Movement Scientists Research Articles

Why are the Dutch so great at swimming?

Abstract Amateur swimmer Sandra Alba interrogates an Olympian turned coach and two movement scientists on how Dutch swimmers defy random error to consistently bring home medals

Michael Turvey: A Legacy of Scientific Excellence and Kindness

Michael Turvey’s research in motor control and coordination influenced many generations of movement scientists, Brazilian scholars included. Throughout his career, Michael Turvey aimed for excellence in research, teaching, and mentoring while treating students and colleagues with kindness.

The biospheric emergency calls for scientists to change tactics.

Our current economic and political structures have an increasingly devastating impact on the Earth's climate and ecosystems: we are facing a biospheric emergency, with catastrophic consequences for both humans and the natural world on which we depend. Life scientists - including biologists, medical scientists, psychologists and public health experts - have had a crucial role in documenting the impacts of this emergency, but they have failed to drive governments to take action in order to prevent the situation from getting worse. Here we, as members of the movement Scientist Rebellion, call on life scientists to re-embrace advocacy and activism - which were once hallmarks of academia - in order to highlight the urgency and necessity of systemic change across our societies. We particularly emphasise the need for scientists to engage in nonviolent civil resistance, a form of public engagement which has proven to be highly effective in social struggles throughout history.

S05-1 Online tool to stimulate physical activity for older people with dementia - development and dissemination

Physical activity (PA) stimulates physical health, quality of life, and potentially cognition in people with dementia. However, home dwelling older people with dementia are in general less active than peers. For those attending daycare, the amount of physical activity is highly dependent on the centre's policy. For those without daycare, municipalities are responsible for support but generally there is no attention to PA for this target group. Professionals and volunteers in day care centers, and informal caregivers lack awareness and knowledge to support the people with dementia. Figures on users of other online information on PA show that video's and practical information are highly rated.As part of a research consortium with 4 scientific partners, we were funded for dissemination of research outcomes to practice and policy. We therefore decided to build an online tool with easy to understand instruction movies and background information on theme's like strong legs and physical activity friendly layout of spaces. Human movement scientists provided the technical exercise information. We tested the information on user-friendliness among professionals. The instrument was launched in the week of World Alzheimer's day 2019. The tool has been viewed often since then. We will present development and dissemination of the tool and will discuss ongoing optimization.

Toward Synergizing Educational Research and Movement Sciences: a Dialogue on Learning as Developing Perception for Action

What could possibly be a meaningful conversation between educational researchers and movement scientists? Curiously, they have much in common. Both groups of researchers increasingly (1) appreciate the human capacity to enact perceptually guided movement as an overarching psychological model of thinking, problem-solving, and learning; (2) theorize the development of perceptual structures, including actual and imaginary percepts, as a key epistemic vehicle for solving motor-control problems; and (3) promote a view of abstract thinking as movement-grounded and movement-oriented perceptual dynamics. Probing toward theoretical synergy between these traditionally disparate fields of research, the present article is built as an interdisciplinary conversation between two researchers—of mathematics education and movement science, respectively—who become aware of their intellectual alignment, garner new insights and inspirations from each other’s work, and speculate on implications of this concordance for their fields. Future exploration into the unity of movement and cognition could enrich dialogue between manifold disciplines, with the overall goal of clarifying, developing, and integrating an interdisciplinary common foundation and framework for the benefit of education.

The accuracy of several pose estimation methods for 3D joint centre localisation

Human movement researchers are often restricted to laboratory environments and data capture techniques that are time and/or resource intensive. Markerless pose estimation algorithms show great potential to facilitate large scale movement studies ‘in the wild’, i.e., outside of the constraints imposed by marker-based motion capture. However, the accuracy of such algorithms has not yet been fully evaluated. We computed 3D joint centre locations using several pre-trained deep-learning based pose estimation methods (OpenPose, AlphaPose, DeepLabCut) and compared to marker-based motion capture. Participants performed walking, running and jumping activities while marker-based motion capture data and multi-camera high speed images (200 Hz) were captured. The pose estimation algorithms were applied to 2D image data and 3D joint centre locations were reconstructed. Pose estimation derived joint centres demonstrated systematic differences at the hip and knee (~ 30–50 mm), most likely due to mislabeling of ground truth data in the training datasets. Where systematic differences were lower, e.g., the ankle, differences of 1–15 mm were observed depending on the activity. Markerless motion capture represents a highly promising emerging technology that could free movement scientists from laboratory environments but 3D joint centre locations are not yet consistently comparable to marker-based motion capture.

