Determining V̇O in competitive swimmers: Comparing the validity and reliability of cycling, arm cranking, ergometer swimming, and tethered swimming.

Objectives: This study aims to identify the optimal method for determining V̇O in competitive swimmers in terms of validity and test-retest reliability.

Design: Controlled experiment.

Methods: Twenty competitive swimmers performed four maximal incremental exercise tests: cycling, arm cranking, ergometer swimming, and tethered swimming.

Exploring running styles in the field through cadence and duty factor modulation.

According to the dual-axis model, running styles can be defined by cadence and duty factor, variables that have been associated with running performance, economy and injury risk. To guide runners in exploring different running styles, effective instructions to modulate cadence and duty factor are needed. Such instructions have been established for treadmill running, but not for overground running, during which speed can be varied.

Perceived cognitive fatigue has only marginal effects on static balance control in healthy young adults.

We examined the influence of perceived cognitive fatigue on static balance control in healthy young adults to gain greater clarity about this issue than provided in previous research. Based on the prevailing assumption in pertinent literature, we hypothesized that the influence of cognitive fatigue on balance control depends on the attentional effort required by the balance tasks being performed. To test this hypothesis, 44 young adults (24 women and 20 men) were alternately assigned to either the experimental group that was cognitively fatigued (using the 16-min TloadDback-task with individualized settings) or the control group (who watched a documentary).

How intrinsically motivating are swimming instructors/lessons in the Netherlands? An observational study through the lens of self-determination theory.

Background: It is desirable that (more) children continue swimming after having completed their swimming lessons to preserve their swimming skills and water safety, and as part of an active, healthy lifestyle. This may be encouraged by stirring children's intrinsic motivation for swimming during swimming lessons. However, it is currently unknown how intrinsically motivating swimming lessons are in Western countries.

A Muscle Load Feedback Application for Strength Training: A Proof-of-Concept Study.

Muscle overload injuries in strength training might be prevented by providing personalized feedback about muscle load during a workout. In the present study, a new muscle load feedback application, which monitors and visualizes the loading of specific muscle groups, was developed in collaboration with the fitness company Gymstory. The aim of the present study was to examine the effectiveness of this feedback application in managing muscle load balance, muscle load level, and muscle soreness, and to evaluate how its actual use was experienced.

Body-and movement-oriented interventions for posttraumatic stress disorder: An updated systematic review and meta-analysis.

This study is an update of the meta-analysis we published in 2019 on the effectiveness of body- and movement-oriented interventions (BMOIs) for adults with posttraumatic stress disorder (PTSD) in decreasing PTSD symptoms and secondary outcomes of depressive symptoms, sleep disturbance, and interoceptive awareness. Search terms for BMOIs and PTSD were combined to identify eligible studies in four bibliographical databases. Articles were selected if they included adult participants with a primary diagnosis of PTSD, included BMOI as one of the investigated therapies, were designed as a comparative outcome trial with any control condition, and involved a standardized outcome measure for PTSD symptom severity.

Running-style modulation: Effects of stance-time and flight-time instructions on duty factor and cadence.

Background: The duty factor (reflecting the ratio of stance to flight time) is an important variable related to running performance, economy, and injury risk. According to the dual-axis model, the duty factor and the cadence are sufficient to describe an individual's running style at a certain speed. To test this model, one should be able to modulate both variables independently.

Implications of the choice of distance-based measures in assessing and investigating tumble turn performance.

Although the tumble turn in swimming has been studied extensively, no consensus exists about which measure is best suited to capture its performance. The aim of this study was to better understand the implications of choosing a particular distance-based performance measure for assessing and investigating tumble turn performance in freestyle swimming. To this end, a large set of retrospective turn data consisting of 2,813 turns performed by 160 swimmers was analyzed statistically in three steps.

Improving tumble turn performance in swimming-the impact of wall contact time and tuck index.

