The influence of gravity on respiratory kinematics during phonation measured by dynamic magnetic resonance imaging

AbstractRespiratory kinematics are important for the regulation of voice production. Dynamic MRI is an excellent tool to study respiratory motion providing high-resolution cross-sectional images. Unfortunately, in clinical MRI systems images can only be acquired in a horizontal subject position, which does not take into account gravitational effects on the respiratory apparatus. To study the effect of body posture on respiratory kinematics during phonation, 8 singers were examined both in an open-configuration MRI with a rotatable gantry and a conventional horizontal MRI system. During dynamic MRI the subjects sang sustained tones at different pitches in both supine and upright body positions. Sagittal images of the respiratory system were obtained at 1–3 images per second, from which 6 anatomically defined distances were extracted to characterize its movements in the anterior, medium and posterior section of the diaphragm as well as the rip cage (diameter at the height of the 3rd and 5th rip) and the anterior–posterior position of the diaphragm cupola. Regardless of body position, singers maintained their general principles of respiratory kinematics with combined diaphragm and thorax muscle activation for breath support. This was achieved by expanding their chest an additional 20% during inspiration when singing in the supine position but not for sole breathing. The diaphragm was cranially displaced in supine position for both singing and breathing and its motion range increased. These results facilitate a more realistic extrapolation of research data obtained in a supine position.

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Effect of Body Positions on Quadriceps Angle Measurement

SciMedicine Journal ◽

10.28991/scimedj-2019-0101-3 ◽

2019 ◽

Vol 1 (1) ◽

pp. 20-24

Author(s):

Swati Paranjape ◽

Nikita Singhania

Keyword(s):

Supine Position ◽

Body Position ◽

Weight Bearing ◽

Muscle Mechanics ◽

Sports Participation ◽

Standing Position ◽

Angle Measurement ◽

Cross Sectional ◽

Q Angle ◽

Important Measurement

Background: Quadriceps angle or Q angle is an index of the vector for the combined pull of extensor mechanisms and patellar tendon. It is a clinical measurement for knee and patella alignment. It is not a static but rather a dynamic consequence to the muscle mechanics, leg loading, and foot and leg position. Therefore in present study we assessed whether change of body position i.e. standing and supine position affects the Q angle measurement. Aims and Objectives: Present study aimed at finding whether there are any variations in Q angle in standing and supine position. Objectives of the study were to measure Q angle in supine position and standing position. We intended to assess the variations in the Q angle with change of body position. Methods: In this cross sectional analytical study, we assessed female participants between age group of 18-25 years, in supine and standing position, Q angle was measured in both the positions. Sample size was 100. Results: The results showed statistically significant increase in Q angle in standing position as compared with the supine position (p <0.0001) (C.I. 1.720 to 3.140). Conclusion: There was statistically significant increase in the Q angle measurement in standing as compared with the measurements in supine. Measuring the Q angle is concerned with assessing the knee functions during daily activities and sports participation, therefore assessing this important measurement not only in supine but also in a weight-bearing functional position in clinical setups would be helpful.

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Colonoscopy-related injury among colonoscopists: an international survey

Endoscopy International Open ◽

10.1055/a-1311-0561 ◽

2021 ◽

Vol 09 (01) ◽

pp. E102-E109

Author(s):

Ammar Al-Rifaie ◽

Mohammed Gariballa ◽

Alhassan Ghodeif ◽

Stephen Hodge ◽

Mo Thoufeeq ◽

...

Keyword(s):

