Scapular Resting Posture and Scapulohumeral Rhythm Adaptations in Volleyball Players: Implications for Clinical Shoulder Assessment in Athletes.

Volleyball players develop shoulder sports-related adaptations due to repetitive overhead motions. It is essential to differentiate between these sports-related adaptations and pathological patterns in clinical assessments, particularly on scapular resting posture and scapulohumeral rhythm. Using an electromagnetic tracking system, the 3D shoulder kinematics of 30 male elite asymptomatic volleyball players and a matching control group were recorded at rest and in eight humeral elevation positions, in 15-degree increments from 15 to 120 degrees. The results indicated that the dominant scapular resting posture of the volleyball group was more anteriorly tilted than the control group (Volleyball: mean = -12.02°, STD = 4.16°; Control: mean = -7.45°, STD = 5.42°; Mean difference = 4.57°; STD = 6.85°; CI95% = 2.1° to 7.1°). The scapulohumeral rhythm in the volleyball group showed greater scapular internal rotation (Volleyball: mean = 41.60°, STD = 9.14°; Control: mean = 35.60°, STD = 6.03°; mean difference = 6.02°, STD = 1.47°; CI95% = 4.80° to 7.25°) and anterior tilt (Volleyball: mean = -9.10°, STD = 5.87°; mean = -2.3°, STD = 9.18°; mean difference = 6.88°, STD = 0.66°; CI95% = 6.34° to 7.43°). These findings suggest that volleyball players have developed a sports-related scapular adaptive pattern. This information may be valuable for clinical assessment and rehabilitation planning in injured volleyball players and may aid in the decision-making process for determining a safe return-to-play after a shoulder injury.

Technical aspects of inter-recti distance measurement with ultrasonographic imaging for physiotherapy purposes: the scoping review.

BACKGROUND: Inter-recti distance (IRD) measurement using musculoskeletal USI has been used in physiotherapy research, in particular, to investigate pregnancy-related diastasis recti abdominis (DRA) and to seek its effective treatment methods. Severe and untreated diastasis may result in the formation of umbilical or epigastric hernias. OBJECTIVE: This study aimed to systematically map physiotherapy-related research articles that included descriptions of IRD measurement procedures using USI to present their similarities and differences, and formulate recommendations on the procedure. DESIGN: A scoping review was conducted according to PRISMA-ScR guidelines, including 49 of 511 publications from three major databases. Publications were selected and screened by two independent reviewers whose decisions were consulted with a third reviewer. The main synthesized data items were: the examinees' body position, breathing phase, measurement sites, and DRA screening methods. The final conclusions and recommendations were the result of a consensus between seven reviewers from four research centers. RESULTS: Studies used 1-5 measurement sites that were differently determined. IRD was measured at the umbilicus (n = 3), at its superior (n = 16) and/or inferior border (n = 9), and at different levels: between 2 and 12 cm above the umbilicus, or a third of the distance and halfway between the umbilicus and xiphoid (n = 37); between 2 and 4.5 cm below the umbilicus or halfway between the umbilicus and pubis (n = 27). Different approaches were used to screen subjects for DRA. CONCLUSIONS: The discrepancies between the measurement procedures prevent between-study comparisons. The DRA screening method should be standardized. IRD measurement protocol standardization has been proposed. CRITICAL RELEVANCE STATEMENT: This scoping review indicates that the inter-recti distance measurement procedures using ultrasound imaging differ between studies, preventing between-study comparisons. Based on the results synthesis, the measurement protocol standardization has been proposed. KEY POINTS: The inter-recti distance measurement procedures using USI differ between studies. Proposed standardization concerns body position, breathing phase, measurements number per location. Determination of measurement locations considering individual linea alba length is suggested. Recommended locations: umbilical top, ½ of umbilical top-xiphoid, » of umbilical top-xiphoid/pubis distances. Diastasis recti abdominis diagnostic criteria are needed for proposed measurement locations.

