Hook Position Research Articles

Docking Strategy for a Space Station Container Docking Device Based on Adaptive Sensing

A fractional-step docking strategy based on adaptive sensing is proposed for an orthogonally distributed container docking device that exhibits various characteristics, including modularization, miniaturization, extensibility, and peripheral layout. A dynamic model of a body combined with a space station container and robotic arm and a contact dynamic model between the combined body and the docking device are established to lay the foundation for the docking determination of the container in limit poses. Taking the structural and dynamic characteristics of the orthogonally distributed docking device into consideration, the actions of a diagonal double-docking hook were matched under limited working conditions. A 6-D force sensor placed at the end of the robotic arm was used to perceive the contact force of the container and the position of the docking hook, providing a basis for selecting a docking strategy. The tolerance of the docking device was analyzed when applying the docking strategy, the results of which demonstrated a much larger tolerance than that found in the synchronous docking. An orthogonally distributed docking device and an experimental platform were developed, and the tolerance of the device when using the adaptive sensing docking strategy was tested and verified. A comparison between the experiment and simulation proves the effectiveness and feasibility of the proposed adaptive sensing docking strategy.

A new species of Creagrutus (Characidae: Stevardiinae) from the upper Río Magdalena, Colombia.

A new species of Creagrutus is described from several localities in the upper Río Magdalena drainage, Colombia. Creagrutus dulima n. sp. differs from all trans-Andean congeners by the combination of a relatively small orbital diameter, the shape and position of hooks on the pelvic-fin rays, in having the third infraorbital not in contact with the preopercle ventrally, and the presence of a dark, reticulated pigmentation pattern on the dorsal portion of body. The distribution of Creagrutus species in the Magdalena-Cauca River Basin is discussed, and an updated identification key for species of trans-Andean Creagrutus is provided.

Knee injuries in Rock climbing and Bouldering - An Update

Aims and Objectives: Rock climbing and bouldering is undergoing a worldwide “boom” and has recently been selected for the next Olympic summer games. Besides ground falls, an injury mechanism in this sport is the so-called heel hook position, which is used more frequently today due to changing training and competition modes, especially in indoor bouldering. With the rising number of knee injuries in climbing and bouldering, we now aimed to analyze this specific injury mechanisms and its underlying pathologies. Materials and Methods: Among 50 climbing athletes with unspecific knee pain, we identified 9 patients with injuries of the lower extremities after performing a heel hook. The outcome was evaluated at a minimum of 6 months after the injury and classified in a sport-specific score. After clinical examination and exclusion of the minor injuries we performed ultrasound and/or magnetic resonance imaging. Patients were treated conservatively with initial partial immobilization and early functional therapy with physiotherapy. Only one patient with a partial meniscus tear needed a surgical procedure. Results: All patients reported sudden dorsal-sided pain in the knee while performing the hook. Seven also reported hearing a snapping sound, similar to those reported in achilles tendon tears. Walking was difficult in all cases and all were limping. Five patients were diagnosed a strain of the lateral collateral ligament and two patients a lateral meniscus tear. The other patients had either a partial tear of the PCL, or a strain of the distal hamstring tendons. In 8 of 9 cases, we received “good” to “excellent” outcomes with a conservative approach. The popping sound at the time of injury may correspond to a change of the pivot of the tractus ileotibialis that then “jumps” over the condyle. While the hook is performed, there is frequently an active knee flexion involved, which thus changes the pivot of the tractus. Conclusion: In climbing and bouldering, injuries of the knee will further increase due to modern training and competition modes requiring the use of heel hooks. MRI shows the proper diagnosis and the proper therapeutic approach is conservative treatment. The outcome after heel hook injuries is good to excellent in most of the cases. Warm-up routine, an avoidance of muscular imbalances, and flexibility training can help to avoid injuries during heel hook.

