Longitudinal changes in Super League match locomotor and event characteristics: A league-wide investigation over three seasons in rugby league

The 2019 and 2020 Super League (SL) seasons included several competition rule changes. This study aimed to quantify the difference between the 2018, 2019 and 2020 SL seasons for duration, locomotor and event characteristics of matches. Microtechnology and match event data were analysed from 11 SL teams, comprising 124 players, from 416 competitive matches across a three-year data collection period. Due to an enforced suspension of league competition as a consequence of COVID-19 restrictions, and subsequent rule changes upon return to play, season 2020 was divided into season 2020a (i.e. Pre-COVID suspension) and season 2020b (i.e. Post-COVID suspension). Duration, locomotor variables, and match events were analysed per whole-match and ball-in-play (BIP) periods with differences between seasons determined using mixed-effects models. There were significant (ρ ≤ 0.05) reductions in whole-match and BIP durations for adjustables and backs in 2019 when compared to 2018; albeit the magnitude of reduction was less during BIP analyses. Despite reduced duration, adjustables reported an increased average speed suggesting reduced recovery time between bouts. Both forwards and adjustables also experienced an increase in missed tackles between 2018 and 2019 seasons. When comparing 2019 to 2020a, adjustables and backs increased their average speed and distance whilst all positional groups increased average acceleration both for whole-match and BIP analyses. When comparing 2020a to 2020b, all positional groups experienced reduced average speed and average acceleration for both whole-match and BIP analyses. Forwards experienced an increased number of tackles and carries, adjustables experienced an increased number of carries, and backs experienced an increased number of missed tackles when comparing these variables between season 2020a and 2020b. Rule changes have a greater effect on whole-match duration and locomotor characteristics than those reported during BIP periods which suggests the implemented rule changes have removed stagnant time from matches. Amendments to tackle related rules within matches (e.g., introduction of the ‘six-again’ rule) increases the number of collision related events such as carries and tackles.

Behavioural responses of juvenile Daphnia magna to two organophosphorus insecticides

In this study, the behaviour of Daphnia magna was studied under equipotent and sub-lethal concentrations of two pesticides congeners: chlorpyrifos (CPF; 5 ng L-1 to 50 ng L-1) and chlorpyrifos-methyl (CPF-m; 30 ng L-1 to 300 ng L-1) with aims to assess and compare the behavioural swimming responses (BSRs) of the cladocerans elicited by both compounds at different concentrations and exposure times. A video tracking analysis after 24 h and 48 h of exposure allowed us to evaluate different behavioural responses (distance moved, average velocity, active time, and average acceleration). The results indicate that BSRs are sensitive indicators of sub-lethal stress. Highly concentration- and time-response changes for both compounds were observed during the experiments. In particular, in the first 24 h of exposure, both compounds elicited a similar decreasing trend in swimming behaviour, in which CPF induced the highest decline. Further, hypoactivity was associated with the narcotic effects of both compounds. Conversely, after 48 h of exposure, we observed an increasing tendency in the swimming parameters, particularly at the highest tested concentrations. However, the compounds did not exhibit the same trend. Rather, CPF-m induced high variations from the control groups. This reversal trend could be due to the activation of compensatory mechanisms, such as feeding, searching, or avoidance behaviours. These results suggest that BSRs are measurable active responses of organisms, which are controlled by time.

Analysis and design of electromagnetic vibration and noise reduction method of permanent magnet motor

Vibration and noise parameters have a significant influence on the performance of permanent magnet motor (PMM). A new method of reducing vibration and noise of PMM was proposed in this study by optimizing the stator teeth profile. The optimal offset distance was determined by finite element method, and the results indicate that the vibration and noise amplitude become larger when the frequency is an even multiple of the fundamental frequency. The maximum and average vibration acceleration of the optimized PMM is reduced by 22.27% and 11.11%, respectively, and the total sound pressure level (SPL) is decreased by 3.67%. Finally, the correctness of the theoretical parameters was verified by the vibration and noise measuring experiment. The experimental data suggest that the average acceleration error is 7.07%, and the average SPL error is 2.28%. The research methods and conclusions of this study may be extended to the vibration and noise optimization of other PMM.

Women's Rugby League: Positional Groups and Peak Locomotor Demands

The aims of this study were to (a) use a data-based approach to identify positional groups within National Rugby League Women's (NRLW) match-play and (b) quantify the peak locomotor demands of NRLW match-play by positional groups. Microtechnology (Global Navigational Satellite System [GNSS] and integrated inertial sensors; n = 142 files; n = 76 players) and match statistics (n = 238 files; n = 80 players) were collected from all NRLW teams across the 2019 season. Data-based clustering of match statistics was utilized to identify positional clusters through classifying individual playing positions into distinct positional groups. Moving averages (0.5, 1, 2, 3, 5, and 10 min) of peak running and average acceleration/deceleration demands were calculated via microtechnology data for each player per match. All analysis was undertaken in R (R Foundation for Statistical Computing) with positional differences determined via a linear mixed model and effect sizes (ES). Data-based clustering suggested that, when informed by match statistics, individual playing positions can be clustered into one of three positional groups. Based on the clustering of the individual positions, these groups could be broadly defined as backs (fullback, wing, and center), adjustables (halfback, five-eighth, and hooker), and forwards (prop, second-row, and lock). Backs and adjustables demonstrated greater running (backs: ES 0.51–1.00; p < 0.05; adjustables: ES 0.51–0.74, p < 0.05) and average acceleration/deceleration (backs: ES 0.48–0.87; p < 0.05; adjustables: ES 0.60–0.85, p < 0.05) demands than forwards across all durations. Smaller differences (small to trivial) were noted between backs and adjustables across peak running and average acceleration/deceleration demands. Such findings suggest an emerging need to delineate training programs in situations in which individual playing positions train in positional group based settings. Collectively, this work informs the positional groupings that could be applied when examining NRLW data and supports the development of a framework for specifically training female rugby league players for the demands of the NRLW competition.

