Occlusion Research Articles

Self-Supervised Tracking via Target-Aware Data Synthesis.

While deep-learning-based tracking methods have achieved substantial progress, they entail large-scale and high-quality annotated data for sufficient training. To eliminate expensive and exhaustive annotation, we study self-supervised (SS) learning for visual tracking. In this work, we develop the crop-transform-paste operation, which is able to synthesize sufficient training data by simulating various appearance variations during tracking, including appearance variations of objects and background interference. Since the target state is known in all synthesized data, existing deep trackers can be trained in routine ways using the synthesized data without human annotation. The proposed target-aware data-synthesis method adapts existing tracking approaches within a SS learning framework without algorithmic changes. Thus, the proposed SS learning mechanism can be seamlessly integrated into existing tracking frameworks to perform training. Extensive experiments show that our method: 1) achieves favorable performance against supervised (Su) learning schemes under the cases with limited annotations; 2) helps deal with various tracking challenges such as object deformation, occlusion (OCC), or background clutter (BC) due to its manipulability; 3) performs favorably against the state-of-the-art unsupervised tracking methods; and 4) boosts the performance of various state-of-the-art Su learning frameworks, including SiamRPN++, DiMP, and TransT.

The effects of pain induced by blood flow occlusion in one leg on exercise tolerance and corticospinal excitability and inhibition of the contralateral leg in males.

Experiencing pain in one leg can alter exercise tolerance and neuromuscular fatigue (NMF) responses in the contralateral leg; however, the corticospinal modulations to nonlocal experimental pain induced by blood flow occlusion remain unknown. In three randomized visits, 13 male participants performed 25% of isometric maximal voluntary contraction (25%IMVC) to task failure with one leg preceded by (i) 6-min rest (CON), (ii) cycling at 80% of peak power output until task failure with the contralateral leg (CYCL), or (iii) CYCL followed by blood flow occlusion (OCCL) during 25%IMVC. NMF assessments (IMVC, voluntary activation [VA], and potentiated twitch [Qtw]) were performed at baseline and task failure. During the 25%IMVC, transcranial magnetic stimulations were performed to obtain motor-evoked potential (MEP), silent period (SP), and short intracortical inhibition (SICI). 25%IMVC was the shortest in OCCL (105±50s)and shorter in CYCL (154±68s)than CON (219±105s)(p<0.05). IMVC declined less after OCCL (-24±19%) and CYCL (-27±18%), then CON (-35±11%) (p<0.05). Qtw declined less in OCCL (-40±25%) compared to CYCL (-50±22%) and CON (-50±21%) (p<0.05). VA was similar amongst conditions. MEP and SP increased and SICI decreased throughout the task, while SP was longer for OCCL compared to CYC condition (p<0.05). The results suggest that pain in one leg diminishes contralateral limb exercise tolerance and NMF development and modulate corticospinal inhibition in males. Novelty: Pain in one leg diminished MVC and twitch force decline in the contralateral limb. Experimental pain induced by blood flow occlusion may modulation corticospinal inhibition of the neural circuitries innervating the contralateral exercise limb.

Heart rate and cardiac autonomic responses to concomitant deep breathing, hand grip exercise, and circulatory occlusion in healthy young adult men and women