Race time can be shortened by improving turn performance in competitive swimming, but this requires insight into the optimal turn technique. The aim of the present study was to examine the effect of Wall Contact Time (WCT) and Tuck Index on tumble turn performance and their interrelations by experimentally manipulating both variables, which has not been done in previous research. Eighteen Dutch national level swimmers (FINA points 552 ± 122) performed tumble turns with three different WCTs (shorter, preferred, longer) and three different Tuck Indices (higher, preferred, lower), which were recorded by four underwater cameras and a wall-mounted force plate.

Sprint Performance in Arms-Only Front Crawl Swimming Is Strongly Associated With the Power-To-Drag Ratio.

To date, optimal propulsion in swimming has been studied predominantly using physical or computational models of the arm and seldom during real-life swimming. In the present study we examined the contributions of selected power, technique and anthropometric measures on sprint performance during arms-only front crawl swimming. To this end, 25 male adult competitive swimmers, equipped with markers on their arms and hands, performed four 25-m sprint trials, which were recorded on video.

Reliability and Validity of Running Cadence and Stance Time Derived from Instrumented Wireless Earbuds.

Instrumented earbuds equipped with accelerometers were developed in response to limitations of currently used running wearables regarding sensor location and feedback delivery. The aim of this study was to assess test-retest reliability, face validity and concurrent validity for cadence and stance time in running. Participants wore an instrumented earbud (new method) while running on a treadmill with embedded force-plates (well-established method).

Effects of acoustically paced cadence modulation on impact forces in running.

Background: Increasing cadence in running has been advocated as a means to improve performance and reduce impact forces. Although acoustic pacing can be used for this purpose, it might by itself lead to an increased impact force, which would counteract the decrease in impact force that is being pursued by increasing the cadence with acoustic pacing and thus have a counterproductive effect.

Research Question: What are the effects of acoustic pacing and cadence on peak impact force and loading rate during running?

Methods: Unpublished data from a previous study, in which 16 participants ran on an instrumented treadmill with various forms of acoustic pacing, were analyzed to address the research question.

The biomechanics of running and running styles: a synthesis.

Running movements are parametrised using a wide variety of devices. Misleading interpretations can be avoided if the interdependencies and redundancies between biomechanical parameters are taken into account. In this synthetic review, commonly measured running parameters are discussed in relation to each other, culminating in a concise, yet comprehensive description of the full spectrum of running styles.

Predicting dive start performance from kinematic variables at water entry in (sub-)elite swimmers.

The dive start is an important component of competitive swimming, especially at shorter race distances. Previous research has suggested that start performance depends on kinematic variables pertaining to the swimmer at water entry, notably the distance from the block, the horizontal velocity of the centre of mass and the angle between body and water surface. However, the combined and relative contributions of these variables to start performance remain to be determined.

A Re-Appraisal of the Effect of Amplitude on the Stability of Interlimb Coordination Based on Tightened Normalization Procedures.

The stability of rhythmic interlimb coordination is governed by the coupling between limb movements. While it is amply documented how coordinative performance depends on movement frequency, theoretical considerations and recent empirical findings suggest that interlimb coupling (and hence coordinative stability) is actually mediated more by movement amplitude. Here, we present the results of a reanalysis of the data of Post, Peper, and Beek (2000), which were collected in an experiment aimed at teasing apart the effects of frequency and amplitude on coordinative stability of both steady-state and perturbed in-phase and antiphase interlimb coordination.

Cadence Modulation in Walking and Running: Pacing Steps or Strides?

A change in cadence during walking or running might be indicated for a variety of reasons, among which mobility improvement and injury prevention. In a within-subject study design, we examined whether walking or running cadences are modulated best by means of step-based or stride-based auditory pacing. Sixteen experienced runners walked and ran on a treadmill while synchronizing with step-based and stride-based pacing at slow, preferred and fast pacing frequencies in synchronization-perturbation and synchronization-continuation conditions.

Avoiding 3D Obstacles in Mixed Reality: Does It Differ from Negotiating Real Obstacles?

