Go big or spin fast? Biomechanical deterministic models for snowboard freestyle tricks performed on a trampoline.

In snowboard freestyle, rotation is the key indicator of trick difficulty, encouraging riders to perform tricks with more rotation. In many cases, snowboarders learn and practice tricks using training tools such as trampolins and/or landingbags before they transfer this tricks on-snow. It has not yet been scientifically investigated which movement parameters are primarily responsible for the acquisistion of increasingly difficult cork tricks.

The Influence of Two Teaching Approaches on Foot Loading in Skiing Beginners-A Comparative Study.

(1) Background: Alpine skiing, with its long history, has experienced numerous innovations and developments on all levels ranging from technology to fashion over the past 120 years. However, teaching approaches for beginners remained quite consistent for many decades and are mainly grounded in experience. The One-Ski-Method (OSM) is an alternative approach to the predominant snowplow (SP) method with the strategy to initially experience and acquire the elementary positions and actions on one ski in order to subsequently transfer these to two skis.

Is a cork a legal shortcut? - A comparison of the measured and assumed amount of rotation in freestyle tricks.

In snowboard freestyle disciplines, the amount of rotation is commonly determined as the sum of rotations around all board axes and is the most important indicator of the trick difficulty across all snowboard freestyle disciplines. Based on the type of rotation, tricks can be classified as flatspins, corks and flips. It is not yet known whether the type of rotation of a trick can influence the actual amount of rotation.

Individualized Technique Feedback for Instant Technique Improvements and Knee Abduction Moment Reductions - A New Approach for 'Sidestepping' ACL Injuries?

Background: Sidestep cutting technique is highly individual and has been shown to influence knee joint loading. However, studies assessing whether individualized technique feedback improves technique and ACL injury-relevant knee joint loads instantly in a sport-specific task are lacking.

Purpose: To determine the instant effects of individualized augmented technique feedback and instructions on technique and the peak external knee abduction moment (pKAM) in a handball-specific sidestep cut.

Lateral Ankle Joint Injuries in Indoor and Court Sports: A Systematic Video Analysis of 445 Nonconsecutive Case Series.

Background: Lateral ankle sprains are one of the most common injuries in indoor and court sports. Self-reports and case studies have indicated that these injuries occur via both contact and noncontact injury mechanisms typically because of excessive inversion in combination with plantarflexion and adduction of the foot. Video-based documentation of the injury mechanism exists, but the number of cases reported in the literature is limited.

How Approaching Angle, Bottleneck Width and Walking Speed Affect the Use of a Bottleneck by Individuals.

Understanding pedestrian dynamics at bottlenecks and how pedestrians interact with their environment-particularly how they use and move in the space available to them-is of safety importance, since bottlenecks are a key point for pedestrian flow. We performed a series of experiments in which participants walked through a bottleneck individually for varying combinations of approaching angle, bottleneck width and walking speed, to investigate the dependence of the movement on safety-relevant influencing factors. Trajectories as well as 3D motion data were recorded for every participant.

A biomechanical report of an acute lateral ankle sprain during a handball-specific cutting movement.

Biomechanical measurements of accidental ankle sprain injuries are rare but make important contributions to a more detailed understanding of the injury mechanism. In this case study, we present the kinematics and kinetics of a lateral ankle sprain of a female athlete performing handball-specific fake-and-cut manoeuvres. Three-dimensional kinematics and kinetics were recorded and six previously performed trials were used as reference.

Unanticipated fake-and-cut maneuvers do not increase knee abduction moments in sport-specific tasks: Implication for ACL injury prevention and risk screening.

Non-contact anterior cruciate ligament injuries typically occur during cutting maneuvers and are associated with high peak knee abduction moments (KAM) within early stance. To screen athletes for injury risk or quantify the efficacy of prevention programs, it may be necessary to design tasks that mimic game situations. Thus, this study compared KAMs and ranking consistency of female handball players in three sport-specific fake-and-cut tasks of increasing complexity.

Futsal playing surface characteristics significantly affect perceived traction and change of direction performance among experienced futsal players.

We aimed to clarify the effect of different futsal playing surface structural properties on the resultant change of direction (COD) performance, perceived traction and frictional properties. Twenty experienced male university soccer players performed a COD slalom-course test and perceived traction evaluation on three different types of playing surfaces (area-elastic: AE, point-elastic no.1: PE1 and point-elastic no.

Athletes with high knee abduction moments show increased vertical center of mass excursions and knee valgus angles across sport-specific fake-and-cut tasks of different complexities.

Young female handball players represent a high-risk population for anterior cruciate ligament (ACL) injuries. While the external knee abduction moment (KAM) is known to be a risk factor, it is unclear how cutting technique affects KAMs in sport-specific cutting maneuvers. Further, the effect of added game specificity (e.

Reliability of Running Economy Measurements: Influence of Shoe Familiarisation.

The purpose was to investigate differences in reliability of running economy measurements between familiar and unfamiliar shoes. Thirty-seven runners were included who all ran in familiar and unfamiliar running shoes while running economy was measured at steady state using a treadmill. Each participant was tested on two different visits (three sessions in total), with two trials in each of the three shoe conditions completed at each visit.

The effect of footwear outsole material on slip resistance on dry and contaminated surfaces with geometrically controlled outsoles.

Previous studies have compared slip resistance of commercially available footwear, however, often lacking the ability to isolate factors such as material and surface properties, or/and geometry. The aim of this study was to compare slip resistance of geometrically identical shoes with varying outsole materials. Three left Ecco Xpedition III shoes were constructed out of three different outsole materials: polyurethane (PU), thermoplastic polyurethane (TPU) and vulcanised rubber (RU).

Carbon Plate Shoes Improve Metabolic Power and Performance in Recreational Runners.

