scholarly journals Differential muscle function between muscle synergists: long and lateral heads of the triceps in jumping and landing goats (Capra hircus)

2008 ◽  
Vol 105 (4) ◽  
pp. 1262-1273 ◽  
Author(s):  
Andrew M. Carroll ◽  
David V. Lee ◽  
Andrew A. Biewener
Keyword(s):  
Muscle Function ◽  
High Speed ◽  
Muscle Activation ◽  
Reaction Force ◽  
Elbow Flexion ◽  
Capra Hircus ◽  
Triceps Brachii ◽  
Joint Work ◽  
Long Head ◽  
Lateral Head

We investigate how the biarticular long head and monoarticular lateral head of the triceps brachii function in goats ( Capra hircus) during jumping and landing. Elbow moment and work were measured from high-speed video and ground reaction force (GRF) recordings. Muscle activation and strain were measured via electromyography and sonomicrometry, and muscle stress was estimated from elbow moment and by partitioning stress based on its relative strain rate. Elbow joint and muscle function were compared among three types of limb usage: jump take-off (lead limb), the step prior to jump take-off (lag limb), and landing. We predicted that the strain and work patterns in the monoarticular lateral head would follow the kinematics and work of the elbow more closely than would those of the biarticular long head. In general this prediction was supported. For instance, the lateral head stretched (5 ± 2%; mean ± SE) in the lead and lag limbs to absorb work during elbow flexion and joint work absorption, while the long head shortened (−7 ± 1%) to produce work. During elbow extension, both muscles shortened by similar amounts (−10 ± 2% long; −13 ± 4% lateral) in the lead limb to produce work. Both triceps heads functioned similarly in landing, stretching (13 ± 3% in the long head and 19 ± 5% in the lateral) to absorb energy. In general, the long head functioned to produce power at the shoulder and elbow, while the lateral head functioned to resist elbow flexion and absorb work, demonstrating that functional diversification can arise between mono- and biarticular muscle agonists operating at the same joint.

Mind-Muscle Connection: Verbal Instructions Alter Electromyographic Activity for Elbow Flexors and Extensors During Co-Contraction Training

2020 ◽  
pp. 003151252094908
Author(s):  
Rafael A. Fujita ◽  
Marina M. Villalba ◽  
Nilson R. S. Silva ◽  
Matheus M. Pacheco ◽  
Matheus M. Gomes
Keyword(s):  
Strength Training ◽  
Elbow Joint ◽  
Biceps Brachii ◽  
Elbow Flexion ◽  
Emg Activity ◽  
Elbow Extension ◽  
Verbal Instruction ◽  
Triceps Brachii ◽  
Verbal Instructions ◽  
Lateral Head

Co-contraction training has demonstrated similar electromyographic (EMG) activity levels compared to conventional strength training. Since verbal instructions can increase EMG activity on target muscles during conventional exercises, the same should occur during co-contraction. In this study we analyzed whether different verbal instructions would alter the EMG activity of target muscles - biceps brachii (BB) and triceps brachii lateral head (TB) - during co-contraction training for the elbow joint. Seventeen males with experience in strength training performed a co-contraction set in two verbal instruction conditions to emphasize either elbow flexion or elbow extension. Surface electrodes were fixed over biceps brachii and triceps brachii lateral head muscles. We measured EMG mean amplitude and analyzed data with 2-way ANOVA. We found a significant interaction between muscle and verbal instruction ( p = 0.002). Post hoc tests indicated that verbal instructions ( p = 0.001) influenced the BB EMG activity (elbow flexion: M = 68.74, SD = 17.96%; elbow extension: M = 53.47, SD = 16.13%); and also showed difference ( p = 0.006) in the EMG activity between BB and TB with verbal instruction emphasizing the elbow extension (BB: M = 53.47, SD = 16.13%; TB: M = 69.18, SD = 21.79%). There was a difference in the EMG ratio of BB/TB ( p = 0.001) when focusing on elbow flexion ( M = 1.09, SD = 0.30) versus elbow extension ( M = 0.81, SD = 0.25). As verbal instruction modified the magnitude of muscle recruitment during co-contractions for elbow joint muscles, there is a clear mind-muscle connection of importance to this method of training. Also, of importance to trainers, verbal instructions seemed to affect individuals differentially.

