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ELECTROCORTICAL CHANGES FOLLOWING ATTENTION BIAS MODIFICATION IN A SAMPLE OF HIGH-BIPOLAR TRAIT INDIVIDUALS
No full textBipolar disorder (BD) is a severe psychiatric condition. It is phasic condition where individuals oscillate between mania or hypomania, depression, and euthymia. It is closely related to major depressive disorder; however, it is distinguished by periods of increased activity typical of (hypo)manic episodes. During these episodes, people may experience enhanced goal-motivate behavior and risk-taking. It is thought that enhanced dopaminergic activity within reward-mediated pathways in the brain underlies these behaviors. Recent research has identified a link between an attentional bias to rewarding feedback and reward sensitivity. Due to this connection, the objective of this study was to investigate the effect of attention bias modification (ABM) on electrocortical markers of attention and reward sensitivity. Seventeen participants completed two sessions for $30 of compensation. In session one, baseline electrocortical measures were obtained for attention (N1) and reward sensitivity (reward positivity; RewP) during a roulette-gambling task. Questionnaires assessing mood, personality, handedness, and demographics were obtained afterward. Participants completed a second session where they completed attentional (or control) training prior to the roulette-gambling task. ABM did not attenuate ΔN1 and ΔRewP in the training group. Exploratory analyses found effects of session on both N1 and RewP raw amplitudes across groups. Considering the small sample size and demographic homogeneity, results and the subsequently derived conclusions should be taken with caution
Effects of temperature and density on the facial malformation of hatchery-reared cisco, Coregonus artedi
No full textCisco, Coregonus artedi, are highly sensitive to environmental variability which likely contributes to the speciation within the Great Lakes cisco clade. Hatcheries are trying to supplement cisco due to population declines. However, hatchery-reared cisco develop flat, subterminal snouts in hatchery environments instead of the pointed, terminal mouth observed in the wild. The cause and onset of the malformation could be the result of physical trauma, diet, genetic predisposition, or responses to an unusual rearing environment. We determined the stage of malformation onset by comparing hatchery-reared cisco (Jordan River National Fish Hatchery) to wild-caught cisco (northern Lake Huron) using geometric morphometrics. Our results suggest that the onset of malformation begins by preflexion, and possibly earlier, during early ontogeny and the beginning of endochondral ossification. The malformation is characterized by an improperly formed vomer and ethmoid bone. Early onset of the malformation suggests physical trauma is not the sole causative factor, and supports diet and/or environment as triggers in the malformation. Further, we tracked the progression of the malformation in juvenile cisco using temperature and density in four treatment groups: low density (LD) warm (12.5℃), high density (HD) warm, LD cold (8℃), and HD cold. As predicted, warm water cisco grew faster than cold water fish, and lower density groups grew better than high density groups. For our trajectory analysis, there was no significant difference between our treatment groups with respect to facial morphology suggesting the malformation develops early and continues to progress into juvenile stages despite temperature or density adjustments
KINETICS, KINEMATICS AND MUSCLE ACTIVATION DURING ECCENTRIC SQUATTING
Get PDFThe purpose of this study was to examine the kinetics, kinematics and muscle activation of the knee and hip extensors during the eccentric (ECC) phase of the squat exercise. Resistance trained males (n=9) performed isotonic loaded ECC squats at loads from 20-150% of squat 1-rep max. Inverse dynamic calculations were used to identify knee and hip joint moment, and iEMG was used to quantify muscle activation of the vastus lateralis and gluteus maximus. In contrast to previous literature examining the concentric phase of the squat, this study found the knee extensors experienced the greatest loading, plateauing when exposed to a load of \u3e120% of 1RM, with no changes in joint kinematics. Vastus lateralis iEMG plateaued after 80% of 1RM, suggesting activation-independent factors for this increase in joint moment. If maximising knee extensor loading to promote adaptation is a training object, this data recommends an ECC load of 120%
