Soccer
ranks as a high-risk activity when injury is concerned (Lambson,
Barnhill & Higgins, 1996). Each season there appears more
and more new boot design innovations yet the number of injuries
continues unabated. Epidemiological studies indicate adult
males are likely to suffer one injury per 167 hours of play;
female soccer players are at higher risk with approximately
one injury per 147 hours of play (Nilsson, Roaas, 1978; Schmidt-Olsen
et al 1985; Sullivan et al 1980). Most injuries are traumatic
but there is a high incidence of overuse injuries also reported.
(60/40 ratio). Traumatic injuries arise during games more
than practice and the risk of injury risk increases with the
playing season. Early injuries tend to prevent the player
from regaining and maintaining fitness although position and
age has little baring on occurrence and severity of injury.
(Morgan & Oberlander, 2001). The trend for females to
suffer moderate injuries is one hundred percent higher than
males. Major injuries for both remain the same i.e between
13 & 14%. (Morgan & Oberlander 2001; Soderman, Adolphson,
Lorentzon, & Alfredson 2001). Between 68%-88% of all soccer
injuries involve the lower limb (Albert, 1983; Ekstrand, Gillquist,
1983; Engstrom, Johansson, & Tornkvist, 1991; Fried, Lloyd,
1992; Nilsson, Roaas, 1978;Schmidt-Olsen et al, 1985;Schmidt-Olsen
et al 1991). The knee and ankle are the most likely to be
injured. (Brynhildsen, Ekstrand, & Jeppsson, 1990; Ekstrand,
Gillquist, 1983; Engstrom, Johansson, & Tornkvist, 1991;
Fried, Lloyd, 1992; McCarroll, Meaney, Sieber, 1984; Schmidt-Olsen
et al 1991). Thought to be the most common occupational injury
associated with soccer and reported by as many as 60% of soccer
players is Anterior Ankle Impingement Syndrome (or Footballer's
Ankle).
The condition
is caused by either; thickening of the tendon and joint capsule
caused by stretching with the downward movement of the foot
when the ball is kicked; or alternatively, osteophytic damage
(bone) to the ankle joint caused by contact with the ball
(Tol, Slim, van Soest, & van Dijk, 2002). Kicking is the
most widely studied soccer skill (maximum velocity instep
kick on a stationary ball) and it would appear modern soccer
boots provide poor protection to the foot and ankle from a
career in kicking the ball. The incidence and severity of
knee injuries has also been significant among football players.
The common factor in Anterior Cruciate Ligament (ACL) injuries
is foot fixation, which has been described as leading cause
of ankle injuries in sport (D'Ambrosia, 1985; Torg, 1982;
Torq, Stilwell, & Rogers, 1996) The exact incidence of
injury attributable to footwear in soccer remains unknown.
Association between cleat design and injury rate is however
reported within the literature (DÕAmbrosia, 1985; Torq
JS Quedenfeld, & Landau,1974). Several specific mechanisms
of injury have been described that produce ACL tears and many
of these do not involve contact with another player. Instead
problems appear to occur from torsional forces transmitted
to the knee when the player makes a sudden directional change
with a planted foot while decelerating. In the event of physical
contact provided the foot can be released from the ground
then injury to the ACL can be reduced. It is generally accepted
high frictional forces between the foot and the playing surface
result in fixation and this fixation is a least partially
responsible for knee ligament injuries. Traditional soccer
boots provide traction with the ground, which is critical
to a playerÕs performance, however it is now thought
this shoe to surface traction may also contribute to injury.
With no traction the player finds difficulty in maintaining
balance when turning and twisting or running on wet surfaces.
Too much traction permits twisting forces to move proximal
on joints above the foot. Application of forces stressing
the knee in a plane other than the normal joint motion results
in injury if the force exceeds the elastic capabilities of
any of the structures being stressed (Torg, Stilwell, &
Rogers, 1996). The axial rotation at the playing surface appears
to be affected by the magnitude and nature of impact. By the
seventies researchers had discovered an association between
cleat design and injury. Higher injuries were recorded in
conventional shoes with a traditional seven-cleat pattern.
The length of the cleats were " 3/4"" long; and "3/8 " in
diameter.It was also found the composition of the cleat was
a contributory factor. Researchers identified different patterns
of injuries between shoe sizes and concluded the smaller distances
between the position of studs, across the ball of the foot,
might account for a higher magnitude of rotation. As a result
of these finding the changes to the games rules have resulted
and size restrictions and other restrictions on cleats. According
to Levy, Skovron, & Agel (1990) any increase in fixation
to the ground increases the risk of injury. Ekstrand &
Nigg speculated as much as 60% of all non-contact soccer injuries
may be due to excessive shoe surface tension. The conclusion
of Bonstingi, Morehouse, & Niehel (1975) was torque developed
between playing shoe and surface as a result of a force applied
to the leg and an athlete depended on the type and design
of the shoeÕs outer sole, the playing surface, the
player weight supported, and the foot stance. The reduction
of rotational force is thought by many to reduce the rate
of injury to the knee. Tests on artificial turf indicate the
more pliable the cleat the greater the release coefficient,
although this alters with changes in surface temperature.
The authors concluded release coefficients both within and
among shoe models across a range of turf temperatures. Ironically
on artificial turf the researchers found flat-soled basketball
shoes performed better than cleated soccer boots did. Of particular
concern was the introduction of a design that included round
spike cleats on the interior portion of the sole with irregular
cleats on the outer rim. Although this design enhanced traction,
it was reported when worn by athletes it was also associated
with a high incidence of serious knee injuries (Majid &
Bader 1993). Some players will risk injury to enhance performance,
by chosing inadequate boots and cleat designs. Most amateurs
remain oblivious to the risks and there have been calls from
concerned consumers for manufacturers to indicate clearly
on theoir labelling the types of playing surface conditions
their shoes are meant for. (Heidt et al, 1996). Further, concerns
have been expressed at deceptive claims found in marketing
sport shoes, according to researchers at McGill University.
False notions of protection may lead to a higher rate of injury
and this could include claims for improved performance. The
majority of career ending injuries involve the knee, ankles
and hips with osteoarthrosis (OA) a serious complication.
Approximately 2% of professional players are forced to quite
the game due to acute injuries. Despite being low this is
higher than many other occupations. However there are a larger
number of players forced to quit due to chronic injuries sustained
and maintained by playing soccer. Further, Drawer, Fuller,
& Waddington (2002) recently reported many retired professional
players have admitted to playing games whilst unfit or receiving
pain killing treatments for existing injuries with the full
knowledge of their employer. Osteoarthritis in a least one
of the lower extremity joints is very high and significantly
greater than in the general population. Health and Safety
regulations in the UK now require employers to identify hazards
and risks from their work activities and to provide appropriate
information and training about the risks. Employers are specifically
required to provide health surveillance to employees where
significant risk to their health is identified. (Drawer, Fuller,
& Waddington 2001). By this token employers are now responsible
for players suffering from industrial related injury which
prevents them from earning a living. Published studies clearly
indicate the provision of injury prevention and socio-economic
services at professional soccer clubs (UK) remains inadequate
and there are now calls to develop a long term strategy for
managing players forced to retire through injury. The UK Industrial
Injuries Advisory Council (IIAC) has so far dismissed these
claims and refused to accept OA of the knee due to soccer
is a boni fidi industrial injury and has refused to include
it in the Industrial Injuries Scheme under Contributions and
Benefits Act (1992). The IIAC are currently considering OA
of the hip.