BackgroundDeep breathing (DB) and handgrip (HG) exercise -with and without circulatory occlusion (OC) in muscle-, have been shown to have beneficial effects on cardiovascular function; however, the combination of these maneuvers on heart rate (HR) and cardiac sympathovagal balance have not been previously investigated. Therefore, the aim of the present study was to evaluate the effect of simultaneous DB, HG, and OC maneuvers on the sympathovagal balance in healthy women and men subjects.Methods and resultsElectrocardiogram and ventilation were measured in 20 healthy subjects (Women: n = 10; age = 27 ± 4 years; weight = 67.1 ± 8.4 kg; and height = 1.6 ± 0.1 m. Men: n = 10; age = 27 ± 3 years; weight = 77.5 ± 10.1 kg; and height = 1.7 ± 0.1 m) at baseline and during DB, DB + HG, or DB + HG + OC protocols. Heart rate (HR) and respiratory rate were continuously recorded, and spectral analysis of heart rate variability (HRV) were calculated to indirectly estimate cardiac autonomic function. Men and women showed similar HR responses to DB, DB + HG and DB + HG + OC. Men exhibited a significant HR decrease following DB + HG + OC protocol which was accompanied by an improvement in cardiac autonomic control evidenced by spectral changes in HRV towards parasympathetic predominance (HRV High frequency: 83.95 ± 1.45 vs. 81.87 ± 1.50 n.u., DB + HG + OC vs. baseline; p < 0.05). In women, there was a marked decrease in HR after completion of both DB + HG and DB + HG + OC tests which was accompanied by a significant increase in cardiac vagal tone (HRV High frequency: 85.29 ± 1.19 vs. 77.93 ± 0.92 n.u., DB + HG vs. baseline; p < 0.05). No adverse effects or discomfort were reported by men or women during experimental procedures. Independent of sex, combination of DB, HG, and OC was tolerable and resulted in decreases in resting HR and elevations in cardiac parasympathetic tone.ConclusionsThese data indicate that combined DB, HG and OC are effective in altering cardiac sympathovagal balance and reducing resting HR in healthy men and women.

Treatment of Serious Occlusal Instability Associated with Temporomandibular Disorders (TMDs) Through Implant and Dynamic Occlusal Schemes Rehabilitation. A Case Report

A case report of 35 years old male patient, partially edentulous with occlusal instability, Disc Displacement with Reduction (DDWR), Local Muscle Soreness (LMS) and Alteration of vertical dimension is presented. Rehabilitation was planned to achieve predictability of long-term treatment, providing static and dynamic occlusal stability. A therapeutic occlus ion with premature contact in the right premolar sector was planned. Implants and cemented/screwed crowns were used to obtain contacts in the molar area. The restoration of dynamic occlusal schemes was made by direct adhesive technique in the anterior sector and Curve of Spee (COS) compensation with temporary anchoring for molar inclusion was used. Patient presents objective and subjective improvements associated with the treatment performed. Temporomandibular disorder is stabilized and controlled by a specialist.

Reliable part-based long-term tracking using multiple correlation filters

Most visual trackers focus on short-term tracking. The target is always in the camera field of view or slight occlusion (OCC). Compared with short-term tracking, long-term tracking is a more challenging task. It requires the ability to capture the target in long-term sequences and undergo frequent disappearances and reappearances of target. Therefore, long-term tracking is much closer to a realistic tracking system. However, few long-term tracking algorithms have been developed and few promising performances have been shown until now. We focus on a long-term visual tracking framework based on parts correlation filters (CFs). Our long-term tracking framework is composed of a part-based short-term tracker and a re-detection module. First, multiple CFs have been applied to locate the target collaboratively and address the partial OCC issue. Second, our method updates the part adaptively based on its motion similarity and reliability score to retain its robustness. Third, a switching strategy has been designed to dynamically activate the re-detection module and interact the search mode between local and global search. In addition, our re-detector is trained by sampling positive and negative samples around the reliable tracking target to adapt to the appearance changes. To evaluate the candidates from the re-detection module, verification has been carried out, which could ensure the precision of recovery. Numerous experimental results demonstrate that our proposed tracking method performs favorably against state-of-the-art methods in terms of accuracy and robustness.

Correlation filter tracking based on superpixel and multifeature fusion

For the correlation filtering (CF) tracking algorithm is not robust enough and cannot adapt to scale changes, target occlusion (OCC) and other complex interferences. We introduce a CF tracking algorithm based on superpixel and multifeature fusion (CFSMF). First, superpixel segmentation and clustering are performed for the target and its surrounding environment in the initial frame. Then, a target appearance is reconstructed through block segmentation-based overlapping analysis to remove redundant information. On this basis, the histogram of gradient (HOG) and HSI color features of the target sub-block are extracted to interact with their respective position filters. Accordingly, the target position is determined by the weighted fusion of the response values. In the scale prediction stage, we independently train a scale filter with a multiscale pyramid constructed at the estimated target location. The object scale is estimated in terms of the filter response, thereby enabling the tracking algorithm to adapt to the object scale change. Lastly, we introduce an OCC criterion for determining whether to update the model or not. Compared with the classical tracking algorithm kernelized correlation filters (KCF), the proposed algorithm boosts the tracking success rate by 20% and tracking accuracy by 15.9%. Our algorithm in this paper could track the target stably even when the target is occluded and its scale changes.

