CSET Practice Test Physical Education

Benefits of Flexibility Training By Chad Tackett,
president of GHF

Flexibility is a joint's ability to move through a full
range of motion. Flexibility training (stretching) helps
balance muscle groups that might be overused during
exercise or physical activity or as a result of bad
posture. It's important to clearly understand the many
benefits that result from a good flexibility program. 

Improved Physical Performance and Decreased Risk of Injury
First, a safe and effective flexibility training program
increases physical performance. A flexible joint has the
ability to move through a greater range of motion and
requires less energy to do so, while greatly decreasing
your risk of injury. Most professionals agree that
stretching decreases resistance in tissue structures; you
are, therefore, less likely to become injured by exceeding
tissue extensibility (maximum range of tissues) during
activity. 

Reduced Muscle Soreness and Improved Posture Recent
studies show that slow, static stretching helps reduce
muscle soreness after exercise. Static stretching involves
a slow, gradual and controlled elongation of the muscle
through the full range of motion and held for 15-30
seconds in the furthest comfortable position (without
pain). Stretching also improves muscular balance and
posture. Many people's soft-tissue structures has adapted
poorly to either the effects of gravity or poor postural
habits. Stretching can help realign soft tissue
structures, thus reducing the effort it takes to achieve
and maintain good posture in the activities of daily
living.

Reduced Risk of Low Back Pain A key benefit, and one I
wish more people would realize, is that stretching reduces
the risk of low back pain. Stretching promotes muscular
relaxation. A muscle in constant contraction requires more
energy to accomplish activities. Flexibility in the
hamstrings, hip flexors, quadriceps, and other muscles
attaching to the pelvis reduces stress to the low back.
Stretching causes muscular relaxation, which encourages
healthy nutrition directly to muscles; the resulting
reduction in accumulated toxins reduces the potential for
muscle shortening or tightening and thus reduces fatigue. 

Increased Blood and Nutrients to Tissues Another great
benefit is that stretching increases blood supply and
nutrients to joint structures. Stretching increases tissue
temperature, which in turn increases circulation and
nutrient transport. This allows greater elasticity of
surrounding tissues and increases performance. Stretching
also increases joint synovial fluid, which is a
lubricating fluid that promotes the transport of more
nutrients to the joints' atricular cartilage. This allows
a greater range of motion and reduces joint degeneration.

Improved Muscle Coordination Another little-known benefit
is increased neuromuscular coordination. Studies show that
nerve-impulse velocity (the time it takes an impulse to
travel to the brain and back) is improved with stretching.
This helps opposing muscle groups work in a more
synergistic, coordinated fashion.

Enhanced Enjoyment of Physical Activities Flexibility
training also means enhanced enjoyment, and a fitness
program should be fun if you want to stick with it. Not
only does stretching decrease muscle soreness and increase
performance, it also helps relax both mind and body and
brings a heightened sense of well-being and personal
gratification during exercise.

As you can see, flexibility training is one of the key
components of a balanced fitness program and should be a
part of your exercise routine. Without flexibility
training, you are missing an important part of overall
health. Flexibility training provides many important
benefits that cannot be achieved by any other exercise or
activity. Good luck: I hope you enjoy all the wonderful
benefits of an effective flexibility training program.

Biomechanics of the Kick/Punt 

The punt kick is a simple kick that can be divided into
three simple phases. The first phase is the swing back
phase, the second phase is the kick, and the third is the
follow through. Each step is important in its own right to
maintain the proper form for the kick. Many of the muscles
that are used are the same throughout the movement, but
the function and contraction of the muscle differs from
phase to phase. By breaking up the movement into different
sections the movements become more definite and distinct. 

