A COMPARISON OF UNDERWATER GLIDING AND KICKING TECHNIQUES

Net forces created when towing swimmers through water were examined for gliding and undelwater kicking. Sixteen experienced male swimmers of similar body shape were towed through water via a motorised winch and pulley system. A load cell measured net force (propulsive force - drag force) at velocities of 1.6, 1.9, 2.2, 2.5 and 3.1 ms-', respectively. At each velocity swimmers performed a prone streamline glide; lateral streamline glide; prone freestyle kick; prone dolphin kick; and lateral dolphin kick. A 2- way repeated measures ANOVA revealed significant differences between the gliding and kicking conditions at different velocities. Results suggest that there is an optimal velocity at which to begin undelwater kicking in order to prevent energy loss from excessive active drag

POSTURAL RESPONSE TO VARIED VELOCITY AND DURATION VISUAL PERTURBATIONS IN VIRTUAL REALITY

The purpose of this study was to examine the center of pressure response to visual perturbations presented in virtual reality (VR). The visual perturbations were an anterior or posterior displacement that varied in velocity (1m/s, 3m/s & 5m/s) and duration (0.6s, 1s and 2 s). The center of pressure distance travelled was measured in the anterior-posterior direction while subjects balance on one foot. Four subjects were evaluated in the pilot. A t-test was used to examine the pooled effect of the perturbations. The visual perturbation significantly increased the distance the center of pressure travelled (p = 0.041). A 2-way repeated measures ANOVA was used to assess the specific affects velocity and duration. The main effect for duration was significant (p =0.014). Duration of the visual perturbation appears to be the most important component to challenge postural control

MOTOR CONTROL PATTERNS IN ELITE SWIMMERS’ FREESTYLE STROKE DURING DRYLAND SWIMMING

The purpose of this study was to compare motor control patterns of elite freestyle swimmers when asked to swim at 100m freestyle pace using a dryland swimbench. Collegiate and masters level swimmers (n=15) whose 100m freestyle time were faster than 75% of the FINA cutoff time, performed four 10 second trials of freestyle swimming on a dryland swimbench. 3-D kinematic analysis was used to calculate displacement in the hand in the cranial-caudal, vertical, and medial-lateral directions. A 2-way repeated measures ANOVA was used to compare hand path between swimmers and within trials (n=58). Data was not statically significant, but three distinct combinations of hand paths were used to perform the 100m freestyle task on the swimbench. These hand paths differed from historical in-water data. Findings imply individual swimmers adjusted kinematics on the swimbench to accommodate for environmental constraints