LMD-TShip⋆: Vision Based Large-Scale Maritime Ship Tracking Benchmark for Autonomous Navigation Applications

Accurate ship tracking is very important for the security of maritime activities, especially the raising requirements of autonomous navigation applications, e.g., autonomous surface vehicles (ASVs). Unlike deep-learning-based object-tracking methods are prevailing in autonomous driving because of good environmental robustness and high tracking accuracy, few deep-tracking models can be found for maritime ships. The main reason for that is the lack of qualified ship datasets, especially datasets with ship-based perspectives. Therefore, a large-scale, high-definition dataset for ship tracking, LMD-TShip (Large Maritime Dataset), is provided in this paper. In this dataset, five types of ships are included, from cargo ships, fishing ships, passenger ships, and speed boats to unmanned ships. Specifically, LMD-TShip consists of 40,240 frames in 191 videos, each of which is carefully and manually annotated with bounding boxes in YOLO format. Moreover, 13 attributes are used to label videos, e.g., scale variation (SV), occlusion (OCC), basically covering tracking challenges of maritime ship tracking. Next, a detailed analysis is carried out to demonstrate the characteristics of LMD-TShip. Finally, experiments with five baseline short-term tracking models on the dataset are performed, e.g., ECO, SiamRPN++, and the experimental results demonstrate its good evaluation ability, which will provide effective means for training and testing tracking models related to maritime ships.

Influence of blood flow occlusion on muscular recruitment and fatigue during maximal-effort small muscle-mass exercise.

The heavy-to-severe intensity exercise threshold (i.e. critical force) distinguishes between steady-state and progressive metabolic and neuromuscular responses to exercise. High levels of skeletal muscle sensory feedback related to peripheral fatigue development are thought to restrict motor unit activation and limit exercise tolerance. Utilizing limb blood flow occlusion, we demonstrate that critical force reflects an oxygen-delivery-dependent balance between motor unit activation and peripheral fatigue development. Our findings suggest that mechanisms which determine the total force-producing capacity of exercising skeletal muscle are significantly altered during blood flow occlusion. These findings may have widespread implications for exercise tolerance in patient populations who experience partial vascular occlusion or altered neuromuscular reflexes. High levels of muscle sensory feedback restrict motor unit activation and limit exercise tolerance. The roles of muscle fatigue development and motor unit activation in determining the heavy- to severe-intensity threshold (critical force; CF) remain unclear. This study utilized blood flow occlusion (OCC) to determine relationships between muscle fatigue development and motor unit activation during the determination of CF. We hypothesized that (1) OCC would exacerbate peripheral fatigue development and increase the rate of motor unit deactivation, and (2) blood flow reperfusion (REP) would result in muscle recovery and re-recruitment of motor units despite continuous maximal effort, (3) resulting in an end-exercise force not different from CF. Seven young, healthy subjects performed maximal-effort rhythmic handgrip exercise for 5min under control conditions (CON) and during OCC and REP. Peripheral fatigue development and motor unit activation were measured via electrical stimulation and electromyography, respectively, during each test. OCC resulted in significantly greater peripheral fatigue development than CON (54.3±34.8%;P<0.001). Motor unit deactivation was only observed during OCC (P<0.001). REP resulted in significant peripheral recovery (P<0.001) and the re-recruitment of motor units (P<0.001) to levels not different from CON. While OCC resulted in a significantly greater reduction in force production compared to CON (65.7±35.6%;P<0.001), REP resulted in the restoration of maximal-effort force production (266±19N;P<0.001) to levels not different from CF (276±55N).These data suggest that CF reflects an oxygen-delivery-dependent balance between motor unit activation and peripheral fatigue development. Furthermore, this study established that mechanisms which determine the total force-producing capacity of exercising skeletal muscle are altered during OCC.

