Standing Research Articles

Feasibility of Heart Rate and Respiratory Rate Estimation by Inertial Sensors Embedded in a Virtual Reality Headset.

Virtual reality (VR) headsets, with embedded micro-electromechanical systems, have the potential to assess the mechanical heart’s functionality and respiratory activity in a non-intrusive way and without additional sensors by utilizing the ballistocardiographic principle. To test the feasibility of this approach for opportunistic physiological monitoring, thirty healthy volunteers were studied at rest in different body postures (sitting (SIT), standing (STAND) and supine (SUP)) while accelerometric and gyroscope data were recorded for 30 s using a VR headset (Oculus Go, Oculus, Microsoft, USA) simultaneously with a 1-lead electrocardiogram (ECG) signal for mean heart rate (HR) estimation. In addition, longer VR acquisitions (50 s) were performed under controlled breathing in the same three postures to estimate the respiratory rate (RESP). Three frequency-based methods were evaluated to extract from the power spectral density the corresponding frequency. By the obtained results, the gyroscope outperformed the accelerometer in terms of accuracy with the gold standard. As regards HR estimation, the best results were obtained in SIT, with Rs2 (95% confidence interval) = 0.91 (0.81−0.96) and bias (95% Limits of Agreement) −1.6 (5.4) bpm, followed by STAND, with Rs2 = 0.81 (0.64−0.91) and −1.7 (11.6) bpm, and SUP, with Rs2 = 0.44 (0.15−0.68) and 0.2 (19.4) bpm. For RESP rate estimation, SUP showed the best feasibility (98%) to obtain a reliable value from each gyroscope axis, leading to the identification of the transversal direction as the one containing the largest breathing information. These results provided evidence of the feasibility of the proposed approach with a degree of performance and feasibility dependent on the posture of the subject, under the conditions of keeping the head still, setting the grounds for future studies in real-world applications of HR and RESP rate measurement through VR headsets.

Prevalence of Impaired Orthostasis after Concussion Injury

To determine the prevalence of orthostatic hypotension (OHypo) and hypertension (OHTN), respectively after a concussion in collegiate athletes. Orthostasis causes a gravity-dependent redistribution of blood volume to the lower extremities. The baroreflex coordinates the cardiovascular autonomic nervous system to mitigate aberrant changes in systolic blood pressure (SBP). In autonomic dysfunction (AD), impaired accommodation may lead to a clinically significant? SBP decreases (OHypo: SBP fall = 20 mm Hg) or paradoxical increases (OHTN: SBP rise = 20 mm Hg) within 3 minutes of assuming the standing (STND) posture. Concussion injuries may induce a transient state of AD. A clinical approach to surveil this state has yet to be defined. A prospective study was performed in 36 concussed (gender: 23 female, 13 male; age: 20 ± 1 years; height: 1.75 ± 0.12 meters; weight: 73 ± 14 kilograms) and 20 non-concussed athletes (gender: 12 female, 8 male; age: 21 ± 2 years; height: 1.74 ± 0.15 meters; weight: 72 ± 18 kilograms). Continuous beat-to-beat SBP was collected for 10-minutes in a resting supine position (SUP) and then for 3-minutes in the STND position within 48 hours (48H) of concussion. The average SBP was computed from the difference between SUP and the final 15 seconds of STND. SBP were then categorized: Normal (NR: SBP -15 to +15 mm Hg); Borderline OHypo (BordOHypo: SBP -16 to -19 mm Hg) and OHTN (BordOHTN: SBP +16 to +19 mm Hg); OHypo; and, OHTN. In concussed athletes, the SBP prevalence rates were 42% NR, 31% OHypo, 11% OHTN, 11% BordOHTN, and 6% BordOHypo compared to 90% NR, 5% OHypo and 5% OHTN in the non-concussed athletes. ?2 test revealed a significant difference in this distribution (p = 0.012). Within 48H of concussion injury, a combined 42% of injured athletes had an abnormal SBP response to orthostasis and a further 6% had borderline responses that warrant re-evaluation. The incidence rates for each circumstance exceeded the control group.

Postural Control When Using an Industrial Lower Limb Exoskeleton: Impact of Reaching for a Working Tool and External Perturbation.