IMPROVING ACCURACY, RELIABILITY AND AGREEMENT OF SWIM COACHES’ HAND-TIMING: EXPLORING A STANDARDIZED METHOD FOR HAND-TIMING
Get PDFThe purpose of this study was to determine the current accuracy and reliability of, and agreement amongst, coaches’ hand-timing (HT) for a 15 m swim, and to assess if a standardized method of performing the HT can improve these. Three national coaches simultaneously timed two swimmers, each performing seven 15 m swims, for a total of fourteen trials. HT from each coach was compared to 2D video-derived timings, as the reference standard, for assessment of accuracy and reliability, while HT between coaches were compared to assess their agreement with one another. These were compared pre- and post-intervention where a method for performing the HT was introduced. Following this intervention, there appears to be a trend for improved accuracy and reliability within coaches, and improved agreement between coaches’ HT, all of which would present the swimmers with more meaningful timings to assess training progress
ESTIMATING THE VARIABILITY OF HAMSTRING FUNCTION WITH INCREASING RUNNING SPEED USING DIRECT COLLOCATION
Get PDFTo investigate the variability in hamstring muscle function, multiple running strides were simulated across a range of running speeds (4 - 9 m/s) using a forward dynamics musculoskeletal model solved using direct collocation (OpenSim Moco). Peak biceps femoris muscle load (force, length, velocity, and power) occurred during the late swing phase, showing variable muscle load across all running speeds. As running speed increased, the time of peak force was consistent at approximately 85% of swing but became less variable in its timing (45 ms [4 m/s] vs 5 ms [9 m/s]). At maximal running speed small changes in variability can result in large changes to muscle function, creating a greater risk of injury and may provide further insight into hamstring strain injuries
PERFORMANCE ASSESSMENTS OF THE MIDDLE AND LATE PHASE OF REHABILITATION FOLLOWING LOWER LIMB INJURY IN PROFESSIONAL RUGBY UNION PLAYERS
Get PDFThe purpose of this study was to characterise the kinetic profile of the jumping strategy employed in rugby union players during the middle and late phases of rehabilitation following lower limb injury. Nine players from a professional rugby union team (height 1.80±0.06 m; mass 96.1±13.2 kg; age 25±3 years) were included in this study. The mean duration of the middle and late phases of rehabilitation were 10±5 weeks and 6±2 weeks respectively. Unilateral drop jump and unilateral lateral hurdle hop were used to characterise the middle and late phases respectively. The variables of interest were Initial peak landing force, ground contact time, net impulse, Instantaneous loading rate, flight time and second peak landing force. Differences were observed in kinetic jump profiles between uniplanar and multiplanar movements. A change in kinetic jumping strategy to attain the same performance magnitudes across both phases of rehabilitation was also observed. The results highlight the importance of practitioners using a range of functional assessments in return to play testing
KINEMATIC AND KINETIC COMPARISON BETWEEN PRE-PROFESSIONAL DOMINICAN REPUBLIC AND AMERICAN BASEBALL PITCHERS
Get PDFThe purpose of this study was to compare elbow valgus torque and shoulder distraction force in pre-professional American and Dominican Republic (DR) pitchers. Kinematics that are known to influence elbow valgus torque and shoulder distraction force were also compared. Three dimensional biomechanical analyses were performed on Dominican Republic (n = 37) and American (n = 37) baseball pitchers. Potential difference between Dominican Republic and American pitchers were assessed through analysis of covariance with 95% confidence intervals. Age, hand dominance, and pitch velocity are known to influence elbow torque and shoulder force, therefore these confounding variables were controlled for within the analyses. Pre-professional Dominican Republic pitchers were found to throw fastballs with slower ball velocity but experienced increased elbow valgus torque compared to their American counterparts. Increased elbow valgus torque and inefficient pitching mechanics among Dominican Republic pitchers should be considered when developing training programs and pitching plans for professional pitchers from the Dominican Republic