Hierarchical Spatiotemporal Context-Aware Correlation Filters for Visual Tracking

Discriminative correlation filters (DCF)-based trackers have been increasingly applied to visual tracking due to their high precision while running at high frame rates. However, most recent DCF-based methods solely concentrate on learning the correlation filter with spatial information and thus do not have sufficient descriptive power to discriminate the target from the background in the complex circumstances, such as full occlusion (OCC) and rapid target variation. In this article, we introduce a novel tracking framework that exploits the relationship between the target and its spatiotemporal context to improve tracking accuracy and robustness. Especially, we present our spatiotemporal context model in a hierarchical way, where each layer of the context pyramid is a spatial correlation filter learned from different temporal instances. For gaining an accurate spatiotemporal model, we propose an optimization fusion approach that can adaptively and efficiently learn the effect of each hierarchical layer and exploit these multiple temporal levels of correlation filters for visual tracking. Moreover, an adaptive model update strategy for correlation filters is introduced into the framework to dynamically select proper hierarchical layers, which boosts the temporal diversity of the target appearance, while radically reduces the number of model parameters and guarantees the real-time performance of the tracking method. The experimental results show that, with conventional handcrafted features, our tracker achieves the best success rates among available state-of-the-art trackers with handcrafted features, and provides state-of-the-art performance comparable to those of deep-learning-based trackers on OTB-2013, OTB-2015, VOT-2016, and UAV-20L benchmarks but runs significantly faster than deep trackers.

Effect of acute myocardial ischemia on inferolateral early repolarization

Inferolateral early repolarization (ER) is associated with an increase in arrhythmic risk, particularly in the presence of myocardial ischemia. The purpose of this study was to determine the effect of myocardial ischemia on ER. We retrospectively analyzed procedural electrocardiograms (ECGs) of patients with ER undergoing a controlled, 1-minute coronary balloon occlusion for collateral function testing. ECG leads with ER were analyzed immediately before coronary balloon occlusion (PRE), at 60 seconds of coronary balloon occlusion (OCCL), and >30 seconds after balloon deflation. Seventy-seven patients with ER in the preprocedural ECG (86% inferior, 20% lateral) underwent 135 coronary balloon occlusions during which a J wave was recorded in 224 leads (ER leads). From PRE to OCCL, ST-segment amplitude (ST) in the ER lead increased in 94 cases (44%) from 0.00 ± 0.03 to 0.05 ± 0.06 mV (P < .0001). In this group, J-wave amplitude (JWA) increased from 0.10 ± 0.07 to 0.13 ± 0.09 mV (P < .0001). ST in the ER lead decreased or was unchanged in 121 cases (56%) from PRE to OCCL (from 0.01 ± 0.05 to -0.02 ± 0.04 mV; P < .0001). In this group, JWA decreased from 0.10 ± 0.05 to 0.08 ± 0.07 mV (P < .0001). The change in JWA was related to the change in ST (linear regression analysis; R2 = 0.34; P < .0001), while there was no relation between the change in R-wave amplitude and the change in ST (R2 = 0.0003; P = .83). During acute ischemia, JWA mirrors ST-segment changes. This may explain increased arrhythmic vulnerability of patients with ER during myocardial ischemia. It also adds weight to the hypothesis of ER being a phenomenon of repolarization.

Effect of fatigue-related group III/IV afferent firing on intracortical inhibition and facilitation in hand muscles.

