scholarly journals Establishing the Role of Elbow Muscles by Evaluating Muscle Activation and Co-contraction Levels at Maximal External Rotation in Fastball Pitching

2021 ◽  
Vol 3 ◽  
Author(s):  
Bart van Trigt ◽  
Eva Galjee ◽  
Marco J. M. Hoozemans ◽  
Frans C. T. van der Helm ◽  
DirkJan H. E. J. Veeger
Keyword(s):  
Injury Risk ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
External Rotation ◽  
Ulnar Collateral Ligament ◽  
Moderate Activity ◽  
Triceps Brachii ◽  
Collateral Ligament ◽  
Medial Side

Background: Baseball pitching is associated with a high prevalence of ulnar collateral ligament injuries, potentially due to the high external valgus load on the medial side of the elbow at the instant of maximal shoulder external rotation (MER). In-vitro studies show that external valgus torque is resisted by the ulnar collateral ligament but could also be compensated by elbow muscles. As the potential active contribution of these muscles in counteracting external valgus load during baseball pitching is unknown, the aim of this study is to determine whether and to what extent the elbow muscles are active at and around MER during a fastball pitch in baseball.Methods: Eleven uninjured pitchers threw 15 fastball pitches. Surface electromyography of six muscles crossing the elbow were measured at 2000 Hz. Electromyography signals were normalized to maximal activity values. Co-contraction index (CCI) was calculated between two pairs of the flexor and extensor elbow muscles. Confidence intervals were calculated at the instant of MER. Four ranges of muscle activity were considered; 0–20% was considered low; 21–40% moderate; 41–60% high and over 60% as very high. To determine MER, the pitching motion was captured with a highspeed camera at 240 Hz.Results: The flexor pronator mass, pronator teres, triceps brachii, biceps brachii, extensor supinator mass and anconeus show moderate activity at MER. Considerable variation between participants was found in all muscles. The CCI revealed co-contraction of the two flexor-extensor muscle pairs at MER.Interpretation: The muscle activation of the flexor and pronator muscles at MER indicates a direct contribution of forearm muscles crossing the medial side of the elbow in counteracting the external valgus load during fastball pitching. The activation of both flexor and extensor muscles indicates an in-direct contributory effect as the combined activity of these muscles counteract opening of the humeroulnar joint space. We believe that active muscular contributions counteracting the elbow valgus torque can be presumed to relieve the ulnar collateral ligament from maximal stress and are thus of importance in injury risk assessment in fastball pitching in baseball.

The Effectiveness of a Hinged Elbow Orthosis in Medial Collateral Ligament Injuries: An In Vitro Biomechanical Study

2019 ◽  
Vol 47 (12) ◽  
pp. 2827-2835
Author(s):  
Ranita H.K. Manocha ◽  
James A. Johnson ◽  
Graham J.W. King
Keyword(s):  
Medial Collateral Ligament ◽  
Muscle Activation ◽  
Mechanical Stability ◽  
Biomechanical Study ◽  
Return To Play ◽  
Collateral Ligament ◽  
Valgus Stress ◽  
Active Motion ◽  
Early Return

