Electromyographic Activity of selected Trunk, Core, and Thigh Muscles in commonly used Exercises for ACL Rehabilitation

Purpose: Most of rehabilitation programmes for Anterior Cruciate Ligament (ACL) injury focus on quadriceps-hamstrings activation imbalances and less is known about kinetically linked muscles. Study investigated electromyographic activity of selected trunk, core, and thigh muscles during common rehabilitation exercises for ACL injury. Subjects and Methods: Twelve active female volunteers participated in this cross-sectional laboratory study. Surface EMG was used to compare activation of eight trunk, hip/core, and lower limb muscles: Erector Spinae (ES), Rectus Abdominis (RA), Gluteus Maximus (GM), Vastus Lateralis (VL), Rectus Femoris (RF), Vastus Medialis (VM), Biceps Femoris (BF), and Semitendinosus (ST) during Forward Lunge, Double Leg Raise, Glute Bridge, Sit-Up, and Squat. Results: Forward lunge produced significantly higher activation in the VM (61.1±19.4), VL (59.2±12.9), and RF (32.0±2.6). Double leg raise generated highest activity in the RF (26.6±2.8) and RA (43.3±4.4); and Glute Bridge in the GM (44.5±19.0) and BF (22.4±4.3). Sit-up produced the highest activation in the RF (36.6±4.7) followed by RA (18.9±3.8). Squat produced a higher activation in VL (55.0±12.9), VM (51.5±18.2), and ES (40.4±18.3). Conclusion: Study provide further evidence for developing training programmes for ACL injury prevention and rehabilitation. A combination of exercises to reinstate quadriceps-hamstrings activation balance and enhance core stability is recommended

Electromyographic Assessment of Forearm Muscle Function in Tennis Players With and Without Lateral Epicondylitis

"There is no consensus about the main aetiology of Lateral Epicondylitis (LE) or Tennis Elbow. While electromyographic assessment of alterations in neuromuscular control and activation patterns of forearm muscles has received increasing interest as potential intrinsic factors in non-tennis players, there has been insufficient attention in tennis players. The purpose of present review was to search the literature for the electromyographic studies of forearm muscles in tennis players in order to 1) identify related implications for LE, 2) highlight key technical and methodological shortcomings, and 3) suggest potential pathways for future research. An electronic search of PubMed, Scopus, Web of Science, and Google Scholars (1980 to October 2014) was conducted. Titles, abstracts, and full-text articles were screened to identify “peer-reviewed” studies specifically looking into “electromyographic assessment of forearm muscles” in “tennis players”. After screening 104 articles, 13 original articles were considered in the main review involving a total of 216 participants (78% male, 22% female). There were indications of increased extensor activity in all tennis strokes and less experiences single-handed players, however with insufficient evidence to support their relationship with the development of LE. Studies varied widely in study population, sample size, gender, level of tennis skills, electrode type, forearm muscles studied, EMG recording protocol, EMG normalisation, and reported parameters. As a result, it was not possible to present combined results of existing studies and draw concrete conclusions in terms of clinical implications of findings. There is a need for establishment of specific guidelines and recommendations for EMG assessment of forearm musculature in terms of electrode and muscle selection. Further studies of both healthy controls and tennis players suffering from TE with adequate sample sizes and well-defined demographics are warranted.

Electromyographic Analysis of Shoulder Girdle Muscles during Common Internal Rotation Exercises