COMPARISON OF ISOKINETIC FORCE OF THE INTERNAL AND EXTERNAL ROTATORS OF THE SHOULDERS BETWEEN SWIMMERS OF ALTERNATE AND SIMULTANEOUS TECHNIQUES
Get PDFThe aim of this study was to compare the peak torque and the strength ratio between the external and internal swimmers’ right and left shoulder rotators between alternate and simultaneous swimming techniques. Sixteen competitive swimmers (3 females and 13 males) were divided equally into two groups, alternate and simultaneous swimming techniques. The experimental protocol consisted of three maximum concentric repetitions of internal rotation and external rotation of the shoulder at an angular velocity of 60°/s and twenty repetitions at a velocity of 180°/s, with a two minutes interval between speeds and four minutes in the change of laterality of the upper limbs on a Biodex isokinetic dynamometer (Biodex System 4.0, Biodex Corp., Shirley, NY, EUA).The peak torque and the strength ratio between the external and internal swimmers’ right and left shoulder rotators were measured. No difference was obtained between swimming techniques for peak torque and the strength ratio between the external and internal swimmers’ right and left shoulder rotators (p \u3e 0.05), except for the right shoulder internal rotation at 180º/s (alternate: 44.13 ± 11.58; simultaneous: 56.25 ± 8.83; p \u3c 0.05). Based on our results, peak torque and the strength ratio between the external and internal swimmers’ right and left shoulder rotators do not seem to be influenced by the athlete\u27s predominant swimming technique, with alternate (front crawl and backstroke) or simultaneous (breast and butterfly) strokes. The main findings of this study show that the balance relationships between the ER/IR rotators of the shoulders do not seem to be differentiated by the alternate and simultaneous swimming techniques. However, observing only the PT/IR at a speed of 180°/s of the right shoulders, there was a significant difference between the groups and, therefore, the ER/IR balance ratio was at the maximum limit of normality. Regardless of the specialization of the swimming technique, that is, alternate or simultaneous, swimmers can present imbalances in the internal and external rotators of the shoulders, which reveal the need for compensatory strength training focused on the rotator muscles of the shoulder
THE IMMEDIATE EFFECT OF A GENTLE HEEL STRIKE ON PERONEAL MUSCLE PRE-LANDING ACTIVATION DURING PROLONGED TREADMILL RUNNING IN MALES
Get PDFAnkle sprains are common in runners. Inactive peroneal longus (PL) is one of the main contributors. The aim of this project was to study the immediate effect of running with a gentle heel strike (GHS) on pre-landing activation of the PL. It was hypothesised that GHS would pre-activate the PL to a greater extent. 11 healthy participants partook in two separate trials. The first involved running on a force plate treadmill with normally, the second with ~70% of mean heel pressure (MHP). GHS showed higher pre-landing PL activated level. There was data showing significant differences between groups at multiple timepoints. The present study showed that running with ~70% MHP compared with 100% increased PL activation for pre-landing phases. Further study should be implemented to see the fatigue level of PL during pro-longed running when running gently
LOOKING FOR OPTIMAL BIOMECHANICAL CONFIGURATIONS IN WEIGHTLIFTING AND POWERLIFTING : THEORETICAL AND EXPERIMENTAL APPROACHES
Get PDFThis work is part of a big project whose goal is to combine mechanical principles with the physical characteristics of athletes to develop a personalized virtual model optimized to help lifters improve their performance while reducing their injury risks. This study concentrates on the qualitative comparison between a virtual skeleton model of a squatting athlete numerically designed on MATLAB and the squatting patterns of elite athletes of the French national team (n=15). Comparing the results of the two approaches revealed differences in the Center Of Pressure (COP) movement during the squat as well as motor behaviour and velocity. After discussion with the athletes and their coaches it seems that the model lacked reality and more studies are needed