Fatiguing exercise causes a reduction in motor drive to the muscle. Group III/IV muscle afferent firing is thought to contribute to this process; however, the effect on corticospinal and intracortical networks is poorly understood. In two experiments, participants performed sustained maximal isometric finger abductions of the first dorsal interosseous (FDI) muscle, with postexercise blood flow occlusion (OCC) to maintain the firing of group III/IV afferents or without occlusion (control; CON). Before and after exercise, single- and paired-pulse transcranial magnetic stimulation (TMS) tested motor evoked potentials (MEPs), intracortical facilitation [ICF (12 ms)], and short-interval intracortical inhibition [SICI2 (2 ms), SICI3 (3 ms)]. Ulnar nerve stimulation elicited maximal M waves (MMAX). For experiment 1 (n = 16 participants), TMS intensities were 70% and 120% of resting motor threshold (RMT) for the conditioning and MEP stimuli, respectively. For experiment 2 (n = 16 participants), the MEP was maintained at 1 mV before and after exercise and the conditioning stimulus individualized. In experiment 1, MEP/MMAX was reduced after exercise (~48%, P = 0.007) but was not different between conditions. No changes occurred in ICF or SICI. In experiment 2, MEP/MMAX increased (~27%, P = 0.027) and less inhibition (SICI2: ~21%, P = 0.021) occurred after exercise for both conditions, whereas ICF decreased for CON only (~28%, P = 0.006). MEPs and SICI2 were modulated by fatiguing contractions but not by group III/IV afferent firing, whereas sustained afferent firing appeared to counteract postexercise reductions in ICF in FDI. The findings do not support the idea that actions of group III/IV afferents on motor cortical networks contribute to the reduction in voluntary activation observed in other studies.NEW & NOTEWORTHY This is the first study to investigate, in human hand muscles, the action of fatigue-related group III/IV muscle afferent firing on intracortical facilitation and inhibition. In fatigued and nonexercised hand muscles, intracortical inhibition is reduced after exercise but is not modulated differently by the firing of group III/IV afferents. However, facilitation is maintained for the fatigued muscle when group III/IV afferents fire, but these results are unlikely to explain the reduction in voluntary activation observed in other studies.

Saliency auxiliary objects for visual tracking

The background contains potential favorable information for visual tracking. The recent correlation filter-based tracking methods achieve great success by densely sampling at the target and its surrounding background. To further improve the tracking ability against deformation (DEF) and occlusion (OCC), we propose to utilize auxiliary objects. First, auxiliary object candidates with objectness are generated with unsupervised salient region detection. Second, the graph model between the target with all auxiliary object candidates is established when these objects are tracked individually. Third, all auxiliary objects vote for correcting the predicting result of the target tracker. Experimental results show that auxiliary objects are helpful for tracking the target, especially for improving the robustness on DEF and OCC.

Visual tracking using objectness-bounding box regression and correlation filters

Visual tracking is a fundamental problem in computer vision with extensive application domains in surveillance and intelligent systems. Recently, correlation filter-based tracking methods have shown a great achievement in terms of robustness, accuracy, and speed. However, such methods have a problem of dealing with fast motion (FM), motion blur (MB), illumination variation (IV), and drifting caused by occlusion (OCC). To solve this problem, a tracking method that integrates objectness-bounding box regression (O-BBR) model and a scheme based on kernelized correlation filter (KCF) is proposed. The scheme based on KCF is used to improve the tracking performance of FM and MB. For handling drift problem caused by OCC and IV, we propose objectness proposals trained in bounding box regression as prior knowledge to provide candidates and background suppression. Finally, scheme KCF as a base tracker and O-BBR are fused to obtain a state of a target object. Extensive experimental comparisons of the developed tracking method with other state-of-the-art trackers are performed on some of the challenging video sequences. Experimental comparison results show that our proposed tracking method outperforms other state-of-the-art tracking methods in terms of effectiveness, accuracy, and robustness.