การพัฒนาอุปกรณ์พยุงน้ำหนักสำหรับฝึกเดินที่สามารถปรับความกว้างได้

หลักการและเหตุผล: การฝึกให้ผู้ป่วยทางระบบประสาทเดินโดยมีการช่วยพยุงน้ำหนักของผู้ป่วยในขณะเดินบนลู่เดินทำให้การเดินของผู้ป่วยดีขึ้น แต่การใช้อุปกรณ์พยุงน้ำหนักสำหรับฝึกเดินในประเทศไทยยังไม่เป็นที่แพร่หลาย เนื่องจากมีราคาแพงและต้องนำเข้าจากต่างประเทศ อีกทั้งความกว้างของอุปกรณ์พยุงน้ำหนักที่กำหนดไว้อย่างแน่นอน ทำให้ใช้ได้กับลู่เดินเพียงบางรุ่นเท่านั้น วัตถุประสงค์: เพื่อประดิษฐ์อุปกรณ์พยุงน้ำหนักสำหรับฝึกเดินที่ถอดประกอบและปรับความกว้างได้ สามารถพยุงน้ำหนักได้ 1 - 40 กก. วิธีการศึกษา: ประดิษฐ์อุปกรณ์พยุงน้ำหนักที่สามารถถอดประกอบได้ จากนั้นทดสอบความแม่นยำในการยกน้ำหนักของเครื่อง โดยเปรียบเทียบกับตุ้มน้ำหนักมาตรฐาน ตั้งแต่ 1 - 40 กก. และเทียบกับอุปกรณ์ที่นำเข้าจากต่างประเทศ (Biodex®) โดยยกน้ำหนักขณะยืน30% ของน้ำหนักตัว ในคนสุขภาพดี 15 คน ที่มีน้ำหนักอยู่ในช่วง 40 - 120 กก. โดยเปรียบเทียบน้ำหนักที่ยกได้และน้ำหนักที่เหลือบนเครื่องชั่งน้ำหนัก วิเคราะห์ข้อมูลโดยใช้สถิติแบบ intraclass correlation และทดสอบความคงที่ในการพยุงน้ำหนักขณะฝึกเดิน ในคนสุขภาพดีจำนวน 7 คน ขณะเดินบนลู่เดินและใช้อุปกรณ์พยุงน้ำหนักทั้ง 2 ประเภท โดยบันทึกค่าน้ำหนักที่ยกขึ้นขณะเดินทุก ๆ 5 นาที แล้วนำมาทดสอบทางสถิติด้วย 2-way repeated measures ANOVA ผลการศึกษา: ผลการทดสอบความแม่นยำในการพยุงน้ำหนักกับน้ำหนักมาตรฐาน พบความคลาดเคลื่อนจากน้ำหนักมาตรฐานคิดเป็น 2% ของน้ำหนักมาตรฐานผลการทดสอบความแม่นยำในการพยุงน้ำหนักโดยเทียบกับอุปกรณ์ที่นำเข้าจากต่างประเทศ พบว่ามีความสัมพันธ์ไปในทิศทางเดียวกันอย่างมีนัยสำคัญทางสถิติ(r = 0.993) และผลการทดสอบความคงที่ในการพยุงน้ำหนักของอุปกรณ์พยุงน้ำหนักขณะเดินในแต่ละช่วงเวลา ระหว่างอุปกรณ์พยุงน้ำหนักที่นำเข้าจากต่างประเทศ และอุปกรณ์พยุงน้ำหนักที่ประดิษฐ์ขึ้น พบว่าทั้ง 2 อุปกรณ์มีความคงที่ในการพยุงน้ำหนักตลอดช่วงเวลา 20 นาที ขณะเดินบนลู่เดินเทียบเท่ากันสรุป: อุปกรณ์พยุงน้ำหนักที่ประดิษฐ์ขึ้นใหม่นั้น มีโครงสร้างที่สามารถถอดประกอบได้ง่าย การขนย้ายสะดวก สามารถประกอบเข้ากับลู่เดินส่วนใหญ่ที่ใช้ภายในศูนย์ฟื้นฟูภายในประเทศไทย และมีความแม่นยำในการพยุงน้ำหนักเทียบเท่ากับอุปกรณ์พยุงน้ำหนักที่นำเข้าจากต่างประเทศคำสำคัญ: body weight support, adjustable BWS, gait rehabilitation, treadmill, gait training_

Positional influence of center of masticatory forces on occlusal contact forces using a digital occlusal analyzer

Statement of problem. Digital occlusal analyzers allow the recording of dental contact forces. Some authors assume a unique location for the center of contact forces at the position of maximum intercuspation, while others indicate variations in dental contact forces when recorded at different times of the day. Which approach is more appropriate is unclear. Purpose. The purpose of this in vitro study was to analyze whether a change in the balance of masticatory forces influences the location of the center of contact forces and its magnitude. Material and methods. Three different dental casts, selected under dental criteria, were mounted in maximum intercuspation on a semiadjustable articulator equipped with a pattern indicating 9 different force application points (intersection point between 3 longitudinal rows and 3 transverse columns). A force of constant magnitude (169 N) was applied 10 times at each of the application points, and occlusal forces were recorded with a digital occlusal analyzer. Then, two variables were studied: the location of the center of contact forces and its magnitude. Each force application position (9 positions × 3 dental casts=27 in total) was repeated 10 times, and measured data were statistically analyzed with 2-way repeated measures ANOVA (a=.05) test. Results. The repeatability of the method indicated that the coefficient of variation mean was 0.37% in the location of the center of contact forces and that its magnitude was 3.70%. The 2-way repeated measures ANOVA test revealed statistically significant variations in the location of the center of contact forces and its magnitude, revealing that longitudinal changes of the application point of masticatory forces affected the magnitude of contact forces and that longitudinal and transverse changes of the application point of masticatory forces affected the location of the center of contact forces. Conclusions. The location of the center of contact force and its magnitude provided by a digital occlusal analyzer at the position of maximum intercuspation are not necessarily unique to each articulated dental cast. Even if the intensity of the masticatory force remains unchanged, changes in its lateral or longitudinal balance also influence the result of the occlusion forces. (J Prosthet Dent 2023;129:930.e1–e8he authors thank the University of the Basque Country (UPV/EHU) for providing the DEHI research laboratory (www.ehu.eus/dehi). The authors also thank Ayesta dental practice and Odontolan dental laboratory for their assistance