Background: High level throwing performance requires the development of effective muscle activation within shoulder girdle muscles particularly during forceful internal rotation (IR) motions. Study Design: Controlled Laboratory Descriptive Study Purpose: To investigate activation pattern of 16 shoulder girdle muscles/muscle sub-regions during three common shoulder IR exercises. Method: EMG was recorded in 30 healthy subjects from 16 shoulder girdle muscles/muscle sub-regions (surface electrode: anterior, middle and posterior deltoid, upper, middle and lower trapezius, serratus anterior, teres major, upper and lower latissimus dorsi, upper and lower pectoralis major; fine wire electrodes: supraspinatus, infraspinatus, subscapularis and rhomboid major) using a telemetric EMG system. Three IR exercises (standing IR at 0o and 90o of Abduction, and IR at Zero-Position) were studied. EMG amplitudes were normalized to EMGmax (EMG at maximal IR force in a standard position) and compared using one-way repeated-measures analysis of variance (ANOVA). Results: There were significant differences in muscles’ activation across IR exercises (p<0.05–p<0.001). Rotator cuff and deltoid muscles were highly activated during IR at 90° of Abduction. Latissimus dorsi exhibited markedly higher activation during IR at Zero-Position. While upper trapezius had the highest activation during IR at Zero-Position, middle and lower trapezius were activated at highest during IR at 90o of Abduction. The highest activation of serratus anterior and rhomboid major occurred in IR at Zero-Position and IR at 90o of Abduction, respectively. Conclusions: Studied exercises have the potential to effectively activate glenohumeral and scapular muscles involved in throwing motions. Results provide further evidence for developing rehabilitation, injury prevention, and training strategies

Pain, Functional Disability, Psychological Status, and Health-Related Quality of Life in Patients with Subacromial Impingement Syndrome

Background Subacromial impingement syndrome (SAIS) is the comments painful shoulder condition leading to considerable functional loss. Considering numerous existing conservative and surgical interventions for SAIS, the use of optimal patient-centred outcome measures is essential. Study assessed various generic and shoulder-specific outcome measures in patients and healthy controls to provide baseline data and facilitate the development of evidence-based interventions. Methods A total of 75 participants including 39 patients and 36 healthy controls were evaluated and compared by a battery of validated outcome tools: McGill Pain Questionnaire, Oxford Shoulder Score, Constant Murley Score, The Disability of the Arm, Shoulder and Hand, Upper Limb Function Index, Functional Impairment Test–Hand and Neck/Shoulder/Arm, Hospital Anxiety and Depression Scale, Short-Form Health Survey, and shoulder muscle strength. Results All selected measures showed significant differences in the pain experience, upper limb functional capacity, psychological status (anxiety and depression), and health-related quality of life between SAIS patients and healthy controls in both female and male participant groups (p<0.05 - p<0.001). Conclusion The use of an array of patient-centred upper limb regional/joint-specific pain and functional measures combined with psychological status and quality of life tools is recommended for the evidence-based assessment of intervention outcome in patients with SAIS

Subacromial Impingement Syndrome: An Electromyographic Study of Shoulder Girdle Muscle Fatigue

Muscle fatigue affecting glenohumeral and/or scapular muscles is suggested as one of the 25 contributing factors to the development of subacromial impingement syndrome (SAIS). 26 Nonetheless, the fatigability of shoulder girdle muscles in association with the pathomechanics 27 of SAIS has not been reported. This study aimed to measure and compare fatigue progression 28 within the shoulder girdle musculature of patients and healthy controls. 75 participants 29 including 39 patients (20 females; 19 males) and 36 healthy controls (15 females; 21 males) 30 participated in the study. Study evaluated the progression of muscle fatigue in 15 shoulder 31 girdle muscles by means of surface and fine-wire EMG during submaximal contraction of four 32 distinct movements (abduction, flexion, internal and external rotation). Shoulder strength, 33 subjective pain experience (McGill Pain Questionnaire), and psychological status (Hospital 34 Anxiety and Depression Scale) were also assessed. The results were compared between patient 35 and control groups according to the gender. Despite marked fatigue observed in the majority 36 of muscles particularly during flexion and abduction at 90°, overall results indicated a lower 37 tendency of fatigue progression in the impingement group across the tests (0.05< p <0.05). 38 Shoulder Strength, pain experience, and psychological status were significantly different 39 between the two groups (P<0.05). Lower tendency to fatigue progression in the impingement 40 group can be attributed to the presence of fear avoidance and pain-related muscle inhibition, 41 which in turn lead to adaptations in motor programme to reduce muscle recruitment and 42 activation. The significantly higher levels of pain experience and anxiety/depression in the 43 impingement group further support this proposition

POSTURAL ALTERATIONS IN PATIENTS WITH SUBACROMIAL IMPINGEMENT SYNDROME.