scholarly journals Ulnar nerve contribution in the innervation of the triceps brachii muscle ulnar nerve to the triceps brachii

1970 ◽  
Vol 6 (1) ◽  
pp. 834-839
Author(s):  
DLR Silva ◽  
MP Barros ◽  
TGS Freire ◽  
L Firmino Júnior ◽  
WRB Almeida Filho ◽  
...  
Keyword(s):  
Brachial Plexus ◽  
Ulnar Nerve ◽  
Terminal Branch ◽  
Upper Limbs ◽  
Triceps Brachii ◽  
Medial Head ◽  
Muscle Innervation ◽  
Triceps Brachii Muscle ◽  
Long Head ◽  
Lateral Head

The ulnar nerve is considered the thickest terminal branch of the medial cord in the brachial plexus and most authors does not mention the possibility of this nerve emitting branches to the arm. However, some studies reported that the ulnar nerve could supply the medial head of triceps brachii muscle. The main objective in this study was identifying the presence of ulnar nerve branches in triceps brachii muscle. Sixty upper limbs of adult Brazilian corpses of both sexes were used. The estimated age was between 25 and 80 years old. Every studied piece had the nerves and their branches quantified and measured with a manual mechanic caliper. The branches were photographed and had the data registered in individual files. Were found ulnar nerve branches for all the heads of triceps brachii muscle: 1 branch (9,1%) to lateral head, 2 branches (18,1%) to long head and 8 branches (72,7%) to medial head. Thus, we can conclude that the contribution of ulnar nerve to triceps brachii muscle constitutes an important anatomical variation.Key words: Ulnar nerve; Triceps brachii muscle; Innervation.

Muscle synergies and isometric torque production: influence of supination and pronation level on elbow flexion

1993 ◽  
Vol 70 (3) ◽  
pp. 947-960 ◽  
Author(s):  
J. C. Jamison ◽  
G. E. Caldwell
Keyword(s):  
Biceps Brachii ◽  
Muscular Activity ◽  
Elbow Flexion ◽  
Normal Subjects ◽  
Analysis Of Covariance ◽  
Triceps Brachii ◽  
Emg Amplitude ◽  
Task Effects ◽  
Long Head ◽  
The Relationship

1. Twenty normal subjects performed a series of isometric elbow flexion (F) maximum voluntary contractions (MVC) while simultaneously maintaining one of seven targeted torque levels in the supination/pronation (S/P) degree of freedom (df). Experimental measures were torque in both df s and surface electromyograms (EMG) from brachioradialis (BRAD), triceps brachii (TB), biceps brachii (BB) short head (BBSH), and a medial and lateral site on biceps brachii long head (MED BB and LAT BB). Task effects were tested for significance using analysis of covariance models for the torque and EMG variables. Polynomial multiple regression models were developed for significant effects. The synergism among muscles was examined by statistically testing the EMG data for differing responses to the S/P torque changes across the five electrode sites. 2. The magnitude of the S/P target torque had a statistically significant effect on flexion MVC (F MVC) torque. Changes in S/P torque markedly influenced the F MVC torque magnitude, with as much as a 25% F torque decrement relative to an F MVC with an S/P torque target of 0. This suggests that the second df task affects some aspect of joint function that causes the CNS to reduce F torque capacity. 3. The S/P torque had a significant effect on EMG amplitude at all electrode sites other than TB. The EMG amplitude at the BB sites responded strongly to both F and S/P torque changes. The F+S tasks tended to facilitate BB EMG, whereas the F+P tasks tended to diminish it. The BRAD EMG, although primarily related to F torque amplitude, also was influenced by the S/P torque changes. The trends for BRAD EMG were opposite those for the BB in that BRAD EMG tended to be enhanced by the F+P tasks and reduced by the F+S tasks. 4. The synergistic pattern of stimulation (i.e., the relationship among the 5 EMG amplitude measures) was also significantly influenced by the S/P df task. Significant differences in the EMG behavior between BBSH and LAT BB were detected; however, no statistically significant differences were found between LAT BB and MED BB. The EMG behaviors at the BRAD and TB electrode sites were significantly different from those at the BB sites. 5. These inversely related responses from the BB and BRAD stress the importance of understanding the relationship between muscular activity and the function of muscles in more than one df. This finding further suggests that the synergistic relationships between muscles are dynamically related to task in all applicable dfs. It is suggested that this dynamic synergism is a natural consequence of the redundant musculoskeletal system.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Muscle Activation in Traditional and Experimental Barbell Bench Press Exercise: A Potential New Tool for Fitness Maintenance

