MOVING ON SLOPES: ISSUES AND CHALLENGES FROM A BIOMECHANICAL PERSPECTIVE

Moving on slopes is part of daily living locomotion, but also several sport disciplines are performed on inclined terrain. From a biomechanical perspective locomotion on slopes is a challenging task as additional work has to be done compared to locomotion on flat terrain. Moving downwards supports the locomotion due to gravity, however, steep slopes often lead to high speeds caused by the transfer of potential to kinetic energy. Then locomotion is accompanied with the challenge to control speed. Another issue is the aspect of joint loading when moving on slopes. An increase of potential or kinetic energy is associated with an enhancement of work done by the joint structures. The purpose of the presentation is to characterize the specificity and challenges when moving on slopes from a biomechanical perspective including performance, coordination, safety and joint loading in daily movement and sport related tasks

KNEE JOINT LOADING IN JUMP LANDINGS IN DIVERSE CONDITIONS

The purpose of this single case study is to provide an overview on knee joint loading in counter movement jumps using different landing strategies and additional loads. One athlete experienced in jump training performed counter movement jumps and jump landings with additional barbell loads of 0 kg, 20 kg, 40 kg, 60 kg, 80 kg and with variations in landing conditions: “regular”,“soft”, “elevated” and “spotted”. GRF and kinematics were measured, and peak forces, peak knee moments and peak knee powers were determined using inverse dynamics. Different loading conditions and landing conditions lead – as expected – to different knee joint loadings and can therefore be used to specifically control the amount of loading during jump or jump strength training. The most effective in terms of high training loads and low landing joint loading are elevated and spotted landing conditions

EFFECT OF A NEUROMUSCULAR HOME TRAINING PROGRAM ON DYNAMIC KNEE VALGUS (DKV) IN LATERAL SINGLE-LEG LANDINGS

The purpose of the study was to investigate if an intervention program with focus on neuromuscular and feedback training in a home-based setting with supervision improves the leg alignment in recreational volleyball and basketball players. 16 players ran a 6-week neuromuscular intervention program in a home setting with video-based supervision. The control group just followed the regular training program. Before and after the intervention the DKV was measured as the peak knee valgus angle during the video-recorded landing after a lateral jump from a box using a 2D video analysis tool. While the DKV improved in the training group, no changes were found for the control group. The intervention was effective and can be recommended as a knee-injury mitigation program

CONCEPTS IN SKI JUMPING BIOMECHANICS AND POTENTIAL TRANSFER TO OTHER SPORTS

The specificity of ski jumping requires particular considerations and methodologies regarding the biomechanical context. In this paper some of these issues are presented and discussed. Furthermore, potential transfer of these concepts and methodologies to other sports will be presented. The topics cover aspects of conceptual considerations regarding experimental research, lab and field measurements, ski jumping specific methodologies, imitation exercises and the relevance of biomechanics research within the complex research network. Starting from ski jumping the conceptual issues are discussed for demonstrating the potential transfer to other sports and optional applications in order to provide scientifically based enhancement of performance, effect of training concepts, comfort and injury prevention

ASPECTS AND CHALLENGES OF APPLIED SPORT BIOMECHANICS RESEARCH

Biomechanics in general and sports biomechanics in particular, are well established scientific disciplines. Due to the wide scope of application, sport biomechanics represents a very strong area within the of biomechanical research field. The specific goals of sports biomechanics research primarily cover issues of performance enhancement, comfort, injury prevention and safety regarding elite, leisure and rehabilitation sport. Due to its specificity, the research of applied sports biomechanics is confronted with significant challenges. The specific circumstances of sport disciplines have to be considered and necessitate the development of the appropriate methodology of data collection and data analysis. A large number of sophisticated and useful solutions have already been reported for many sport disciplines. These methods have to cover the scientific demands of validity, reliability and accuracy along with the more practical issues like range of usage, complexity, costs and the amount of interference with the athletes. One important challenge in sports biomechanics is to overcome the discrepancy between reliability and validity of the collected data sets. This conflict often corresponds to the issue of collecting data in a lab or field situation. Usually, data collected in the lab are more accurate and reliable, but the validity can be substantially restricted. Data collected in the field typically provide the opposite situation: high validity, but restricted accuracy and reliability. In elite sport, the highest level of validity can only be guaranteed when data are collected during competitions; however, the regulations often hamper the usage of biomechanical methodology. To overcome these problems data should be collected in semi-competitive situations. This can be performed in field studies, but also by mimicking competitions using simulation and/or imitation conditions. Furthermore, sport biomechanists should perform detailed error estimation in each specific situation of data collection for providing detailed information on data accuracy. In the literature sophisticated solutions regarding the aspects, issues and challenges on applied sports biomechanics research have already been reported. Further examples with a specific focus on walking, mountaineering and winter sports using both lab and field studies are presented with respect to usability, validity, reliability, accuracy and error estimation