Normal width of the inter-recti distance in pregnant and postpartum primiparous women.

STUDY DESIGN: Longitudinal descriptive exploratory study. OBJECTIVES: Evaluate the normal width of the linea alba in first-time pregnant women during pregnancy and postpartum. BACKGROUND: There are normative values on the width of the linea alba for nulliparous women, but limited knowledge about the normal width of the inter-rectus distance (IRD) in pregnant and postpartum women. METHODS: Ultrasound images were recorded in 84 primiparous women, at 3 locations on the linea alba (2 cm below the umbilicus, and 2 and 5 cm above the umbilicus) and at 4 time points (gestational weeks 35-41 and 6th to 8th, 12th to 14th, and 24th to 26th weeks postpartum). The 20th and 80th percentiles were used to define the normal width of the linea alba. RESULTS: During pregnancy, the 20th and the 80th percentile corresponded to 49-79 mm below the umbilicus, 54-86 mm at 2 cm above the umbilicus and 44-79 mm at 5 cm above the umbilicus. At 6 months postpartum, the 20th and the 80th percentile corresponded to 9-21 mm at 2 cm below the umbilicus, from 17 to 28 mm at 2 cm above the umbilicus and from 12 to 24 mm at 5 cm above the umbilicus. CONCLUSION: Different normative values for the width of the linea alba were found at different locations of the anterior abdominal wall. In primiparous women, the IRD may be considered "normal" up to values wider than in nulliparous.

The Immediate Effects on Inter-rectus Distance of Abdominal Crunch and Drawing-in Exercises During Pregnancy and the Postpartum Period.

STUDY DESIGN: Longitudinal descriptive exploratory study. OBJECTIVES: To evaluate in primigravid women the immediate effect of drawing-in and abdominal crunch exercises on inter-rectus distance (IRD), measured at 4 time points during pregnancy and in the postpartum period. BACKGROUND: There is scant knowledge of the effect of different abdominal exercises on IRD in pregnant and postpartum women. METHODS: The study included 84 primiparous participants. Ultrasound images were recorded with a 12-MHz linear transducer, at rest and during abdominal drawing-in and abdominal crunch exercises, at 3 locations on the linea alba. The IRD was measured at 4 time points: gestational weeks 35 to 41, 6 to 8 weeks postpartum, 12 to 14 weeks postpartum, and 24 to 26 weeks postpartum. Separate 2-way, repeated-measures analyses of variance (ANOVAs) were performed for each exercise (drawing-in and abdominal crunch) and each measurement location to evaluate the immediate effects of exercises on IRD at each of the 4 time points. Similarly, 2-way ANOVAs were used to contrast the effects of the 2 exercises on IRD. RESULTS: Performing the drawing-in exercise caused a significant change in width of the IRD at 2 cm below the umbilicus, narrowing the IRD by a mean of 3.8 mm (95% confidence interval [CI]: 1.2, 6.4 mm) at gestational weeks 35 to 41, and widening the IRD by 3.0 mm (95% CI: 1.4, 4.6 mm) at 6 to 8 weeks postpartum, by 1.8 mm (95% CI: 0.6, 3.1 mm) at 12 to 14 weeks postpartum, and by 2.5 mm (95% CI: 1.4, 3.6 mm) at 24 to 26 weeks postpartum (P<.01). Performing the abdominal crunch exercise led to a significant narrowing of the IRD (P<.01) in all 3 locations at all 4 time points, with the exception of 2 cm below the umbilicus at postpartum weeks 24 to 26. The average amount of narrowing varied from 1.6 to 20.9 mm, based on time and location. CONCLUSION: Overall, there was a contrasting effect of the 2 exercises, with the abdominal crunch exercise consistently producing a significant narrowing of the IRD. In contrast, the drawing-in exercise generally led to a small widening of the IRD.

