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Muscular coordination of biceps brachii and brachioradialis in elbow flexion with respect to hand position.

Kleiber T, Kunz L, Disselhorst-Klug C - Front Physiol (2015)

Bottom Line: Normalized to MVC the sEMG amplitudes of both muscles contributing to elbow flexion movements were compared in pronated, supinated, and neutral hand position over elbow joint angle.Significant differences in the contribution of brachioradialis were found in pronated hand position compared to supinated and neutral hand position while the muscular activity of biceps brachii shows no significant changes in any hand position.In conclusion, a statistical significant dependency of the inter-muscular coordination between biceps brachii and brachioradialis during elbow flexion with respect to hand position has been observed depending on a biomechanical disadvantage of biceps brachii.

View Article: PubMed Central - PubMed

Affiliation: Department of Rehabilitation and Prevention Engineering, Institute of Applied Medical Engineering, RWTH Aachen University Aachen, Germany ; German Research School for Simulation Sciences, Joint Graduate School of RWTH Aachen University and Forschungszentrum Jülich Jülich, Germany.

ABSTRACT
Contribution of synergistic muscles toward specific movements over multi joint systems may change with varying position of distal or proximal joints. Purpose of this study is to reveal the relationship of muscular coordination of brachioradialis and biceps brachii during elbow flexion with respect to hand position and biomechanical advantages and disadvantages of biceps brachii. A group of 16 healthy subjects has been advised to perform 20 repetitions of single elbow flexion movements in different hand positions (pronated, neutral, and supinated). With a speed of 20°/s, simultaneously sEMG of biceps brachii and brachioradialis and kinematics of the movement were recorded in a motion analysis laboratory. Normalized to MVC the sEMG amplitudes of both muscles contributing to elbow flexion movements were compared in pronated, supinated, and neutral hand position over elbow joint angle. Significant differences in the contribution of brachioradialis were found in pronated hand position compared to supinated and neutral hand position while the muscular activity of biceps brachii shows no significant changes in any hand position. In conclusion, a statistical significant dependency of the inter-muscular coordination between biceps brachii and brachioradialis during elbow flexion with respect to hand position has been observed depending on a biomechanical disadvantage of biceps brachii.

No MeSH data available.


Stepwise mean normalized sEMG amplitude of brachioradialis in three different hand positions in intervals of 25° of elbow flexion joint angle showing statistical significant differences in pronated hand position in comparison to neutral and supinated hand position.
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Figure 3: Stepwise mean normalized sEMG amplitude of brachioradialis in three different hand positions in intervals of 25° of elbow flexion joint angle showing statistical significant differences in pronated hand position in comparison to neutral and supinated hand position.

Mentions: Statistical analysis shows significant differences (*) in muscular activation pattern of brachioradialis during elbow flexion with respect to hand position (p < 0.05). The Post-hoc Tukey Test shows not only a general difference between the activation patterns of both elbow flexors with respect to hand position but additionally a significantly higher difference in pronated than in supinated and neutral hand position while the activity of biceps brachii remains constant. Between supinated and neutral hand position there were no significantly differences in muscular coordination pattern of both muscles (biceps p = 0.75, brachioradialis p = 0.67). In biceps brachii there are no significant differences (p = 0.63) in any hand position. Figure 3 shows the mean value of the activation level of brachioradialis in steps of 25° of elbow joint angle in all three different hand positions. Significant differences are found in pronated in comparison to supinated and neutral hand position in all considered intervals.


Muscular coordination of biceps brachii and brachioradialis in elbow flexion with respect to hand position.

Kleiber T, Kunz L, Disselhorst-Klug C - Front Physiol (2015)

Stepwise mean normalized sEMG amplitude of brachioradialis in three different hand positions in intervals of 25° of elbow flexion joint angle showing statistical significant differences in pronated hand position in comparison to neutral and supinated hand position.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526813&req=5

Figure 3: Stepwise mean normalized sEMG amplitude of brachioradialis in three different hand positions in intervals of 25° of elbow flexion joint angle showing statistical significant differences in pronated hand position in comparison to neutral and supinated hand position.
Mentions: Statistical analysis shows significant differences (*) in muscular activation pattern of brachioradialis during elbow flexion with respect to hand position (p < 0.05). The Post-hoc Tukey Test shows not only a general difference between the activation patterns of both elbow flexors with respect to hand position but additionally a significantly higher difference in pronated than in supinated and neutral hand position while the activity of biceps brachii remains constant. Between supinated and neutral hand position there were no significantly differences in muscular coordination pattern of both muscles (biceps p = 0.75, brachioradialis p = 0.67). In biceps brachii there are no significant differences (p = 0.63) in any hand position. Figure 3 shows the mean value of the activation level of brachioradialis in steps of 25° of elbow joint angle in all three different hand positions. Significant differences are found in pronated in comparison to supinated and neutral hand position in all considered intervals.

Bottom Line: Normalized to MVC the sEMG amplitudes of both muscles contributing to elbow flexion movements were compared in pronated, supinated, and neutral hand position over elbow joint angle.Significant differences in the contribution of brachioradialis were found in pronated hand position compared to supinated and neutral hand position while the muscular activity of biceps brachii shows no significant changes in any hand position.In conclusion, a statistical significant dependency of the inter-muscular coordination between biceps brachii and brachioradialis during elbow flexion with respect to hand position has been observed depending on a biomechanical disadvantage of biceps brachii.

View Article: PubMed Central - PubMed

Affiliation: Department of Rehabilitation and Prevention Engineering, Institute of Applied Medical Engineering, RWTH Aachen University Aachen, Germany ; German Research School for Simulation Sciences, Joint Graduate School of RWTH Aachen University and Forschungszentrum Jülich Jülich, Germany.

ABSTRACT
Contribution of synergistic muscles toward specific movements over multi joint systems may change with varying position of distal or proximal joints. Purpose of this study is to reveal the relationship of muscular coordination of brachioradialis and biceps brachii during elbow flexion with respect to hand position and biomechanical advantages and disadvantages of biceps brachii. A group of 16 healthy subjects has been advised to perform 20 repetitions of single elbow flexion movements in different hand positions (pronated, neutral, and supinated). With a speed of 20°/s, simultaneously sEMG of biceps brachii and brachioradialis and kinematics of the movement were recorded in a motion analysis laboratory. Normalized to MVC the sEMG amplitudes of both muscles contributing to elbow flexion movements were compared in pronated, supinated, and neutral hand position over elbow joint angle. Significant differences in the contribution of brachioradialis were found in pronated hand position compared to supinated and neutral hand position while the muscular activity of biceps brachii shows no significant changes in any hand position. In conclusion, a statistical significant dependency of the inter-muscular coordination between biceps brachii and brachioradialis during elbow flexion with respect to hand position has been observed depending on a biomechanical disadvantage of biceps brachii.

No MeSH data available.