Performance Evaluation of Knitted and Stitched Textile Strain Sensors.

By embedding conductive yarns in, or onto, knitted textile fabrics, simple but robust stretch sensor garments can be manufactured. In that way resistance based sensors can be fully integrated in textiles without compromising wearing comfort, stretchiness, washability, and ease of use in daily life. The many studies on such textile strain sensors that have been published in recent years show that these sensors work in principle, but closer inspection reveals that many of them still have severe practical limitations like a too narrow working range, lack of sensitivity, and undesired time-dependent and hysteresis effects. For those that intend to use this technology it is difficult to determine which manufacturing parameters, shape, stitch type, and materials to apply to realize a functional sensor for a given application. This paper therefore aims to serve as a guideline for the fashion designers, electronic engineers, textile researchers, movement scientists, and human–computer interaction specialists planning to create stretch sensor garments. The paper is limited to textile based sensors that can be constructed using commercially available conductive yarns and existing knitting and embroidery equipment. Within this subtopic, relevant literature is discussed, and a detailed quantitative comparison is provided focusing on sensor characteristics like the gauge factor, working range, and hysteresis.

Investigation of the pedaling forces in a cycling field test using the non-linear measure ML1

The study of biomechanical and physiological variables allows human movement scientists to investigate the characteristics of movement patterns in cyclists. While straightforward and well-investigated, linear measures may not adequately capture the underlying complexity of movements during cycling. Therefore, a non-linear phase-space measure (ML1) was applied to forces and heart rates of nine cyclists in a field test. The test was repeated two times with different instructions on how to alter the bike’s gearing while cycling a 12.5 km long level track. Pedaling forces and heart rates were measured. Future aim of the underlying study is the investigation of innovative control algorithms for e-bike propulsions. Force-time curves were sequenced into single cycles, linearly interpolated in the time domain, and z-score normalized. ML1 was calculated in a flowing window algorithm of 50 cycles. With fixed gearing, a contrast analysis showed that changes in terrain inclination were strongly associated with changes in the non-linear measure ML1. The calculation of Spearman’s cross correlation showed high coefficients of correlation between ML1 and delayed heart rate. The results indicate systematic changes of the pedaling movement as an adaptive response to changes in terrain inclination. Future research may utilize the findings from this study to investigate possible relationships between subjective measures of exhaustion, comfort, and discomfort with biomechanical characteristics of the pedaling movement.

Crouch gait or flexed-knee gait in cerebral palsy – Is there a difference? A systematic review

Flexed knee gait is a common gait dysfunction in individuals with bilateral spastic cerebral palsy (BSCP) and is often addressed with single event multilevel surgery (SEMLS). SEMLS has been shown to have positive short-term effects especially on sagittal knee joint kinematics with less knee flexion during stance phase. However, mid- and long-term observations are rare, and results are reported in discrete parameters or summary statistics where temporal aspects are not considered.Does the improved knee joint kinematics after patellar tendon shortening (PTS) as part of SEMLS persist in the long-term in individuals with BSCP?Data of instrumented gait analysis of twelve participants (females/males: 5/7, mean age: 15.3 ± 3.4 years) with BSCP treated with PTS as part of SEMLS were retrospectively analyzed. Participants had had follow-up gait analysis 1, 5 and 7 years or more after surgery. Three-dimensional lower extremity kinematics of walking at a self-selected speed were collected using a 12-camera motion capture system and 4 embedded force plates. One-dimensional statistical parametric mapping (SPM) was used for data analysis, permitting time point comparisons of continuous data.Time point comparison revealed no significant differences in the sagittal plane for knee joint kinematics (p > 0.05) over the tree measurement time points. Hip and ankle joint kinematics as well as normalised walking speed remained stable over the observation period.This is the first study investigating lower extremity kinematics in patients with BSCP and flexed knee gait after SEMLS with SPM. Results demonstrate that positive effects on sagittal knee joint kinematics of PTS as part of SEMLS persist up to 9 years after surgery and progressivity does not reoccur. Thus, if clinical examination indicates an operation in individuals with BSCP, improved kinematics through SEMLS persist into adulthood. With the relatively new statistical procedure SPM gait can be displayed and analysed in established joint angle curves making them easier to understand (e.g. physiotherapists, movement scientists, physicians).