Habitat-specific performance of vertical line gear in the western Gulf of Mexico: A comparison between artificial and natural habitats using a paired video approach

Gear performance is often assumed to be constant over various conditions encountered during sampling; however, this assumption is rarely verified and has the potential to introduce bias. We used fishery-independent vertical line surveys to evaluate whether gear efficiency and selectivity is similar while assessing reef fish populations at oil and gas platforms, artificial reefs, and natural banks in the western Gulf of Mexico. We conducted 192 vertical line sets with cameras placed on a subset of these deployments to validate any differences in efficiency among habitat types. Red snapper (Lutjanus campechanus) accounted for 93% of the catch. No difference in red snapper CPUE among habitats was detected. When evaluating fish size, 8/0 and 11/0 hooks sampled significantly larger red snapper at natural banks than at artificial habitats. While CPUE was similar among all hooks at artificial habitats, CPUE at natural banks was lower for shallower hooks and increased towards the bottom hooks along the backbone. At all habitats, red snapper TL decreased from shallow to deep hook positions. Simultaneous camera deployments revealed other processes affecting efficiency such as bait removal and depredation. Vermilion snapper (Rhomboplites aurorubens) were effective at removing bait while avoiding capture. Perhaps related to this observation, Red snapper CPUE was negatively correlated with the vermilion snapper video index of abundance. Video confirmed gear saturation was prevalent (70% of deployments), occurring more frequently on artificial habitats. Furthermore, the time fished was effectively “shorter” at artificial habitats as the number of available baited hooks declined rapidly. These results point towards higher relative abundance at artificial habitats; however, the prevalence of saturation indicates vertical line CPUE may not always be proportional to true abundance, hindering our ability to detect differences at the scale examined in this study. Vertical line surveys should evaluate the prevalence of saturation as inferences regarding relative abundance may be compromised when this information is unknown.

Determination Method of Capture for an Orthogonal Distributed Satellite Capture Device

An analytical method is proposed to determine the success or failure of capture for an orthogonal distributed satellite capture device with the characteristics of modularization, miniaturization, extensibility, and peripheral layout. A dynamic model of a body combined with an spacecraft, a robotic arm, and a satellite is established, and the time-varying position and position of the satellite are obtained. An impact dynamic model of the capture device and the satellite in the combined body is built. A kinematic model of the impact surfaces of the capture frame and the capture hook is established, and the position and time of the impact point are obtained by solving the common intersection point. In order to simplify the analysis process, the shortest time to capture the satellite and the corresponding position of capture hook are determined when the velocity of capture hook is fixed. After several impacts and follow-up process analysis, it is determined whether the capture task is successful by judging whether the capture frame is always within the capture area during the shortest capture time. Finally, an example is used to verify the proposed method. Compared with the simulation analysis, the same capture results and similar position and attitude curves of satellite are obtained, which proves the effectiveness of this method.

Morphometric and molecular characterisation of Tenuiproboscis keralensis n. sp. infecting marine and brackish water fishes from the south-west coast of India with a note on morphological plasticity.

A new species of acanthocephalan infecting marine and brackish water fishes from the south-west coast of India is described. The parasite belongs to the genus Tenuiproboscis, and the fish hosts include Lutjanus argentimaculatus, L. ehrenbergii, Siganus javus, Epinephelus malabaricus, E. coioides, Scatophagus argus, Parascolopsis aspinosa, Caranx ignobilis, Gerres filamentosus and Lates calcarifer. The parasite inhabits mid- and hindgut regions and is characterised by an elongated, cylindrical, bulbous and posteriorly tapering metasoma and a claviform proboscis having 14-15 rows of 14-15 hooks each. Females larger than males, measured 3898.16-10,318.00μm (6430.00±1417.30) in length and 458.93-1435.68μm (929.81±250.39) in width. Males measured 3234.89-8644.20μm (5729.50±1176.60) in length and 388.30-1584.61μm (795.88±184.12) in width. Parasites recovered from different host species showed morphological/morphometric variations. However, principal component analysis (PCA) revealed significant overlapping of characters indicating their similarities. Proboscis profiling based on variations in size and position of hooks also yielded similar results. Further, in molecular phylogenetic analysis, parasites from different fish hosts formed a monophyletic clade with strong bootstrap support, again indicating their conspecific nature. These morphological/morphometric variations can be ascribed to differences in host species. Morphology and morphometrics in combination with PCA, proboscis profiling and molecular analysis suggest the present acanthocephalan parasite is different from other described species of Tenuiproboscis. Hence, it is considered as a new species and named T. keralensis n. sp. Prevalence, intensity and abundance of the parasite in different hosts are also discussed.

