Ballistic Movements Research Articles

A Calculation Method of Bearing Balls Rotational Vectors Based on Binocular Vision Three-Dimensional Coordinates Measurement

The rotational speed vectors of the bearing balls affect their service life and running performance. Observing the actual rotational speed of the ball is a prerequisite for revealing its true motion law and conducting sliding behavior simulation analysis. To address the need for accuracy and real-time measurement of spin angular velocity, which is also under high-frequency and high-speed ball motion conditions, a new measurement method of ball rotation vectors based on a binocular vision system is proposed. Firstly, marker points are laid on the balls, and their three-dimensional (3D) coordinates in the camera coordinate system are calculated in real time using the triangulation principle. Secondly, based on the 3D coordinates before and after the movement of the marker point and the trajectory of the ball, the mathematical model of the spin motion of the ball was established. Finally, based on the ball spin motion model, the three-dimensional vision measurement technology was first applied to the measurement of the bearing ball rotation vector through formula derivation, achieving the analysis of bearing ball rolling and sliding characteristics. Experimental results demonstrate that the visual measurement system with the frame rate of 100 FPS (frames per second) yields a measurement error within ±0.2% over a speed range from 5 to 50 RPM (revolutions per minute), and the maximum measurement errors of spin angular velocity and linear velocity are 0.25°/s and 0.028 mm/s, respectively. The experimental results show that this method has good accuracy and stability in measuring the rotation vector of the ball, providing a reference for bearing balls' rotational speed monitoring and the analysis of the sliding behavior of bearing balls.

Microballistics in fungi and plants

Ballistic movements in biology are powered by muscle contraction, explosive chemical reactions, the formation and collapse of gas bubbles, merger of fluid droplets, and release of hydrostatic pressure. At the macroscopic end of this kinetic carnival we find jumping fleas, violent spider jaws, shrimp claw hammers, and squirting beetles and cucumbers. The speeds are startling, but the mechanisms seem familiar because they occur on a spatial scale that overlaps with our physical experiences. We jump, albeit more slowly than fleas, for example, and it does not seem strange that seeds will spurt from a swollen cucumber when it hits the ground. Ballistics in microscopic dimensions are very different, operating in a seemingly alien world of fluid mechanics where thin air becomes soup and gravity vanishes.

Real-Time Table Tennis Scoring and Player Position Tracking System Using Computer Vision

This study focuses on developing a system that uses state-of-the-art computer vision techniques to improve the accuracy and efficiency of table tennis tracking. The table tennis ball's trajectory and movement are tracked automatically by the system using a mobile camera array, allowing for real-time score updates without the need for human participation. This method guarantees precise and seamless scoring, freeing players from worrying about maintaining score and allowing them to concentrate fully on the game. The system uses player pose estimation technologies in addition to real-time scoring to track and record player positions and motions during the match. The system may provide a thorough study of player motions, including tracking posture and finding important motion patterns, by gathering and analyzing skeletal data.