Background: Medial collateral ligament (MCL) injuries are common after elbow trauma and in overhead throwing athletes. A hinged elbow orthosis (HEO) is often used to protect the elbow from valgus stress early after injury and during early return to play. However, there is minimal evidence regarding the efficacy of these orthoses in controlling instability and their influence on long-term clinical outcomes. Purpose: (1) To quantify the effect of an HEO on elbow stability after simulated MCL injury. (2) To determine whether arm position, forearm rotation, and muscle activation influence the effectiveness of an HEO. Study Design: Controlled laboratory study. Methods: Seven cadaveric upper extremity specimens were tested in a custom simulator that enabled elbow motion via computer-controlled actuators and motors attached to relevant tendons. Specimens were examined in 2 arm positions (dependent, valgus) and 2 forearm positions (pronation, supination) during passive and simulated active elbow flexion while unbraced and then while braced with an HEO. Testing was performed in intact elbows and repeated after simulated MCL injury. An electromagnetic tracking device measured valgus angulation as an indicator of elbow stability. Results: When the arm was dependent, the HEO increased valgus angle with the forearm in pronation (+1.0°± 0.2°, P = .003) and supination (+1.5°± 0.0°, P = .006) during active motion. It had no significant effect on elbow stability during passive motion. In the valgus position, the HEO had no effect on elbow stability during passive or active motion in pronation and supination. With the arm in the valgus position with the HEO, muscle activation reduced instability during pronation (–10.3°± 2.5°, P = .006) but not supination ( P = .61). Conclusion: In this in vitro study, this HEO did not enhance mechanical stability when the arm was in the valgus and dependent positions after MCL injury. Clinical Relevance: After MCL injury, an HEO likely does not provide mechanical elbow stability during rehabilitative exercises or when the elbow is subjected to valgus stress such as occurs during throwing.

scholarly journals Professional and Amateur Pitchers’ Perspective on the Ulnar Collateral Ligament Injury Risk

2019 ◽  
Vol 7 (6) ◽  
pp. 232596711985077
Author(s):  
Danica D. Vance ◽  
Frank J. Alexander ◽  
Brian W. Kunkle ◽  
Mark Littlefield ◽  
Christopher S. Ahmad
Keyword(s):  
Injury Risk ◽  
Ulnar Collateral Ligament ◽  
Cross Sectional Study ◽  
Ligament Injury ◽  
Collateral Ligament ◽  
Chi Square ◽  
Cross Sectional ◽  
Elbow Injury ◽  
Increased Risk ◽  
Baseball Pitchers

Background: Medial ulnar collateral ligament (UCL) injury is increasingly prevalent in professional baseball pitchers, and significant research has been devoted to understanding the risk factors and prevention strategies associated with it. To date, no study has investigated what the players themselves believe causes and prevents the injury. Purpose: To evaluate the opinions of UCL injuries among pitchers, including professional athletes. Study Design: Cross-sectional study. Methods: A total of 214 baseball pitchers (45 high school/college, 169 Major League Baseball [MLB]/Minor League Baseball) completed a 52-item questionnaire designed to evaluate their opinions on the cause of UCL injuries, injury prevention, and Tommy John surgery. Overall, 51 of the 214 pitchers had previously experienced a UCL injury. The frequency of the selection of each answer option was measured. Additionally, chi-square tests were used to compare (1) responses between professional and nonprofessional pitchers and (2) responses between pitchers with and without a previous UCL injury. Results: Only 45% of pitchers thought that UCL injuries are avoidable in MLB. Additionally, 55% of pitchers with a UCL injury had a history of elbow injuries as an adolescent/child, compared with 18% in the uninjured group ( P < .0001). Also, 72% of all surveyed pitchers agreed that fatigue over the course of a season increases the risk of UCL injuries, and the majority of pitchers agreed that inadequate rest from throwing both during the off-season (61%) and the season (59%) increases the risk of UCL injuries. Moreover, 59% of pitchers believed that a 6-man starting rotation would decrease the incidence of UCL injuries. Professional and nonprofessional pitchers significantly differed ( P = .005) in the type of pitch most prone to causing UCL injuries. Conclusion: Pitchers with a previous childhood elbow injury had a significantly higher incidence of UCL injuries during their adult career, suggesting possible predisposition to UCL injury and warranting further research. Fatigue and inadequate rest were of greatest concern among all pitchers for an increased risk of UCL injuries. Understanding and acknowledging the opinions that players have regarding UCL injuries are important to improve UCL education, prevention, and treatment.

scholarly journals The Role of Motor Learning on Measures of Physical Requirements and Motor Variability During Repetitive Screwing