BackgroundAn aberrant upper body posture has been proposed as one of the etiological factors contributing to the development of subacromial impingement syndrome (SAIS). Clinicians have translated this supposition into assessment and rehabilitation programs despite insufficient and conflicting evidence to support this approach.PurposeThe purpose of this study was to compare several postural variables between the SAIS patients and asymptomatic healthy controls.Study designCase-Control Study.MethodsA total of 75 participants including 39 patients (20 females; 19 males) and 36 healthy controls (15 females; 21 males) participated in the study. Study evaluated several postural variables including forward head posture (FHP), forward shoulder posture (FSP), thoracic kyphosis index (TKI), scapular index (SI), normalized scapular protraction (NSP), and the lateral scapular slide test (LSST). The variables were compared between patient and control groups according to sex.ResultsSignificant differences were observed in the female patients compared to asymptomatic controls for the FHP (49.38 + 9.6o vs 55.5o+8.38, p=0.03), FSP (45.58 + 10.1o vs 53.68 + 7.08, p=0.02), and LSST in third position (10.2 + 2.1cm vs 11.5 + 0.7cm, p=0.01). Male patients showed a significant difference only in the FSP compared to controls (61.9o+9.4o vs 49.78 + 9.28, pConclusionsWhile inadequate data on the relationship between dysfunctional posture and SAIS has led to broad variations in current rehabilitation strategies, the results of the present study revealed different patterns of postural aberrations in female and male patients with SAIS. This clarifies the need to develop individualized or sex-specific approaches for assessing posture in men and women with SAIS and rehabilitation programs based on the assessment results.Level of evidence3b

A2 milk enhances dynamic muscle function following repeated sprint exercise, a possible ergogenic aid for a1-protein intolerant athletes?

�� 2019 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher���s website: https://doi.org/10.3390/nu9020094Hyperaminoacidemia following ingestion of cows-milk may stimulate muscle anabolism and attenuate exercise-induced muscle damage (EIMD). However, as dairy-intolerant athletes do not obtain the reported benefits from milk-based products, A2 milk may offer a suitable alternative as it lacks the A1-protein. This study aimed to determine the effect of A2 milk on recovery from a sports-specific muscle damage model. Twenty-one male team sport players were allocated to three independent groups: A2 milk (n = 7), regular milk (n = 7), and placebo (PLA) (n = 7). Immediately following muscle-damaging exercise, participants consumed either A2 milk, regular milk or PLA (500 mL each). Visual analogue scale (muscle soreness), maximal voluntary isometric contraction (MVIC), countermovement jump (CMJ) and 20-m sprint were measured prior to and 24, 48, and 72 h post EIMD. At 48 h post-EIMD, CMJ and 20-m sprint recovered quicker in A2 (33.4 �� 6.6 and 3.3 �� 0.1, respectively) and regular milk (33.1 �� 7.1 and 3.3 �� 0.3, respectively) vs. PLA (29.2 �� 3.6 and 3.6 �� 0.3, respectively) (p < 0.05). Relative to baseline, decrements in 48 h CMJ and 20-m sprint were minimised in A2 (by 7.2 and 5.1%, respectively) and regular milk (by 6.3 and 5.2%, respectively) vs. PLA. There was a trend for milk treatments to attenuate decrements in MVIC, however statistical significance was not reached (p = 0.069). Milk treatments had no apparent effect on muscle soreness (p = 0.152). Following muscle-damaging exercise, ingestion of 500 mL of A2 or regular milk can limit decrements in dynamic muscle function in male athletes, thus hastening recovery and improving subsequent performance. The findings propose A2 milk as an ergogenic aid following EIMD, and may offer an alternative to athletes intolerant to the A1 protein.Published versio

Gaze training supports self-organization of movement coordination in children with developmental coordination disorder

