Evaluating the energetics of entrainment in a human-machine coupled oscillator system.

During locomotion, humans sometimes entrain (i.e. synchronize) their steps to external oscillations: e.

Do infants avoid a traversable slope leading into deep water?

Ramps used to access swimming pools are designed with a shallow slope that affords easy access for all including infants. Locomotor experience has been linked to infants' avoidance of falling into the water from drop-offs; however, the effect of such experience on infants' behavior when a slope is offered to access the water has not been addressed. Forty-three crawling infants (M  = 10.

Experienced crawlers avoid real and water drop-offs, even when they are walking.

Crawling experience was recently linked to crawling and walking infants' avoidance of falling on real and water cliffs, whereas walking experience had no effect on walkers' avoidance behavior (Burnay et al., 2021). In the current study, the behavior of 25 infants was analyzed on the Real Cliff/Water Cliff apparatus using a longitudinal study design.

The effect of specific locomotor experiences on infants' avoidance behaviour on real and water cliffs.

Infants' avoidance of drop-offs has been described as an affordance learning that is not transferable between different locomotor postures. In addition, there is evidence that infants perceive and act similarly around real and water cliffs. This cross-sectional study investigated the effects of specific locomotor experiences on infants' avoidance behaviour using the Real Cliff/Water Cliff paradigm.

Form in the context of function: Fundamentals of an energy effective striding walk, the role of the plantigrade foot and its expected size.

What morphological and functional factors allow for the unique and characteristic upright striding walk of the hominin lineage? Predictive models of locomotion that arise from considering mechanisms of energy loss indicate that collision-like losses at the transition between stance limbs are important determinants of bipedal gait. Theoretical predictions argue that these collisional losses can be reduced by having "functional extra legs" which are physically the heel and the toe part of a single anatomical foot. The ideal spacing for these "functional legs" are up to a quarter of a stride length, depending on the model employed.

Load carrying with flexible bamboo poles: optimization of a coupled oscillator system.

In Asia, flexible bamboo poles are routinely used to carry substantial loads on the shoulder. Various advantages have been attributed to this load-carrying strategy (e.g.

'Mini-interval gait' switching: understanding the positive implications of a novel training regime.

The neuromechanical reorganization required to change gaits imposes an energetic cost 75% greater than either a walking or running step at the same speed. By combining walking and running with the requisite gait switching transition steps, an exercise protocol can be generated with virtually any desired metabolic output even at relatively slow treadmill speed. Gait switching increases metabolic demand through discrete events, which can be tolerated more easily by individuals recovering from health problems, just as interval training allows greater work production for healthy individuals.

The Landscape of Movement Control in Locomotion: Cost, Strategy, and Solution.

Features of gait are determined at multiple levels, from the selection of the gait itself (e.g., walk or run) through the specific parameters utilized (stride length, frequency, etc.

Determinants of optimal leg use strategy: horizontal to vertical transition in the parkour wall climb.

This study examined the mechanics of the horizontal to vertical transition used by parkour athletes in wall climbing. We used this task as an alternative to normal running - where the functional options differ substantially - exposing the movement control priorities required to successfully complete the task. Ground reaction forces were measured in several expert parkour athletes and centre of mass trajectory was calculated from force plates embedded in the ground and the wall.

Properties of traditional bamboo carrying poles have implications for user interactions.

Compliant bamboo poles have long been used for load carriage in Asian cultures. Although this custom differs from Western conventions of rigid body attachments (e.g.

Affordance Boundaries Are Defined by Dynamic Capabilities of Parkour Athletes in Dropping from Various Heights.

Available behaviors are determined by the fit between features of the individual and reciprocal features of the environment. Beyond some critical boundary certain behaviors become impossible causing sudden transitions from one movement pattern to another. Parkour athletes have developed multiple movement patterns to deal with their momentum during landing.

Watch Where You're Going? Interferer Velocity and Visual Behavior Predicts Avoidance Strategy During Pedestrian Encounters.

Pedestrians can avoid collisions with other pedestrians by modifying some combination of their velocity and their path. The authors investigated how path constraints (constrained or unconstrained), interferer velocity (slow or fast), and vision (looking or not looking; time spent looking at the interferer) influenced collision avoidance to an oblivious interferer walking on a perpendicular path. Ten participants walked 6 m to either a point or line target on either a constrained or unconstrained path while wearing an eye-tracking device and avoiding an oblivious interferer that walked at 2 speeds.

