King Grub
2018-07-17, 21:55
Background
Dumbbell curl (DC) and barbell curl in its two variants, straight (BC) or undulated bar (EZ) are typical exercises to train the elbow flexors. The aim of the study was to verify if the execution of these three variants could induce a selective electromyographic (EMG) activity of the biceps brachii (BB) and brachioradialis (BR).
Methods
Twelve participants performed one set of ten repetitions at 65% of their 1-RM for each variant of curl. Pre-gelled electrodes were applied with an inter-electrode distance of 24 mm on BB and BR. An electrical goniometer was synchronously recorded with EMG signals to determine the concentric and eccentric phases of each variant of curl.
Results
We detected higher activation profile of both BB (P < 0.05) and BR (P < 0.01) during the EZ compared to the DC. Higher levels of activation was found during the concentric phase for only the BR performed with an EZ compared to DC (P < 0.001) and performing BC compared to DC (P < 0.05). The eccentric phase showed a higher activation of the BB muscle in EZ compared to DC (P < 0.01) and in BC compared to DC (P < 0.05). The BR muscle showed a higher activation performing EZ compared to DC (P < 0.01).
Discussion
In the present work, the EZ variant exhibited the highest level of EMG activity for both BB and BR. However, significant differences were observed only in comparison with the DC variant. The concentric phase analysis of the BB showed that the EZ variant induced the highest level of EMG activity (+7% with respect to BC and +11% with respect to DC) although there were no statistically significant differences. Conversely, the variation of curls on BR muscle activity during the concentric phase resulted to be statistically significant when comparing the EZ to the DC as well as the BC to the DC.
The eccentric phase showed lower EMG activity with respect to the concentric phase for both muscles investigated. Specifically, EZ and BC variants elicited a statistically significant higher EMG activity of the BB muscle with respect to the DC variant. BR muscle activity was found to be significantly higher only in the EZ variant compared to the DC.
We can conclude that the EZ barbell curl was the most effective variant considering the overall EMG activity of the BB and BR. On the other hand, the DC variant was found to be less effective, while the BC variant could be placed in an intermediate position but with an activation closer to the EZ than to the DC variant for the two muscles investigated.
Our findings suggested that the EZ barbell curl may be preferred to DC considering the whole phase of the repetition and the eccentric phase both for BB and BR. The small difference between the BC and EZ variants with regards to the EMG activity of the BB and BR, makes the choice between these two variants purely a matter of subjective comfort related to the handgrip position.
Differences in electromyographic activity of biceps brachii and brachioradialis while performing three variants of curl. Peer J, July 13, 2018.
https://peerj.com/articles/5165/
Dumbbell curl (DC) and barbell curl in its two variants, straight (BC) or undulated bar (EZ) are typical exercises to train the elbow flexors. The aim of the study was to verify if the execution of these three variants could induce a selective electromyographic (EMG) activity of the biceps brachii (BB) and brachioradialis (BR).
Methods
Twelve participants performed one set of ten repetitions at 65% of their 1-RM for each variant of curl. Pre-gelled electrodes were applied with an inter-electrode distance of 24 mm on BB and BR. An electrical goniometer was synchronously recorded with EMG signals to determine the concentric and eccentric phases of each variant of curl.
Results
We detected higher activation profile of both BB (P < 0.05) and BR (P < 0.01) during the EZ compared to the DC. Higher levels of activation was found during the concentric phase for only the BR performed with an EZ compared to DC (P < 0.001) and performing BC compared to DC (P < 0.05). The eccentric phase showed a higher activation of the BB muscle in EZ compared to DC (P < 0.01) and in BC compared to DC (P < 0.05). The BR muscle showed a higher activation performing EZ compared to DC (P < 0.01).
Discussion
In the present work, the EZ variant exhibited the highest level of EMG activity for both BB and BR. However, significant differences were observed only in comparison with the DC variant. The concentric phase analysis of the BB showed that the EZ variant induced the highest level of EMG activity (+7% with respect to BC and +11% with respect to DC) although there were no statistically significant differences. Conversely, the variation of curls on BR muscle activity during the concentric phase resulted to be statistically significant when comparing the EZ to the DC as well as the BC to the DC.
The eccentric phase showed lower EMG activity with respect to the concentric phase for both muscles investigated. Specifically, EZ and BC variants elicited a statistically significant higher EMG activity of the BB muscle with respect to the DC variant. BR muscle activity was found to be significantly higher only in the EZ variant compared to the DC.
We can conclude that the EZ barbell curl was the most effective variant considering the overall EMG activity of the BB and BR. On the other hand, the DC variant was found to be less effective, while the BC variant could be placed in an intermediate position but with an activation closer to the EZ than to the DC variant for the two muscles investigated.
Our findings suggested that the EZ barbell curl may be preferred to DC considering the whole phase of the repetition and the eccentric phase both for BB and BR. The small difference between the BC and EZ variants with regards to the EMG activity of the BB and BR, makes the choice between these two variants purely a matter of subjective comfort related to the handgrip position.
Differences in electromyographic activity of biceps brachii and brachioradialis while performing three variants of curl. Peer J, July 13, 2018.
https://peerj.com/articles/5165/