Download The Boxing Cross

Chris Crawford
The Boxing Cross (Punch)
By Chris Crawford
Chris Crawford
Starting position
Regular Stance
In boxing, a cross is a straight
punch delivered from the right hand in
regular stance, and the left hand in
southpaw (left-handed) stance. For the
sake of simplicity, this report will
describe the movements of a right-cross
made by a boxer starting in regular
stance; with the left leg leading and both
feet pointed at an angle of about 45
degrees away from the opponent. Both
elbows are bend with the right hand
behind the left as both hands are held at
or just below mouth level and both knees
slightly bent. In stance, the trunk and
shoulders should start off in a position
where they are facing the same direction
as the feet. Weight is placed fairly
equally between feet, as the stance
serves as a defensive position as well as
an offensive one.
Chris Crawford
Joints Involved
The cross involves the movement of 3 major joints, and many more joints in the
wrist and hand, which must be stabilized upon impact with the opponent. The joints that
move the most are the elbow, shoulders and trunk, while lower body joints such as the
ankles and knees also move to accommodate the weight transfer used to create a powerful
punch.
The Trunk
In the right cross, the trunk is the first thing to move. It rotates along the polar
axis, through the transverse plane. Sometimes to get even more power, the boxer may
rotate the hips rather than the actual trunk, pointing the front of the pelvis directly
towards the opponent. This motion would also occur on the polar axis through the
transverse plane.
Shoulders
In starting stance, the shoulders are usually slightly flexed, somewhat
perpendicular to the floor because the back is hunched over as well. Also, the arms may
be slightly abducted from the body. When the punching motion begins, the arm is
brought posteriorly to the point that the elbow may be behind the shoulder joint in order
to create more power. When this motion is made the arm also abducts even more, as the
hand pronates in preparation for the strike. When the forward motion of the punch begins,
the humerus may be abducted to the point that it is parallel with the clavicle. The
shoulder then rotates along the polar axis as the humerus moves through the transverse
plane, until the shoulder is in a flexed position, with the right arm straight out anterior to
the rest of the body. It is also important to note that the scapula protracts during the
punching motion to provide extra reach and power to the punch.
Chris Crawford
Elbows
The elbows start of in a flexed position. As the arm is brought posteriorly to
gather power for the punch, the right elbow is flexed even more. As arm begins to move
anteriorly, the elbow begins to extend until it hits the opponent. Ideally, the elbow should
snap into full extension just as the boxing glove hits the opponent, or else earlier to avoid
injury to the elbow joint from hyperextension. Because the arm is abducted during the
punching motion, most of the elbow flexion and extension that occurs takes place on the
polar axis, through the transverse plane.
Muscles Involved
The main muscles used in the right cross are the pectoralis major, anterior, lateral
and posterior deltoids, triceps brachii, serratus anterior, external obliques, rectus
abdominus, wrist flexors & extensors as well as some lower body muscles such as
gastrocnemeus and the quadriceps group which may be used to provide extra power.
Pectoralis Major
As the shoulder joint rotates the humerus along the polar axis, the contractions
that cause the movement are made by either the pectoralis major or the posterior deltoid.
The pectoralis major is able to generate a large amount of power that goes towards the
punch, as it contracts concentrically to bring the right shoulder and arm forward.
Deltoids
The anterior deltoid assists the pectoralis major in drawing the arm forwards
during the punching motion, contracting concentrically. Both the anterior and lateral
deltoids stabilize the humerus upon contact with the opponent. The lateral deltoid is
responsible for the abduction of the humerus to raise the arm into a position where the
arm is “cocked” for the punch. The posterior deltoid also contracts concentrically to assist
in this motion, pulling the arm back to prepare for the punch. The posterior deltoid also
works to balance the shoulder joint during the punch where the pectoralis major and
anterior deltoid are contracting to exert punching force.
Triceps Brachii
The triceps brachii create most of the power used in the extension of the elbow
joint. The contract concentrically during the punching motion, while the arm and
shoulder are being drawn forward towards the opponent.