THE EFFECT OF DEPTH OF HOOKS, SET AND SOAK TIME TO THE CATCH PER UNIT OF EFFORT OF TUNA IN THE EASTERN INDIAN OCEAN

Yellowfin (Thunnus albacares) and bigeye (T. obesus) tuna have been intensively exploited by longline fleets since 1980’s, however, a large proportion of zero catch per set of target species still accurred. Zero catch data contributed significantly to the low catch per unit of effort (CPUE) compared to other countries at the same fishing area. Therefore, understanding the factors contributed to the CPUE of tuna is essential, in order to improve longline fishing efficiency. A total of 2.115 set-by-set data were obtained from Indonesian Scientific Observer Program. The onboard observations were carried out at commercial tuna longline operated in Eastern Indian Ocean from August 2005 to December 2014. Several analytical approaches were conducted in this paper. First, General Linear Model (GLM) was applied in order to model the relationship between CPUE with all the variables involved. Second, boxplot diagram, polynomial and linear regression were applied to fit the relationship between CPUE with set time, soak time and depth (represented by hook position) respectively. The result showed that, there was no significant relationship between set time and CPUE of bigeye and yellowfin tuna. Soak time was positively related with CPUE of yellowfin and affect adversely on bigeye. Depth also have significant relationship with CPUE of tuna, where catch of yellowfin decreased linearly with hook depth, whereas catch of bigeye was performed the opposite. Improvement in tuna longline fishery in eastern Indian Ocean can be achieved through implementation of the specific soak time and hook depth for each target species, i.e. yellowfin and bigeye tuna.

Finite element analysis of different load mode on tooth movement for space closure in patient with bimaxillary protrusion

To investigate the stress distribution on the maxillary anterior teeth retracted with sliding mechanics and micro-implant anchorage using different retraction hook heights and positions. DICOM image data including maxilla and upper teeth were obtained with cone-beam CT. The three-dimensional finite element model was constructed using Mimics software. Brackets and archwire model were constructed using Creo software. The models were instantiated using Pro/Engineer software. Abaqus software was used to simulate the sliding mechanics by loading 2 N force on 0, 2, 4, 6, 8, 10 mm retraction hooks and three different positions, repectively. Rotation of the occlusal plane, the initial displacement and stress distribution of teeth were analyzed. Lingual rotation of maxillary central incisor(0.021°), gingival movement of the maxillary first molar(0.005 mm), and clockwise rotation of the maxillary occlusal plane(0.012°) were observed when the force application point located at the archwire level (0 mm). In contrast, 0.235° labial rotation of the maxillary central incisor, 0.015 mm occlusal movement of the maxillary first molar, and 0.075° anti-clockwise rotation of the maxillary occlusal plane were observed when the force application point located at the higher level(10 mm retraction hook). The more the force application point was located posteriorly at the archwire level, the less lingual rotation of the maxillary central incisor and the more buccal displacement of maxillary first molar was observed. Maxillary anterior tooth rotation and retraction, vertical displacement of posterior segment, and rotation of the occlusal plane could be controlled by adjusting the height and position of the retraction hook in space closure using miniscrew and sliding mechanics.