Children's perception of action boundaries and how it affects their climbing behavior.

There are some concerns that children today may be less calibrated to their action capabilities because of the "risk-free" culture that has proliferated during recent decades. This study investigated the extent to which judgments of reaching affordances presented in different directions (i.e.

Role of route previewing strategies on climbing fluency and exploratory movements.

This study examined the role of route previewing strategies on climbing fluency and on exploratory movements of the limbs, in order to understand whether previewing helps people to perceive and to realize affordances. Eight inexperienced and ten experienced climbers previewed a 10 m high route of 5b difficulty on French scale, then climbed it with a top-rope as fluently as possible. Gaze behavior was collected from an eye tracking system during the preview and allowed us to determine the number of times they scanned the route, and which of four route previewing strategies (fragmentary, ascending, zigzagging, and sequence-of-blocks) they used.

The goal of locomotion: Separating the fundamental task from the mechanisms that accomplish it.

Human locomotion has been well described but is still not well understood. This is largely true because the observable aspects of locomotion-neuromuscular activity that generates forces and motions-relate to both the task solution and the problem being solved. Identifying the fundamental task achieved in locomotion makes it possible to critically evaluate the motor control strategy used to accomplish the task goal.

A New Qualitative Typology to Classify Treading Water Movement Patterns.

This study proposes a new qualitative typology that can be used to classify learners treading water into different skill-based categories. To establish the typology, 38 participants were videotaped while treading water and their movement patterns were qualitatively analyzed by two experienced biomechanists. 13 sport science students were then asked to classify eight of the original participants after watching a brief tutorial video about how to use the typology.

Interacting Factors Associated with Adult Male Drowning in New Zealand.

Objectives: i) to identify factors that contribute to the global trend of the higher incidence of male drowning relative to females, and; ii) to explore relationships between such factors from mortality data in New Zealand.

Methods: Drownings from 1983 to 2012 were examined for: Age, Ethnicity, Site, Activity, Buoyancy and Alcohol. Conditional frequency tables presented as mosaic plots were used to assess the interactions of these factors.

Integrative physiological and behavioural responses to sudden cold-water immersion are similar in skilled and less-skilled swimmers.

We examined the initial physiological responses and subsequent capacity to swim following cold-water immersion. An ecologically-valid model was used whereby immersion was sudden (<2s) and participants had to actively remain afloat. Participants (15 skilled swimmers, 17 less-skilled swimmers) undertook four experimental test sessions: a physiological test and a swimming test in both cold (10°C) water and temperate (27°C) water in a swimming flume (temperature order counter-balanced).

Responses to sudden cold-water immersion in inexperienced swimmers following training.

Background: When suddenly immersed in cold water, humans typically exhibit the cold shock response, although training can attenuate hyperventilation. This study extends previous findings by considering the influence of physical activity to maintain buoyancy and subsequent swimming performance.

Methods: Six inexperienced swimmers (three men and three women; mean age 22.

Effects of bicycle saddle height on knee injury risk and cycling performance.

Incorrect bicycle configuration may predispose athletes to injury and reduce their cycling performance. There is disagreement within scientific and coaching communities regarding optimal configuration of bicycles for athletes. This review summarizes literature on methods for determining bicycle saddle height and the effects of bicycle saddle height on measures of cycling performance and lower limb injury risk.

Movement variability and muscle activity relative to center of pressure during unipedal stance on solid and compliant surfaces.

Compliant surfaces are used to challenge postural stability, but assessments are frequently limited to summary measures of center of pressure that do not provide insights into the temporal dynamics of motor coordination. Here, we measured center-of-pressure changes on three surfaces (solid, foam, and air-filled disc) and quantified the relative timing of changes in joint angles and muscle activity with respect to center-of-pressure changes. Nine active male subjects (20-30 years old) performed ten 30-s trials of unipedal stance on each of the three surfaces.

Gaze behavior of spotters during an air-to-ground search.

Objective: This study was designed to develop methods for evaluating the gaze behaviors of spotters during air-to-ground search and to compare field-derived measures with previous lab results. Secondary aims were to assess adherence to a prescribed scan path, evaluate search effectiveness, and determine the predictors of task success.

Background: Crashed aircraft must be located quickly to minimize loss of life, often requiring visual search from the air.