Long-term follow-up after patellar tendon shortening for flexed knee gait in bilateral spastic cerebral palsy

BackgroundFlexed knee gait is a common gait dysfunction in individuals with bilateral spastic cerebral palsy (BSCP) and is often addressed with single event multilevel surgery (SEMLS). SEMLS has been shown to have positive short-term effects especially on sagittal knee joint kinematics with less knee flexion during stance phase. However, mid- and long-term observations are rare, and results are reported in discrete parameters or summary statistics where temporal aspects are not considered. Research questionDoes the improved knee joint kinematics after patellar tendon shortening (PTS) as part of SEMLS persist in the long-term in individuals with BSCP? MethodsData of instrumented gait analysis of twelve participants (females/males: 5/7, mean age: 15.3 ± 3.4 years) with BSCP treated with PTS as part of SEMLS were retrospectively analyzed. Participants had had follow-up gait analysis 1, 5 and 7 years or more after surgery. Three-dimensional lower extremity kinematics of walking at a self-selected speed were collected using a 12-camera motion capture system and 4 embedded force plates. One-dimensional statistical parametric mapping (SPM) was used for data analysis, permitting time point comparisons of continuous data. ResultsTime point comparison revealed no significant differences in the sagittal plane for knee joint kinematics (p > 0.05) over the tree measurement time points. Hip and ankle joint kinematics as well as normalised walking speed remained stable over the observation period. SignificanceThis is the first study investigating lower extremity kinematics in patients with BSCP and flexed knee gait after SEMLS with SPM. Results demonstrate that positive effects on sagittal knee joint kinematics of PTS as part of SEMLS persist up to 9 years after surgery and progressivity does not reoccur. Thus, if clinical examination indicates an operation in individuals with BSCP, improved kinematics through SEMLS persist into adulthood. With the relatively new statistical procedure SPM gait can be displayed and analysed in established joint angle curves making them easier to understand (e.g. physiotherapists, movement scientists, physicians).

Winter School on sEMG Signal Processing: An Initiative to Reduce Educational Gaps and to Promote the Engagement of Physiotherapists and Movement Scientists With Science

The application of surface electromyography (sEMG) in neurology is sometimes limited by a scientific background in the use of sEMG. Students frequently use sEMG only when developing their graduate studies. To reduce these barriers, we promoted a free Winter School on sEMG to Latin American students. The school was a 3-day event with theoretical classes and computer programming in Matlab. Lectures were delivered in Portuguese and Spanish to 50 participants. All lectures were recorded and made available on YouTube®. After the School, participants completed a written exam to receive a certificate. The written exam revealed the average effectiveness of 71 ± 20% in the comprehension of topics addressed during the school. Participants rated the School as “excellent” and considered the event as having changed their thoughts about the use of sEMG. Limited mathematical skills or background were the main barriers identified to follow the lectures and to make use of sEMG. We conclude that the Winter School had a positive impact on participant's formation, especially by showing them the importance of continuous involvement with the concepts related to sEMG to become proficient in its use. From the participant's point of view, the activity was excellent and the follow up of the school on YouTube® suggests that combining face-to-face activities followed by the online availability of lectures is a valid strategy to reinforce the learning process and to reduce barriers in the use of sEMG. Whether similar results would be achieved for a paid registration event in an economically developing region, still requires further investigation.