Anatomical Safety of the U.S.S. Pedicular Hook-Screw in the Adult Thoracic Spine

Introduction Pedicle hooks have been extensively used in spine surgery. One of the major concerns of such instrumentation is the pullout of the implants. Recently, a screw that anchors the pedicle was added to secure the hook, and to improve both pullout strength as well as purchase. An anatomical study was performed on human cadavers to assess the anatomical safety of these implants. From this study, we can conclude that the use of screws to hold the pedicle hooks is generally safe. Further studies should be done to assess this in deformed spines. Materials & Methods: Eleven embalmed human cadavers with a mean age of 76 years (6 male bodies and 5 female bodies) were used for this study. The same staff spine surgeon performed all surgical procedures. The thoracic pedicles were instrumented bilaterally starting from T1 down to T12 with an AO Universal Spine System Pedicular Hook Screw. Abandoning the procedures was permitted whenever the safety of any neural structures was jeopardized or the implant could not be placed correctly. The surgeon's comments were documented. For subsequent analyses after instrumentation, the spines were harvested en-bloc and later dissected into individual vertebrae. Two independent blinded observers did a visual inspection to grade the hook and screw positions. All specimens were then radiographed individually in three dimensions (antero-posterior, medio-lateral & cranio-caudal). Two blinded observers independently evaluated the hook and screw positions following the visual classification system. Only the antero-posterior and lateral radiographs were provided, because only these would be available in a clinical situation. Results Thirty-five implant placements (ten in T11, eighteen in T12 and seven in all other levels) were abandoned prior to the surgical procedure. Six hooks were requested to be repositioned. Four implant placements were abandoned after drilling the screw hole (three screws with a medial deviation, and one screw with a lateral deviation). Of the remaining 225 implants, 29 were lost during harvesting and preparation, leaving 196 implants for further evaluation. One hundred and eighty three implants were considered safe by the surgeon at the end of the surgical procedure, 13 were believed not to be safe and were removed. No screws were found to be disrupting the integrity of the neural structures in the canal or in the foramen. A comparison between the visual and radiological evaluations of both the screw and hook positions was performed. The visual evaluation showed an inter-observer agreement of 85% for the hooks and 78% for the screws. The radiographic evaluation showed an agreement of 75% for the hooks, and of 43% for the screw between observers, a value considerably lower than expected. When comparing each of the two radiological evaluations to the “gold standard,” only 62% to 67% of the hooks and 42% to 48% of the screws had an agreement. Conclusion Overall, the use of U.S.S. pedicle hook-screws is suggested to be safer than either the conventional pedicle hook, which is often malpositioned inside the canal, or the classical pedicle screw, which is too large for the thoracic pedicles.

The “Heel Hook”—A Climbing-Specific Technique to Injure the Leg

Acute injuries in rock climbing either come from a fall onto the lower leg or from performing a hard move and injuring the upper extremity. Further evaluations of lower leg injuries in rock climbing athletes have been performed recently finding sport characteristics such as peroneal tendon dislocations or chronic deformations of the feet. One injury mechanism described in case reports is the so-called heel hook position, which is used more frequently today compared with the beginngs of rock climbing. In addition, the number of these injuries is expected to rise with the increase in popularity of climbing and bouldering. Therefore, it is important to further analyze this pathology. We investigated 17 patients with injuries of the lower extremities after performing a heel hook.

Effect of craniocervical posture on abdominal muscle activities.

[Purpose] The aim of this study was to investigate the influence of the craniocervical posture on abdominal muscle activities in hook-lying position. [Subjects] This study recruited 12 healthy young adults. [Methods] Each subject was asked to adopt a supine position with the hip and knee flexed at 60°. Surface electromyographic signals of transversus abdominis/internal oblique, rectus abdominis, and external oblique in different craniocervical postures (extension, neutral, and flexion) were compared. [Results] The transversus abdominis and rectus abdominis showed increased muscle activities in craniocervical flexion compared to craniocervical extension and neutral position. Greater muscle activities of the external oblique were seen in craniocervical flexion than in craniocervical extension. [Conclusion] Craniocervical flexion was found to be effective to increase the abdominal muscle activities. Consideration of craniocervical posture is recommended when performing trunk stabilization exercises.