Children with developmental coordination disorder (DCD) struggle with the acquisition of coordinated motor skills. This paper adopts a dynamical systems perspective to assess how individual coordination solutions might emerge following an intervention that trained accurate gaze control in a throw and catch task. Kinematic data were collected from six upper body sensors from twenty-one children with DCD, using a 3D motion analysis system, before and after a 4-week training intervention. Covariance matrices between kinematic measures were computed and distances between pairs of covariance matrices calculated using Riemannian geometry. Multidimensional scaling was then used to analyse differences between coordination patterns. The gaze trained group revealed significantly higher total coordination (sum of all the pairwise covariances) following training than a technique-trained control group. While the increase in total coordination also significantly predicted improvement in task performance, the distinct post-intervention coordination patterns for the gaze trained group were not consistent. Additionally, the gaze trained group revealed individual coordination patterns for successful catch attempts that were different from all the coordination patterns before training, whereas the control group did not. Taken together, the results of this interdisciplinary study illustrate how gaze training may encourage the emergence of coordination via self-organization in children with DCD

Total elbow arthroplasty: a prospective clinical outcome study of Discovery Elbow System with a 4-year mean follow-up

BACKGROUND: Total elbow arthroplasty (TEA) is increasingly used for the treatment of advanced elbow conditions to reduce pain and improve function. However, TEA is still associated with a higher complication rate than total hip and knee arthroplasty despite advances in the design and surgical techniques. This prospective clinical study reports the outcome of the Discovery Elbow System (Biomet, Warsaw IN, USA), which has been in clinical use in the United Kingdom since 2003. METHODS: The study included a total of 100 Discovery Elbows (April 2003 to January 2010) with a minimum 2-year follow-up, including 75 primary and 25 revisions (60% women and 40% men; mean age, 62 years). Outcome was assessed by means of the Liverpool Elbow Score, pain experience, patient satisfaction, range of motion, and radiographic imaging. RESULTS: The mean follow-up period was 48.5 months (range, 24-108 months). The Liverpool Elbow Score improved from 3.79 to 6.36 (P < .001). The percentage of pain-free patients was substantially increased from 7% preoperatively to 64% at the final follow-up. The patient satisfaction rate was over 90%. The flexion-extension arc and pronation-supination arc increased from 72° to 93° and from 86° to 111°, respectively (P < .001). Major postoperative complications included deep infection (2%), progressive aseptic loosening requiring revision (primary, 5%; revision 12%), persistent ulnar neuropathy (3%), and periprosthetic fracture (primary, 6.8%; revision, 8%). CONCLUSION: The Discovery Elbow System resulted in improved function, reduced pain, and high patient satisfaction. Long-term results are required to assess the survivorship of this syste

Responsiveness of the Liverpool Elbow Score in elbow arthroplasty.

BACKGROUND Responsiveness and floor and ceiling effect are important parameters for evaluating the sensitivity of an outcome instrument in detecting the changes in the clinical condition of patients after an intervention as well as evaluating the content validity of the instrument. The aim of this prospective observational study was to assess these parameters for the Liverpool Elbow Score (LES) in total elbow replacement (TER). METHODS The study included 121 cemented TER cases with linked elbow prosthesis (Discovery Elbow, Biomet Orthopaedics, Swindon, UK) for various conditions, including inflammatory arthritis, noninflammatory arthritis, trauma, and loosening. The proportion of patients with the lowest score (0 points; floor effect) and maximum score (10 points; ceiling effect) was checked preoperatively and 1 year postoperatively. Distribution-based methods (effect size [ES], standardized response mean [SRM], Guyatt responsiveness ratio [GRR]) and anchor-based methods (receiver operating characteristic [ROC] curve and Spearman correlation coefficient) were used to assess responsiveness. Patient satisfaction after TER was used as an external anchor. RESULTS Patients were a mean age of 63 years (range, 20-86 years). Large ES (1.64), SRM (1.25), and GRR (1.69) were found during the follow-up period. Area under the ROC curve was 0.71 (95% confidence interval, 0.56-0.87; P = .03). There was significant positive correlation (Spearman correlation coefficient, 0.35; P = .004) between changes in LES and satisfaction level. LES showed no floor and ceiling effect preoperatively and at 1 year postoperatively. CONCLUSION LES is a responsive measure and has no floor and ceiling effect. LEVEL OF EVIDENCE This encourages its use as an outcome instrument for TER. Basic Science Study, Development or Validation of Outcome Instruments