Introduction: Cutting is an important skill in team-sports, but unfortunately is also related to non-contact ACL injuries. The purpose was to examine knee kinetics and kinematics at different cutting angles. Material and methods: 13 males and 16 females performed cuts at different angles (45 , 90 , 135 and 180 ) at maximum speed. 3D kinematics and kinetics were collected. To determine differences across cutting angles (45 , 90 , 135 and 180 ) and sex (female, male), a 4 2 repeated measures ANOVA was conducted followed by post hoc comparisons (Bonferroni) with alpha level set at a 0.05 a priori. Results: At all cutting angles, males showed greater knee flexion angles than females (p < 0.01). Also, where males performed all cutting angles with no differences in the amount of knee flexion 42.53 ± 8.95 , females decreased their knee flexion angle from 40.6 ± 7.2 when cutting at 45 to 36.81 ± 9.10 when cutting at 90 , 135 and 180 (p < 0.01). Knee flexion moment decreased for both sexes when cutting towards sharper angles (p < 0.05). At 90 , 135 and 180 , males showed greater knee valgus moments than females. For both sexes, knee valgus moment increased towards the sharper cut- ting angles and then stabilized compared to the 45 cutting angle (p < 0.01). Both females and males showed smaller vGRF when cutting to sharper angles (p < 0.01). Conclusion: It can be concluded that different cutting angles demand different knee kinematics and kinet- ics. Sharper cutting angles place the knee more at risk. However, females and males handle this differ- ently, which has implications for injury prevention.
Background: Retention of movement technique is crucial in anterior cruciate ligament (ACL) injury pre- vention programs. It is unknown if specific instructions or video instructions result in changes in kine- matic and kinetic measures during a relatively short training session, and in a retention test one week later.Hypothesis/Purpose: The purpose was to determine the effects of verbal external focus (EF), verbal inter- nal focus (IF) and video instructions (VI) on landing technique (i.e. kinematics and kinetics) during train- ing and retention.Study Design: Randomized Controlled Trial.Methods: This study compared verbal EF, verbal IF, VI and CTRL group. Forty healthy athletes were assigned to the IF (n=10), EF (n=10), VI (n=10) or CTRL group (n=10). A jump-landing task was per- formed as a baseline, followed by two training blocks (TR1 and TR2) and a post test. Group specific instruc- tions were offered in TR1 and TR2. In addition, subjects in the IF, EF and VI groups were free to ask for feedback after every jump in TR1 and TR2. One week later, a retention test was conducted without specific instructions or feedback. Kinematics and kinetics were captured using an 8-camera motion analysis system.Results: Males and females in the EF and VI instruction group showed beneficial results during and after the training session, in terms of improved landing technique. Retention was achieved after only a short training session.Conclusion: ACL injury prevention programs should include EF and/or VI instructions to improve kine- matics and kinetics and achieve retention.Level of Evidence: 3bKey words: Injury prevention, motor learning, movement technique, retention
Development of novel testing strategies to detect adverse human health effects is of interest to replace in vivo-based drug and chemical safety testing. The aim of the present study was to investigate whether physiologically based kinetic (PBK) modeling-facilitated conversion of in vitro toxicity data is an adequate approach to predict in vivo cardiotoxicity in humans. To enable evaluation of predictions made, methadone was selected as the model compound, being a compound for which data on both kinetics and cardiotoxicity in humans are available. A PBK model for methadone in humans was developed and evaluated against available kinetic data presenting an adequate match. Use of the developed PBK model to convert concentration–response curves for the effect of methadone on human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) in the so-called multi electrode array (MEA) assay resulted in predictions for in vivo dose–response curves for methadone-induced cardiotoxicity that matched the available in vivo data. The results also revealed differences in protein plasma binding of methadone to be a potential factor underlying variation between individuals with respect to sensitivity towards the cardiotoxic effects of methadone. The present study provides a proof-of-principle of using PBK modeling-based reverse dosimetry of in vitro data for the prediction of cardiotoxicity in humans, providing a novel testing strategy in cardiac safety studies.
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Recycling of plastics plays an important role to reach a climate neutral industry. To come to a sustainable circular use of materials, it is important that recycled plastics can be used for comparable (or ugraded) applications as their original use. QuinLyte innovated a material that can reach this goal. SmartAgain® is a material that is obtained by recycling of high-barrier multilayer films and which maintains its properties after mechanical recycling. It opens the door for many applications, of which the production of a scoliosis brace is a typical example from the medical field. Scoliosis is a sideways curvature of the spine and wearing an orthopedic brace is the common non-invasive treatment to reduce the likelihood of spinal fusion surgery later. The traditional way to make such brace is inaccurate, messy, time- and money-consuming. Because of its nearly unlimited design freedom, 3D FDM-printing is regarded as the ultimate sustainable technique for producing such brace. From a materials point of view, SmartAgain® has the good fit with the mechanical property requirements of scoliosis braces. However, its fast crystallization rate often plays against the FDM-printing process, for example can cause poor layer-layer adhesion. Only when this problem is solved, a reliable brace which is strong, tough, and light weight could be printed via FDM-printing. Zuyd University of Applied Science has, in close collaboration with Maastricht University, built thorough knowledge on tuning crystallization kinetics with the temperature development during printing, resulting in printed products with improved layer-layer adhesion. Because of this knowledge and experience on developing materials for 3D printing, QuinLyte contacted Zuyd to develop a strategy for printing a wearable scoliosis brace of SmartAgain®. In the future a range of other tailor-made products can be envisioned. Thus, the project is in line with the GoChem-themes: raw materials from recycling, 3D printing and upcycling.
