Dieter Heinrich

University of Innsbruck | UIBK · Department of Sport Science

In alpine skiing, estimation of the joint moments acting onto the skier is essential to quantify the loading of the skier during turning maneuvers. In the present study, a novel forward dynamics optimization framework is presented to estimate the joint moments acting onto the skier incorporating a three dimensional musculoskeletal model (53 kinemat...

Competitive skiers encounter a high risk of sustaining an ACL injury during jump-landing in downhill ski racing. Facing an injury-prone landing manoeuvre, there is a lack of knowledge regarding optimum control strategies. So, the purpose of the present study was to investigate possible neuromuscular control patterns to avoid injury during injury-pr...

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Injury analysis may be one of the most beneficial applications of deep learning based human pose estimation. To facilitate further research on this topic, we provide an injury specific 2D dataset for alpine skiing, covering in total 533 images. We further propose a post processing routine, that combines rotational information with a simple kinemati...

Zwölfer M, Heinrich D, Schindelwig K, Wandt B, Rhodin H, Spörri J, Nachbauer W. Improved 2D Keypoint Detection in Out-of-Balance and Fall Situations –combining input rotations and a kinematic model. Workshop on Computer Vision 4 Winter Sports (CV4WS), 2022 Winter Conference on Applications of Computer Vision (WACV), 2022. https://dx.doi.org/10.4855...

Towards the goal of obtaining non-invasive biomarkers reflecting the anterior cruciate ligament’s (ACL) loading capacity, this project aimed to develop a magnetic resonance imaging (MRI)-based method facilitating the measurement of ACL elongations during the execution of knee stress tests. An MRI-compatible, computer-controlled, and pneumatically d...

Jump landing is a common situation leading to knee injuries involving the anterior cruciate ligament (ACL) in sports. Although neuromuscular control is considered as a key injury risk factor, there is a lack of knowledge regarding optimum control strategies that reduce ACL forces during jump landing. In the present study, a musculoskeletal model-ba...

Trajectory optimization with musculoskeletal models can be used to reconstruct measured movements and to predict changes in movements in response to environmental changes. It enables an exhaustive analysis of joint angles, joint moments, ground reaction forces, and muscle forces, among others. However, its application is still limited to simplified...

Bone and ligament injuries are one of the most common serious injuries in sports. Musculoskeletal simulation models are popular to investigate injury situations on a computer. The existing musculoskeletal simulation models typically consist of a rigid multi-body model (representing the skeleton) and muscles, which actuate the movement of the skelet...

This paper compares predictions of metabolic energy expenditure in gait using seven metabolic energy expenditure models to assess their correlation with experimental data. Ground reaction forces, marker data, and pulmonary gas exchange data were recorded for six walking trials at combinations of two speeds, 0.8 m/s and 1.3 m/s, and three inclines,...

Objectives: Ski boots are designed to transfer forces from skier to ski. This transfer is among others affected by the flexion stiffness (FS) and so effects safety and skiing performance. Previous studies have used devices with prosthetic legs to evaluate FS, however, influencing factors like the foot and lower leg shape or individual buckle closu...

This paper compares predictions of metabolic energy expenditure in gait using seven metabolic energy expenditure models to assess their correlation with experimental data. Ground reaction forces, marker data, and pulmonary gas exchange data were recorded for six walking trials at combinations of two speeds, 0.8 m/s and 1.3 m/s, and three inclines,...

ACL-injuries are one of the most common knee injuries in noncontact sports. Kinematic data of injury prone situations provide important information to study the underlying ACL-injury mechanisms. However, these data are rare. In this work an approach is presented to generate injury prone situations for noncontact ACL-injuries on a computer. The inju...

Background Competitive skiers face a high risk of sustaining an ACL injury during jump landing in downhill skiing. There is a lack of knowledge on how landing height affects this risk. Objectives To evaluate the effect of varied landing height on peak ACL force during jump landing and to compare the effect of the landing height with the effect of...