2019 ◽  
Vol 16 (7) ◽  
pp. 1231 ◽  
Author(s):  
Tessy Luger ◽  
Robert Seibt ◽  
Monika Rieger ◽  
Benjamin Steinhilber
Keyword(s):  
Muscle Activation ◽  
Biceps Brachii ◽  
Extensor Digitorum ◽  
Body Parts ◽  
Triceps Brachii ◽  
Experimental Conditions ◽  
Motor Variability ◽  
Physical Requirement ◽  
Flexor Carpi Radialis ◽  
Arm Muscles

We investigated whether physical requirements and motor variability decreased over days in novices during a repetitive screwing task. Fifty-seven subjects performed one hour of repetitive screwing and fastening on three days, separated by 2–7 days. The average physical requirement and relative cycle-to-cycle variability (coefficient of variation, i.e., CV) were calculated from continuous recordings of electromyography of four arm muscles (biceps brachii, triceps brachii, flexor carpi radialis, extensor digitorum), forearm acceleration, and electrocardiography. Muscle activity levels, heart rate, and forearm acceleration decreased from day 1 to day 2 (range: ~4% to ~20%) and/or 3 (range: ~4% to ~28%). Not all muscles showed a similar pattern. Activity of the extensor digitorum and biceps brachii decreased already between days 1 and 2 (range: ~6% to ~13%), whereas activity of the flexor carpi radialis and triceps brachii decreased between days 1 and 3 (range: ~13% to ~20%). No changes in physical requirement were detected between days 2 and 3. Relative motor variability did not change across days, except that variability of forearm acceleration increased from day 1 to 3 (~5%). This study found consistent changes in physical requirements and indicated that several arm muscles show earlier decreases of muscular activity, like the extensor digitorum, compared to other body parts, like the flexor carpi radialis. Moreover, movement strategies may develop differently than muscle activation strategies, based on the different developments of physical requirements and motor variability. The development of physical requirements in industrial tasks is part of daily living and starts at task onset, highlighting the importance of task familiarization and the randomization of experimental conditions in scientific studies.

A validated approach for collecting fine-wire electromyographic recordings in four canine shoulder muscles during highly dynamic tasks

2015 ◽  
Vol 11 (2) ◽  
pp. 65-74 ◽  
Author(s):  
K.L. Cullen ◽  
J.P. Dickey ◽  
S.H.M. Brown ◽  
S.G. Nykamp ◽  
L.R. Bent ◽  
...  
Keyword(s):  
Data Collection ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Electrode Placement ◽  
Electromyographic Activity ◽  
Anatomical Landmarks ◽  
Triceps Brachii ◽  
Performance Tasks ◽  
Fine Wire ◽  
Shoulder Muscles

This study investigated the feasibility of obtaining ultrasound-guided intramuscular fine-wire electromyographic (fEMG) recordings from four canine shoulder muscles during highly dynamic activities. Four cadaveric canines were utilised to confirm the appropriate anatomical landmarks and the use of real time ultrasound guidance for electrode placement for four shoulder muscles: Biceps Brachii (BB), Supraspinatus (SP), Infraspinatus (IF), and Triceps Brachii – Long Head (TBLH). Electromyographic activity of the left BB, S P, IF, and TBLH was then recorded in two research dogs while walking and trotting to refine the data collection procedures. Finally, the full experimental protocol was piloted with two client-owned, specially-trained agility dogs, confirming the feasibility of collecting fEMG recordings while performing dynamic, highly-specific agility-related tasks and verifying our EMG amplitude normalisation protocol to enable comparisons across muscles and performance tasks. We present specific guidelines regarding the placement of fEMG electrodes and data collection/normalisation procedures to enable investigations of muscle activation during dynamic activities.