Integrated regression and whale optimization algorithm to post-stroke rehabilitation analysis: A case study for serious games (Preprint)

BACKGROUND Stroke is one of the leading causes of death and long-term disability worldwide. The primary goal of post-stroke rehabilitation is to maximize the independence of the affected individuals by facilitating both neurological and compensatory functional recoveries in their daily lives. OBJECTIVE The research objective finding the best games settings for MIRA. METHODS This paper presents an integrated study, using multiple linear regression (MLR) and whale optimization algorithm, for optimizing the post-stroke rehabilitation performance using Medical Interactive Rehabilitation Assistant (MIRA). RESULTS Results demonstrated that the developed MLR models for average acceleration and distance were significant, with P=0.018 and P<0.000, respectively. Data from 41 stroke patients revealed that the maximum muscle strength that can be achieved was 2.56 cm/s2 while the maximum distance was 104.83 cm. The results showed that all patients outperformed the optimal average acceleration value by between 6% and 29%, whereas only two patients outperformed the optimal distance value. CONCLUSIONS The results from this study may be integrated using MIRA (exergames) to guide therapists in finding the best combination of input settings that can maximise the performance output of post-stroke patients. CLINICALTRIAL None

SLAMMING IMPACT ACCELERATIONS ANALYSIS ON SMALL HIGH SPEED PASSENGER CRAFTS

Small high speed passenger crafts (HSC) are commonly known for their poor seakeeping qualities. These crafts are frequently exposed to large slamming impacts and these repetitive shocks may pose danger to passengers’ safety and health. In Malaysia, small high speed passenger crafts having lengths between 7 to 9 meters are mainly used to transport tourists between popular island destinations. Evaluation on impact and vibration for this type of craft was conducted by using accelerometers attached to several locations on craft’s deck. The test was conducted at speeds ranged between 20 to 30 knots and the highest peak accelerations were recorded. The highest acceleration record during the sea trial was recorded at 4.22 g and the average acceleration measure is 2.20 g. Apart from this test, evaluation on effectiveness of the current foam seat typically used in this craft were evaluated using Dynamic Response Index (DRI) and results have shown that the seat is less efficient when impact reaches more than 1g at speeds of more than 20 knots. It is concluded that safety measures such as the use of more efficient suspension seat and limiting the operational speed need to be taken into consideration.

Analisis Pergerakan Vertikal Titik Pantau Jembatan Penggaron, Kabupaten Semarang, Propinsi Jawa Tengah

Penggaron bridge toll highway is located in road Semarang-Ungaran, 20th kilometer in the Susukan region, East Ungaran, Semarang regency, Central Java province. Penggaron bridge has a 400 m length and nine pillars that support the weight of the bridge. This bridge has began operation since 2010. The bridge visually deformed as indicated by small cracks in the pillars of the bridge. Natural factors such as unstable soil conditions are suspected as the cause of deformation. To minimize and prevent damage that may occur on the bridge then the Penggaron bridge deformation monitoring should be performed. Therefore, this study analyze the vertical movement on the Penggaron bridge using height difference observation data by waterpass in 2014 s.d. 2015. This study used four epoch height different observation data on the 18 bridge monitoring points. The 18 monitoring bridges points was tied to two reference points around the bridge. These observation data is processed by Least Squares Adjustment parameter method to get the height and its standard deviation, vertical movement and its standard deviation, vertical movement velocity and its standard deviation as well as average velocity and average acceleration on every bridge monitoring points on each epoch. The next step includes the computation and analysis of vertical movement, as well as the significance of two parameter different test. The results of this study are the vertical movement vector of the 18 monitoring points with magnitude from 3,1 mm to 170,3 mm with the majority down direction. The vertical movement velocity has a range between 3,05 mm/month to 89,35 mm/month with the movement direction tends to downward. The average velocity of vertical movement for epoch I and II is 7,08 mm/month, epoch II and III is 4,93 mm/month, epoch I and III is 6,00 mm/month, epoch III and IV is 6,03 mm/month, epoch I and IV is 1,29 mm/month with the movement direction tends to downward. The average acceleration of vertical movement for epoch I and II is 7,08 mm/month2, epoch II and III is 4,93 mm/month2, epoch I and III is 3,00 mm/month2, epoch III and IV is 6,03 mm/month2. The majority of the significance of two parameter different test parameters is rejected, it means that monitoring points had a significant movement.

Vibration Response Evaluation under Shock-Type Loading with Emphasis on Finite Element Model Updating

In some cases, impulse- or shock-type excitations as the dynamic loading are inevitable, and obtaining proper response with the well-known numerical methods is not easy. This paper focuses on dynamic response estimation against short-time loading with an updated finite element model using frequency response functions (FRF) and particle swarm optimization (PSO) technique. Because there is not an analytical method for assessing the numerical responses under shock-type excitations, in this paper, experimental tests are designed on a laboratory scale to evaluate the numerical responses. The vibration responses of the system against shock loading are compared with the Newmark average acceleration scheme and also with experimental data. The results reveal that the unconditionally stable Newmark method against regular loads has an appropriate performance. Still, under short-time loading, it faces numerical damping error, and this method should not be blindly applied under shock-type loads.