Body Position ◽

Health Hazard ◽

Significant Proportion ◽

Musculoskeletal Injuries ◽

British Society ◽

Treatment Modalities ◽

Cross Sectional ◽

Electronic Survey ◽

Repetitive Movements ◽

Level Of Experience

Abstract Background and study aims Colonoscopy is physically demanding for endoscopists and patients. Repetitive movements during colonoscopy can lead to overuse injuries. We aimed to explore the prevalence and range of colonoscopy-related musculoskeletal injuries (CRIs) in endoscopists. Methods A cross-sectional electronic survey of 1825 endoscopists was performed. The sample was composed of members of the British Society of Gastroenterology, European Society of Gastrointestinal Endoscopy, and National Nurse Endoscopy Group (UK). The survey comprised 20 questions. These included: endoscopists’ workload, level of experience, and their perceived CRIs. All endoscopists who perform colonoscopy independently were included in the analysis. Results A total of 368 questionnaires were completed of 1825 surveyed (20.16 %). Of those, 319 participants (17.48 %) were fully independent in colonoscopy. Of 319 endoscopists, 254 (79.6 %) have experienced musculoskeletal injuries. These were reported as either possibly (n = 143, 56.3 %) or definitely (n = 90, 35.4 %) related to colonoscopy. Commonly injured areas were the lower back (n = 85, 36.5 %), neck (n = 82, 35.2 %) and left thumb (n = 79, 33.9 %). Of the injured endoscopists, 98 (30.7 %) made some modification to their practice, such as stretching exercises and ergonomic changes. Of the endoscopists, 134 (42.0 %) thought that repetitive limb strain was a likely causative mechanism. Around 40 % believed that torquing the scope and challenging body position were precipitating CRIs. Several treatment modalities were used to treat CRIs. These included; physiotherapy (n = 109), medications (n = 70), rest (n = 43), splinting (n = 31), steroid injections (n = 26) and surgery (n = 11). Conclusions A significant proportion of colonoscopists experience CRIs. The majority of the suggested modifications to practice can be adopted by any endoscopist. These results highlight the need to recognise CRI as an important occupational health hazard and to adopt preventative strategies routinely in the future.

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Reproducibility and agreement between three positions for handgrip assessment

Scientific Reports ◽

10.1038/s41598-021-92296-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Olga-Cecilia Vargas-Pinilla ◽

Eliana-Isabel Rodríguez-Grande

Keyword(s):

Supine Position ◽

Cross Sectional Study ◽

Sitting Position ◽

Average Difference ◽

Cross Sectional ◽

Hand Grip ◽

Standardization Process ◽

The One ◽

Level Of Agreement ◽

Apparently Healthy

AbstractThe protocol established for taking hand grip dynamometry measurements determines that the patient must be in a sitting position. This protocol cannot be applied due to the patient’s conditions in some cases, such as abdominal surgery, musculoskeletal spine or hip injuries. The purpose was to determine the reproducibility and level of agreement between the Handgrip dynamometry in supine position with the elbow flexed or extended, and the one measured in the sitting position, the design was a descriptive cross-sectional study. The population were young apparently healthy between 18 and 30 years of age (N = 201). Handgrip measurement was performed on both upper limbs in a sitting position with a flexed elbow, a supine position with a flexed elbow, and supine position with the elbow extended. Reproducibility was nearly perfect in all positions (ICC 0.95–0.97). Regarding the level of agreement for the comparison between sitting and supine positions with a flexed elbow, an average difference of − 0.406. For supine position with an extended elbow and supine position with a flexed elbow, the average difference was − 1.479. Considering the results, clinicians or researchers can choose any of the positions evaluated herein and obtain reliable results as long as the standardization process is followed.

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Effects of body position change on thoracoabdominal motion

Journal of Applied Physiology ◽

10.1152/jappl.1978.45.4.581 ◽

1978 ◽

Vol 45 (4) ◽

pp. 581-589 ◽

Cited By ~ 51

Author(s):

V. P. Vellody ◽

M. Nassery ◽

W. S. Druz ◽

J. T. Sharp

Keyword(s):

Supine Position ◽

Muscle Force ◽

Body Position ◽

Tidal Breathing ◽

Position Change ◽

Rib Cage ◽

Inspiratory Muscles ◽

Residual Capacity ◽

Lateral Decubitus ◽

Local Compliance

With a linearized respiratory magnetometer, measurements of anteroposterior and lateral diameters of both the rib cage and the abdomen were made at functional residual capacity and continuously during tidal breathing. Twenty-five subjects with normal respiratory systems were studied in the sitting, supine, lateral decubitus, and prone body positions. When subjects changed from sitting to supine position anteroposterior diameters of both rib cage and abdomen decreased while their lateral diameters increased. Both anteroposterior and lateral tidal excursions of the rib cage decreased; those of the abdomen increased. When subjects turned from supine to lateral decubitus position both anteroposterior diameters increased and the lateral diameters decreased. This was associated with an increase in both lateral excursions and a decrease in the abdominal anteroposterior excursions. Diameters and tidal excursions in the prone position resembled those in the supine position. Diameter changes could be explained by gravitational effects. Differences in tidal excursions accompanying body position change were probably related to 1) differences in the distribution of respiratory muscle force, 2) differences in the activity or mechanical advantage of various inspiratory muscles, and 3) local compliance changes in parts of the rib cage and abdomen.

