BIOMECHANICS OF SWIMMING

2.  Approximately 100 million americans consider
themselves as swimmer (Johnsonn D 1988)
 Highly regarded as aerobic activity
 Arms are the powerhouse of propulsion thus
making shoulder vulnerable to injury
 Competitive swimmers cover 10000-14000
m/day equates to 16000 shoulder revolutions per
week.(Johnsonn D 1988)

3.  1000 shoulder revolutions per week for
professional tennis player, 300 revolutions per
week for college javelin thrower and 200 per
week for a professional golfer
 Understanding the action of swimming and its
effect on the shoulder is vital to a sports
physiotherapist, for swimming injuries that occur
in upper quadrant are intimately related to
mechanics and pathomechanics of stroke
movement

4. An extremely important principle in
understanding the mechanism of lift.
Brown and Counsilman promoted the
theory of propulsion through Bernoulli’s
theory of differential pressures as water
passes the back of the hand convex
surface) more quickly than across the palm
of the hand ( flat surface) as the hand
stroked through the water.

5. This produces a lift force much the same
way as a aircraft wing and provided the
propulsive phase for swimmers.
Lift always acts perpendicular to the fluid
flow and therefore to the drag force.

6. For every action there is equal and
opposite reaction.
That is when swimmer pushes water
backwards, the body is accelerated
forward by reaction forces.

7. A. The head and the Trunk :
3 important function.
 Minimizing resistance
 Enabling the swimmer to breathe
 Provide a stable anchorage for arm and leg muscles.
The flatter the body lesser the drag.

8.  Exact position of body varies with the
anatomical build and buoyancy of the
individual.
 Common mistake- lifting head too much.
 Spine held in slight flexion and pelvis
slightly decreased inclination.
 Lateral movt of trunk to be minimized.

9.  Head rotation for breathing on its
longitudinal axis
 Sprint better swum with fewer breathing
cycle.
 By the alternating action of R and L
oblique abdominal and spinal extensors,
the spine and pelvis are stabilized
against the pull of the shoulder and hip
muscles.

10. B. The Arm Stroke :
The arm stroke provides 85% of the total
power and Arm coordination is one of the
most important factors contributing to the
generation of propulsive forces.

11. Mechanics of free style: [ Costill et al 1992]
1. Entry - Its position on entry is with the forearm
high and elbow pointing to the side and palm out.
 Elbow is flexed and then extends during glide.
 Brief movement between entry and the
beginning of the chief propulsive action is known
as support phase.
 Pressure of forearm and hand is mostly
downward and then backward. [Reaction force.
Upward & forward]

12.  2. Downsweep - Elbow and shoulder flexion
keeping elbow higher than hand.
 3. Catch - Beginning of propulsive stroke, occurs
about one-third of way through the underwater
stroke.
 The moment at which the chief propulsive action
changes from downward to backward constitutes
the catch.
 The upper arm almost vertical, a position that
favours large muscles. [ PM & LD]

13. 4. Insweep –
 The maximum bend occurring halfway through
the pull at elbow constitutes the s-curve, which
allows for creation of propulsive lift.
 Semicircular movements to bring hand breath
midline of body and the feel is as if the hand is
being pushed backward through the water.
 The lift and drag act to stabilize the hand in
water. The body is then pulled forward over the
relatively stationary hand.

14. 5.Up Sweep- Strongest propulsive movement, arm is
brought up and outward toward the surface of water,
force easing as hand passes the thing.
6. Release & Recovery –
 Former overlaps with upsweep, palm turns into thigh
and propulsive force is released.
 In latter, the hand comes forward in straight line with
elbow kept high to allow sufficient external rotation of
humerus to prevent impingement.
 No break should occur from release to the completion
of recovery since this would mean a loss of momentum
and necessitates additional force to overcome inertia.

15. Arm coordination: [Potdevin. E et al,
2006]
Three major patterns of arm coordination
are usually referred to :
a. The catch up coordination: Which
consists of a lag time between the
propulsive phases of the two arms?
b. the superposition coordination :
consists of overlap propulsive phases of
both arms.