A THREE-DIMENSIONAL KINEMATIC ANALYSIS OF THE STAND-AND JUMPSERVE IN FISTBALL

The purposes of the study were a detailed 3D kinematic description of the stand and jump serve in fistball, a comparison of players of different performance levels regarding kinematic parameters and a kinematic comparison of the stand and the jump serve. 19 male fistball players -separated in 3 (stand) respectively 2 Uump) performance based groups -performed a long stand and jump serve. The movements were filmed with two digital cameras (60 Hz) and were analysed using SIMI Motion. The peak velocity of the hip, shoulder, elbow, wrist, fist and ball as well as body angles (shoulder axis, pelvis axis, body torsion and spread angle) and ball parameters were analysed. The results showed significant differences regarding all velocities and ball hitting heights between the groups, but only tendencies concerning the body angles. Thus, peak body segment velocities and -to a certain extent -peak body segment angles during stand and jump serve in fistball were found to be performance limiting factors

EFFECT OF LATERALLY MOVEABLE PEDALS (BIUS) ON KINEMATICS, PEDAL FORCES AND MUSCLE ACTWIN IN RECREATIONAL CYCLING

The purpose of this study was to investigate the effect of a laterally moveable pedal on the kinematics, kinetics and muscle activity in recreational cycling compared to cycling with a standard pedal on an ergometer. Four healthy participants cycled at 100 W and 200 W at 80 rpm with a standard and the BIUS pedal. Kinematics, kinetics and muscle activation have been measured in both conditions. No differences were found regarding the joint angles and in the lateral movement of the pedal. Some differences were partly observed for the ground reaction forces and the muscle activation pattern. In the ergometer setting the BIUS pedal does not lead to kinematic changes of the cycling movement, but causes effects on pedal forces and muscle activation

DETECTION OF BIOMECHANICAL ADAPTATION IN TREADMILL RUNNING

This study aims to propose a procedure for the detection of adaptation to treadmill running regarding biomechanical variables. Male novices in treadmill running (n=12) participated in one session of treadmill running while 3D motion analysis was executed. Statistical and analytical analyses supplemented with optimization algorithms within the proposed approach were applied to 14 common biomechanical variables. Overall, a low number of adapting data set was found. Even though adaptation has possibly been overrated, these processes have to be considered if study outcome might be influenced. However, due to unsystematic occurrence of adaptation, familiarization to treadmill condition cannot be generalized within a test group

CHARACTERISTICS OF THE FORCE APPLICATION POINT - A METHOD TO IDENTIFY LEARNING PROCESSES IN ALPINE SKIING?

Since many years teaching concepts in alpine skiing are based on practice experiences and scientific research. Different tools are available to improve specific deficits. One of these tools is the so called “Alpine Basic Position” (ABP), which describes a particular body position. If one is trained in this, he is able to react on balance fluctuations, immediately. Furthermore it is possible to control movements in a harmonic and precise way, which is very important for steering skies exact and controlled. The determination of the force application point (FAP) is an important parameter to analyze body movements. In this study a fully qualified ski instructor (A) and an intermediate skier (B) were asked to fulfil five different exercises, which were developed for training the ABP. While A was skiing in a constant way, B was responding differently. Some exercises occurred a similar characteristic – in accordance to A -, some not

THE USE OF THE GRADUAL YIELDING MECHANISM DURING DOWNHILL WALKING IN TRANSFEMORAL AMPUTEE GAIT – A CASE STUDY

To facilitate downhill walking in transfemoral amputees, some prostheses contain knee joints that have a yielding mechanism. The aim of this case study was to investigate 1) at which gradient unilateral transfemoral (UTF) amputees first utilised the yielding mechanism, 2) whether this mechanism is linked to altered spatio-temporal parameters and 3) if the switch occurs at a different gradient when the prosthetic ankle component is altered. Two UTF amputees walked at different slopes (0° to -15°) with an articulating and a rigid prosthetic ankle component. Results showed that the gradient at which the UTFs first used the yielding mechanism is highly individual (UTF1: -6°; UTF2: -12°). UTF2 showed with the switch a decreased speed, step & stride length. The use of an articulating compared to a rigid ankle component did not influence the yielding pattern