Chris Crawford
Rectus Abdominus and External Obliques
The rectus abdominus and external obliques generate much of the power that is
created through the rotation of the trunk and also help to stabilize and keep balance by
contracting isometrically, especially if the boxer leans forward to land the punch. The
external obliques provide power for the twisting motion as the upper body rotates to bring
the punching arm towards the opponent.
Serratus Anterior
The serratus anterior provides additional power to the final part of the motion. As
the elbow becomes fully extended and the arm is almost straight, the serratus anterior
contracts concentrically to protract the scapula and move the entire shoulder joint
anteriorly, ending the punching motion with one last push.
Wrist Flexors & Extensors
Wrist flexors and extensors also contract isometrically in order to transfer the
maximal force of the punch through the arm into the opponent. If the wrists are not kept
straight, the force of the punch is lessened, and the potential for injury increases as well.
Possible Injuries
Upon contact with the opponent, force is exerted on impact through the right arm to the
shoulder and through the body.
Wrists and Fingers
The first joints to receive the impact of a landed punch are the fingers, metacarpals,
carpals and the wrist joint. The many small bones in the hand are susceptible to fractures,
and the tearing of the small ligaments that hold them together. Commonly, boxers break
the 4th and 5th metacarpals, which are known as “Boxer’s fractures”. The wrist may be
sprained during competition or training, and in most severe incidents the ligaments that
hold the bones of the wrist joint together may be torn to the point that the bones are
moved out of place, into partial dislocation. If the boxer does not have some sort of
support for their wrists, and they may not have strong enough wrist flexors and extensors
they are more likely to injure the joint or muscles that extend the wrist. Most boxers use
tape or wrap to support their wrists.
Chris Crawford
Elbow
If the elbow is fully extended upon impact with the opponent, there is the risk of
hyperextension if the muscles antagonistic to the triceps brachii (the biceps brachii,
brachialis etc.) are not able to balance the force applied by the triceps. Since the cross is
not a completely straight punch, the elbow may hyperextend, causing damage to the
ligaments of the elbow joint.
Shoulder
When the punch hits the opponent or training bag, the muscles are susceptible to
tears because of the rapid deceleration caused by the impact. The shoulder joint may slow
down slower than the arm does, which can result in an injury to the rotator cuff. Repeated
punching may also cause tendonitis and even dislocation of the shoulder joint.
Treatment and Prevention
If an athlete fractures one of the many small bones in their hand, they will need to
see a doctor to have the bones set and a cast applied and rest the injury for at least 8
weeks. In more severe incidents, the boxer may crush multiple bones in the hand, which
could require surgery and an even longer resting period. Injuries to the wrist such as
sprains can be treated with by following the R.I.C.E. method and rested for about 3
weeks, although in some cases a splint may be needed to provide stability for the joint. If
the wrist becomes dislocated surgery may be required to repair torn ligaments. To prevent
future wrist and hand injuries from occurring, proper taping should be applied to both
hands to secure and support the joints.
Elbow hyperextension is a somewhat rare injury, but can cause severe pain and
discomfort for the athlete. Depending on the severity, treatment can range from resting
and icing the joint to the possibility of surgery.
Injuries to the rotator cuff muscles, depending on the severity of the tear, may
require resting, icing and rehabilitation before the athlete is ready to box again. The same
rule applies to a dislocated shoulder caused by the punch, however if many of the
ligaments of the shoulder joint are completely or mostly torn surgery is the most likely
solution. Following surgery, rehabilitation is required to improve the strength and
flexibility of the joint. The best way to avoid shoulder injuries in boxing is to practice
proper training techniques, keeping muscle strength balanced and getting the muscles
used to the repeated punching.
Chris Crawford
I hope that this information has been useful in developing any equipment that may
help to prevent injuries that an athlete may sustain while performing a cross punch in
boxing. Often the injuries caused to the joints of athletes through performing a punch are
overlooked because of the high impact nature of boxing, as professional boxers are
known to experience head and spinal injuries very often from taking so many punches. I
hope that this information will be helpful in improving the quality and technology of the
equipment.
References
Exercise Science textbook
http://www.body-basics.com/iap3.html#dan
http://tkdtutor.com/11Training/SparringInjuries.htm
http://sport.scotsman.com/boxing.cfm?id=311802007