16. c. The opposition pattern: the one arm
begins the pull phase at exactly the same
time as the other finishes the push phase.
In expert swimmers arm coordination
changes from a catch-up to a
superposition mode when race velocity
increases [Chollett. D, 2000]

17. Superposition coordination could be a
result of
i. Technical adaptation in order to minimize
the energy cost. [Chatard JC, 1990]
ii. By reducing active drag [Kolgonorov Sv,
1992]
iii. Increasing relative duration of
propulsive phases. [ Keskinen KL, 1993]

19. If all active muscles are considered, the
estimate is 170 single muscle hence it is
considered an excellent total body
exercise. [Clarys and Cabri 1993]
Shoulder Joint & Shoulder girdle :
• During hand entry and forward reach – upper
trapezius elevates the scapula and rhomboids
retract it.
• Serratus anterior produces protraction and upward
rotation of the scapula.

20. • The force couple formed by the upper 3 muscles
firmly tethers scapula in all corner.
• This muscle action positions the glenoid fossa for
the humeral head
• Pectoralis major responsible for initial humeral
adduction and extension.
• Pectoralis major also causes IR, thus the Teres
minor fires with pectoralis major to provide an
antagonistic external rotation force.

21. • Latissimus dorsi : because of mechanical
advantage becomes the primary muscle of
propulsion after mid pull-through.
• Subscapularis forms force couple with latissimus
dorsi.
• Serratus anterior active as it pulls the body over
the arm and through the water.

22. • Posterior deltoid contributes to final part of pulling
while it begins to lift the humerus out of water.
• As hand exits water, the group of muscles that
were active at hand entry once again begins to
function.
• The middle deltoid is active to abduct and
continue lifting the arm.

23. b. Elbow and radioulnar joint :
 Flexion, slight pronation, partial extension
towards end.
 Muscles : brachialis, brachioradialis, biceps
brachii, pronator teres, pronator quadratus and
triceps anconeus.
c. Wrist :
 Held in mid position, possibly slight flexion
toward end of propulsion.
 Muscles : palmaris longus, FCR, FCU.

24. d. Fingers :
Held in extension and adduction.
Muscles : flexors in static contraction.
The Kick
During the free style stroke, the lower
extremities do a reciprocal diagonal sweep
called the flutter kick.
Used both for stabilization and propulsion.

25.  Multiple studies show that kicking causes a
demonstrable increase in the energy cost of
swimming . [Adrian M et al, 1996; Astrand & ,
1978; Charbonnier JP et al 1975, Holmer et al,
1974].
 Distance swimmers may minimize the efforts of
Swimming to reduce fatigue.
 Flexibility in ankles is important in the kick, and
those with a greater range of plantar flexion have
an advantage.

26.  Downstroke
1. begins with a
downward drive of the
thigh
2. The Thigh flexes only
slightly and the knee
extends completely by
the end of the
downward movement.
 Upstroke
1. at the completion of
downstroke the thigh
is in a position of
slight flexion, the
knee is completely
extended, ankle
incompletely planter
flexed.
2. Upstroke begins with
thigh extension.

27.  3. the ankle and foot
remains in plantar
flexion by pressure of
water against dorsum of
foot.
 3. The movements of LL
are force full in upstroke
but in good control as
foot stops just below
water.
 4. Breaking through
water result in reduction
of propulsion force.

28.  1. Hip Joint : partial
flexion: iliopsoas,
TFL, Pectineus,
Sartorius and
gracilis.
 2. Knee joint:
passive flexion due
to water pressure
then forceful
extension, muscle –
quadriceps.
 1. Strong extension –
G. max, and
hamstrings.
 2. Slight flexion
against resistance
muscle hamstring,
sartorius , gracilis,
popliteus and
gastrocnemius.

29. 3.Ankle Joint :
incomplete PF by
pressure of water.
Muscles : TA, EDL,
EHL, may contract
 statically to stabilize
foot.
 PF; Muscles-
gastrocnemius,
soleus, peroneus
longus and brevis,
tibialis posterior, FDL,
FHL.