Kinematic comparison and description of the 3-dimensional shoulder kinematics of 2 shoulder rotation tests.

OBJECTIVES: The purpose of this study was to compare shoulder external rotation range of motion (ROM) during the hand-behind-neck (HBN) test and a standard shoulder external rotation test and to describe the 3-dimensional scapular motion during the HBN test. METHODS: An electromagnetic tracking device was used to assess the dominant shoulder of 14 healthy participants while performing active full ROM in a standard shoulder external rotation test in an elevated position (EREP) and in the HBN test. The humeral and scapular 3-dimensional positions at the end of EREP and HBN were compared using a paired-sample t test. A correlation analysis was performed between humeral and scapular angles to assess the contribution of scapular motion to the full shoulder ROM during the HBN test. RESULTS: No significant differences were found between the HBN test and the EREP at the end-range of the glenohumeral external rotation (HBN: 15.6° ± 6.3° vs EREP: 23.4° ± 4.7°; P = .08) and on scapular internal-external rotation (HBN test: 21.2° ± 6.3° vs EREP: 15.6° ± 1.8°; P = .23). Significant differences were found in scapular upward rotation (HBN: 21.2° ± 6.3° vs EREP: 15.6° ± 1.8°; P < .01) and scapular spinal tilt (HBN: -0.4° ± 2.3° vs EREP: 8.1° ± 2.1°; P < .01). There was a positive correlation between the humeral angles and scapular internal and posterior spinal tilt angles with the HBN test. CONCLUSIONS: The results of the present study showed that, in young asymptomatic participants with no known shoulder pathology, the end-range of shoulder rotation was similar in the HBN test and in a standard shoulder rotation test. During the HBN test, the scapula assumed a more internal and anterior spinal tilted position at the end-range of active shoulder external rotation. These results suggest that the HBN test may be used to assess the end-range of glenohumeral external rotation.

Prevalence and risk factors of diastasis recti abdominis from late pregnancy to 6 months postpartum, and relationship with lumbo-pelvic pain.

Diastasis recti abdominis (DRA) is an impairment characterized by a midline separation of the rectus abdominis muscles along the linea alba. It has its onset during pregnancy and the first weeks following childbirth. There is scant knowledge on both prevalence and risk factors for development of the condition. The aim of this study was to investigate the prevalence of DRA at gestational week 35 and three timepoints postpartum, possible risk factors, and the relationship between DRA and lumbo-pelvic pain. Ultrasound images of inter rectus distance (IRD) were recorded in 84 healthy primiparous women, at three locations on the linea alba. The IRD was measured at: gestational week 35 and 6-8, 12-14, and 24-26 weeks postpartum. Diagnosis of DRA was defined as 16 mm at 2 cm below the umbilicus. Independent sample t-test and binary logistic regression was used to assess differences and risk factors in women with and without DRA and women with and without lumbo-pelvic pain. P < 0.05 was considered statistically significant. The prevalence of DRA decreased from 100% at gestational week 35-39% at 6 months postpartum. No statistically significant differences were found in prepregnancy body mass index (BMI), weight gain, baby's birth weight or abdominal circumference between women with and without DRA at 6 months postpartum. Women with DRA at 6 months postpartum were not more likely to report lumbo-pelvic pain than women without DRA. DRA is prevalent at 6 months postpartum, but is not linked with lumbo-pelvic pain.

Modulation of cortical interhemispheric interactions by motor facilitation or restraint.