Improved accuracy of biomechanical motion data obtained during impacts using a time-frequency low-pass filter

Biomechanical motion data involving impacts are not adequately represented using conventional low-pass filters (CF). Time-frequency filters (TFF) are a viable alternative, but have been largely overlooked by movement scientists. We modified Georgakis and Subramaniam’s (2009) fractional Fourier filter (MFrFF) and demonstrated it performed better than CFs for obtaining lower leg accelerations during football instep kicking. The MFrFF displayed peak marker accelerations comparable to a reference accelerometer during foot-to-ball impact (peak % error = −5.0 ± 11.4%), whereas CFs severely underestimated these peaks (30–70% error). During the non-impact phases, the MFrFF performed comparably to CFs using an appropriate (12–20 Hz) cut-off frequency (RMSE = 37.3 ± 7.6 m/s2 vs. 42.1 ± 11.4 m/s2, respectively). Since accuracy of segmental kinematics is fundamental for understanding human movement, the MFrFF should be applied to a range of biomechanical impact scenarios (e.g. locomotion, landing and striking motions) to enhance the efficacy of study in these areas.

Muscle Contributions to Upper-Extremity Movement and Work From a Musculoskeletal Model of the Human Shoulder.

Musculoskeletal models enable movement scientists to examine muscle function by computing the mechanical work done by muscles during motor tasks. To estimate muscle work accurately requires a model that is physiologically plausible. Previous models of the human shoulder have coupled scapula movement to humeral movement. While coupled movement produces a stereotypical scapulohumeral rhythm, it cannot model shrugging or independent movement of the scapula and humerus. The artificial coupling of humeral elevation to scapular rotation permits muscles that cross the glenohumeral joint, such as the rotator-cuff muscles and deltoids, to do implausible work to elevate and rotate the scapula. In reality, the motion of the scapula is controlled by thoracoscapular muscles, yet the roles of these muscles in shoulder function remains unclear. To elucidate the roles of the thoracoscapular muscles, we developed a shoulder model with an accurate scapulothoracic joint and includes scapular muscles to drive its motion. We used the model to compute the work done by the thoracoscapular muscles during shrugging and arm elevation. We found that the bulk of the work done in upper-extremity tasks is performed by the largest muscles of the shoulder: trapezius, deltoids, pectoralis major, and serratus-anterior. Trapezius and serratus anterior prove to be important synergists in performing upward-rotation of the scapula. We show that the large thoracoscapular muscles do more work than glenohumeral muscles during arm-elevation tasks. The model, experimental data and simulation results are freely available on SimTK.org to enable anyone to explore our results and to perform further studies in OpenSim 4.0.

About this title - Subaqueous Mass Movements and Their Consequences: Assessing Geohazards, Environmental Implications and Economic Significance of Subaqueous Landslides

The challenges facing submarine mass movement researchers and engineers are plentiful and exciting. This book follows several high-profile submarine landslide disasters that have reached the world's attention over the past few years. For decades, researchers have been mapping the world's mass movements. Their significant impacts on the Earth by distributing sediment on phenomenal scales is undeniable. Their importance in the origins of buried resources has long been understood. Their hazard potential ranges from damaging to apocalyptic, frequently damaging local infrastructure and sometimes devastating whole coastlines. Moving beyond mapping advances, the subaqueous mass movement scientists and practitioners are now also focussed on assessing the consequences of mass movements, and the measurement and modelling of events, hazard analysis and mitigation. Many state-of-the-art examples are provided in this book, which is produced under the auspices of the United Nations Educational, Scientific and Cultural Organisation Program S4SLIDE (Significance of Modern and Ancient Submarine Slope LandSLIDEs).

Systematic Review and Meta-Analysis on Proximal-to-Distal Sequencing in Team Handball: Prospects for Talent Detection?