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Effect of Lateral Positioning on Upper Airway Size and Morphology in Sedated Children

Anesthesiology ◽

10.1097/00000542-200509000-00009 ◽

2005 ◽

Vol 103 (3) ◽

pp. 484-488 ◽

Cited By ~ 51

Author(s):

Ronald S. Litman ◽

Nicole Wake ◽

Lai-Ming Lisa Chan ◽

Joseph M. McDonough ◽

Sanghun Sin ◽

...

Keyword(s):

Magnetic Resonance ◽

Supine Position ◽

Upper Airway ◽

Lateral Position ◽

Magnetic Resonance Images ◽

Magnetic Resonance Imaging Examination ◽

Vocal Cords ◽

Cross Sectional ◽

Spontaneously Breathing ◽

Lateral Positioning

Background Lateral positioning decreases upper airway obstruction in paralyzed, anesthetized adults and in individuals with sleep apnea during sleep. The authors hypothesized that lateral positioning increases upper airway cross-sectional area and total upper airway volume when compared with the supine position in sedated, spontaneously breathing children. Methods Children aged 2-12 yr requiring magnetic resonance imaging examination of the head or neck region using deep sedation with propofol were studied. Exclusion criteria included any type of anatomical or neurologic entity that could influence upper airway shape or size. T1 axial scans of the upper airway were obtained in the supine and lateral positions, with the head and neck axes maintained neutral. Using software based on fuzzy connectedness segmentation (3D-VIEWNIX; Medical Imaging Processing Group, University of Pennsylvania, Philadelphia, PA), the magnetic resonance images were processed and segmented to render a three-dimensional reconstruction of the upper airway. Total airway volumes and cross-sectional areas were computed between the nasal vomer and the vocal cords. Two-way paired t tests were used to compare airway sizes between supine and lateral positions. Results Sixteen of 17 children analyzed had increases in upper airway total volume. The total airway volume (mean +/- SD) was 6.0 +/- 2.9 ml in the supine position and 8.7 +/- 2.5 ml in the lateral position (P < 0.001). All noncartilaginous areas of the upper airway increased in area in the lateral compared with the supine position. The region between the tip of the epiglottis and vocal cords demonstrated the greatest relative percent change. Conclusions The upper airway of a sedated, spontaneously breathing child widens in the lateral position. The region between the tip of the epiglottis and the vocal cords demonstrates the greatest relative percent increase in size.

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Upright versus supine MRI: effects of body position on craniocervical CSF flow

Fluids and Barriers of the CNS ◽

10.1186/s12987-021-00296-7 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Marco Muccio ◽

David Chu ◽

Lawrence Minkoff ◽

Neeraj Kulkarni ◽

Brianna Damadian ◽

...

Keyword(s):

Stroke Volume ◽

Supine Position ◽

Cardiac Cycle ◽

Body Position ◽

Csf Flow ◽

Position Change ◽

Phase Duration ◽

Brain Functions ◽

Systolic Phase ◽

The Brain

Abstract Background Cerebrospinal fluid (CSF) circulation between the brain and spinal canal, as part of the glymphatic system, provides homeostatic support to brain functions and waste clearance. Recently, it has been observed that CSF flow is strongly driven by cardiovascular brain pulsation, and affected by body orientation. The advancement of MRI has allowed for non-invasive examination of the CSF hydrodynamic properties. However, very few studies have addressed their relationship with body position (e.g., upright versus supine). It is important to understand how CSF hydrodynamics are altered by body position change in a single cardiac phase and how cumulative long hours staying in either upright or supine position can affect craniocervical CSF flow. Methods In this study, we investigate the changes in CSF flow at the craniocervical region with flow-sensitive MRI when subjects are moved from upright to supine position. 30 healthy volunteers were imaged in upright and supine positions using an upright MRI. The cranio-caudal and caudo-cranial CSF flow, velocity and stroke volume were measured at the C2 spinal level over one cardiac cycle using phase contrast MRI. Statistical analysis was performed to identify differences in CSF flow properties between the two positions. Results CSF stroke volume per cardiac cycle, representing CSF volume oscillating in and out of the cranium, was ~ 57.6% greater in supine (p < 0.0001), due to a ~ 83.8% increase in caudo-cranial CSF peak velocity during diastole (p < 0.0001) and extended systolic phase duration when moving from upright (0.25 ± 0.05 s) to supine (0.34 ± 0.08 s; p < 0.0001). Extrapolation to a 24 h timeframe showed significantly larger total CSF volume exchanged at C2 with 10 h spent supine versus only 5 h (p < 0.0001). Conclusions In summary, body position has significant effects on CSF flow in and out of the cranium, with more CSF oscillating in supine compared to upright position. Such difference was driven by an increased caudo-cranial diastolic CSF velocity and an increased systolic phase duration when moving from upright to supine position. Extrapolation to a 24 h timeframe suggests that more time spent in supine position increases total amount of CSF exchange, which may play a beneficial role in waste clearance in the brain.