ObjectiveTo investigate postural control related to a lower limb exoskeleton (Chairless Chair) when (a) reaching for a working tool, and (b) an external perturbation occurs.BackgroundLower limb exoskeletons aiming to reduce physical load associated with prolonged standing may impair workers’ postural control and increase the risk of falling.MethodForty-five males were reaching for an object (3-kg dumbbell) at the lateral end of their reaching area without the exoskeleton in upright standing (STAND) and with the exoskeleton at a high (EXOHIGH.SEAT) and low sitting position (EXOLOW.SEAT). The task was performed with the object placed in three different angles (120°, 150°, and 180°) in the transversal plane. The minimum absolute static postural stability (SSABS.MIN) as the shortest distance (mm) of the center of pressure to the base of support border was measured (zero indicates risk of falling). Additionally, eight subjects were standing without the exoskeleton or sitting on it (EXOHIGH.SEAT and EXOLOW.SEAT) while being pulled backward. The tilting moment when subjects lost their balance was assessed.ResultsSSABS.MIN was lower when using the exoskeleton (p < .05) but still about 17 mm. The location of the object to be reached had no influence. Tilting moments of less than 30 nm were sufficient to let people fall backward when sitting on the exoskeleton (50 nm for STAND).ConclusionImpairments in postural control by the exoskeleton may not be relevant when reaching laterally for objects up to 3 kg. When an external perturbation occurs, the risk of falling may be much higher; irrespective of factors like uneven or slippery flooring.ApplicationThe risk of falling using the exoskeleton seems to be low when reaching laterally for an object of up to 3 kg. In situations where, for example, a collision with coworkers is likely, this exoskeleton is not recommended.

Standing in Solidarity

Standing in Solidarity

Locomotion replacement exercise cannot counteract cartilage biomarker response to 5 days of immobilization in healthy adults.

Biomarkers of cartilage metabolism are sensitive to changes in the biological and mechanical environment and can indicate early changes in cartilage homeostasis. The purpose of this study was to determine if a daily locomotion replacement program can serve as a countermeasure for changes in cartilage biomarker serum concentration caused by immobilization. Ten healthy male subjects (mean ± 1 standard deviation; age: 29.4 ± 5.9 years; body mass: 77.7 ± 4.1 kg) participated in the crossover 5-day bed rest study with three interventions: control (CON), standing (STA), and locomotion replacement training (LRT). Serum samples were taken before, during, and after bed rest. Biomarker concentrations were measured using commercial enzyme-linked immunosorbent assays. Cartilage oligomeric matrix protein (COMP) levels after 24 hours of bed rest decreased independently of the intervention (-16.8% to -9.8%) and continued to decrease until 72 hours of bed rest (minimum, -23.2% to -20.6%). LRT and STA did not affect COMP during bed rests (P = .056) but there was a strong tendency for a slower decrease with LRT (-9.4%) and STA (-11.7%) compared with CON (-16.8%). MMP-3 levels decreased within the first 24 hours of bed rest (CON: -22.3%; STA: -14.7%; LRT: -17%) without intervention effect. Both COMP and MMP-3 levels recovered to baseline levels during the 6-day recovery period. MMP-1, MMP-9, and TNF-α levels were not affected by immobilization or intervention. COMP and MMP-3 are mechano-sensitive cartilage biomarkers affected by immobilization, and simple interventions such as standing upright or LRT during bed rest cannot prevent these changes. Clinical significance: simple locomotion interventions cannot prevent cartilage biomarker change during bed rest.

Yaşlı Bireylerde Üst Ekstremite Fonksiyonları ile Denge Arasındaki İlişkinin İncelenmesi

Yaşlı bireylerde üst ekstremite fonksiyonlarını ve dengeyi ayrı ayrı inceleyen birçok çalışma bulunmasına rağmen, üst ekstremite fonksiyonları ile denge arasındaki ilişkiyi inceleyen çalışmaların yetersiz olduğu tespit edilmiştir. Bu çalışmanın amacı yaşlı bireylerde üst ekstremite fonksiyonları ile denge arasındaki ilişkiyi incelemektir. Bu çalışmaya yaşları 65 ve üzeri olan 80 yaşlı birey dahil edilmiştir. Bireylerin üst ekstremite fonksiyonlarını değerlendirmek için Jamar El Dinamometresi, 9 Delikli Peg Testi ve purdue peg board testi kullanılmıştır. Bireylerin dengelerini değerlendirmek için Berg Denge Ölçeği, Tinetti Denge ve Yürüme Testi, Biodex Denge Sistemi ve Tek Ayak Üzerinde Durma Testi kullanılmıştır. Bireylerin Jamar El Dinamometresi, 9 Delikli Peg Testi ve purdue peg board testi ile Berg Denge Ölçeği, Tinetti Denge ve Yürüme Testi, Biodex Denge Sistemi ve Tek Ayak Üzerinde Durma Testi aralarında anlamlı ilişki bulunmuştur (p<0,05). Bu çalışmanın sonunda üst ekstremite fonksiyonları ile denge arasında ilişki olduğu tespit edilmiştir. Yaşlı bireylerde üst ekstremite fonksiyonları ile ilgili kavrama kuvvetini, el becerilerini arttıran yaklaşımların bozulan denge ve buna bağlı günlük yaşam aktivitelerinde yaşanan sorunlar için yararlı olacağını düşünmekteyiz.