Force-velocity profiling in elite luge athletes during the simulated luge start

Introduction & Purpose The idea of some athletes having high strength levels but being too slow for a particular movement while others are fast but not strong enough for the demands of their sport exists among many coaches. Therefore, planning decisions are often based on the measurement results of speed and force capabilities and the interest in the relationships between additional load, force, velocity and power during the required movement is high. The luge start is a ballistic movement that requires both high forces and velocities to reach maximal performance (i.e. fast starting times). Examining the load, force, velocity and power capabilities of elite luge athletes during the luge start could deliver insights for training prescription to improve individual weak points and improve performance. This study investigated the relationship between the calculated maxima of force-velocity (FV), load-velocity (LV) and power-velocity (PV) profiles during a simulated luge start and on-ice start times in elite luge athletes. Methods Eleven Austrian national luge team athletes (1 female, 10 male, 25 [4.4] y, 182.4 [7.3] cm, 86.65 [10.4] kg) participated in this study. Measurements were conducted during a single testing session on a specially designed start simulator. Each athlete performed starts against 5 increasing resistances relative to their bodyweight (0%, 25%, 50%, 75%, 100%). For each pull, relative maximum force (Fmax), maximum power (Pmax) and maximum velocity (Vmax) were calculated using the measurements of a linear position transducer (GymAware PowerTool). An experimental approach was used to create the FV-, LV- and PV-profiles showing the highest R2. On-ice start times [s] were measured by photoelectric sensors (ALGE). A correlation matrix (p < 0.05) was used to analyze the relationships between the theoretical Pmax, Fmax (i.e. theoretical isometric maximum force), theoretically unloaded Vmax (Vmax(F0)), theoretical relative maximum loads (Lmax(V0)) and starting times obtained from the profiles. Results Ten linear FV profiles and 11 exponential LV were created (Figure 1; FV: R2mean = 0.9532 ± 0.06; LV: R2mean = 0.9918 ± 0.01). There were significant negative relationships between Vmax(F0) and on-ice starting times (r(9) = -.74, p < .05; r(9) = -.71, p < .05; r(9) = -.74, p < .05) and significant positive correlations between Lmax(V0) and ice start times (r(9) = .71, p < .05; r(9) = .71, p < .05; r(9) = .72, p < .05). Discussion The FV relationship during a simulated luge start can be represented mostly through a linear regression line, supporting the findings of former studies which showed a quasilinear relationship between force and velocity in multi-joint movements (Bobbert, 2012; Jaric, 2015). In line with earlier approaches, PV relationships could be represented quite accurately by use of second-degree polynomial regressions (Allison et al., 2013; Padulo et al., 2017). Contradictory to the linear LV relationships found in other movements (García-Ramos et al., 2018), the luge start LV profile can be better represented by exponential regression curves which could be due to the minimized friction in the luge start setup. Conclusion The abilities of accelerating high external loads and producing high velocities both affect luge start time.

Implicit sensorimotor learning in ballistic movement for transporting an object to a target

To enhance and sustain movement accuracy, humans make corrections in subsequent trials based on previous errors. Trial-by-trial learning occurs unconsciously and has mostly been studied using reaching movements. Goal-directed projection movements, such as archery, have an inherent delay between releasing an object and observing an outcome (e.g. the arrival position of the object), and this delay may prevent trial-by-trial implicit learning. We aimed to investigate the learning in the projection movement and the impacts of the inherent delay. During the experiment, a joystick was flicked once to transport a cursor from the starting location to a target. To manipulate the length of the delay between the cursor release and outcome observation, the speed of the cursor movement was varied: a fast speed can lead to a short delay. We found trial-by-trial implicit learning under all speed conditions, and the error sensitivity was not significantly different across speed conditions. Furthermore, the error sensitivity depended on the target location, that is, the movement direction. The results indicate that trial-by-trial implicit learning occurred in goal-directed projection movement, despite the length of the inherent delay. Additionally, the degree of this learning was affected by the movement direction.

An intense electrical stimulus can elicit a StartReact effect but with decreased incidence and later onset of the startle reflex.

Planned actions can be triggered involuntarily by a startling acoustic stimulus (SAS), resulting in very short reaction times (RT). This phenomenon, known as the StartReact effect, is thought to result from the startle-related activation of reticular structures. However, other sensory modalities also can elicit a reflexive startle response. Here, we assessed the effectiveness of an intense startling electric stimulus (SES) in eliciting the StartReact effect as compared to a SAS. We tested SES intensities at 15 and 25 times the perceptual threshold of each participant, as well as SAS intensities of 114 dB and 120 dB. The electrical stimulation electrodes were placed over short head of the biceps brachii on the arm not involved in the task. Intense electric and acoustic stimuli were presented on 20% of the trials in a simple RT paradigm requiring a targeted ballistic wrist extension movement. The proportion of trials showing short latency (≤ 120 ms) startle reflex-related activation in sternocleidomastoid was significantly lower on intense electrical stimulus trials compared to intense acoustic trials, and the startle response onset occurred significantly later on SES trials compared to SAS. However, when a startle reflex was observed, RTs related to the prepared movement were facilitated to a similar extent for both SES and SAS conditions, suggesting that the accelerated response latency associated with the StartReact effect is independent of stimulus type.