The proximal-to-distal sequence has previously been discussed in the light of performance and injury prevention. Sports biomechanics literature in general, and in team handball in specific, has claimed to be of importance to inform coaches on what constitutes a ‘good’ technical performance. However, hitherto no prospective studies exist on how this information may be used and this may in part be due to the general small sample sizes. We therefore performed a systematic review and meta-analysis of proximal-to-distal sequencing in team handball throwing motions. A total of fourteen articles were included in the systematic review. Meta-analyses were performed for the timing of maximal angles and angular velocities as well as initiation of joint angular velocities in the penalty throw, the standing throw with run-up and the jump shot of experienced team handball players. For the initiation of joint angular velocities, the overall sequence was estimated to start with pelvis rotation, followed by trunk rotation, trunk flexion, shoulder internal rotation and elbow extension. For maximal velocities, the sequence started with pelvis rotation, followed by trunk rotation, trunk flexion, elbow extension, and shoulder internal rotation (post ball release). The obtained results were discussed in the light of talent identification purposes. Limitations to individual study methodology and of the present meta-analysis were also discussed. Much more research will be necessary, but at the very least, this review can provide a starting point for evidence-based discussions between movement scientists and team handball coaches to include proximal-to-distal sequencing as a measure of coordination to gauge early onset of talent.

A stepwise science-industry collaboration to optimize the calculation of energy expenditure during walking and running with a consumer-based activity device

Physical activity (PA) and sedentary behavior (SB) have important implications for health benefits. A growing number of people use consumer available wearables such as activity trackers, which claim to objectively monitor PA and SB in free-living conditions. These devices could provide essential information to understand the influence of behavior on health. This understanding assumes that available consumer products correctly monitor PA in the everyday life. A general approach in science is to validate such activity devices in a controlled environment. The classical procedure to investigate criterion validity is to examine new devices based on the gold standard. To our knowledge, the resulting validation data are not often analyzed and shared with manufacturers to further develop and improve the activity device. The current study can be seen as a validation study to check the criterion validity of a consumer-level activity device. The novelty of this study was the application of a stepwise approach to optimize the calculations of a consumer available activity device (i.e., Activ8; www.activ8all.com/product/activ8-professional-activity-monitor/) for estimating energy expenditure (EE) in walking and running.Forty adults (27 males and 13 females) participated in three substudies. Each substudy consisted of several walking and running activities in which EE was simultaneously measured with indirect calorimetry (as reference value) and the Activ8 activity device. EE values at each walking and running speed were compared to identify the accuracy of the Activ8 device. After completion of the first and second substudies, the results were shared and discussed with the manufacturer of Activ8. Next, the calculations for EE were adapted to the indirect calorimetry values to improve accuracy. In the second and third substudies, the modifications were tested, and results were used to further optimize the calculation of EE.The results of this study show an improved correlation between EE measured by indirect calorimetry and the Activ8 activity device (R2 from 0.91 to 0.95); a decrease in differences between substudy A and substudy B considering EE measured (indirect calorimetry) and calculated (Activ8 calculation) was observed. The second modification in the calculation showed a further increase in correlation (R2 from 0.95 to 0.97) between the measured and calculated EE; however, the absolute difference between the two values increased. The results from a validation study are valuable to use for further adaptation of accelerometer device calculations. A stepwise science-industry collaboration can improve the calculation accuracy and may be a practical approach for validation studies in which human movement scientists and technology manufacturers work together to successfully improve the validity and accuracy of consumer-based activity devices.

Single reach plans in dorsal premotor cortex during a two-target task

In many situations, we are faced with multiple potential actions, but must wait for more information before knowing which to perform. Movement scientists have long asked whether in these delayed-response situations the brain plans both potential movements simultaneously, or if it simply chooses one and then switches later if necessary. To answer this question, we used simultaneously recorded activity from populations of neurons in macaque dorsal premotor cortex to track moment-by-moment deliberation between two potential reach targets. We found that the neural activity only ever indicated a single-reach plan (with some targets favored more than others), and that initial plans often predicted the monkeys’ behavior on both Free-Choice trials and incorrect Cued trials. Our results suggest that premotor cortex plans only one option at a time, and that decisions are strongly influenced by the initial response to the available set of movement options.