Sports ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 224
Author(s):  
Andrea Melani ◽  
Giuliana Gobbi ◽  
Daniela Galli ◽  
Cecilia Carubbi ◽  
Elena Masselli ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Professional Training ◽  
Muscle Activation ◽  
Bench Press ◽  
Biceps Brachii ◽  
Elbow Flexion ◽  
Upper Body ◽  
Triceps Brachii ◽  
Extended Position ◽  
Lower Load

Background: The bench press exercise (BP) is commonly practiced in both recreational and professional training. The weight is lowered from a position where the elbows are at a 90° angle at the start and <90° at the end of eccentric phase, and then returned to the elbows extended position. In order to focus the exercise more on the triceps brachii (TB) rather than the pectoralis major (PM), the inter-handle distance (IHD) is decreased diminishing the involvement of the PM in favor of the TB. Purpose: To improve performance of the exercise by reducing force dissociation and transmitting 100% of the external load to the muscle tissue we propose a prototype of the barbell with a bar on which two sleeves are capable of sliding. The dynamic modifications of the IHD keep the elbow flexion angle constant at 90°. Results: Analysis of the inter-handle distance (IHD) signals of the upper body muscles showed a marked increase in muscle activity using the experimental barbell for the PM (19.5%) and for the biceps brachii (173%). Conclusions: The experimental barbell increased the muscle activity typical of the bench press exercise, obtaining the same training induction with a lower load and consequently preventing articular stress.

scholarly journals Mind-muscle connection: effects of verbal instructions on muscle activity during bench press exercise

2019 ◽  
Vol 29 (2) ◽  
Author(s):  
Antonio Paoli ◽  
Laura Mancin ◽  
Matteo Saoncella ◽  
Davide Grigoletto ◽  
Francesco Q. Pacelli ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Bench Press ◽  
Pectoralis Major ◽  
Triceps Brachii ◽  
Repetition Maximum ◽  
Verbal Instructions ◽  
Anterior Deltoid ◽  
Long Head ◽  
Electromyographic Signals

Different attentional foci may modify muscle activation during exercises. Our aim was to determine if it is possible to selectively activate the pectoralis major or triceps brachii muscles according to specific verbal instructions provided during the bench press exercise. 13 resistance-trained males (25.6±5.4 yrs, 182.7±9.1 cm, 86.4±9.7 kg) underwent an electromyographic signals acquisition of the sternocostal head, clavicular head of the pectoralis major, the anterior deltoid, and the long head of the triceps brachii (LT) during bench press exercise. Participants performed one non-instructed set (NIS) of 4 repetitions at 50% 1-repetition maximum (1-RM) and one NIS of 4 repetitions at 80% 1-RM. Four additional sets of 4 repetitions at 50% and 80% 1-RM were randomly performed with verbal instructions to isolate the chest muscles (chest instructed set, CIS) or to isolate the triceps muscles (triceps instructed set, TIS). Participants showed significantly higher LT activation during TIS compared to non-instructed set both at 50% (p=0.0199) and 80% 1-RM (p=0.0061) respectively. TIS elicited a significant (p=0.0250) higher activation of LT compared to CIS. Our results suggest that verbal instructions seem to be effective for increasing activity of the triceps brachii but not the pectoralis major during the bench press.