Disentangling acute motor deficits and adaptive responses evoked by the loss of cerebellar output.

Our study examined the impact of cerebellar dysfunction on movement control by reversibly blocking the cerebellar output in monkeys. During a cerebellar block, reaching movements initially slowed due to an acute deficit in generating muscle torque. Beyond this primary deficit, there appeared to be a secondary, strategic slowing down of movements aimed at mitigating inter-joint interactions associated with rapid, ballistic movements. Finally, during the cerebellar block we observed movement variability increased independently of the reduced velocity, likely reflecting errors in movement planning. These findings highlight the role of the cerebellar in movement control and delineate the processes following cerebellar dysfunction that culminate in a broad range of motor impairments.

Balance Board or Motion Capture? A Meta-Analysis Exploring the Effectiveness of Commercially Available Virtual Reality Exergaming in Enhancing Balance and Functional Mobility Among the Elderly.

Force platforms and motion capture are commonly used as feedback mechanisms in exergaming; nevertheless, their therapeutic effectiveness may vary. Therefore, the primary objective of this study was to evaluate the effectiveness of commercially available virtual reality (VR) exergaming systems on balance and functional mobility, with a supplementary analysis considering the administered dose of exergaming. The search was conducted in five databases. Commercially available exergaming platforms were classified into two categories: VR exergaming with a balance board (including Wii Balance Board) and motion capture (including Xbox Kinect). Two categories of control interventions (treatment as usual [TAU] and no treatment [NT]) were extracted. The meta-analysis was performed separately for static, dynamic, and proactive balance outcomes and for the aggregated results of all included outcomes with subgroup analysis of lower, moderate, and higher doses. In total, 28 studies with 1457 participants were included. Both exergaming systems were particularly effective in improving the single leg stance outcome. VR exergaming with motion capture was found to be more effective than TAU with a standardized mean difference (SMD) of 0.48 (P = 0.006) and NT (SMD = 0.86; P = 0.02). In conclusion, commercially available VR exergaming with a motion capture feedback mechanism has demonstrated effectiveness as an intervention for balance training when compared with NT. Specifically, high doses (above 134 minutes per week) appear to be more beneficial for healthy older adults. Moreover, the findings provide some weak evidence supporting the effectiveness of VR exergaming with a balance board for improving functional mobility, particularly when compared with NT.

Improvement of mechanochemical leaching of zinc oxide ore — Optimization of grinding parameters for basket grinder

The mechanochemical leaching (MCL) process presents promising potential for efficiently extracting zinc from zinc oxide ores. This study analyzed the effects of several grinding parameters, including the agitator type, grinding ball size and material, grinding ball addition, and stirring speed, on the zinc leaching. Among them, the agitator type affects the flow form and mass transfer rate of the solution, the grinding ball size and material affects the crushing effect of the mineral powder, the grinding ball addition affects the state of motion of the grinding ball, and the stirring speed affects the grinding effect of the grinding ball on the mineral powder, which in turn affects the extraction of zinc. Experimental results show that optimization of these grinding parameters results in higher zinc leaching rates at lower energy costs. Under optimal conditions, the zinc leaching rate can reach 86.02% through the optimized MCL process, which is 9.38% higher than the conventional leaching process. Analysis techniques, such as XRD, particle size analysis, SEM-EDS, and EPMA, were utilized to examine leaching residues. The leaching mechanism of MCL process is derived under mechanical activation to destroy the insoluble product layer of zinc oxide ores (such as gangue), expose the zinc containing components, change the physical and chemical properties (such as mineral structure, particle size, and specific surface area), and enhance the reactivity of zinc oxide ore, and enhancing zinc leaching. The optimized MCL process offers the benefits of a straightforward process, reduced energy consumption, and eco-friendliness. This process has vast potential in the development and utilization of low-grade refractory zinc oxide ores in the Lanping area.

