This article critically reviews kinematic measures of prospective motor control. Prospective motor control, the ability to anticipatorily adjust movements with respect to task demands and action goals, is an important process involved in action planning. In manual object manipulation tasks, prospective motor control has been studied in various ways, mainly using motion tracking. For this matter, it is crucial to pinpoint the early part of the movement that purely reflects prospective (feed-forward) processes, but not feedback influences from the unfolding movement. One way of defining this period is to rely on a fixed time criterion; another is to base it flexibly on the inherent structure of each movement itself. Velocity—as one key characteristic of human movement—offers such a possibility and describes the structure of movements in a meaningful way. Here, I argue for the latter way of investigating prospective motor control by applying the measure of peak velocity of the first movement unit. I further discuss movement units and their significance in motor development of infants and contrast the introduced measure with other measures related to peak velocity and duration.
Janna M. Gottwald
Elaine Leonezi Guimarães, Andréa Baraldi Cunha, Daniele de Almeida Soares and Eloisa Tudella
The aim of this systematic literature review was to examine and discuss studies that investigated reaching in preterm infants during the first year of life. Databases were searched using keywords such as reaching, grasping, preterm, and premature, in addition to specific terms from the Medical Subject Headings (MeSH) (motor skills, infant, movement, premature birth, hands) regardless of year of publication. One hundred thirty-five studies were identified, 9 of which were selected. The results showed that preterm infants adopt strategies (bimanual reaches and reaches with less rectilinear trajectories toward an object in motion, reaches with semi-open and open hand, reaches at lower speeds, with increased movement units, and variable postural muscle activity) compared with full-term infants. However, the results on how intrinsic factors (e.g., prematurity) and extrinsic factors (e.g., body position, physical properties of the object) influence early reaching are still limited.
Live S. Luteberget and Matt Spencer
International women’s team handball is a physically demanding sport and is intermittent in nature. The aim of the study was to profile high-intensity events (HIEs) in international women’s team handball matches with regard to playing positions.
Twenty female national-team handball players were equipped with inertial movement units (OptimEye S5, Catapult Sports, Australia) in 9 official international matches. Players were categorized in 4 different playing positions: backs, wings, pivots, and goalkeepers (GKs). PlayerLoad™, accelerations (Acc), changes of direction (CoD), decelerations (Dec), and the sum of the latter 3, HIEs, were extracted from raw-data files using the manufacturer’s software. All Acc, Dec, CoD, and HIEs >2.5 m/s were included. Data were log-transformed and differences were standardized for interpretation of magnitudes and reported with effect-size statistics.
Mean numbers of events were 0.7 ± 0.4 Acc/min, 2.3 ± 0.9 Dec/min, and 1.0 ± 0.4 CoD/min. Substantial differences between playing positions, ranging from small to very large, were found in the 3 parameters. Backs showed a most likely greater frequency for HIE/min (5.0 ± 1.1 HIE/min) than all other playing positions. Differences between playing positions were also apparent in PlayerLoad/min.
HIEs in international women’s team handball are position specific, and the overall intensity depends on the positional role within a team. Specific HIE and intensity profiles from match play provide useful information for a better understanding of the overall game demands and for each playing position.
Daniela Corbetta, Rebecca F. Wiener, Sabrina L. Thurman and Emalie McMahon
durations were becoming shorter as well. The number of changes in trajectory corrections also diminished as a function of age and was progressively replaced by an increasingly longer approach phase. By the time infants were 36 weeks of age, the approach phase, which corresponded to the first movement unit
supine. Touch locations and durations (on the body, floor, or in the air) were coded from the videos and movement speed and movement units were computed from the kinematics. Preliminary analyses of two infants, in two conditions (baseline & toys in view), over every other week revealed marked individual