Search results for "position"

Causal analysis of short-term cardiovascular variability: state-dependent contribution of feedback and feedforward mechanisms.

2016

Baroreflex function is usually assessed from spontaneous oscillations of blood pressure (BP) and cardiac RR interval assuming a unidirectional influence from BP to RR. However, the interaction of BP and RR is bidirectional—RR also influences BP. Novel methods based on the concept of Granger causality were recently developed for separate analysis of feedback (baroreflex) and feedforward (mechanical) interactions between RR and BP. We aimed at assessing the proportion of the two causal directions of the interactions between RR and systolic BP (SBP) oscillations during various conditions, and at comparing causality measures from SBP to RR with baroreflex gain indexes. Arterial BP and ECG sig…

Role of causality in the evaluation of coherence and transfer function between heart period and systolic pressure in humans

2004

To elicit the effects of considering causality in the study of the interactions between RR interval and systolic pressure (SP) variability, the traditional noncausal cross-spectral analysis was compared with a causal method able to separate the two arms of the RR-SP regulatory loop. Estimates of coherence (K) and causal coherences from SP to RR (Ksr) and from RR to SP (Krs), and of noncausal (G) and causal (Gsr) baroreflex gain were evaluated at 0.1 Hz in 10 healthy young subjects in the supine position and after head-up tilt. While K was high in both conditions, at rest Ksr was significantly lower than Krs. After tilt, Ksr increased and Krs decreased significantly. With respect to G, Gsr w…

Differences in Inter-Rectus Distance and Abdominopelvic Function between Nulliparous, Primiparous and Multiparous Women

2021

Widening of the inter-rectus distance (IRD) is highly prevalent among postpartum women and can lead to dysfunction of abdominopelvic muscles. The aim of this study was to evaluate the differences in IRD and abdominopelvic function between nulliparous, primiparous and multiparous women. A cross-sectional study was conducted on 75 women (25 nulliparous, 25 primiparous and 25 multiparous at 6 months postpartum). The participants underwent ultrasound assessment under three conditions (at rest, abdominal draw-in maneuver (ADIM) and curl-up) at two locations (2 cm above and 2 cm below the umbilicus). Furthermore, abdominopelvic muscle function was determined by prone, supine and side bridge tests…

Diagnostik von Pleuraergüssen und Atelektasen: Sonographie und Radiologie im Vergleich

1991

In a prospective study it was shown that chest ultrasonography is superior to conventional x-ray diagnosis of recumbent patients in diagnosing pleural effusion and lung atelectasis. In 110 supine radiographs we found a sensitivity of 47% and a specificity of 71% for right pleural effusions and a sensitivity of 55% and a specificity of 93% for left pleural effusions in comparison to 110 sonographic examinations. The results of supine radiographs in detection of atelectasis were less efficient: sensitivity for the right side: 7%; sensitivity for the left side: 13.5%. Hence, the knowledge of chest ultrasonographic diagnosis can improve the interpretation of supine radiographs.

Relationship between heart rate variability and the serum testosterone-to-cortisol ratio during military service

2009

Abstract The autonomic nervous system and circulating hormones control a stress reaction through a complex interaction. We tested the hypothesis that changes in cardiac vagal regulation may be positively associated with the serum testosterone-to-cortisol ratio during the first week of military service in 24 conscripts aged 19.0±0.3 years. Cardiac autonomic function was assessed by measuring high-frequency (HF: 0.15–0.4 Hz) and low-frequency (LF: 0.04–0.15 Hz) power spectral indices of R-R intervals during supine rest and during a controlled standing condition (5 min for both) from the second to the seventh mornings at the beginning of military service. Blood samples were collected to analys…

2019

Objective: In two independent study arms, we determine the effects of strength training (ST) and high-intensity interval training (HIIT) overload on cardiac autonomic modulation by measuring heart rate (HR) and vagal heart rate variability (HRV). Methods: In the study, 37 well-trained athletes (ST: 7 female, 12 male; HIIT: 9 female, 9 male) were subjected to orthostatic tests (HR and HRV recordings) each day during a 4-day baseline period, a 6-day overload microcycle, and a 4-day recovery period. Discipline-specific performance was assessed before and 1 and 4 days after training. Results: Following ST overload, supine HR, and vagal HRV (Ln RMSSD) were clearly increased and decreased (small …

Slow 0.1 Hz Breathing and Body Posture Induced Perturbations of RRI and Respiratory Signal Complexity and Cardiorespiratory Coupling

2020

Objective: We explored the physiological background of the non-linear operating mode of cardiorespiratory oscillators as the fundamental question of cardiorespiratory homeodynamics and as a prerequisite for the understanding of neurocardiovascular diseases. We investigated 20 healthy human subjects for changes using electrocardiac RR interval (RRI) and respiratory signal (Resp) Detrended Fluctuation Analysis (DFA, α1RRI, α2RRI, α1Resp, α2Resp), Multiple Scaling Entropy (MSERRI1−4, MSERRI5−10, MSEResp1−4, MSEResp5−10), spectral coherence (CohRRI−Resp), cross DFA (ρ1 and ρ2) and cross MSE (XMSE1−4 and XMSE5−10) indices in four physiological conditions: supine with spontaneous breathing, stand…

2019

We investigated the ability of energy expenditure, movement sensing, and muscle activity to discriminate sedentary and non-sedentary activities in children. Thirty-five 7-11-year-old children participated in the study. Simultaneous assessment of oxygen uptake (VO2), triaxial accelerometry, and thigh muscle electromyography (EMG) were performed during eight different sedentary and non-sedentary activities including lying down, sitting-, standing-, and walking-related activities, which were performed in a random order. Mean values of VO2, accelerometry, and EMG from the concurrent 2 min epochs during each activity were computed. Resting energy expenditure (REE) was measured during 30 min supi…

Relationship between lower limb position and pelvic floor muscle surface electromyography activity in menopausal women: a prospective observational s…

2017

Tomasz Halski,1 Kuba Ptaszkowski,2 Lucyna Słupska,1 Robert Dymarek,3 Małgorzata Paprocka-Borowicz2 1Department of Physiotherapy, Opole Medical School, Opole, 2Department of Clinical Biomechanics and Physiotherapy in Motor System Disorders, 3Department of Nervous System Diseases, Faculty of Health Science, Wroclaw Medical University, Wroclaw, Poland Objectives: In physiotherapeutic practice, special attention is being given to the reciprocal anatomical, physiological, and biomechanical relationship of the pelvis and the structures connected to it. However, the scientific literature shows mainly the theoretical information about their mutual connections. The lack of information about these …

Regional Lung Blood Perfusion Measured With Laser Doppler Method During Body Position Change, Valsalva Manoeuvre and Cardiopulmonary Bypass

2008

Regional Lung Blood Perfusion Measured With Laser Doppler Method During Body Position Change, Valsalva Manoeuvre and Cardiopulmonary Bypass Methodological approaches to investigate local regulatory mechanisms of lung blood supply in humans are restricted. We tried a new approach using laser Doppler technique. During bronchoscopy, an angled laser Doppler flow probe was introduced through a biopsy channel and wedged into small bronchus. Laser light penetrated the wall of small bronchus and was reflected from blood cells running through neighbouring capillaries. Regional blood perfusion changes were recorded during body position change from vertical to supine and back to vertical, while perfor…