scholarly journals Muscle activation time and free-throw effectiveness in basketball

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paweł Pakosz ◽  
Przemysław Domaszewski ◽  
Mariusz Konieczny ◽  
Dawid Bączkowicz
Keyword(s):  
High Speed ◽  
Muscle Activation ◽  
Activation Time ◽  
Triceps Brachii ◽  
Training Experience ◽  
Basketball Players ◽  
Free Throw ◽  
Triceps Brachii Muscle ◽  
The Right ◽  
The Relationship

AbstractThis study attempts to analyze the relationship between free-throw efficiency and the time of arm muscle activation in players from 3 basketball teams with different levels of experience was investigated. During the experiment each player made 20 free throws during which the activation time of his right and left biceps and triceps brachii muscles were measured with the use of surface electromyography and high-speed cameras. Significant differences in muscle activation time (t) during a free throw were found between the groups of basketball players (p = 0.038) (novices: t = 0.664 ± 0.225 s, intermediate-level players: t = 1.15 ± 0.146 s, experts: t = 1.01 ± 0.388 s). In the right triceps brachii muscle in expert basketball players the coefficient of variation (CV) amounted to 44.60% at 81% efficiency, and in novices to 27.12% at 53% efficiency. The time of arm muscle activation during a free throw and its fluctuations vary along with the training experience of basketball players. In all studied groups of players, the variability of muscle activation time in accurate free throws is greater than in inaccurate free throws. Free-throw speed is irrelevant for free-throw efficiency.

scholarly journals Altered muscle activation in agility dogs performing warm-up exercises: an acoustic myography study

2020 ◽  
pp. 1-12
Author(s):  
L.H. Fuglsang-Damgaard ◽  
A.P. Harrison ◽  
A.D. Vitger
Keyword(s):  
Muscle Function ◽  
Muscle Activation ◽  
Spatial Summation ◽  
Firing Frequency ◽  
Muscle Fibres ◽  
Training Level ◽  
Triceps Brachii ◽  
Warm Up ◽  
Before And After ◽  
Acoustic Myography

Agility is physically demanding and dogs encounter a considerable risk of injury during training and competition. Pre-performance warm-up is used routinely among human athletes to prepare the tissues for these physical demands, but in canine sports evidence for effects of warm-up is lacking. The aim of this study was to investigate the effects of warm-up in dogs on two major muscles involved in locomotion. It was hypothesised that, after warm-up, the muscles would be used more efficiently (more fibre resting time/total time), recruit fewer fibres (reduced spatial summation) and/or activated with a lower firing frequency (reduced temporal summation). The following factors ‘sex, age, weight, height, training level and agility experience’ were evaluated for their potential impact on muscle function parameters. Fourteen large (≥46 cm at the withers) agility dogs of different breeds and training levels performed a 5 min warm-up program three times, with a 2 min break between the programs for recording purposes. Acoustic myography sensors were attached on the skin over the muscles m. triceps brachii (TB) and m. gluteus superficialis (GS). Recordings of muscle activity were made, while the dogs trotted before warm-up and after each 5 min warm-up program. The dogs used TB more efficiently after 5 min (P<0.05), 10 min (P<0.05) and 15 min (P<0.001) of exercise compared to pre-warm-up values. No changes were found in the activity of GS. For well-trained dogs, TB recruited fewer muscle fibres after 10 and 15 min of warm-up compared to dogs that trained less than 1 h weekly (P<0.03). For dogs with more than 2 years of experience, GS had a lower firing frequency before and after 10 min warm-up compared to dogs with less experience. The results indicate that warm-up alters muscle activation by an increased muscular efficiency. Training level and experience have an influence on muscle function parameters.