Construction and Validation of a Cognitive Engagement Scale and Its Relationship with Ball Movement Sequence Performance in Rhythmic Gymnastics

The research aims to: build and record a measure of cognitive participation among second-year female students at the College of Physical Education and Sports Sciences, University of Baghdad. The researchers used the descriptive approach in the survey style for the research sample. The sample was selected from female students and divided into: (10) female students for the survey sample, and (80) female students for the construction and codification sample. The data were statistically analyzed by the researchers using SPSS, the T-test for independent and correlated samples, Pearson's simple correlation coefficient, Cronbach's alpha, Chi-square, and Spearman-Brown. They were recruited for the samples. The study concluded that constructing a measure of cognitive participation for students in the second stage could be applied through the ease and difficulty of its expressions that are appropriate to the research sample, as well as the grades and levels that were reached, which showed that the sample fell within the rating (good and acceptable), and on the other hand the sample was characterized by participation. Cognitive through the results of the scale and its four axes. In conclusion, cognitive participation plays a positive role in performing the ball movement sequence in rhythmic gymnastics.

A Ball-Track-NES for the vibration control of flexible structures under seismic excitation

Track Nonlinear Energy Sinks (T-NESs) are gravity-based dynamic absorbers oscillating over properly designed curved tracks. Due to the resulting nonlinear restoring forces, they exhibit effective control performance even when the natural frequencies of the host structure shift due to damage. Among the available configurations for gravity-based devices, ball absorbers present a cost-effective option characterized by space efficiency and minimal maintenance requirements. Nevertheless, a comprehensive literature survey reveals that, due to the greater mathematical modeling complexity, fewer works on ball absorbers are available than their translational counterparts. Moreover, all existing papers addressing ball absorbers focus on circular tracks; to the best of the author’s knowledge, not a single paper on Ball Track Nonlinear Energy Sinks (BT-NES) can be found. Hence, this work introduces an original approach dealing with the optimum track shape of BT-NESs installed in flexible structures under seismic excitations. A nonlinear 2D model is developed to capture the motion of a heavy ball on an arbitrarily shaped track installed on the top floor of generic multi-degree of freedom (MDOF) structures modeled through the Finite Element (FE) method. Instead of imposing a fixed shape curvature, a generic rational function obtained from the Padé expansion of the circle equation is integrated into the optimization. The scheme allows for exploring a diverse set of arbitrary curvatures to describe the BT-NES track shape. The application case featured a typical soft-story building subjected to earthquake loadings. The BT-NES exhibited effective control performance, reducing the building’s ISDR by almost 30%.

Lubrication failure mechanism of rolling‑sliding steel ball against oil-impregnated porous polyimide and bearing steel in double friction pair

Oil-impregnated Porous Polyimide (O-PPI) cages have been widely applied in aerospace bearings because of their exceptional performance and self-lubricating characteristics, where the surface blackening failure of the O-PPI cage during the operation process significantly shortens the service lifetime. However, the blackening failure mechanisms are still not fully understood due to the complex multiple contacts between steel balls, the cage, and the inner/outer rings in the bearing system. This study aims to deeply detect the surface blackening failure mechanism of PPI materials with a relevant improvement measuring method. A double-contact rolling-sliding ball holder was developed to simulate the contact and the motion in aerospace bearings with PPI cages, where the blackening phenomenon on the O-PPI surface was replicated as the bearing ball rubbed against the PPI and steel surfaces. Comparative experiments and subsequent characterization results revealed that the iron debris generated at the ball-steel sliding interface was infiltrated into the PPI surface pores along the rolling motion of the steel ball, and then the splitting reaction of PAO oil at the steel-PPI interface catalyzed by the iron (Fe) during friction resulted in the formation of blackening products and further lubrication failure. Based on these findings, effective countermeasures are proposed to prevent similar failures in the future. This analysis is expected to enhance the operational reliability and enlarge the service lifetime of the space-bearing systems.