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Function, strength, and muscle activation of the shoulder complex in Crossfit practitioners with and without pain: a cross-sectional observational study

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-022-02915-x ◽

2022 ◽

Vol 17 (1) ◽

Author(s):

Elisa Raulino Silva ◽

Nicola Maffulli ◽

Filippo Migliorini ◽

Gilmar Moraes Santos ◽

Fábio Sprada de Menezes ◽

...

Keyword(s):

Shoulder Pain ◽

Surface Electromyography ◽

Shoulder Joint ◽

Muscle Activation ◽

National Registry ◽

Kinetic Chain ◽

Balance Test ◽

Cross Sectional ◽

Significant Difference ◽

Lower Trapezius

Abstract Background The shoulder joint is the most commonly injured joint in CrossFit practitioners, because of the high intensity and loads associated with this sport. Despite the large number of clinical cases, there is a shortage of studies that investigate influence of biomechanical aspects of upper limbs' injuries on CrossFit practitioners. This study hypothesized that there would be a difference in function, strength, and muscle activation between Crossfit practitioners with and without shoulder pain. Methods We divided 79 Crossfit practitioners into two groups according to whether they reported pain (n = 29) or no pain (n = 50) in the shoulder during Crossfit training. Muscle function, strength, and activation were assessed using the Disability Arm, Shoulder and Hand function questionnaire, Upper Quarter Y Balance Test and Closed Kinetic Chain Upper Extremity Stability Test shoulder tests, isometric muscle strength assessment by manual dynamometry and muscle activation by surface electromyography and pain report. Results The function based on questionnaire was associated with pain (p = 0.004). We observed a statistically significant difference between the two groups only in the surface electromyography activity of the lower trapezius, and in the variables of shoulder pain and function (p = 0.038). Conclusion Crossfit practitioners with shoulder pain occurring during training showed good function and stability of the shoulder joint, but there was a reduction in the activation of stabilizing muscles, especially the lower trapezius. Trial registration Registro Brasileiro de Ensaios Clinico (Brasilian National Registry) with the ID: RBR-2gycyv.

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Force Production during the Sustained Phase of Rugby Scrums: A Systematic Literature Review

10.21203/rs.2.20547/v3 ◽

2020 ◽

Author(s):

Eric Martin ◽

George Beckham

Keyword(s):

Literature Review ◽

Systematic Literature Review ◽

Statistical Power ◽

Assessment Tool ◽

Body Position ◽

Body Height ◽

Force Production ◽

Cross Sectional ◽

Testing Procedures ◽

Rugby Players

Abstract Background: Since World Rugby changed the laws regarding scrums in the 2013-2014 season, the sustained push phase of the scrum has increased in tactical importance. Therefore, the purpose of this systematic literature review was to examine the biomechanical demands during the sustained push phase of individual, unit, and full pack scrummaging. Methods: Pubmed, EBSCO (specifically and simultaneously searching Academic Search Premier, CINAHL, and SPORTDiscus), and Google Scholar were searched for any research that presented force production in a live or simulated rugby scrum. Study quality was appraised using the National Institute of Health's Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Recorded scrum forces, positioning of players including joint angles, and testing procedures were extracted and narratively synthesized. Results: Twenty six studies were included in the review. 50% of included studies were rated good, 31% fair, and 19% poor. Major limitations included not reporting any effect size, statistical power, or reliability. Reported group mean values for average sustained forces against a machine generally ranged from 1000-2000 N in individual scrums and 4000-8000 N for full packs of male rugby players older than high school age. Individuals seem to optimize their force generation when their shoulders are set against scrum machine pads at approximately 40% of body height, with feet parallel, and with knee and hip angles around 120°. A 10% difference in pack force seems to be necessary for one pack to drive another back in the scrum, but little data exist to quantify differences in force production between winning and losing packs during live scrums. Data collection within studies was not standardized, making comparisons difficult. There is a lack of data in live scrums, and the current research indicates that machine scrums may not replicate many of the demands of live scrums. There is a lack of data for female rugby players. Conclusions: This review indicates an optimal individual body position for players to strive to achieve during scrummaging, consisting of a low body height (40% of stature) and large extended hip and knee angles (120° each).