Ultrasound assessment of trunk muscles and back flexibility, strength and endurance in off-road cyclists with and without low back pain.

To compare the thickness of lateral abdominal muscles and Cross Sectional Area (CSA) of lumbar Multifidus Spinae (LM) muscles of competitive off-road cyclists with and without Low Back Pain (LBP). We also aimed to compare the maximum isometric back strength and endurance, as well as flexibility of lower back in cyclists with LBP and in the controls. The thickness of Transversus Abdominis (TrA), Internal Oblique (IO) and External Oblique (EO) along with the CSA of LM muscles of 14 professional competitive off-road cyclists with LBP and 24 controls were measured by ultrasound (US) in hook-lying position on the examination table, and mounted on the bicycle. In addition, the back strength and endurance of the subjects and the flexibility of the participants were measured. Data showed a significantly lower thickness of Transversus Abdominis (TrA) and CSA of LM muscles in cyclists with LBP comparing to controls in all positions. No significant result regarding the flexibility of the subjects in case group comparing with the controls was found (p= 0.674). In addition, it was found that there is no significant difference in isometric back strength of the subjects between the groups (p= 0.105). However, we found that subjects with LBP have a lower endurance in back dynamometry with 50% of their maximum isometric back strength (p= 0.016). In this study, useful information regarding possible factors associated with low back pain in off- road cyclists was found (lower thickness of TrA and LM muscles and decreased back endurance).

Reliability and Validity of Transversus Abdominis Measurement at the Posterior Muscle-Fascia Junction with Ultrasonography in Asymptomatic Participants

ObjectiveThe purposes of this study were (1) to establish the intrarater sliding and change in thickness of the transversus abdominis (TrA) measurement at the posterior muscle-fascia junction and (2) to examine the relationship between the muscle thickness and sliding of the TrA at the anterior and posterior sites. MethodsAsymptomatic participants (n = 20) were placed into the hook-lying position to perform the abdominal drawing-in maneuver viewed in B-mode with a 5- to 12-MHz linear ultrasound transducer. The outcome variables included the resting thickness, the thickness during contraction, the change of thickness, and the change of sliding length. Both intraclass correlation coefficient and Pearson correlation were used for analysis. ResultsMeasuring the thickness and sliding of the TrA at the posterior muscle-fascia junction showed good reliability (intraclass correlation coefficient (3,3), 0.89-0.98). The correlations between the sliding measurements of the TrA at the anterior and posterior sites were moderate to good (r = 0.41-0.74). ConclusionThis study found that measuring the musculofascial corset from the posterior site using ultrasonography is reliable, allowing for ultrasound measurements at both the anterior and posterior sites of the TrA to provide a comprehensive evaluation of the TrA fascia.

A Car Exhaust System Hook Position Optimization Analysis

Based on the study of a car exhaust system, use HyperMesh Software and its build-in finite element software to build FEM , Analysis the free modal of exhaust system, Calculate its natural frequency, Then optimize the position of hook based on the ways of average degrees of freedom (ADDOFD), Makes its modal frequencies avoiding engine idling frequency. Finally, through the calculated constraint mode, Verify whether coupling with the excitation frequency of engine, and further verify the reasonableness of the position of the hook.