Conference Recovery During a Time of Disaster m m The contents of this article were derived from the author's, Standing Committee Chair's Welcome Message to COMPSAC 2020 registrants.

Conference Recovery During a Time of Disaster m m The contents of this article were derived from the author's, Standing Committee Chair's Welcome Message to COMPSAC 2020 registrants.

Kenneth G. Standing (April 3, 1925–March 21, 2019)

Kenneth G. Standing (April 3, 1925–March 21, 2019)

Why Aren't More Pediatricians Utilizing Standing Orders for Vaccinations?

Standing orders for vaccinations (SOVs) enable nonphysician healthcare professionals to administer vaccines without direct involvement of a physician.

Design and Implementation of User Standing Posture Recognition-Based Interaction System Using Multi-Channel Large Area Pressure Sensors

Design and Implementation of User Standing Posture Recognition-Based Interaction System Using Multi-Channel Large Area Pressure Sensors

Interpretative Issues on the Standing Sue of the Business Owner on the Administrative Measure to Recognize Occupational Disaster

Interpretative Issues on the Standing Sue of the Business Owner on the Administrative Measure to Recognize Occupational Disaster

“You Can Get Lost When Standing Still Too.” On the Ways of Educating Lawyers

“You Can Get Lost When Standing Still Too.” On the Ways of Educating Lawyers

A Transfer Entropy Approach for the Assessment of the Impact of Inspiratory Muscle Training on the Cardiorespiratory Coupling of Amateur Cyclists.

The strength of cardiorespiratory interactions diminishes with age. Physical exercise can reduce the rate of this trend. Inspiratory muscle training (IMT) is a technique capable of improving cardiorespiratory interactions. This study evaluates the effect of IMT on cardiorespiratory coupling in amateur cyclists. Thirty male young healthy cyclists underwent a sham IMT of very low intensity (SHAM, n = 9), an IMT of moderate intensity at 60% of the maximal inspiratory pressure (MIP60, n = 10) and an IMT of high intensity at the critical inspiratory pressure (CIP, n = 11). Electrocardiogram, non-invasive arterial pressure, and thoracic respiratory movement (RM) were recorded before (PRE) and after (POST) training at rest in supine position (REST) and during active standing (STAND). The beat-to-beat series of heart period (HP) and systolic arterial pressure (SAP) were analyzed with the RM signal via a traditional non-causal approach, such as squared coherence function, and via a causal model-based transfer entropy (TE) approach. Cardiorespiratory coupling was quantified via the HP-RM squared coherence at the respiratory rate (K2HP–RM), the unconditioned TE from RM to HP (TERM→HP) and the TE from RM to HP conditioned on SAP (TERM→HP| SAP). In PRE condition we found that STAND led to a decrease of TERM→HP| SAP. After SHAM and CIP training this tendency was confirmed, while MIP60 inverted it by empowering cardiorespiratory coupling. This behavior was observed in presence of unvaried SAP mean and with usual responses of the baroreflex control and HP mean to STAND. TERM→HP and K2HP–RM were not able to detect the post-training increase of cardiorespiratory coupling strength during STAND, thus suggesting that conditioning out SAP is important for the assessment of cardiorespiratory interactions. Since the usual response of HP mean, SAP mean and baroreflex sensitivity to postural stressor were observed after MIP60 training, we conclude that the post-training increase of cardiorespiratory coupling during STAND in MIP60 group might be the genuine effect of some rearrangements at the level of central respiratory network and its interactions with sympathetic drive and vagal activity.