Activation of the hamstrings has been discussed as a measure for reducing strain on the ACL during jump landings in alpine skiing. The current study tested the hypothesis that hamstring and quadriceps activation can be voluntarily increased by the athlete. Specifically, two different instructions – to increase hamstring activation or to increase up...

Background: Maintaining balance is an essential requirement for the performance of daily tasks and sporting activities, particularly in older adults to prevent falls and associated injuries. Kinesiology tape has gained great popularity in sports and is frequently used as a tool for performance enhancement. However, there is little research investi...

A common anterior cruciate ligament (ACL) injury situation in alpine ski racing is landing back-weighted after a jump. Simulated back-weighted landing situations showed higher ACL-injury risk for increasing ski boot rear stiffness (SBRS) without considering muscles. It is well known that muscle forces affect ACL tensile forces during landing. The p...

Wool in outdoor clothing systems is stated to be a good temperature and humidity regulator giving the wearer a warm and dry feeling during physical activities in the cold. The objective was to compare two different battings (sheep wool “tirolwool” (TW) versus polyester microfiber (PMF)) in an outdoor jacket of a two-layer outdoor clothing system co...

To investigate the effect of a maximal shuttle-run shock microcyle in hypoxia on repeated sprint ability (RSA,6x40-m/20”), Yo-Yo-intermittent-recovery (YYIR) test performance and redox-status. Fourteen players (age:23.9±2.1yr), randomly assigned to hypoxia (~3300m) or normoxia training, performed 8 maximal shuttle-run training sessions within 12 da...

The objective of this investigation was to achieve an understanding about the relationship between heat stress and performance limitation when wearing a two-layer fire-resistant light-weight workwear (full-clothed ensemble) compared to an one-layer short sports gear (semi-clothed ensemble) in an exhaustive, stressful situation under moderate therma...

Context: During sport activity knee proprioception might worsen. This decrease in proprioceptive acuity negatively influences motor control and therefore may increase injury risk. Hiking is a common activity characterized by a higher intensity exercise phase during uphill walking and a lower intensity exercise phase during downhill walking. Pain a...

Objectives: Kinesiology tape has gained significant popularity in recent years and is widely used as an adjunct for treatment and prevention of musculoskeletal injuries. However, evidence regarding its influence on knee proprioception is scarce. The purpose of this study was to evaluate the effect of Kinesiology tape on knee proprioception after p...

The study evaluated the predictive value of arterial oxygen saturation (SaO2) after 30-min hypoxic exposure on subsequent development of acute mountain sickness (AMS) and tested if additional resting cardio-respiratory measurements improve AMS prognosis. Fifty-five persons were exposed to a simulated altitude of 4,500 m (normobaric hypoxia, FiO2 =...

Hiking is a backcountry activity suitable for people in every age. Pain and injuries are reported in hiking especially during downhill walking. This increased injury risk is caused primarily by high loads on the lower extremities’ joints and the optimal coordination control therefore required. Through the use of knee supports during hiking the inju...

Workwears are required to maintain optimum performance during dangerous, exhausting activities (e.g. those involving the fire brigade or police). The purpose of the present study was to compare two workwears (A and B) composed of underwear and outerwear with different fiber blends (A: 100% aramid; B: combination of fire resistant (FR) viscose/merin...

Recent data highlight that competitive skiers face a high risk of injuries especially during off-balance jump landing maneuvers in downhill skiing. The purpose of the present study was to develop a musculo-skeletal modeling and simulation approach to investigate the cause-and-effect relationship between a perturbed landing position, i.e., joint ang...

A ski-snow interaction model is presented. The force between ski and snow is decomposed into a penetration force normal to the snow surface, a shear force parallel to it, and friction. The purpose of this study was to investigate the benefits of a hypoplastic vs an elastic contact for penetration in the simulation of skiing turns. To reduce the num...