Influence of angler hook-set behaviour relative to hook type on capture success and incidences of deep hooking and injury in a teleost fish

One of the primary factors associated with mortality in catch-and-release recreational fisheries is depth of hook position relative to the snout, with deeper hooking locations (i.e., gullet) increasing risk of injury to vital tissues. As a result, there have been attempts to develop angling methods and gear that are less likely to result in deep hooking. Circle hooks represent an alternative to conventional “J” style hooks (J-hooks), and in general circle hooks have been shown to reduce the tendency for deep hooking in a variety of species, which can significantly improve post-release survival. Relative to fishing with J-hooks, circle hook manufacturers typically recommend that anglers use a rod movement (i.e., hook-set) of reduced intensity and force (i.e., a light hook-set), thereby maximizing the benefit of circle hooks by reducing the tendency for deep hooking and injury. To evaluate whether hook-set technique can affect hooking and injury in fish, we tested different combinations of hooks (circle hooks and J-hooks) and hook-set techniques (e.g., light, moderate, or heavy force, or with a bobber) in an angling study for bluegill (Lepomis macrochirus) in Lake Opinicon, Ontario, Canada. Binary responses of capture success and deep hooking were analysed with logistic regression. There was no significant interaction between hook type and hook-set, but overall, J-hooks increased the odds of successfully capturing a bluegill and also the odds of deep hooking a bluegill relative to circle hooks. The bobber hook-set technique increased the odds of deep hooking a bluegill relative to the active hook-setting techniques. This study suggests both deep hooking and capture of bluegill are significantly affected by both hook types and hook-set techniques.

Effects of Appendaged Circle Hook Use on Catch Rates and Deep Hooking of Black Sea Bass in a Recreational Fishery

AbstractPrevious studies have demonstrated that circle hooks modified with an appendage can reduce the occurrence of deep hooking in some fishes. To determine whether this modification affects total catch and deep‐hooking rate of Black Sea Bass Centropristis striata in a recreational fishery off the coast of Florida, anglers were provided with standardized gear that included one appendaged and one nonappendaged hook. Both hook types were fished equally, and a greater number of Black Sea Bass were caught on appendaged hooks (n = 301) than on nonappendaged hooks (n = 221). There was no significant difference in the mean TL (P = 0.80) of jaw‐ or deep‐hooked fish during the study. Logistic regression was applied to the data using anatomical hooking location as the dependent variable and angler, hook position, and hook type as categorical factors. Hook type was the only significant variable in the final model (P = 0.03) in which fewer fish were deep hooked on appendaged hooks (0.96%) than on nonappendaged hooks (2.11%). Our findings indicate appendaged hooks are capable of reducing deep hooking of Black Sea Bass without reducing catch rates or altering size composition of the catch.Received February 3, 2014; accepted August 14, 2014

Comparison of the Thickness of Lateral Abdominal Muscles Between Pregnant Women With and Without Low Back Pain

ObjectivesTo compare the thickness of the external oblique, internal oblique, and transversus abdominis muscles in pregnant subjects with and without low back pain (LBP) by the use of ultrasound to measure thickness. DesignA case-control study. SettingAn academic and tertiary care referral spine and sports medicine center. ParticipantsFifty pregnant women with LBP during pregnancy and 54 pregnant control subjects. MethodsCase and control subjects were matched for body mass index, gestational age, and number of previous pregnancies. A multiple linear regression model with adjustment for the gestational age of the subjects, as the potential confounder of the primary outcomes, was used to evaluate the association between LBP appearance and abdominal muscles thickness of the subjects. Main Outcome MeasuresThe thickness of lateral abdominal muscles was measured by ultrasound with the subject in a hook-lying position on the examination table. ResultsWe found that there was no significant difference between pregnant subjects with and without LBP in terms of the thickness of external oblique, internal oblique, and transversus abdominis muscles. ConclusionThese findings suggest that other factors rather than the thickness of core stabilizing muscles are influential in the etiology of LBP during pregnancy. We hypothesize that enlargement of uterus during pregnancy might influence the thickness of the lateral abdominal muscles.