To the Last Tree Standing? Ottoman-Hungarian Wars and Forests in Transdanubia

To the Last Tree Standing? Ottoman-Hungarian Wars and Forests in Transdanubia

Standing up for what’s right –despite the risks

Standing up for what’s right –despite the risks

SCAPULAR MUSCLE ELECTROMYOGRAPHIC ACTIVITY DURING ABDUCTION EXERCISES IN THE SCAPULAR PLANE IN THREE POSITIONS

Hyperactivity of the anterior deltoid (AD) has been shown to produce adverse effects on subacromial space width as a result of humeral head superior translation during rehabilitation exercises used with overhead athletes. Also, the importance of the ratio of upper trapezius (UT) to lower trapezius (LT) muscle activity has been examined during rehabilitation exercises particularly for those who develop scapular dyskinesis. The purpose of this study was to investigate the level of LT and SA muscle activity during scapular plane elevation (scaption) in three positions while maintaining a moderate level of AD muscle activity. A secondary purpose was to identify the ratio of UT to LT muscle activity during the varied scaption exercises. The authors hypothesized that the activation of these two important muscles and the UT/LT ratio would vary with exercise position and throughout the range of scapular plane elevation. Fourteen active young subjects performed scaption exercises in three different positions: standing (STAN), quadruped (QUAD), and prone (PRON) with three different weight loads: 0 kg, 1.8 kg, and 4.1 kg. Surface electromyography (EMG) was used to record muscular activity. Tested muscles included the UT, LT, SA, AD, and posterior deltoid muscles on the dominant side. QUAD scaption exercises with a load of 1.8 kg at 4 sec after the initial movement activated the LT muscle up to 49% of maximum voluntary isometric contraction (MVIC) while maintaining a moderate level of AD muscle activity (30% MVIC). STAN scaption exercises with the weight load of 1.8 kg at 3 sec after the initial movement activated 43% MVIC of the SA muscle while maintaining a moderate level of AD muscle activity (39% MVIC). The PRON condition generated significantly less SA muscle activity with both 1.8 and 4.1 kg weight loads than during the QUAD condition. The ratios of UT to LT muscle activity were significantly less in QUAD than those of STAN up to 4 sec after the initial movement. No significant difference was observed in the UT/LT ratio between QUAD and PRON conditions. QUAD scaption exercise effectively activated both LT and SA muscles without over activating the AD and produced favorable ratios of UT to LT muscle activity. Descriptive Cohort Study, Level 4.

Intraocular Pressure Measurements in Standing Position with a Rebound Tonometer.

Background and Objectives: It has been established that body position can play an important role in intraocular pressure (IOP) fluctuation. IOP has been previously shown to increase significantly when lying down, relative to sitting; this type of investigation has not been extensively reported for the standing (ST) position. Therefore, this study aims to look for eventual significant IOP changes while ST, sitting, and lying down. Materials and Methods: An Icare PRO was used to measure the IOP of 120 eyes of 60 healthy individuals, with age ranging from 21 to 55 years (mean 29.22 ± 9.12 years), in sitting, supine and ST positions; IOP was measured again, 5 min after standing (ST-5m). Results: Mean IOP difference between sitting and ST position was 0.39 ± 1.93 mmHg (95% CI: 0.04 to 0.74 mmHg) (p = 0.027); between sitting and ST-5m, it was −0.48 ± 1.79 mmHg (95% CI: −0.8 to −0.16 mmHg) (p = 0.004); between the sitting and supine position, it was −1.16±1.9 mmHg (95% CI: −1.5 to −0.82 mmHg) (p < 0.001); between the supine and ST position, it was 1.55 ± 2.04 mmHg (95% CI: 1.18 to 1.92 mmHg) (p < 0.001); between supine and ST-5m, it was 0.68 ± 1.87 mmHg (95% CI: 0.34 to 1.02 mmHg) (p < 0.001); and between ST-5m and ST, it was 0.94 ± 1.95 mmHg (95% CI: 0.58 to 1.29 mmHg) (p < 0.001). Mean axial eye length was 24.45 mm (95% CI: 24.22 to 24.69 mm), and mean central corneal thickness was 535.30 μm (95% CI: 529.44 to 541.19 μm). Conclusion: Increased IOP in the ST-5m position suggests that IOP measurements should be performed in this position too. The detection of higher IOP values in the ST-5m position than in the sitting one, may explain the presence of glaucoma damage or progression in apparently normal-tension or compensated patients.

Effects of inspiratory muscle-training intensity on cardiovascular control in amateur cyclists.