This study compared metabolic power (MP) and time trial (TT) running performance between Adidas Adizero Adios (AAA) and Nike VaporFly 4% (NVP). Thirty-seven runners completed three laboratory sessions and two field sessions (n=30). After familiarization (visit 1), participants completed eight 6-min treadmill running bouts (four with each shoe, counterbalanced) at their preferred pace, and MP was assessed using indirect calorimetry (visits 2 and 3).

The influence of shaft stiffness on joint kinematics and kinetics during hiking.

Hiking boots provide an interface for walking in challenging environments, typically equipped with a shaft to provide ankle joint stability in rough terrains. Currently it is unclear if the ankle joint is stabilized to an extent that protects against ankle injuries, and if so, to what degree this added ankle stability sacrifices ankle mobility and hence decreases efficient gait propulsion. The aim of the present study was to compare the effect of shaft construction and stiffness on lower extremity kinematics and kinetics during level and step-down walking to simulate hiking conditions.

Shoulder function after constraint-induced movement therapy assessed with 3D kinematics and clinical and patient reported outcomes: A prospective cohort study.

Introduction: We hypothesised that reduced shoulder function post stroke improves during constraint-induced movement therapy and that improvement in scapula upward rotation measured with three-dimensional kinematics is associated with improvements in clinical and patient reported outcomes.

Methods: Thirty-seven patients were tested pre and post constraint-induced movement therapy and again at three-month follow-up. Kinematic outcome measures - with scapula upward rotation as the primary outcome - during tasks 5 (ReachLow) and 6 (ReachHigh) from the Wolf Motor Function Test were included together with clinical and patient reported outcomes.

Asymmetries in Ground Reaction Forces During Turns by Elite Slalom Alpine Skiers Are Not Related to Asymmetries in Muscular Strength.

The ground reaction forces (GRF) associated with competitive alpine skiing, which are relatively large, might be asymmetric during left and right turns due to asymmetries in the strength of the legs and torso and the present investigation was designed to evaluate this possibility. While skiing a symmetrical, 20-gate slalom course, the asymmetries of 9 elite alpine skiers were calculated on the basis of measurements provided by inertial motion units (IMU), a Global Navigation Satellite System and pressure insoles. In addition, specialized dynamometers were utilized to assess potential asymmetry in the strength of their legs and torso in the laboratory.

A new method for measuring treadmill belt velocity fluctuations: effects of treadmill type, body mass and locomotion speed.

Treadmills are essential to the study of human and animal locomotion as well as for applied diagnostics in both sports and medicine. The quantification of relevant biomechanical and physiological variables requires a precise regulation of treadmill belt velocity (TBV). Here, we present a novel method for time-efficient tracking of TBV using standard 3D motion capture technology.

Does the Spraino low-friction shoe patch prevent lateral ankle sprain injury in indoor sports? A pilot randomised controlled trial with 510 participants with previous ankle injuries.

Background: Lateral ankle sprains are common in indoor sports. High shoe-surface friction is considered a risk factor for non-contact lateral ankle sprains. Spraino is a novel low-friction patch that can be attached to the outside of sports shoes to minimise friction at the lateral edge, which could mitigate the risk of such injury.

Application of Inertial Motion Unit-Based Kinematics to Assess the Effect of Boot Modifications on Ski Jump Landings-A Methodological Study.

Biomechanical studies of winter sports are challenging due to environmental conditions which cannot be mimicked in a laboratory. In this study, a methodological approach was developed merging 2D video recordings with sensor-based motion capture to investigate ski jump landings. A reference measurement was carried out in a laboratory, and subsequently, the method was exemplified in a field study by assessing the effect of a ski boot modification on landing kinematics.

Effect of Box Height on Box Jump Performance in Elite Female Handball Players.

Koefoed, N, Dam, S, and Kersting, UG. Effect of box height on box jump performance in elite female team handball players. J Strength Cond Res 36(2): 508-512, 2022-This study aimed at investigating whether a link exists between performance in a countermovement jump and the height of the box an athlete could successfully jump onto.

Acquisition of a simple motor skill: task-dependent adaptation and long-term changes in the human soleus stretch reflex.

Changing the H reflex through operant conditioning leads to CNS multisite plasticity and can affect previously learned skills. To further understand the mechanisms of this plasticity, we operantly conditioned the initial component (M1) of the soleus stretch reflex. Unlike the H reflex, the stretch reflex is affected by fusimotor control, comprises several bursts of activity resulting from temporally dispersed afferent inputs, and may activate spinal motoneurons via several different spinal and supraspinal pathways.

Three-dimensional kinematics of shoulder function in stroke patients: Inter- and intra-rater reliability.

Background: It is important to monitor progress during rehabilitation of stroke patients. To that end, clinical function tests may be supported by three-dimensional kinematic measures. The aim of this study was to evaluate the inter- and intra-rater reliability of three-dimensional kinematic measures of shoulder movements in stroke patients with reduced shoulder function.

Prediction of running-induced Achilles tendinopathy with pain sensitivity - a 1-year prospective study.

Background and aims Achilles tendinopathy is common among runners, but the etiology remains unclear. High mechanical pain sensitivity may be a predictor of increased risk of developing Achilles tendinopathy in this group. The purpose of this study was to investigate whether local pain sensitivity could predict the development of Achilles tendinopathy in recreational male runners.

Differences in impact characteristics, joint kinetics and measurement reliability between forehand and backhand forward badminton lunges.

This study identified the effect of badminton lunging directions on impact characteristics, joint kinetics and measurement reliability. A total of 14 badminton players performed 20 lunges in both forehand and backhand sides. Ground reaction force (GRF) and three-dimensional joint moment variables were determined for further analyses.