PATTERNS AND CONSISTENCY OF MUSCLE RECRUITMENT FOR A KARATE JAB

2011 ◽  
Vol 23 (01) ◽  
pp. 75-82 ◽  
Author(s):  
Yu-Lin Ning ◽  
Jia-Da Li ◽  
Wei-Ching Lo ◽  
Chih-Hung Huang ◽  
Chu-Fen Chang ◽  
...  
Keyword(s):  
Upper Limb ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Erector Spinae ◽  
Lower Limbs ◽  
Medial Gastrocnemius ◽  
Muscle Recruitment ◽  
Triceps Brachii ◽  
Motor Time ◽  
Karate Athletes

Adequate pattern and consistency of the muscle recruitment is essential to symbolize the destruction of the opponent with high movement velocities and precise targeting of the opponent's head and body during a karate jab. The purpose of this study was to evaluate the reaction time (RT), motor time (MT), and total response time (TRT), as well as their correlation during a karate jab, and to investigate the recruitment pattern and consistency of muscles during motor time. As many as 14 professional karate athletes (age: 23.67 ± 2.64 years; height: 174.57 ± 7.13 cm; and weight: 72.75 ± 10.65 kg) participated in the current study. Each subject was instructed to pose in combat stance first and then to use their left hand to jab at an instrumented kicking target as soon as they saw the start signal. Surface electromyograms (EMGs) were recorded from 16 muscles, namely the pronator teres, biceps brachii, triceps brachii, and deltoid of the left upper limb, right erector spinae, left rectus abdominis, and gluteus maximus, rectus femoris, biceps femoris, tibialis anterior, and medial gastrocnemius of the right and left lower limbs. Start and stop signals from the instrumented target were also recorded synchronously to obtain the TRT. Significant correlation between MT and TRT indicated that MT was a key determinant for the TRT of the jab. When performing a karate jab, the karate athletes initiated the movement with postural adjustments of the legs and trunk prior to the onset of the voluntary jab by the upper limb, and with a proximal-to-distal sequence of muscle activation in the left arm. Good consistencies of muscle recruitment of the trunk, left arm, and leg, and cocontraction of the left triceps and biceps brachii also indicated a well-controlled jab by the left arm. These results provide important information on the patterns and the consistencies of the muscle recruitment for coaching a karate jab, which should be helpful for a better understanding of the motor control strategies of a karate jab and for developing a suitable training protocol.

Kinematics, Kinetics, and Muscle Activation during Explosive Upper Body Movements

1996 ◽  
Vol 12 (1) ◽  
pp. 31-43 ◽  
Author(s):  
Robert U. Newton ◽  
William J. Kraemer ◽  
Keijo Häkkinen ◽  
Brendan J. Humphries ◽  
Aron J. Murphy
Keyword(s):  
Muscle Activation ◽  
Biceps Brachii ◽  
Average Power ◽  
Upper Body ◽  
Emg Activity ◽  
Neural Activation ◽  
Loading Conditions ◽  
Force Output ◽  
Triceps Brachii ◽  
Average Force

The aim of this study was to investigate the kinematics, kinetics, and neural activation of the traditional bench press movement performed explosively and the explosive bench throw in which the barbell was projected from the hands. Seventeen male subjects completed three trials with a bar weight of 45% of the subject's previously determined 1RM. Performance was significantly higher during the throw movement compared to the press for average velocity, peak velocity, average force, average power, and peak power. Average muscle activity during the concentric phase for pectoralis major, anterior deltoid, triceps brachii, and biceps brachii was higher for the throw condition. It was concluded that performing traditional press movements rapidly with light loads does not create ideal loading conditions for the neuromuscular system with regard to explosive strength production, especially in the final stages of the movement, because ballistic weight loading conditions where the resistance was accelerated throughout the movement resulted in a greater velocity of movement, force output, and EMG activity.

scholarly journals Glenohumeral Muscle Activation During Provocative Tests Designed to Diagnose Superior Labrum Anterior-Posterior Lesions

2011 ◽  
Vol 39 (12) ◽  
pp. 2670-2678 ◽  
Author(s):  
Vanessa J.C. Wood ◽  
Michelle B. Sabick ◽  
Ron P. Pfeiffer ◽  
Seth M. Kuhlman ◽  
Jason H. Christensen ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
External Rotation ◽  
Slap Lesion ◽  
Radiographic Findings ◽  
Superior Labrum ◽  
Long Head ◽  
Supination External Rotation ◽  
Anterior Posterior