Inertial Measurement Units for Clinical Movement Analysis: Reliability and Concurrent Validity.

The aim of this study was to investigate the reliability and concurrent validity of a commercially available Xsens MVN BIOMECH inertial-sensor-based motion capture system during clinically relevant functional activities. A clinician with no prior experience of motion capture technologies and an experienced clinical movement scientist each assessed 26 healthy participants within each of two sessions using a camera-based motion capture system and the MVN BIOMECH system. Participants performed overground walking, squatting, and jumping. Sessions were separated by 4 ± 3 days. Reliability was evaluated using intraclass correlation coefficient and standard error of measurement, and validity was evaluated using the coefficient of multiple correlation and the linear fit method. Day-to-day reliability was generally fair-to-excellent in all three planes for hip, knee, and ankle joint angles in all three tasks. Within-day (between-rater) reliability was fair-to-excellent in all three planes during walking and squatting, and poor-to-high during jumping. Validity was excellent in the sagittal plane for hip, knee, and ankle joint angles in all three tasks and acceptable in frontal and transverse planes in squat and jump activity across joints. Our results suggest that the MVN BIOMECH system can be used by a clinician to quantify lower-limb joint angles in clinically relevant movements.

Effects of scaling task constraints on emergent behaviours in children's racquet sports performance

Manipulating task constraints by scaling key features like space and equipment is considered an effective method for enhancing performance development and refining movement patterns in sport. Despite this, it is currently unclear whether scaled manipulation of task constraints would impact emergent movement behaviours in young children, affording learners opportunities to develop relevant skills. Here, we sought to investigate how scaling task constraints during 8 weeks of mini tennis training shaped backhand stroke development. Two groups, control (n = 8, age = 7.2 ± 0.6 years) and experimental (n = 8, age 7.4 ± 0.4 years), underwent practice using constraints-based manipulations, with a specific field of affordances designed for backhand strokes as the experimental treatment. To evaluate intervention effects, pre- and post-test match-play characteristics (e.g. forehand and backhand percentage strokes) and measures from a tennis-specific skills test (e.g. forehand and backhand technical proficiency), were evaluated. Post intervention, the experimental group performed a greater percentage of backhand strokes out of total number of shots played (46.7 ± 3.3%). There was also a significantly greater percentage of backhand winners out of total backhand strokes observed (5.5 ± 3.0%), compared to the control group during match-play (backhands = 22.4 ± 6.5%; backhand winners = 1.0 ± 3.6%). The experimental group also demonstrated improvements in forehand and backhand technical proficiency and the ability to maintain a rally with a coach, compared to the control group. In conclusion, scaled manipulations implemented here elicited more functional performance behaviours than standard Mini Tennis Red constraints. Results suggested how human movement scientists may scale task constraint manipulations to augment young athletes' performance development.

Bernstein’s levels of movement construction: A contemporary perspective

Explanation of how goal-directed movements are made manifest is the ultimate aim of the field classically referred to as “motor control”. Essential to the sought-after explanation is comprehension of the supporting functional architecture. Seven decades ago, the Russian physiologist and movement scientist Nikolai A. Bernstein proposed a hierarchical model to explain the construction of movements. In his model, the levels of the hierarchy share a common language (i.e., they are commensurate) and perform complementing functions to bring about dexterous movements. The science of the control and coordination of movement in the phylum Craniata has made considerable progress in the intervening seven decades. The contemporary body of knowledge about each of Bernstein’s hypothesized functional levels is both more detailed and more sophisticated. A natural consequence of this progress, however, is the relatively independent theoretical development of a given level from the other levels. In this essay, we revisit each level of Bernstein’s hierarchy from the joint perspectives of (a) the ecological approach to perception-action and (b) dynamical systems theory. We review a substantial and relevant body of literature produced in different areas of study that are accommodated by this ecological-dynamical version of Bernstein’s levels. Implications for the control and coordination of movement and the challenges to producing a unified theory are discussed.