Paper 21: Anatomic Medial Ulnar Collateral Ligament Reconstruction with Internal Brace Augmentation in Throwing Athletes

Objectives: Injury to the Medial Ulnar Collateral Ligament (MUCL) is a common setback experienced by many throwing athletes often requiring reconstruction with 12-18 months of rehabilitation. Current reconstructive techniques fail to anatomically restore the MUCL which may contribute to the prolonged course of rehabilitation. In recent years, we described an anatomic MUCL reconstruction with internal brace augmentation which demonstrated improved biomechanical strength when compared to the docking technique in cadaveric specimens. The purpose of this study was to evaluate the postoperative course of both amateur and professional throwing athletes that underwent anatomic MUCL reconstruction with internal brace augmentation. We hypothesized that throwers would return to the same level of play and that return to play (RTP) would be a shorter duration compared to current reported outcomes. Methods: In this surgical technique, the native MUCL is formally repaired. The graft and a suture tape are folded over a suspensory loop and secured in a socket of the medial epicondyle of the humerus to maximize tendon to bone contact. On the ulnar side, the graft and internal brace are secured proximally by two suture anchors on either side of the sublime tubercle and further secured across the sublime tubercle ridge distally to re-create the anatomic triangular insertion of the native ligament. All surgeries were performed by a single surgeon. Patient reported outcomes in addition to date of RTP, level of play, and functional outcomes were retrospectively gathered. All patients initially followed an Accelerated Rehabilitation Protocol and were converted to a Standard Paced protocol if setbacks were encountered. Results: A total of 26 baseball players underwent primary (n=23) or revision (n=3) MUCL reconstruction with the Anatomic Technique. Of these, 15 were professional and 11 were amateur athletes. 92% of throwers returned to play at a mean of 9.9 months following reconstruction. 89% were able to advance through the accelerated postoperative protocol without issues and 85% returned to the same role and level of play. Post injury KJOC scores improved from 41 to 86.9 and SANE scores improved from 32.5 to 95.5. No significant difference was identified in pre-injury versus post-reconstruction throwing velocity, ball spin rate, or horizontal/vertical ball movement. Conclusions: Anatomic reconstruction of the MUCL with internal bracing is a viable option for MUCL injuries. Advantages include increased tendon-bone contact of the reconstruction, multiple fixation points, and anatomic restoration of the MUCL. This technique allowed an expedited return to sport for these baseball athletes.

Case study based on ball trajectory and motion analysis of international long-drive distance golf player

This study aimed to measure the ball trajectory, club face control, and body movements of a long-drive distance golf player (LDP) who excels in international competitions. The participant randomly executed 10 shots of three trajectory types—straight, draw, and fade—using a driver in an indoor facility. The results indicated that the fade shot exhibited a significantly longer ball carry distance (S: 329.7 ± 31.7, D: 301.8 ± 30.6, F: 345.7 ± 18.4 yards). The offline distance also showed a significant increase (S: 3.6 ± 37.3, D: −12.0 ± 26.4, F: 30.8 ± 42.2 yards) for the fade shot. If shots exceeding the 60-yard width of the offline distance resulting in invalid attempts were counted, there were 2 of 10 attempts for straight, 0 of 10 attempts for draw, and 4 of 10 attempts for fade. Analysis of the ball trajectory of draw shots revealed a statistically significant trend towards lower peak height and descent angle. In all three trajectories, there were no significant differences observed in ball speed (S: 189.3±6.3, D: 192.1±5.0, F: 193.3±4.1 mph) and club head speed (S: 137.2 ± 1.6, D: 137.0 ± 1.2, F: 137.7 ± 2.2 mph). For the draw shots, the club path exhibited in-to-out trajectory, moving the club face, and the face angle was open during the ball impact. It is evident that even in golf players aiming for the maximum distance in a single shot, club head speed and grip speed tend to remain relatively constant. The findings indicate that the LDP executes precise movement and face control tailored to the three ball trajectories, demonstrating sophisticated motor control.

Self-Powered Acceleration Sensor for Distance Prediction via Triboelectrification.