Ultrasonographic median nerve changes under tendon gliding exercise in patients with carpal tunnel syndrome and healthy controls

Study designCase control study. Purpose of the studyTo evaluate the ultrasonographic median nerve changes under tendon gliding exercise in patients with carpal tunnel syndrome (CTS) and healthy controls. MethodsSeventy-three patients with CTS and 53 healthy volunteers were consecutively recruited. Each subject underwent a physical examination, nerve conduction studies and ultrasonographic examinations of the median nerve during tendon gliding exercises. ResultsSignificant changes in the cross-sectional area of the median nerve were found while moving from the straight position to the hook position and from the hook position to the fist position. There were also significant changes in the flattening ratio when moving from the hook position to the fist position. ConclusionsUltrasonography revealed that the median nerve was compressed in the fist position in both CTS patients and healthy volunteers. Thus, forceful grasping should be avoided during tendon gliding exercises performed in the fist position. Level of evidence3b

Trade‐offs among Catch, Bycatch, and Landed Value in the American Samoa Longline Fishery

The interspecific preferences of fishes for different depths and habitats suggest fishers could avoid unwanted catches of some species while still effectively targeting other species. In pelagic longline fisheries, albacore (Thunnus alalunga) are often caught in relatively cooler, deeper water (>100 m) than many species of conservation concern (e.g., sea turtles, billfishes, and some sharks) that are caught in shallower water (<100 m). From 2007 to 2011, we examined the depth distributions of hooks for 1154 longline sets (3,406,946 hooks) and recorded captures by hook position on 2642 sets (7,829,498 hooks) in the American Samoa longline fishery. Twenty-three percent of hooks had a settled depth <100 m. Individuals captured in the 3 shallowest hook positions accounted for 18.3% of all bycatch. We analyzed hypothetical impacts for 25 of the most abundant species caught in the fishery by eliminating the 3 shallowest hook positions under scenarios with and without redistribution of these hooks to deeper depths. Distributions varied by species: 45.5% (n = 10) of green sea turtle (Chelonia mydas), 59.5% (n = 626) of shortbill spearfish (Tetrapturus angustirostris), 37.3% (n = 435) of silky shark (Carcharhinus falciformis), and 42.6% (n = 150) of oceanic whitetip shark (C. longimanus) were caught on the 3 shallowest hooks. Eleven percent (n = 20,435) of all tuna and 8.5% (n = 10,374) of albacore were caught on the 3 shallowest hooks. Hook elimination reduced landed value by 1.6-9.2%, and redistribution of hooks increased average annual landed value relative to the status quo by 5-11.7%. Based on these scenarios, redistribution of hooks to deeper depths may provide an economically feasible modification to longline gear that could substantially reduce bycatch for a suite of vulnerable species. Our results suggest that this method may be applicable to deep-set pelagic longline fisheries worldwide.

Effects of different types of contraction in abdominal bracing on the asymmetry of left and right abdominal muscles.

[Purpose] The purpose of this study was to investigate the effective strength levels of abdominal muscle contraction using the bracing contraction method. [Subjects] The experiment was conducted with 31 healthy male (M=15) and female (F=16) adults attending D University in Busan; all participants had less than obesity level BMI (BMI<30). [Methods] Bracing contraction was performed by the subjects in the hook-lying position at maximum and minimum pressure levels, five times each, using a Pressure Biofeedback Unit (PBU), and the mean measurement value was calculated. The maximum pressure level was set at 100% and the half maximum pressure level was set at 50%. Each subject’s left and right abdominal muscle thicknesses were then measured by ultrasound imaging in each state: at rest, 100% contraction, and 50% contraction. [Results] No significant differences were found between the left and right sides of the transversus abdominis (TrA) at rest, 50%, or 100% contraction. The external oblique abdominis (EO) and internal oblique abdominis (IO) showed no significant difference at rest or at the 50% contraction. However, a significant difference was noted at 100% contraction for the EO and IO. [Conclusion] Application of abdominal contraction using bracing can achieve symmetry in the left and right abdominal muscles at less than the maximum contractile strength. The occurrence of asymmetry in the left and right abdominal muscles at the maximum contractile strength suggests that the most suitable contractile strength in this exercise is less than the maximum contractile strength.