Chronic effects of inspiratory muscle training (IMT) on autonomic function and baroreflex regulation are poorly studied. This study aims at evaluating chronic effects of different IMT intensities on cardiovascular control in amateur cyclists. A longitudinal, randomized, controlled blind study was performed on 30 recreational male cyclists undergoing IMT for 11 wk. Participants were randomly allocated into sham-trained group (SHAM, n = 9), trained group at 60% of the maximal inspiratory pressure (MIP60, n = 10), and trained group at critical inspiratory pressure (CIP, n = 11). Electrocardiogram, finger arterial pressure, and respiratory movements were recorded before (PRE) and after (POST) training at rest in supine position (REST) and during active standing (STAND). From the beat-to-beat series of heart period (HP) and systolic arterial pressure (SAP), we computed time domain markers, frequency domain indexes in the low frequency (0.04-0.15 Hz) and high frequency (HF, 0.15-0.4 Hz) bands, an entropy-based complexity index (CI), and baroreflex markers estimated from spontaneous HP-SAP sequences. Compared with SHAM, the positive effect of MIP60 over the HP series led to the HF power increase during REST (PRE: 521.2 ± 447.5 ms2; POST: 1,161 ± 878.9 ms2) and the CI rise during STAND (PRE: 0.82 ± 0.18; POST: 0.97 ± 0.13). Conversely, the negative effect of CIP took the form of the decreased HP mean during STAND (PRE: 791 ± 71 ms; POST: 737 ± 95 ms). No effect of IMT was visible over SAP and baroreflex markers. These findings suggest that moderate-intensity IMT might be beneficial when the goal is to limit cardiac sympathetic hyperactivity at REST and/or in response to STAND.

Effects of Rest Position on Morphology of the Vastus Lateralis and Its Relationship with Lower-Body Strength and Power.

Ultrasonography of the lower body typically encompasses supine rest due to fluid shifts affecting tissue size and composition. However, vastus lateralis (VL) examination is completed in the lateral recumbent position, and this positional change may influence morphology and its ability to predict function. This study aimed to examine the effect of position on VL morphology and its relationship with lower-body performance. Cross-sectional area (CSA), muscle thickness (MT), pennation angle (PA), echo intensity (UnCorEI), subcutaneous adipose tissue thickness (SFT), and echo intensity corrected for SFT (CorEI) were assessed in 31 resistance-trained males (23.0 ± 2.1 yrs; 1.79 ± 0.08 m; 87.4 ± 11.7 kg) immediately after transitioning from standing to supine (IP), after 15 min of standing (ST), and after 15 min of rest in three recumbent positions: supine (SUP), dominant lateral recumbent (DLR), non-dominant lateral recumbent (NDLR). Participants also completed unilateral vertical jumps, isometric/isokinetic tests, and a one-repetition maximum leg press. CSA, MT, PA, and SFT were greater in ST compared to NDLR, DLR, and SUP (p < 0.05). CSA, UnCorEI, and CorEI were different between recumbent positions; however no differences were observed for MT, PA, and SFT. Different magnitudes of relationships were observed between muscle morphological characteristics measured after rest in different positions and performance variables. Muscle morphology in IP generally appears to be the best predictor of performance for most variables, although utilizing the NDLR and DLR positions may provide comparable results, whereas morphology measured in ST and SUP provide weaker relationships with physical performance. IP also requires less time and fewer requirements on the technician and subject, thus researchers should consider this positioning for VL examination.

Can Replacing Sitting Time with Standing Time Improve Adolescents' Cardiometabolic Health?

This study aimed to assess the effects of isotemporal replacement of sitting time (SIT) with standing (STA) on cardiometabolic biomarkers. In this cross-sectional study, male adolescents wore the GT3X+ activity monitor for 7 days to measure the SIT and STA. Moderate-to-vigorous physical activity (MVPA) was estimated by a youth-specific cut-off point. An isotemporal substitution approach was used to examine the effects of replacing different periods of SIT (15, 30, 60, and 120 min) with STA on cardiometabolic biomarkers [total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), non-HDL-c, low-density lipoprotein cholesterol (LDL-c), triglycerides (TG), glucose, insulin, HOMA2-β, HOMA2-S, and HOMA2-IR]. Analysis of covariance (ANCOVA) with a post-hoc Bonferroni test was used to compare the adjusted means between the four subgroups that were clustered according to SIT and STA amount. Adolescents (n = 84; age, 16.7 ± 0.9 years) wore GT3X+ for 15.2 ± 2.3 h, for 6.7 ± 0.6 days. Isotemporal substitution of SIT with STA was associated with TC, non-HDL-c, LDL-c, and TG. ANCOVA results showed a statistically significant difference for TC, non-HDL-c, and LDL-c. These findings showed that for male adolescents, sitting less and standing more may be an effective alternative to reduce cardiometabolic biomarker levels related to lipid metabolism, regardless of MVPA.