It was hypothesized that for each mountain running competition, there is a certain individual performance level below which running times increase dramatically. The running times of 869 finishers of 3 international mountain running competitions have been analysed. A hyperbolic association was demonstrated between finish times in mountain running co...

The ordinary differential equations for musculoskeletal dynamics are often numerically stiff and highly nonlinear. Consequently, simulations require small time steps, and optimal control problems are slow to solve and have poor convergence. In this paper, we present an implicit formulation of musculoskeletal dynamics, which leads to new numerical m...

The deformation of skis and the contact pressure between skis and snow are crucial factors for carved turns in alpine skiing. The purpose of the current study was to develop and to evaluate an optimization method to determine the bending and torsional stiffness that lead to a given bending and torsional deflection of the ski. Euler-Bernoulli beam t...

The macroscopic contact area between ski and snow and the contact pressure are crucial influencing factors for carved turns in Alpine skiing. In the present paper, a simulation model is developed to quantify these factors. The ski is modelled as an Euler-Bernoulli beam with variable cross section, camber, bending and torsional stiffness using measu...

The skier was modeled by seven rigid segments: trunk, left and right thighs, shanks, and skis. The segments were connected by four rotational joints in the knees and ankles and two spherical joints in the hips. The user can specify the slope, the track of the right ski, and driving constraints for right ankle, right knee and both hips. Further, a b...

A computer model was developed to simulate consecutive ski turns. The model consists of a segment model for two skis and a single body for the skier. It was implemented in the multibody simulation software LMS Virtual. Lab. The interaction of ski and snow leads to a normal and a shearing force. For the normal force a hypoplastic relation between fo...

The satellite navigation system GPS has gradually gained a usability that was never expected during ist design 30 years ago. Similar statements can also be made for other central elements of modern navigation technology like gyroscopes and accelerometers as well as microprocessors for synchronizing and processing sensor signals. GPS receivers and o...

Carved turns with alpine skis are investigated. During the movement of a ski, snow is loaded and unloaded. Compacted snow is not elastic, i.e. deformations remain. Such effects are modeled by a hypoplastic constitutive equation. During a turn the shovel digs into the snow and the tail maintains nearly the same penetration depth as the part under ma...

Carved turns with Alpine Skis were investigated using a computer simulation model. Varied input data to the model were the bending stiffness of the skis, the edging angle, and the velocity. Results include the turn radius and the force distribution along the running surface of the skis.

INTRODUCTION: The pressure distribution between ski and snow is an important factor for turns in Alpine skiing describing the interaction between ski and snow (Kaps, 2001; Federolf, 2005). The aim of the present study was to compute the pressure distribution during two consecutive turns using a validated computer simulation model. Additionally the...

INTRODUCTION: At jumps in downhill skiing a potential injury situation involving the anterior cruciate ligament (ACL) arises if the skier gets in a backward, off-balance position during the landing movement (Gerritsen et al. 1996, Kietlinski & Rzymkowski 2005). The purpose of the study was to investigate this scenario by means of a computer simulat...

Carved turns with Alpine Skis were investigated using a computer simulation model. Varied input data to the model were snow conditions, edging of the skis, and the velocity of the skier. Results include the pressure distribution along the running surface of the skis and the trajectory of the skier.

Einleitung Seit der Entwicklung von Carvingski wird den geometrischen Eigenschaften von Alpinski große Beachtung von Seiten der Skiindustrie, des Spitzensports und des Breitensports geschenkt. Neben den geometrischen Eigenschaften spielen aber auch die mechanischen Eigenschaften, wie die Biege-und Torsionssteifigkeit, eine wichtige Rolle (Lind, 199...

Purpose: The aim of this study was to develop a simulation tool to simulate consecutive skiing turns. Results and Discussion The model of the skier was successfully implemented to simulate a sequence of turns. To keep the skier in balance the inward lean had to be selected in such a way that the resultant force on the skier's center of mass pointed...