Accurately predicting the distance an object will travel to its destination is very important in various sports. Acceleration sensors as a means of real-time monitoring are gaining increasing attention in sports. Due to the low energy output and power density of Triboelectric Nanogenerators (TENGs), recent efforts have focused on developing various acceleration sensors. However, these sensors suffer from significant drawbacks, including large size, high complexity, high power input requirements, and high cost. Here, we described a portable and cost-effective real-time refreshable strategy design comprising a series of individually addressable and controllable units based on TENGs embedded in a flexible substrate. This results in a highly sensitive, low-cost, and self-powered acceleration sensor. Putting, which accounts for nearly half of all strokes played, is obviously an important component of the golf game. The developed acceleration sensor has an accuracy controlled within 5%. The initial velocity and acceleration of the forward movement of a rolling golf ball after it is hit by a putter can be displayed, and the stopping distance is quickly calculated and predicted in about 7 s. This research demonstrates the application of the portable TENG-based acceleration sensor while paving the way for designing portable, cost-effective, scalable, and harmless ubiquitous self-powered acceleration sensors.

Are Surface Electromyography Parameters Indicative of Post-Activation Potentiation/Post-Activation Performance Enhancement, in Terms of Twitch Potentiation and Voluntary Performance? A Systematic Review.

The aim was to identify if surface electromyography (sEMG) parameters are indicative of post-activation potentiation (PAP)/post-activation performance enhancement (PAPE), in terms of twitch potentiation and voluntary performance. Three databases were used in April 2024, with the following inclusion criteria: (a) original research, assessed in healthy human adults, and (b) sEMG parameters were measured. The exclusion criteria were (a) studies with no PAP/PAPE protocol and (b) non-randomized control trials. The following data were extracted: study characteristics/demographics, PAP/PAPE protocols, sEMG parameters, twitch/performance outcomes, and study findings. A modified physiotherapy evidence database (PEDro) scale was used for quality assessment. Fifteen randomized controlled trials (RCTs), with a total of 199 subjects, were included. The M-wave amplitude (combined with a twitch torque outcome) was shown to generally be indicative of PAP. The sEMG amplitudes (in some muscles) were found to be indicative of PAPE during ballistic movements, while a small decrease in the MdF (in certain muscles) was shown to reflect PAPE. Changes in the Hmax/Mmax ratio were found to contribute (temporally) to PAP, while the H-reflex amplitude was shown to be neither indicative of PAP nor PAPE. This review provides preliminary findings suggesting that certain sEMG parameters could be indicative of PAP/PAPE. However, due to limited studies, future research is warranted.

Hebbian priming of human motor learning

Motor learning relies on experience-dependent plasticity in relevant neural circuits. In four experiments, we provide initial evidence and a double-blinded, sham-controlled replication (Experiment I-II) demonstrating that motor learning involving ballistic index finger movements is improved by preceding paired corticospinal-motoneuronal stimulation (PCMS), a human model for exogenous induction of spike-timing-dependent plasticity. Behavioral effects of PCMS targeting corticomotoneuronal (CM) synapses are order- and timing-specific and partially bidirectional (Experiment III). PCMS with a 2 ms inter-arrival interval at CM-synapses enhances learning and increases corticospinal excitability compared to control protocols. Unpaired stimulations did not increase corticospinal excitability (Experiment IV). Our findings demonstrate that non-invasively induced plasticity interacts positively with experience-dependent plasticity to promote motor learning. The effects of PCMS on motor learning approximate Hebbian learning rules, while the effects on corticospinal excitability demonstrate timing-specificity but not bidirectionality. These findings offer a mechanistic rationale to enhance motor practice effects by priming sensorimotor training with individualized PCMS.

Robotic-assisted differential total knee arthroplasty with patient-specific implants: surgical techniques and preliminary results