Mechanomyographic Responses to Blood Flow Restricted, Fatiguing Isometric Muscle Actions

Blood flow restriction (BFR) during low intensity resistance exercise (LIRE) has been shown to increase activation of lower body musculature. It is unclear if this is due to increases in motor unit recruitment (MU) or firing rate. Mechanomyography (MMG) has been used to investigate motor unit recruitment (MMG amplitude) and motor unit firing rate (MMG frequency). PURPOSE: To use MMG to investigate the neuromuscular effects of BFR in the lower body during LIRE. METHODS: Ten males (age = 27.1 ± 3.1y; height = 177.6 ± 6.2 cm; mass = 86.9 ± 13.0 kg) performed 3 knee extensor maximal voluntary isometric contractions (MVIC) with the right limb. Occlusion (OCC) was then applied to the right thigh using a KAATSU master unit while two sets (set 1 = 30 ± 7.96 repetitions; set 2 = 13.7 ± 11.29 repetitions) of repeated 5-second isometric knee extensions at 30% of peak torque were performed. Each set was performed to fatigue, defined as the inability to reach 30% of MVIC torque, with 2-seconds rest between repetitions. The same procedure was repeated during a second visit without occlusion (NONOCC), while matching the number of repetitions per set to the first visit. An accelerometer was used to collect MMG data from the vastus lateralis during the MVICs and both sets. Prior to data analysis, repetitions were normalized as percentages (25%, 50%, 75% and 100%) of total repetitions completed, and MMG data were normalized to the values from MVIC testing. RESULTS: For MMG frequency, a significant 3-way interaction between set (2), condition (2) and percent repetitions (4) (p=0.046) was found. Follow-up tests revealed no interaction or main effects for set 1 (p>0.05), and no interactions for set 2. When collapsed across percent repetitions, MMG frequency was lower for OCC (0.837 ± 0.045) than for NONOCC (1.116 ± 0.099) during set 2 (p=0.046). For MMG amplitude, there was a significant condition by set interaction (p=0.023). MMG amplitude was higher for the OCC condition (0.754 ± 0.187) than for the NONOCC condition during set 2 (0.481 ± 0.163; p=0.001). MMG amplitude during set 1 (0.599 ± 0.179) was lower than set 2 (0.754 ± 0.187; p=0.042) for OCC. CONCLUSION: OCC exhibited lower levels of MMG frequency and higher values for MMG amplitude. This suggests that higher MU recruitment, rather than firing rate, was responsible for increased muscle activation during BFR.

Muscle Metaboreflex Modulation of Heart Rate Kinetics During the Transition to Low-Moderate and High-Moderate Exercise Intensities

Our classical understanding of heart rate kinetics is that a sympathovagal balance favouring parasympathetic tone at rest or during low level exercise contributes to a rapid heart rate adaptation (i.e. fast kinetics) during low level exercise transitions. Conversely, higher-level exercise transitions elicit slower heart rate kinetics, due in part to a sympathovagal shift to greater sympathetic tone. PURPOSE: To test the hypothesis that increasing sympathetic activity to the heart via muscle metaboreflex activation would slow heart rate kinetics during lower vs higher level exercise transitions. METHODS: Twelve healthy, active, and untrained adults (m/f = 6/6; age = 23 ± 3 yrs; peak VO2 = 40 ± 3 ml/kg/min) performed square-wave moderate intensity exercise transitions in two equal step changes between 20W to 90% ventilatory threshold (VT). The first transition was in the low moderate domain (LMD: 20W to 55 ± 13 W) and the second transition in the high moderate domain (HMD: 55 ± 13 W to 90 ± 27 W). These transitions were performed without (control; LMD-CTL and HMD-CTL) and with muscle metaboreflex activation induced by 2 min of handgrip at 40% maximal voluntary contraction during the pre-transition baseline followed by 5 min of brachial occlusion (OCC) during either the LMD (LMD-OCC) or HMD (HMD-OCC) transition. Trials were randomized and three repetitions of each condition were completed, time-aligned, and averaged by condition. Heart rate kinetics were determined using mono-exponential curve fitting. Data was analysed with non-parametric tests. P < 0.05 was significant. RESULTS: Heart rate amplitude was lower during LMD-OCC vs LMD-CTL (15 ± 5 vs 17 ± 6 beats/min; P = 0.012) and the heart rate time constant, tau, was faster during LMD-OCC vs LMD-CTL (18 ± 9 vs 26 ± 11 s; P = 0.01). Heart rate amplitude was not different between HMD-OCC vs HMD-CTL (18 ± 6 vs 19 ± 8 beats/min) and heart rate tau was not different between HMD-OCC vs HMD-CTL (49 ± 28 vs 45 ± 24 s; all P > 0.05). CONCLUSIONS: Contrary to our hypothesis, an increase in sympathetic activity induced by the muscle metaboreflex speeded heart rate kinetics during LMD but not HMD exercise transitions. Our data suggests that elevating sympathetic activity can speed heart rate kinetics to a certain point, beyond which heart rate kinetics via sympathetic activity may already be maximized.