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Tai Chi training’s effect on lower extremity muscle co-contraction during single- and dual-task gait: Cross-sectional and randomized trial studies

PLoS ONE ◽

10.1371/journal.pone.0242963 ◽

2021 ◽

Vol 16 (1) ◽

pp. e0242963

Author(s):

Peter M. Wayne ◽

Brian J. Gow ◽

Fengzhen Hou ◽

Yan Ma ◽

Jeffrey M. Hausdorff ◽

...

Keyword(s):

Lower Extremity ◽

Postural Control ◽

Usual Care ◽

Randomized Trial ◽

Dual Task ◽

Muscle Activation ◽

Tai Chi ◽

Mean Difference ◽

Cross Sectional ◽

Lower Extremity Muscle

Background Tai Chi (TC) mind-body exercise has been shown to reduce falls and improve balance and gait, however, few studies have evaluated the role of lower extremity muscle activation patterns in the observed benefits of TC on mobility. Purpose To perform an exploratory analysis of the association between TC training and levels of lower extremity muscle co-contraction in healthy adults during walking under single-task (ST) and cognitive dual-task (DT) conditions. Methods Surface electromyography of the anterior tibialis and lateral gastrocnemius muscles was recorded during 90 sec trials of overground ST (walking normally) and DT (walking with verbalized serial subtractions) walking. A mean co-contraction index (CCI), across all strides, was calculated based on the percentage of total muscle activity when antagonist muscles were simultaneously activated. A hybrid study design investigated long-term effects of TC via a cross-sectional comparison of 27 TC experts and 60 age-matched TC-naïve older adults. A longitudinal comparison assessed the shorter-term effects of TC; TC-naïve participants were randomly allocated to either 6 months of TC training or to usual care. Results Across all participants at baseline, greater CCI was correlated with slower gait speed under DT (β(95% CI) = -26.1(-48.6, -3.7)) but not ST (β(95% CI) = -15.4(-38.2, 7.4)) walking. Linear models adjusting for age, gender, BMI and other factors that differed at baseline indicated that TC experts exhibited lower CCI compared to TC naives under DT, but not ST conditions (ST: mean difference (95% CI) = -7.1(-15.2, 0.97); DT: mean difference (95% CI) = -10.1(-18.1, -2.4)). No differences were observed in CCI for TC-naive adults randomly assigned to 6 months of TC vs. usual care. Conclusion Lower extremity muscle co-contraction may play a role in the observed benefit of longer-term TC training on gait and postural control. Longer-duration and adequately powered randomized trials are needed to evaluate the effect of TC on neuromuscular coordination and its impact on postural control. Trial registration The randomized trial component of this study was registered at ClinicalTrials.gov (NCT01340365).

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Effect of gravity and kinematic constraints on muscle synergies in arm cycling.

Journal of Neurophysiology ◽

10.1152/jn.00415.2020 ◽

2021 ◽

Author(s):

Lilla Botzheim ◽

Jozsef Laczko ◽

Diego Torricelli ◽

Mariann Mravcsik ◽

José L. Pons ◽

...

Keyword(s):

Motor Control ◽

Muscle Activation ◽

Biceps Brachii ◽

Body Position ◽

Medical Rehabilitation ◽

Muscle Synergies ◽

Muscle Coordination ◽

Arm Cycling ◽

Custom Made ◽

Crank Length

Arm cycling is a bi-manual motor task used in medical rehabilitation and in sports training. Understanding how muscle coordination changes across different biomechanical constraints in arm cycling is a step towards improved rehabilitation approaches. This exploratory study aims to get new insights on motor control during arm cycling. To achieve our main goal, we used the muscle synergies analysis to test three hypotheses: 1) body position with respect to gravity (sitting and supine) has an effect on muscle synergies; 2) the movement size (crank length) has an effect on the synergistic behavior; 3) the bimanual cranking mode (asynchronous and synchronous) requires different synergistic control. Thirteen able-bodied volunteers performed arm cranking on a custom-made device with unconnected cranks, which allowed testing three different conditions: body position (sitting versus supine), crank length (10cm versus 15cm) and cranking mode (synchronous versus asynchronous). For each of the eight possible combinations, subjects cycled for 30 seconds while electromyography of 8 muscles (4 from each arm) were recorded: biceps brachii, triceps brachii, anterior deltoid and posterior deltoid. Muscle synergies in this 8-dimensional muscle space were extracted by non-negative matrix factorization. Four synergies accounted for over 90% of muscle activation variances in all conditions. Results showed that synergies were affected by body position and cranking mode but practically unaffected by movement size. These results suggest that the central nervous system may employ different motor control strategies in response to external constraints such as cranking mode and body position during arm cycling.

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