ObjectiveIn total knee arthroplasty (TKA), achieving soft-tissue balance while retaining acceptable lower limb alignment is sometimes difficult and may lead to patient dissatisfaction. Theoretically, patient-specific implants can bring great benefits, while the lack of precise surgical tools may hinder the improvement of outcomes. The objective of this study was to illustrate surgical techniques and evaluate kinematics and early clinical outcomes of robotic-assisted TKA using patient-specific implants.MethodsBased on preoperative CT scan, femoral and tibial components were 3D printed. Medial and lateral tibial liners were separate with different thicknesses, posterior slopes and conformity. TiRobot Recon Robot was used for surgery, and was armed with smart tools that quantify gap, force and femoral-tibial track. We collected data on demographics, intraoperative gap balance and femoral-tibial motion. In the follow-up, we evaluated the range of motion, Visual Analogue Scale (VAS), forgotten joint score (FJS), Knee injury and Osteoarthritis Outcome Score, Joint Replacement (KOOS, JR) score. Radiological data were also harvested.ResultsFifteen patients (17 knees) were enrolled with a mean age of 64.6 ± 6.4 (53–76) years. In 5 knees, we used symmetric tibial liners, the rest were asymmetric. After surgery, the average alignment was 1.6 ± 2.0 (-3–5) degrees varus. The average follow-up lasted 6.7 ± 4.2 (1–14) months. The mean visual analogue scale was 0.8 ± 0.7 (0–2), FJS was 62.4 ± 25.3 (0–87), KOOS was 86.5 ± 9.4 (57–97). 11 patients were “very satisfied”, 3 were “satisfied" with the result, and one patient was neutral due to restricted extension and unsatisfactory rehabilitation at five months’ follow-up.ConclusionsWith patient-specific implants and robotics, TKA could be performed by a mathematical way, which was dubbed a “differential” TKA. Intraoperative kinematics was excellent in terms of gap-force balancing and femoral-tibial relative motion. Preliminary clinical outcomes were overall satisfactory.

Reliability of energy landscape analysis of resting-state functional MRI data.

Energy landscape analysis is a data-driven method to analyse multidimensional time series, including functional magnetic resonance imaging (fMRI) data. It has been shown to be a useful characterization of fMRI data in health and disease. It fits an Ising model to the data and captures the dynamics of the data as movement of a noisy ball constrained on the energy landscape derived from the estimated Ising model. In the present study, we examine test-retest reliability of the energy landscape analysis. To this end, we construct a permutation test that assesses whether or not indices characterizing the energy landscape are more consistent across different sets of scanning sessions from the same participant (i.e. within-participant reliability) than across different sets of sessions from different participants (i.e. between-participant reliability). We show that the energy landscape analysis has significantly higher within-participant than between-participant test-retest reliability with respect to four commonly used indices. We also show that a variational Bayesian method, which enables us to estimate energy landscapes tailored to each participant, displays comparable test-retest reliability to that using the conventional likelihood maximization method. The proposed methodology paves the way to perform individual-level energy landscape analysis for given data sets with a statistically controlled reliability.

Benefits of Resistance Training During Pregnancy for Maternal and Fetal Health: A Brief Overview.

Research demonstrates resistance training is not only safe but also beneficial for pregnant women. However, exercise recommendations for pregnant women still minimize the importance of resistance exercise and provide minimal guidance. With a large increase in strength-focused sports among women, it is critical to re-evaluate the risk/benefit ratio of these exercises and ensure the latest recommendations reflect the latest clinical research. The purpose of this review is to highlight the safety and benefits of resistance training for both maternal and fetal health, particularly focusing on recent work. Relevant research involving resistance training during pregnancy was accessed and analyzed via a quasi-systematic search. Results demonstrate that appropriate prenatal resistance training can help alleviate some of the common symptoms of pregnancy, such as fatigue, back pain, and poor mental health. Resistance exercise can assist with glucose control in gestational diabetes mellitus, as well as decrease the risk of infant macrosomia and childhood metabolic dysfunction associated with uncontrolled gestational diabetes. Resistance training can also increase the likelihood of a vaginal delivery, which is beneficial for both mother and baby. Concerning fetal health, resistance training increases uterine blood flow, decreases the risk of neonatal macrosomia, and improves cognitive function and metabolic health in childhood. As with all forms of exercise, pregnant women should avoid resistance exercises that involve the supine position for extended bouts of time, trauma (or risk of trauma) to the abdomen, ballistic movements, movements that rely heavily on balance, and conditions that prohibit appropriate temperature control. With these considerations in mind, resistance training's benefits far surpass the lack of risk to the fetus. Resistance training is a safe and effective way to improve and maintain physical fitness during pregnancy and represents no risk to fetal health and development. Thus, healthcare providers should recommend resistance training for pregnant women.