Outline
1. Injuries of lower extremity in tennis
Injuries of lower
extremity in tennis player
2. Biomechanics of movement in tennis
3. Biomechanics of shoes and surface
4. Summary
Reporter: Chin-Dai Wu
Adviser : Hung-Ta Chiu
Injuries of
lower extremity in tennis
In most cases, injuries to the lower extremities
are surface related:
1. 21% of tennis injuries requiring medical treatment
were due to uncontrolled slipping (Biener & Caluori,
1977) .
2. Fifteen top-ranked tennis players had more back
and lower extremities injuries when playing on hard
court than when playing on clay (Von Salis-Soglio,
1979).
3. Lower extremity injuries on hard court were twice
as frequent as either upper extremity or central
body injuries during the US National Boy’s Tennis
Championship from 1986~1988 (Hutchinson et al.,
1995).
5. Future
Injuries of
lower extremity in tennis
Carrying out three electronic databases (Pubmed,
Embase ＆ CINAHL) from 1966 to 2005 on to identify
relevant article relating to tennis injuries.
Finding about lower extremities :
1. Most injuries occur in the lower extremities, followed
by the upper extremities and than the trunk.
＊ tendon injuries, plantar facia tears, muscles tears, stress fractures,
and intra-articular knee injury.
2. Most acute injuries occurred in the lower extremities
Plum, Staal, Windler ＆ Jayanthi, 2006
Biomechanics
of movement in tennis
Injuries of
lower extremity in tennis
Lower extremity injuries are twice as common as those to
the upper extremity or spine, with ankle injury being the
most common (Joseph and Mark, 1998).
Recording USA National Boy’s tennis Championships
from 1986-1992, the analysis of injuries showed a higher
rate of lower than upper extremity injuries (Mark et al., 1995).
Injuries types: strains and sprains were most common (71% of all
injuries).
The lower extremity injuries provided the majority of sprain type
injuries (87.5%) , ligament sprains coming from the knee and
ankle.
Sprinting,
stopping
and cutting
Upon
striking
the ground,
the motions specific to FOOT
&
ANKLE.
foot is in a supinated position.
Upon landing, the foot
immediately pronates or flattens.
The foot and ankle re-supinate
prior to pushing off the ground.
As failure to re-supinate prior to
pushing off the court surface
can lead to injury and non右腳
efficient propulsion.
Paul & Todd,2001
Biomechanics
of shoes and surface
1
To analyzed the behavior of frictional forces and
torques produced during an open stance forehand.
Method:
1.12 tennis player.
2. Four playing surface :
Three layers: polyurethane with EDPM sandwiched
between textile) (1) 、(2):
(1) Tennis Fluid Texilast (smaller than .5mm)
(2) Chevron 400 Fluid (12 mm).
(3) Master Turf 20 SF (fill with sand).
(4) Mondo Sportflex (5-mm rubber and 50 Shore-A).
Van and Deporte, 1992
Biomechanics
of shoes and surface
3.Three types of tennis shoes:
(1) Nike Royal : PU outsole; air wedge cushioned rear foot.
(2) Wimbledon GTS : rubber outsole, pillar cushioning.
(3) Nike All Court: low cost all-surface shoe.
4. Open stance forehand.
5. For evaluation of friction generated by the same
shoe/surface combinations in controlled laboratory
conditions.
Van and Deporte, 1992
1
Biomechanics
of shoes and surface
1
Biomechanics
of shoes and surface
1
Laboratory condition:
Human condition:
1. Frictional torque is not significantly affected by shoes different,
1. Frictional force and torque display no significantly on different
shoes.
may be limited shoes sample.
2. Upon turning the foot, shoes also produce the largest variations
on frictional force , may easily exceed 300N.
2. Nike All Court shoe displays the highest frictional force scores
for all playing surface, except for the turf.
3. Turf may produced unexpected low friction force for shoes with
cushioning ,PU and rubber of outsole.
3. Sportflex: Highest frictional torques; lowest frictional force.
4. Surfaces of friction: Sportflex ＜Fluid ＜ sand with turf.
4. For the playing surface, Al l court shoe have significant different
in frictional force and torque, and displays highest friction force
and torque on the Sportflex.
5. Lowest friction force : Texilast Fluid＜turf.
Van and Deporte, 1992
Van and Deporte, 1992
Biomechanics
of shoes and surface
1
Biomechanics
of shoes and surface
Surfaces of the fluid type mostly display the lowest friction
Six female tennis player.
and likely to induce less frictional overload.
Wearing same tennis shoe (Adidas Big Court ).
Three tennis surfaces:
Real forehand and laboratory reveal different condition.
1. Sportflex ＜Fluid ＜ sand with turf.
2. Texilast Fluid＜turf＜Sportflex.
1. Sand-filled artificial turf: high cushioning .
2. Cushioned acrylic hard-court (12-mm thickness):
moderate cushioning.
3. Carpet (6-mm thickness): low cushioning.
4. Baseline : zero cushioning.
Van and Deporte, 1992
Stiles & Dixon, 2006
2
Biomechanics
of shoes and surface
2
Biomechanics
of shoes and surface
3
Ten females tennis players
Baseline compare with other surfaces :
Four surface condition:
1. Low impact force (p＜.005).
2. High braking force (p＜.006).
1.Top layer: Acrylic multi-sport surface
3. Low average rate of loading (.039).
2. second layer: three different cushions pads:
4. Low Impact peak force for the resultant ground reaction force
(.006).
(1) Rubber tiles.
(2) Thin foam (13mm).
5. High peak friction coefficient (.005).
A lower peak vertical impact force for the baseline surface
was unexpected.
More dynamic skill used in stiff surface, that resulted in
overcompensation.
(3) Thick foam (45mm).
3. Forehand posture
4. shoes: (1) non-laced basic shoes.
(2) Canvas upper.
Stiles & Dixon, 2006
(3) Vulcanized rubber sole.
Biomechanics
of shoes and surface
3
↑
Peak and average rates of
loading were significantly lower,
because of lower peak impact
force were later .
Stiles & Dixon, 2007
Biomechanics
of shoes and surface
Increasing deformation of
foam reduces peak pressure,
so that reducing the injuries risk.
↓
Stiles & Dixon, 2007
Stiles & Dixon, 2007
3
Biomechanics
of shoes and surface
3
Biomechanics
of shoes and surface
3
Small initial foot angle
can adjust with changes
in different cushioning,
specially in stiff surface
Stiles & Dixon, 2007
Stiles & Dixon, 2007
summary
The surface with amount of cushioning would be greater,
when we doing the sport specific movement and taskorientate, because of these types movement restrict on
inherent impact-moderating adjustment.
Increasing surface cushioning yielded significantly lower
force and pressure loading rate, horizontal force, and
peak heel pressures, these factors thought to be
beneficial in lower risk and reducing the injuries.
Picking good cushioning of surface and shoes can
prevention the lower extremity injuries.
Selecting the shoes has good cushioning when playing
stiffer surface.
Improving muscle strength ability have benefit in
performance.
Future
Purpose: Comparing kinematics and dynamics
parameter when we perform the forehand and backhand
movement, more understanding about the lower
extremity in tennis movement.
Method:
1. Tennis player
2. The ball speed is controlled.
3. Motion
4. Force plate
5. EMG
Thank you
very much