The mechanisms underlying the muscle metaboreflex modulation of sweating and cutaneous blood flow in passively heated humans.

Metaboreceptors can modulate cutaneous blood flow and sweating during heat stress but the mechanisms remain unknown. Fourteen participants (31 ± 13 years) performed 1‐min bout of isometric handgrip (IHG) exercise at 60% of their maximal voluntary contraction followed by a 3‐min occlusion (OCC), each separated by 10 min, initially under low (LHS, to activate sweating without changes in core temperature) and high (HHS, whole‐body heating to a core temperature increase of 1.0°C) heat stress conditions. Cutaneous vascular conductance (CVC) and sweat rate were measured continuously at four forearm skin sites perfused with 1) lactated Ringer's solution (Control), 2) 10 mmol L‐NAME [inhibits nitric oxide synthase (NOS)], 3) 10 mmol Ketorolac [inhibits cyclooxygenase (COX)], or 4) 4 mmol theophylline (THEO; inhibits adenosine receptors). Relative to pre‐IHG levels with Control, NOS inhibition attenuated the metaboreceptor‐mediated increase in sweating under LHS and HHS (P ≤ 0.05), albeit the attenuation was greater under LHS (P ≤ 0.05). In addition, a reduction from baseline was observed with THEO under LHS during OCC (P ≤ 0.05), but not HHS (both P > 0.05). In contrast, CVC was lower than Control with L‐NAME during OCC in HHS (P ≤ 0.05), but not LHS (P > 0.05). We show that metaboreceptor activation modulates CVC via the stimulation of NOS and adenosine receptors, whereas NOS, but not COX or adenosine receptors, contributes to sweating at all levels of heating.

Effects of two programs of metabolic resistance training on strength and hypertrophy

Abstract Introduction: The effects of low intensity resistance training combined with vascular occlusion have been investigated by several studies. Similar results on strength and hypertrophy have been observed when such method was compared to high intensity protocols. However, due to the specific apparatus needed to apply vascular occlusion (ex.: Kaatsu) on some exercises, alternative forms of metabolic training might be used. In the present study, an isometric contraction was performed within each concentric-eccentric transition phase, for every repetition, to elicit metabolic stress. Objective: The aim of the present study was to analyze the effects of two resistance training protocols with metabolic characteristics on strength (1MR), circumference (CIRC) and muscle thickness (measured with ultrasonography [MT]). Subjective perception of discomfort was also recorded with an analogical-visual pain scale (AVP). Methods: Twelve young, healthy men were trained with two different methods during 10 weeks. The right limb was trained with an isometric contraction within each concentric-eccentric transition phases for every repetition (ISO) whereas the left limb was trained with a pneumatic cuff to apply vascular occlusion (OC) on the knee extensor muscles. Both methods were trained at 20% 1MR. Results: It was observed increases on medial tight CIRC, proximal MT, medial MT, distal MT and 1MR, with no difference between both methods. The perception of discomfort was greater for ISO at the end of the third set and lower than reported by OC, at the beginning and end of the training program. Conclusions: Both protocols produced similar gains on strength and hypertrophy. The advantages of training with low loads are important to elderly or rehabilitation training programs. Other studies that compare this method with conventional resistance training are warranted.

Vascular Occlusion and Sequential Compression for Recovery After Resistance Exercise.