Cortical interhemispheric interactions in motor control are still poorly understood and it is important to clarify how these depend on inhibitory/facilitatory limb movements and motor expertise, as reflected by limb dominance. Here we addressed this problem using functional magnetic resonance imaging (fMRI) and a task involving dominant/nondominant limb mobilization in the presence/absence of contralateral limb restraint. In this way we could modulate excitation/deactivation of the contralateral hemisphere. Blocks of arm elevation were alternated with absent/present restraint of the contralateral limb in 17 participants. We found the expected activation of contralateral sensorimotor cortex and ipsilateral cerebellum during arm elevation. In addition, only the dominant arm elevation (hold period) was accompanied by deactivation of ipsilateral sensorimotor cortex, irrespective of presence/absence of contralateral restraint, although the latter increased deactivation. In contrast, the nondominant limb yielded absent deactivation and reduced area of contralateral activation upon restriction. Our results provide evidence for a difference in cortical communication during motor control (action facilitation/inhibition), depending on the "expertise" of the hemisphere that controls action (dominant versus nondominant). These results have relevant implications for the development of facilitation/inhibition strategies in neurorehabilitation, namely, in stroke, given that fMRI deactivations have recently been shown to reflect decreases in neural responses.

Resting scapular posture in healthy overhead throwing athletes.

INTRODUCTION: On shoulder examination, asymmetric scapular posture is often associated to abnormalities of the shoulder complex joint. However, shoulder asymmetries may also be related to adaptations to sports practice. The overhead throwing motion is a highly repetitive skilled motion performed at high velocities. Due to overuse of the dominant overhead-throwing shoulder, athletes may develop some kind of overhead throwing shoulder adaptation pattern that possibly includes scapular asymmetry at the resting position. PURPOSE: To quantify the asymmetry between dominant and non-dominant resting scapular posture in 3 groups of healthy subjects (volleyball players, team-handball players and a control group). METHODS: Bilateral 3D scapular kinematics with the arm at rest was measured using a 6 degrees-of-freedom electromagnetic tracking device. RESULTS: In handball athletes, the dominant scapula was more in internal rotation and anteriorly tilted than in volleyball players. Between athletes and non-athletes groups, the dominant scapula was more anteriorly tilted in the athletes. CONCLUSIONS: Clinicians should be aware that some degree of scapular asymmetry may be normal in some athletes. It should not be considered automatically as a pathological sign but rather an adaptation to sports practice and extensive use of upper limb.

Reliability of the inter-rectus distance measured by palpation. Comparison of palpation and ultrasound measurements.

An increased inter-rectus distance (IRD) is a common condition in late pregnancy and in the postnatal period. The condition is difficult to assess. Palpation is the most commonly used method to assess IRD. To date there is scant knowledge of intra and inter-tester reliability of palpation to measure IRD and how palpation compares with ultrasound measurements. The aims of this study were: 1) evaluate intra and inter-rater reliability of abdominal palpation; 2) validate abdominal palpation of IRD measurements using ultrasound imaging as a reference. Two physiotherapists (PTs) conducted the palpation study in random order, blinded to each other's assessments. IRD was measured as finger widths between the two rectus abdominis (RA) muscles. Ultrasound images were recorded at the same locations as the palpation test. A blinded investigator measured the IRD offline. Palpation showed good intra-rater reliability between days expressed by a weighted Kappa (wK) higher than 0.7 for both physiotherapists, and moderate inter-rater reliability (wK = 0.534). Ultrasound was found to be more responsive for differences in IRD compared with values obtained by palpation. The intra-rater reliability was higher than the inter-rater reliability. Besides the difference in experience with palpation testing between the PTs, this result may be due to differences in finger width and/or the subjective interpretation of abdominal soft-tissues pressure. Ultrasound measures are highly sensitive to changes of IRD, which is not possible to replicate by palpation assessment using a finger width scale. Palpation has sufficient reliability to be used in clinical practice. However, ultrasound is a more accurate and valid method and is recommended in future research of IRD.

Scapular positioning assessment: is side-to-side comparison clinically acceptable?