Mixed-reality technologies are evolving rapidly, allowing for gradually more realistic interaction with digital content while moving freely in real-world environments. In this study, we examined the suitability of the Microsoft HoloLens mixed-reality headset for creating locomotor interactions in real-world environments enriched with 3D holographic obstacles. In Experiment 1, we compared the obstacle-avoidance maneuvers of 12 participants stepping over either real or holographic obstacles of different heights and depths.

Body- and Movement-Oriented Interventions for Posttraumatic Stress Disorder: A Systematic Review and Meta-Analysis.

To assess the efficacy of body- and movement-oriented interventions (BMOIs) in traumatized adults with posttraumatic stress disorder (PTSD), we conducted a systematic review and meta-analysis of pertinent literature. Four bibliographical databases (PsycINFO, Ovid MEDLINE(R), EMBASE, and the Cochrane Central Register of Controlled Trials) were searched using keywords and text words for trials on BMOIs addressing PTSD. The search included articles published between October 2005 and August 2017.

Clinical characteristics of individuals with intellectual disability who have experienced sexual abuse. An overview of the literature.

Background: Sexual abuse in individuals with average IQ or above is associated with a wide range of behavioural, psychological and body-related characteristics. It is unknown whether individuals with intellectual disability (ID) and a history of sexual abuse suffer from similar clinical characteristics.

Objective: The aim of the review is to provide an overview of the literature on the clinical characteristics of individuals with ID who have experienced sexual abuse.

Differences in swimming smoothness between elite and non-elite swimmers.

The aim of the study was to investigate whether jerk cost (JC) can discriminate between swimming levels. Nine elite and nine non-elite swimmers swam a 50-m front-crawl sprint wearing a 3D accelerometer on their back between the inferior angles of the scapulae. Lap times and JC were calculated from the acceleration signal and compared between groups and between swimmers within a group.

Automatized, Standardized, and Patient-Tailored Progressive Walking-Adaptability Training: A Proof-of-Concept Study.

Background: Treadmill training augmented with visual images projected on the belt's surface can help improve walking adaptability. Moreover, patient-tailored automatization and standardization can increase the feasibility of walking-adaptability therapy. We developed C-Gait, a treadmill protocol consisting of a baseline walking-adaptability assessment involving 7 putatively distinct walking-adaptability tasks and a decision algorithm, to automatically update training content and execution parameters to a patients' performance and perceived challenge.

Real-Time Feedback on Mechanical Power Output: Facilitating Crew Rowers' Compliance With Prescribed Training Intensity.

Purpose: Athletes require feedback in order to comply with prescribed training programs designed to optimize their performance. In rowing, current feedback parameters on intensity are inaccurate. Mechanical power output is a suitable objective measure for training intensity, but due to movement restrictions related to crew rowing, it is uncertain whether crew rowers are able to adjust their intensity based on power-output feedback.

Dual-Task Walking in Challenging Environments in People with Stroke: Cognitive-Motor Interference and Task Prioritization.

Cognitive-motor interference may contribute to the risk of falling in people with stroke, as may be the associated phenomenon of inappropriate task prioritization. Examining dual-task walking could provide valuable insights as to how to best evaluate and treat walking in people with stroke. This study aimed to examine the effect of different walking environments on cognitive-motor interference and task prioritization in dual-task walking in people with stroke.

Evidence for Sequential Performance Effects in Professional Darts.

The study of sequential effects in aiming tasks might shed light on the organization of repetitive motor performances over time. To date, investigations of such effects in sports have been limited and yielded mixed results. Given the relatively short time intervals between successive attempts, and the absence of defensive interventions, dart throwing provides a potentially fruitful testing ground for examining the presence of sequential performance effects in the motor domain.

Mechanical power output in rowing should not be determined from oar forces and oar motion alone.

Mechanical power output is a key performance-determining variable in many cyclic sports. In rowing, instantaneous power output is commonly determined as the dot product of handle force moment and oar angular velocity. The aim of this study was to show that this commonly used proxy is theoretically flawed and to provide an indication of the magnitude of the error.