scholarly journals Comparison of shoulder and trunk muscle activation between different pullover exercises

2020 ◽  
Vol 13 (3) ◽  
pp. 127-133
Author(s):  
Pedro R Pezarat-Correia ◽  
Pedro R Medeiros ◽  
Orlando J Fernandes ◽  
João R Vaz ◽  
Luis Silva ◽  
...  
Keyword(s):  
Surface Electromyography ◽  
Latissimus Dorsi ◽  
Muscle Activation ◽  
Random Order ◽  
Transversus Abdominis ◽  
Electromyographic Activity ◽  
Triceps Brachii ◽  
Serratus Anterior ◽  
Long Head ◽  
Swiss Ball

Objective: To quantify and compare the electromyographic activity of 10 muscles in three pullover exercises. Methods: 15 healthy men, with at least two years of experience in resistance training, executed in random order six repetitions with 60% of 1 Maximum Repetition for three different pullover exercises: lying on a step with a barbell, grip 100% biacromial (E1); lying on a step with a barbell, grip 150% (E2); lying on a Swiss ball with a barbell, grip 100% (E3). Surface electromyography was recorded from the Deltoideus (Clavicular and Spinalis Pars), Pectoralis Major (Clavicular and Sternocostalis Pars), Serratus Anterior, Triceps Brachii (Long Head), Latissimus Dorsi, Infraspinatus, Rectus Abdominis, Obliquus Internus Abdominis and Transversus Abdominis. The normalized Maximum Repetition electromyographyc of each muscle was calculated for each exercise. Results: The most engaged muscles were Infraspinatus (51-53%) and Posterior Deltoid (49-51%). Surface electromyography activity was similar between the E1, E2 and E3 exercises. Conclusions: This study quantified muscular solicitation during pullover exercises performed with 60% Maximum Repetition. The muscles with higher level of activation were the Posterior Deltoid and the Infraspinatus, suggesting that pullover may be a valid option for strengthening the dynamic stabilizing muscles of shoulder joint in trained individuals. No significant differences in muscle electromyography intensity were observed when grip distance and trunk stabilization were altered, showing that these conditions do not influence muscle activation levels. However, the 1 Maximum Repetition was lower when the pullover was performed on a Swiss ball, suggesting that it is possible to obtain higher level of muscle recruitment with lower weights in unstable exercises.

Strategies for muscle activation during isometric torque generation at the human elbow

1989 ◽  
Vol 62 (6) ◽  
pp. 1201-1212 ◽  
Author(s):  
T. S. Buchanan ◽  
G. P. Rovai ◽  
W. Z. Rymer
Keyword(s):  
Muscle Activation ◽  
Biceps Brachii ◽  
Human Subjects ◽  
Elbow Flexion ◽  
Emg Activity ◽  
Elbow Extension ◽  
Triceps Brachii ◽  
Pronator Teres ◽  
Flexion Extension ◽  
Torque Generation