Clinicians routinely assess scapular position and motion of the symptomatic shoulder taking as reference for the contralateral asymptomatic side. A different positioning between sides (scapular asymmetry) is often assumed as pathological, however, the symmetry of scapular kinematics in healthy individuals is yet to be demonstrated. This study tested the hypothesis of scapular symmetry during arm elevation. The 3-dimensional scapular positioning of the dominant and non-dominant shoulders of fourteen healthy young adults was simultaneously measured by a 6 degrees of freedom electromagnetic tracking device at three positions of arm elevation: rest, hands on hips, and 90° of shoulder abduction with internal rotation. The scapula on the dominant shoulder showed greater retraction (P < 0.001; η(2)(p) = 0.68) and upward rotation (P < 0.001; η(2)(p) = 0.70) at all positions of arm elevation. From rest to 90° of shoulder abduction, the mean (±SD) amount of scapular angular displacement was, respectively for dominant and non-dominant shoulders, 7.2° (±7.8°) and 7.2° (±4.4°) for retraction, 17.4° (±5.1°) and 17.8° (±6.4°) for upward rotation, and 3.8° (±3.6°) and 0.9° (±3.6°) for posterior tilting. These findings suggest that scapular positioning on the thorax are not the same despite the observation of an identical kinematic pattern during arm elevation. This should be taken into consideration when comparing scapular position and motion of symptomatic and contralateral shoulders.

Test-retest and intrarater reliability of 2-dimensional ultrasound measurements of distance between rectus abdominis in women.

STUDY DESIGN: Single-group test-retest reliability study. OBJECTIVES: To evaluate the test-retest intraobserver reliability of 2-dimensional ultrasound measurement of the distance between the rectus abdominis muscles, the interrectus distance (IRD). BACKGROUND: Diastasis recti is defined as the separation of the 2 rectus abdominis muscles, with a reported prevalence of between 30% and 70% in women during pregnancy and in the postpartum period. The condition is difficult to measure, and ultrasound imaging has been suggested as a useful method to quantify the diastasis. However, to date, no studies have investigated intratester or intertester reliability of ultrasound to measure the distance between the rectus abdominis muscles during rest and contraction. METHODS: Ultrasound images from the rectus abdominis were recorded in 24 healthy female volunteers at rest and under 2 conditions of abdominal contraction: abdominal crunch and drawing-in exercises. The probe was positioned at 2 locations: below and above the umbilicus. A blinded investigator measured the IRD offline from 2 different ultrasound images collected on 2 different days (test-retest). Additionally, reanalyses of the same ultrasound images were done on 2 separate occasions (intra-image). RESULTS: Test-retest measurements of IRD demonstrated good to very good reliability, with intraclass correlation coefficient values between 0.74 and 0.90. The only exception was for IRD measured 2 cm below the umbilicus during the abdominal crunch exercise, which had an intraclass correlation coefficient of 0.50. For intratester reliability of the same images, the intraclass correlation coefficient values were all above 0.90. CONCLUSION: Ultrasound imaging is a reliable method for measuring the IRD at rest and during abdominal crunch and drawing-in exercises.

Scapular contribution for the end-range of shoulder axial rotation in overhead athletes.

The aim of this study was to analyze the relative contribution of the scapular motion on the extreme range-of-motion of shoulder external and internal rotation, in overhead athletes. An electromagnetic tracking device (Flock of Birds) was used to record humeral and scapular kinematics. The dominant arm of 26 male subjects (13 athletes and 13 non-athletes) was studied while subjects actively reached end-range of internal and external rotation. Humeral and scapular angles were calculated and compared across groups by means of a t-test for independent samples. A bivariate correlation approach was used to describe the relationship between humeral angles and scapular variables. The range-of-motion of the thoracohumeral angles, during shoulder external rotation was significantly less (p < 0.05) on the athletes group, athletes also positioned their dominant scapula more retracted and posteriorly tilted. A positive correlation was found between glenohumeral angles and scapular tilt (r = 0.6777; p < 0.05). Concerning internal rotation; athletes showed significantly greater (highest) thoracohumeral angles (p < 0.05). Scapula assumed a position more in retraction and anterior tilt. Based on these findings, it is suggested that differences found in athletes seem to reveal an eventual shoulder adaptation to the throwing mechanics.