The purpose of this study was to evaluate vascular occlusion (OCC) and sequential intermittent pneumatic compression (SIPC) as recovery strategies after fatiguing resistance exercise. Twelve strength-trained male participants (age: 24.0 ± 6.3 years, height: 180.4 ± 9.7 cm, and weight: 84.8 ± 9.6 kg) participated in a randomized cross-over study. Participants performed a fatiguing resistance exercise bout consisting of 10 sets with 10 repetitions of back squats at 70% 1 repetition maximum with 3-minute rest between sets. Outcome measures of perceived recovery status, muscle soreness, concentric peak isokinetic torque of the quadriceps, squat jump (SJ) height, and countermovement jump (CMJ) height were taken before the fatiguing resistance exercise bout and repeated immediately post, 1 hour, and 24 hours later. Immediately after the postexercise measures, participants undertook 1 of the 3 recovery strategies: OCC, SIPC, and a passive control (CON). Concentric peak isokinetic torque of the quadriceps was decreased significantly immediately post and 1 hour after the fatiguing resistance exercise bout compared with baseline values (p ≤ 0.05). Mean SJ and CMJ jump height decreased significantly immediately post and 1 hour compared with baseline measures, but only the SJ was significantly decreased at 24 hours. There were no significant differences between conditions for any of the postexercise measures (p > 0.05). In conclusion, this study indicates that OCC and SIPC are not effective for attenuating muscle performance loss after a fatiguing resistance exercise bout relative to passive recovery.

Correction of unilateral scissor bite using Periodontally Accelerated Osteogenic Orthodontics

This article is regarding a case report presenting a true unilateral posterior crossbite in an adolescent patient, a challenging mal­ occlu sion to treat. Conventional expansion methods are expec ted to have some of its shortcomings. The aim of this paper is to introduce a technique for treating unilateral posterior crossbite in an adolescent or adult patient, advocating Periodontally Accelerated Osteogenic Orthodontics (PAOO) TM as a part of adjunctive protocol in the orthodontic realm. The procedure promises to radically shorten the treat­ ment time. Methods: PAOO as an adjunctive procedure in orthodontics for treatment of unilateral posterior scissor bite. Results: Effective unilateral expansion was achieved using PAOO, and functional occlusion was established as well. Conclusion: Unilateral PAOO presents an effective and reliable technique to treat true unilateral crossbite.

A40 Session 11: Cardiovascular Disease Intervention: A new cryo balloon efficacy and safety monitoring: Distal balloon impedance and temperature recording

Presently pulmonary vein (PV) occlusion (OCCL), ice formation and thickness monitoring is lacking. It was hypothesized that measurement of the impedance (Imp) and temperature (T) at the front of the Cryo balloon can be calibrated to measure PV OCCL, ice formation and thickness. One mm thick ring electrode and Thermocouple sensor were placed on the balloon shaft adjacent to the anterior surface of the balloon with a reference electrode behind it. Continuous Imp (using 12.5 kHz electrical current) and T measurements were made throughout Cryo in a T constant bath, constant 5 mmHg pressure perfused superior vena cava (SVC) – right atrium (RA) setup and intact hearts’ PV (2 pigs and 2 canine). Ice thickness was assessed with 1.5–3.6 MHz ultrasound transducer and directly in the SVC circulating bath. Electrical isolation was used to define efficacy in the intact hearts. As shown in the figure below, circumferential OCCL caused the Imp to rise rapidly with T crossing the 0 °C mark beginning 60 s (sec) into Cryo and continued until saturation at 2000 ohms ( Ω ) and −37.8 ± 3.3 °C at 120 ± 25 s. Without OCCL, Imp did not rise above 500 Ω, with the T reaching only −9.2 ± 12.1 °C. Ice thickness was measured on the epicardial SVC tissues growing significantly starting at 60 s. into Cryo before stabilizing at 3 ± 0.5 mm. Impedance rose 950 Ω in chronic PV sleeve ablations. (Panel B). 1. The use of Imp and distal T provides evidence of OCCL. 2. Ice thickness correlates with Imp if OCCL is present. 3. PV isolation was achieved with 3 mm of ice formation and Imp rise of >2000 Ω.