling action)
FDRAG on hand in ? direction (forward)due to
backward motion of the hand
6
HANDLE for Propulsion

• FDRAG retards hand/foot moving backward
• ? hand has a handle foot has a wall to work
  against
• ? shoulder and hip muscles move body more forward
  than hand/foot move backwards
• Slipping Handle involves use of Drag only
• Stable/Fixed Handle uses both Drag and Lift
• FIG 14.13 on page 471 FIG 14.14 on pg 473

7
a FIXED HANDLE
bSLIPPING HANDLE
pg 471 FIG 14.13
8
Pg 473 FIG 14.14 ARMS pg 478
FIG 14.18 LEGS
9
Propulsion from Legs/Trunk

• Flutter kick less for forward thrust, more for
  upward thrust to reduce profile drag
• Propeller-like action of whip kick provides lift
• Knee/Hip extensions provide drag stable handle
• see FIG 14.18 on page 478
• Dolphin Kick trunk wave LIFT DRAG
• FIG 14.20 on page 480 FIG 14.22 page 482

10
pg 480 FIG 14.20 pg 482 FIG 14.22
11
SWIMMING SPEED

• SWIMMING velocity SL x SFstroke length x
  stroke frequency
• SL is most significant factor
• ? SL via ? Technique and ? Strength
• SL affected by the degree of slipping
• ?FLIFT FDRAG acting on hand/arm/leg/footresult
  s in ? slippage ? ? SL

12
Swimming Efficiency

• competitive swimmers need optimal efficiency
• Efficiency is the ratio of the propulsive force
  generated to the energy expended in achieving the
  force
• skilled swimmers have greater SL due to effective
  use of Lift along with propulsive Drag
• skilled swimmers have less profile drag
• slow swimming and fast swimming is less efficient
  than moderate paced swimming