Mel Siff Asks is There A Biceps Curl

Dr Mel Siff (www.drmelsiff.com) has posted this extract from his public Supertraining Discussion Group - http://health.groups.yahoo.com/group/supertraining - which originally came from his must-have book - Facts and Fallacies of Fitness.



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For some strange reason, the size of the arm biceps has become almost

synonymous with bodybuilding and even to strength, in some cases. The topic

of bicep building, or more correctly, elbow flexor hypertrophy, appears

prominently in every book on bodybuilding and in many letters to Internet

lists. Thus, I felt that it might be helpful to share this extract from my

"Facts and Fallacies of Fitness" book, which discusses hundreds of beliefs,

fallacies, myths, methods and ideas in the world of strength, fitness,

sports, rehabilitation and health. For those who may be curious about which

other topics are covered, the Table of Contents of this book appears in our

Supertraining files at:



http://groups.yahoo.com/group/Supertraining/files



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Is There A Biceps Curl?



The apparently simple biceps curl, although one of the trademarks of

bodybuilding, remains poorly understood by gymnasium users and scientists

alike. Even EMG (electromyographic) studies have proved notoriously

contradictory during attempts to ascertain exactly which arm muscles are

involved at a specific instant during elbow flexion.



Elbow flexion is produced by the cooperative action of the biceps brachii,

brachialis and brachioradialis. Of these, the biceps cross the shoulder and

the elbow joints, whereas the other two flexors act strictly on the elbow.

Thus, if strict arm flexion is to take place, there must be no movement about

the shoulder joint. This fact is well known to bodybuilders who execute the

curl with elbows dug into the sides of the trunk or with the back leaning

firmly against a wall.



Several basic factors profoundly effect which elbow flexors become involved

in any type of forearm curl:



- orientation of hand (pronated, supinated or neutral)

- the intensity of resistance to movement

- speed of movement

- degree of shoulder extension/flexion

- degree of shoulder abduction.



A detailed EMG study of elbow flexion performed with variations of these

factors was carried out by Basmajian (Muscles Alive, 1978). His time

analysis of activity revealed that there is a completely random sequence of

appearance and disappearance of activity in the different elbow flexors of

his subjects. In any sample of subjects, there appears to be no predictable

pattern among the muscles for activating, sustaining and terminating

flexion.



Moreover, muscles which display the greatest activity in individual subjects

only begin the movement first and end it last. He concluded that there is a

fine interplay between the biceps, brachialis and brachioradialis throughout

elbow flexion, so that it is inappropriate to identify a specific muscle as

playing a specific role at any given instant. Most remarkable was the wide

variation in the response produced by a given muscle. Although a general

trend may be described, the same type or sequence of activity rarely occurs

in different subjects.



The long head of the biceps (whose tendon passes through the shoulder joint

capsule) shows more activity than the short head in most subjects during slow

elbow flexion, during supination of the hand against resistance, and during

shoulder flexion. There is little difference in electrical activity between

the two heads of the biceps during isometric contraction or during eccentric

elbow extension. These observations are directly relevant to the bodybuilder

who wishes to exercise a specific head of the biceps more strongly.



Miwa and Matoba (quoted by Basmajian) found that, during slow elbow flexion,

biceps brachii is much more active electrically at certain angles of flexion.

Unlike the variation of isometric force with angle, the EMG reveals peak

activity at 160 degrees, almost nil at 90 degrees (surprisingly, where

isometric force is near a maximum), and strong activity at full flexion

(where isometric force is relatively low). Clearly, much still has to be

learned about the interaction between the nervous and muscular systems.



Biceps brachii is usually active during flexion of the supinated forearm for

all intensities of loading and during flexion of the semi-prone forearm

against resistance (as with 'hammer curls'). However, if the forearm is

prone (as with reverse grip curls), the biceps play a minimal role during

concentric and eccentric elbow flexion. This finding directly contradicts

the traditional belief among bodybuilders that the biceps continue to play a

major role during all forms of elbow flexion. It is brachialis which

displays this prominence, since it is active during fast and slow elbow

flexion with forearm prone, semi-prone or supinated at all intensities of

loading. It appears that brachialis contributes to all variations of elbow

flexion, since its line of pull does not change with pronation or supination.

This fact reveals that the term 'biceps curl' should be eliminated from the

exercise manuals and be replaced by the more accurate term 'arm curls' or

'elbow flexions'.



Brachioradialis does not play any significant role during any form of elbow

flexion without a weight, although it becomes much more strongly involved d

uring rapid flexion and extension with the forearm in all three positions of

rotation. This muscle, therefore, is seen to act as assistant mover when

rapid or strongly resisted flexion occurs.



All three elbow flexors contract strongly when a resistance is overcome

during flexion of the semi-prone forearm. Basmajian describes the semi-prone

orientation of the forearm as the natural position, the position of rest and

the position of greatest mechanical advantage for most functions of the upper

limb. In other words, the hammer curl, with palms facing the sides of the

body, rather than the supinated (palms up) curl, should be regarded as the

fundamental type of arm curl.



Another interesting finding is that the triceps - traditionally regarded as

only an extensor of the elbow - is strongly active during pulling movements

(such as seated rowing) with the elbow flexed. The biceps are powerfully

involved while the elbow is close to full extension, but the triceps

contribute as the angle of flexion increases, undoubtedly since the shoulder

is extended backwards, thereby making use of the long head of the triceps as

a shoulder extensor.



The apparently simple act of elbow flexion, often regarded as synonymous

with the so-called biceps curl, displays subtle nuances of functional

anatomy which have eluded much of the fitness community for many years. A

greater appreciation of the richness of all variations of elbow flexion would

contribute significantly to the implementation of more effective normal and

rehabilitative training.



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Mel Siff

http://www.melsiff.com

Mel Siff

Author of Supertraining

Author of Facts and Fallacies of Fitness

www.melsiff.com