Localização especial de estímulos sonoros em indivíduos cegos congênitos: estudo comparativo da posição tridimensional da cabeça em adultos cegos congênitos e indivíduos videntes / Spatial localization of sounds in blind individuals: comparative study of three dimensional position of the head in blind and non blind adults

A capacidade para localizar objetos fixos ou em movimento no espaço tridimensional depende da função visual. No indivíduo cego, as modalidades sensoriais remanescentes, nomeadamente a audição, poderiam compensar a visão na localização espacial. O objetivo deste estudo foi analisar o papel da audição no mecanismo de localização espacial por meio da habilidade de orientar de forma precisa a cabeça face à fonte sonora. Cinco adultos cegos congênitos foram comparados com cinco sujeitos videntes vendados. A tarefa consistiu na orientação da cabeça ao estímulo sonoro, emitido por sete fontes diferentes, com localização fixa. A posição tridimensional da cabeça e tronco foi registrada por um sistema de varredura eletromagnético (Flock of Birds System). Para cada som produzido foi calculado o "erro de localização". Esta medida correspondeu à diferença entre o registro da posição obtido durante o teste e durante uma posição de controle. Os resultados revelaram que nos indivíduos cegos congênitos a magnitude de erro de localização dos estímulos auditivos foi superior aos indivíduos videntes. Conclui-se que a representação mental formada com base na visão constitui um dos pré-requisitos para um bom desempenho nas tarefas espaciais.

The ability to locate stationary or moving objects in space depends on visual function. It is thought that for blind individuals, the remaining sensory modalities, in particular hearing, will compensate for the absence of vision in spatial localization. This study aimed to analyze the role of hearing on the spatial localization mechanism by looking at the ability to accurately direct the head to the source of sound. Five congenitally blind adults were compared to five sighted people who wore blindfolds. The task consisted of turning the head toward the sound stimulus, coming from seven different fixed point sources. The three dimensional position of the head and trunk was registered by an electromagnetic scanning device (Flock of Birds System). The "error of localization" was calculated for each sound produced. This measurement corresponded to the difference between the recorded positions during the test and the control position. The results revealed that in congenitally blinded individuals the magnitude of the "error of localization" was greater than in sighted individuals. The conclusion was that mental representations formed based on vision constitutes one of the prerequisites to good performance on spatial tasks.

The unstable shoulder in arm elevation: a three-dimensional and electromyographic study in subjects with glenohumeral instability.

BACKGROUND: Although an altered scapulohumeral rhythm is believed to be related to some shoulder dysfunctions, there is scarce evidence on the scapulohumeral rhythm and shoulder muscle activation patterns in subjects with glenohumeral instability. METHODS: Six subjects with glenohumeral instability performed arm elevation in trials of 8 successive stationary positions. Kinematics were recorded on each stationary position using a 6 DOF electromagnetic tracking device. Scapular kinematics was analysed by comparison between recorded scapular angles and those estimated by a linear regression model of the scapulohumeral rhythm which served as standard for normality. Surface electromyographic activity was recorded from the upper and lower trapezius, serratus anterior and deltoid. FINDINGS: Differences in the scapulohumeral rhythm were observed between subjects. Significant differences were founded in scapular protraction and spinal tilt. No differences were found in scapular lateral-rotation in all subjects. Activity of the lower trapezius and serratus anterior seem to increase mostly during the second third of arm elevation. INTERPRETATION: In a particular angle of arm elevation, changes in scapular protraction and/or spinal tilt rotation could introduce changes on the alignment of the humeral head and the glenoid, predisposing/contributing to shoulder instability. These kinematics scapular changes are perhaps due to an inadequate muscular activity. RELEVANCE: The results of this study reinforce the relevance of the scapulohumeral rhythm assessment in the rehabilitation of patients with shoulder instability.