The swing back phase marks the preparatory or the pre-
stretch motion of the kick. In the swing back phase the
hip muscles contract and cause extension at the hip joint.
The gluteus maximus is the most active extensor muscle in
the movement, with little to no help from the biceps
femoris (Young 3). Both of these muscles are
concentrically contracting to produce this movement.
Studies have also shown that the iliopsoas muscle is
active throughout the range of motion of the kick (Dorge).
Although the iliopsoas muscle primarily works to flex the
hip, the muscle is active in the extension movement as the
antagonist to the gluteus maximus. The iliopsoas
eccentrically contracts to slow down the extension of the
hip. While the hip is extending, the knee is flexing and
the ankle is dorsiflexed. Knee flexion is primarily caused
by the hamstring muscles, more specifically, the
semitendonosis, which is most active at the initiation of
movement (young 3). Knee flexion actually begins
simultaneously when the hip begins extension (Young 3).
The knee stays flexed for about 50% of the movement, where
as the hip only stays extended 40% of the time ( Young 3).
Tibialis Anterior is the primary dorsiflexor in the
movement. The ankle stays dorsiflexed for 50% of the
entire kicking movement (Young 3). Although the position
of the ankle is not incredibly important in this phase, it
plays a small but crucial role in the generation of force
at the knee joint. The knee cannot produce maximum force
when the knee is in a plantar flexed position because of
the shortened position of the gastrocnemius (Croce). When
the ankle is dorsiflexed, the knee is allowed to produce
the maximum force at the joint, which will eventually be 

The hip stops extending when it is just below the
horizontal, this point marks the beginning of the second
phase, the kick. The next two phases are very short in
time span, but they are fast and create a lot of power,
which is then transferred to the ball. Flexion of the hip,
extension of the knee and plantar flexion at the ankle are
the movements that define this phase of the kick. Hip
flexion is caused by the primary hip flexors, the
iliopsoas muscle. When the hip stops extending just below
the horizontal, the iliopsoas changes from an eccentric
contraction to a concentric contraction, thus pulling the
hip into a flexed position. Just after the hip begins to
flex, the knee begins extension (Young 3). The primary
knee extensors are the quadriceps muscles. All of the
quadriceps contract forcefully throughout the range of
motion (Eloranta). However, the vastus lateralis becomes
the most active towards the end of the motion (Young 3).
The increased activation of the vastus lateralis was
probably due the increased effort of the muscle group to
keep the leg from inward rotation. At the same time the
knee begins extension, the ankle begins plantar flexion.
The primary plantar flexor is the peroneus longus muscle.
Plantar flexion positions the foot so the dorsal surface
is facing out ready to kick the ball. 

When the ball is struck the phase shifts from the kicking
phase to the follow through. Most of the follow through is
just an extension of the kicking motion. The hip is still
flexing and the knee is still flexing. The only changes
occur in the contractions of the muscles and the return to
dorsiflexion at the ankle. Again, the primary dorsiflexor
at the ankle is the tibilalis anterior muscle. The
contraction is concentric, but it is not as forceful as
contractions made in the preparatory and kicking phases.
The biggest change in muscle contraction comes from the
hamstring muscles. The peak EMG of the hamstrings is not
when the knee is flexing, but rather when the ball is
struck and the knee is extending (Wahrenberg). The
contraction that is taking place is an eccentric
contraction, and its purpose is to prevent the knee from
hyper-extending under such large forces. The forces that
are put on the patellar tendon under such circumstances
can reach 5200 N (Wahrenberg). The hamstrings are
antagonistic to the quadriceps and they help to disperse
some of the force put on the joint. The purpose of the
follow through motion is to create a smooth movement and
easy end the forceful contractions of all the muscles
involved in the kick. Thus, while the quadriceps,
hamstrings, hip flexors and tibilais anterior continue to
contract, the contractions are not forceful and they tend
to end gradually and smoothly. 

The last part of the movement to be analyzed is the role
of the stationary leg. The stationary leg serves to
balance the body and support its weight while the other
leg is performing the kick. The position of the stationary
leg is very important to the success of a kick, and
changes in its position can greatly effect the kicking leg
will have on the ball (Beraud). The muscles involved in
keeping the leg stationary are the tibilais anterior, the
hamstrings, the iliopsoas and the quadriceps. All of these
muscles perform isometric contractions to keep the leg in
a position that has the ankle slightly dorsiflexed, the
hip in a slight posterior tilt and the knee slightly bent.
This position keeps the body stable yet ready to move if
the situation calls for quick movement.