Background: Despite considerable medical advances, arthroscopy remains the only definitive means of superior labrum anterior-posterior (SLAP) lesion diagnosis. Natural shoulder anatomic variants limit the reliability of radiographic findings and clinical evaluations are not consistent. Accurate clinical diagnostic techniques would be advantageous because of the invasiveness, patient risk, and financial cost associated with arthroscopy. Purpose: The purpose of this study was to examine the behavior of the joint-stabilizing muscles in provocative tests for SLAP lesions. Electromyography was used to characterize the muscle behavior, with particular interest in the long head of the biceps brachii (LHBB), as activation of the long head and subsequent tension in the biceps tendon should, based on related research, elicit labral symptoms in SLAP lesion patients. Study Design: Controlled laboratory study. Methods: Volunteers (N = 21) without a history of shoulder injury were recruited. The tests analyzed were active compression, Speed’s, pronated load, biceps load I, biceps load II, resisted supination external rotation, and Yergason’s. Tests were performed with a dynamometer to improve reproducibility. Muscle activity was recorded for the long and short heads of the biceps brachii, anterior deltoid, pectoralis major, latissimus dorsi, infraspinatus, and supraspinatus. Muscle behavior for each test was characterized by peak activation and proportion of muscle activity. Results: Speed’s, active compression palm-up, bicep I, and bicep II produced higher long head activations. Resisted supination external rotation, bicep I, bicep II, and Yergason’s produced a higher LHBB proportion. Conclusion: Biceps load I and biceps load II elicited promising long head behavior (high activation and selectivity). Speed’s and active compression palm up elicited higher activation of the LHBB, and resisted supination and Yergason’s elicited selective LHBB activity. These top performing tests utilize a unique range of test variables that may prove valuable for optimal SLAP test design and performance. Clinical Relevance: This study examines several provocative tests that are frequently used in the clinical setting as a means of evaluating a potential SLAP lesion.

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.

Variations in Rupture Site and Surface Strains at Failure in the Maturing Rabbit Medial Collateral Ligament

1995 ◽  
Vol 117 (4) ◽  
pp. 455-461 ◽  
Author(s):  
T. C. Lam ◽  
N. G. Shrive ◽  
C. B. Frank
Keyword(s):  
Medial Collateral Ligament ◽  
Surface Strain ◽  
Collateral Ligament ◽  
Anterior Portion ◽  
Femoral Insertion ◽  
Tibial Insertion ◽  
Medial Side ◽  
Optical Strain Measurement ◽  
Optical Strain

The relationship between the pattern of surface strain and the site of failure in maturing rabbit ligaments was studied in vitro. Bone-medial collateral ligament (MCL)-bone complexes of 24 female New Zealand White rabbits at 3, 6, 9 and 12 months of age (n = 6 rabbits, 12 MCLs per group) were tested in tension to failure. A video dimension analysis (VDA) system was used to map the surface strain at failure across the width and along the length of the medial side of each MCL during testing. Results showed that the highest strains were consistently located at the femoral insertion decreasing towards the midsubstance, with the highest strain occurring in the anterior portion of the MCL immediately adjacent to the femoral insertion. Strains of the complex at failure increased with rabbit maturation. The strain distribution however, did not change dramatically, even though the locations of MCL failure changed from exclusively tibial avulsion in the three month old rabbits to predominantly midsubstance failures in the 12 month old rabbits. In the six month old rabbits, there was a particular dissociation with all MCLs failing near the tibial insertion while femoral strains were apparently the highest. These results suggest two possibilities beyond that of some unknown artifacts of optical strain measurement. First, since failure sites rarely correlated with areas of maximum surface strain in this study, it seems possible that higher strains could exist deeper in the tissue, particularly at the bone-ligament interface of the tibial insertion in immature animals and somewhere within the midsubstance of the MCL in the adult. Secondly, it is possible that the ligament material may be heterogeneous.

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