1. We studied the patterns of electromyographic (EMG) activity in elbow muscles of 14 normal human subjects. The activity of five muscles that act in flexion-extension and forearm supination-pronation was simultaneously recorded during isometric voluntary torque generation, in which torques generated in a plane orthogonal to the long axis of the forearm were voluntarily coupled with torques generated about the long axis of the forearm (i.e., supination-pronation). 2. When forearm supination torques were superimposed on a background of elbow flexion torque, biceps brachii activity increased substantially, as expected; however, brachioradialis and brachialis EMG levels decreased modestly, a less predictable outcome. The pronator teres was also active during pure flexion and flexion coupled with mild supination (even though no pronation torque was required). This was presumably to offset inappropriate torque contributions of other muscles, such as the biceps brachii. 3. When forearm supination torque was superimposed on elbow extension torque, again the biceps brachii was strongly active. The pronator teres also became mildly active during extension with added pronation torque. These changes occurred despite the fact that both the pronator and biceps muscles induce elbow flexion. 4. In these same elbow extension tasks, triceps brachii activity was also modulated with both pronation or supination loads. It was most active during either supination or pronation loads, again despite the fact that it has no mechanical role in producing forearm supination-pronation torque. 5. Recordings of EMG activity during changes in forearm supination-pronation angle demonstrated that activation of the biceps brachii followed classic length-tension predictions, in that less EMG activity was required to achieve a given supination torque when the forearm was pronated (where biceps brachii is relatively longer). On the other hand, EMG activity of the pronator teres did not decrease when the pronator was lengthened. Triceps EMG was also more active when the forearm was supinated, despite its having no direct functional role in this movement. 6. Plots relating EMG activity in biceps brachii, brachialis, and brachioradialis at three different forearm positions revealed that there was a consistent positive near-linear relationship between brachialis and brachioradialis and that biceps brachii is often most active when brachioradialis and brachialis are least active. 7. We argue that, for the human elbow joint at least, fixed muscle synergies are rather uncommon and that relationships between muscle activities are situation dependent.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Measurements of Tendon Movement Within the Bicipital Groove After Suprapectoral Intra-articular Biceps Tenodesis in a Cadaveric Model

2021 ◽  
Vol 9 (1) ◽  
pp. 232596712097753
Author(s):  
Brian J. Kelly ◽  
Alan W. Reynolds ◽  
Patrick J. Schimoler ◽  
Alexander Kharlamov ◽  
Mark Carl Miller ◽  
...  
Keyword(s):  
Biceps Tendon ◽  
Full Range ◽  
Elbow Flexion ◽  
Biceps Tenodesis ◽  
Bicipital Groove ◽  
Biceps Tenotomy ◽  
Flexion Extension ◽  
Before And After ◽  
Long Head ◽  
Scapular Motion

Background: Lesions of the long head of the biceps can be successfully treated with biceps tenotomy or tenodesis when surgical management is elected. The advantage of a tenodesis is that it prevents the potential development of a cosmetic deformity or cramping muscle pain. Proponents of a subpectoral tenodesis believe that “groove pain” may remain a problem after suprapectoral tenodesis as a result of persistent motion of the tendon within the bicipital groove. Purpose/Hypothesis: To evaluate the motion of the biceps tendon within the bicipital groove before and after a suprapectoral intra-articular tenodesis. The hypothesis was that there would be minimal to no motion of the biceps tendon within the bicipital groove after tenodesis. Study Design: Controlled laboratory study. Methods: Six fresh-frozen cadaveric arms were dissected to expose the long head of the biceps tendon as well as the bicipital groove. Inclinometers and fiducials (optical markers) were used to measure the motions of the scapula, forearm, and biceps tendon through a full range of shoulder and elbow motions. A suprapectoral biceps tenodesis was then performed, and the motions were repeated. The motion of the biceps tendon was quantified as a function of scapular or forearm motion in each plane, both before and after the tenodesis. Results: There was minimal motion of the native biceps tendon during elbow flexion and extension but significant motion during all planes of scapular motion before tenodesis, with the most motion occurring during shoulder flexion-extension (20.73 ± 8.21 mm). The motion of the biceps tendon after tenodesis was significantly reduced during every plane of scapular motion compared with the native state ( P < .01 in all planes of motion), with a maximum motion of only 1.57 mm. Conclusion: There was a statistically significant reduction in motion of the biceps tendon in all planes of scapular motion after the intra-articular biceps tenodesis. The motion of the biceps tendon within the bicipital groove was essentially eliminated after the suprapectoral biceps tenodesis. Clinical Relevance: This arthroscopic suprapectoral tenodesis technique can significantly reduce motion of the biceps tendon within the groove in this cadaveric study, possibly reducing the likelihood of groove pain in the clinical setting.

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