Half-time and high-speed running in the second half of soccer

This study investigated if the quantity of high-speed running (movements >15 km.h-1) completed in the first 15 minutes of competitive football matches differed from that completed in the corresponding 15 minutes of the second half. Twenty semi-professional soccer players (age 21.2 ± 3.6 years, body mass 76.4 ± 3.8 kg, height 1.89 ± 0.05 m) participated in the study. Fifty competitive soccer matches and 192 data files were analysed (4 ± 2 files per match) using Global Positioning Satellite technology. Data were analysed using 2-way repeated measures ANOVA and Pearson correlations. No differences were found between the first 15 min of each half for the distance completed at high-speed (>15 km.h-1) or sprinting (>21 km.h-1), or in the number of sprints undertaken (p>0.05). However, total distance covered was shorter (1st half vs. 2nd half: 1746 ± 220 vs. 1644 ± 224 m; p<0.001) and mean speed lower (1st half vs. 2nd half: 7.0 ± 0.9 vs. 6.6 ± 0.9 km.h-1; p<0.001) in the first 15 min of the second half compared to the first. The correlations between the duration of the half-time interval and the difference in the high-speed running or sprinting between first and second halves (0-15 min) were very small (r=0.08 [p=0.25] and r=0.04 [p=0.61] respectively). Therefore, this study did not find any difference between the amount of high-speed running and sprinting completed by semi-professional soccer players when the first 15 minutes of the first and second half of competitive matches were compared The maintenance of high-speed running and sprinting, as total distance and mean speed declined, may be a function of the pacing strategies adopted by players in competitive matches

Carbohydrate Mouth Rinse Improves 1.5 h Run Performance: Is There a Dose-Effect?

There is a substantial body of recent evidence showing ergogenic effects of carbohydrate (CHO) mouth rinsing on endurance performance. However, there is a lack of research on the dose-effect and the aim of this study was to investigate the effect of two different concentrations (6% and 12% weight/volume, w/v) on 90 minute treadmill running performance. Seven active males took part in one familiarization trial and three experimental trials (90-minute self-paced performance trials). Solutions (placebo, 6% or 12% CHO-electrolyte solution, CHO-E) were rinsed in the mouth at the beginning, and at 15, 30 and 45 minutes during the run. The total distance covered was greater during the CHO-E trials (6%, 14.6 ± 1.7 km; 12%, 14.9 ± 1.6 km) compared to the placebo trial (13.9 ± 1.7 km, P 0.05). There were no between trial differences (P > 0.05) in ratings of perceived exertion (RPE) and feeling or arousal ratings suggesting that the same subjective ratings were associated with higher speeds in the CHO-E trials. Enhanced performance in the CHO-E trials was due to higher speeds in the last 30 minutes even though rinses were not provided during the final 45 minutes, suggesting the effects persist for at least 20-45 minutes after rinsing. In conclusion, mouth rinsing with a CHO-E solution enhanced endurance running performance but there does not appear to be a dose-response effect with the higher concentration (12%) compared to a standard 6% solution

A Subgroup Analysis of the Impact of Self-testing Frequency on Examination Scores in a Pathophysiology Course

Objective: To determine if the frequency of self-testing of course material prior to actual examination improves examination scores, regardless of the actual scores on the self-testing. Methods: Practice quizzes were randomly generated from a total of 1342 multiple-choice questions in pathophysiology and made available online for student self-testing. Intercorrelations, 2-way repeated measures ANOVA with post hoc tests, and 2-group comparisons following rank ordering, were conducted. Results: During each of 4 testing blocks, more than 85% of students took advantage of the self-testing process for a total of 7042 attempts. A consistent significant correlation (p≤0.05) existed between the number of practice quiz attempts and the subsequent examination scores. No difference in the number of quiz attempts was demonstrated compared to the first testing block. Exam scores for the first and second testing blocks were both higher than those for third and fourth blocks. Conclusion: Although self-testing strategies increase retrieval and retention, they are uncommon in pharmacy education. The results suggested that the number of self-testing attempts alone improved subsequent examination scores, regardless of the score for self-tests

Gait analysis in a <i>Mecp2</i> knockout mouse model of Rett syndrome reveals early-onset and progressive motor deficits

Rett syndrome (RTT) is a genetic disorder characterized by a range of features including cognitive impairment, gait abnormalities and a reduction in purposeful hand skills. Mice harbouring knockout mutations in the &lt;i&gt;Mecp2&lt;/i&gt; gene display many RTT-like characteristics and are central to efforts to find novel therapies for the disorder. As hand stereotypies and gait abnormalities constitute major diagnostic criteria in RTT, it is clear that motor and gait-related phenotypes will be of importance in assessing preclinical therapeutic outcomes. We therefore aimed to assess gait properties over the prodromal phase in a functional knockout mouse model of RTT. In male &lt;i&gt;Mecp2&lt;/i&gt; knockout mice, we observed alterations in stride, coordination and balance parameters at 4 weeks of age, before the onset of other overt phenotypic changes as revealed by observational scoring. These data suggest that gait measures may be used as a robust and early marker of &lt;i&gt;Mecp2&lt;/i&gt;-dysfunction in future preclinical therapeutic studies