LOWER EXTREMITY JOINT MOMENTS IN ATHLETICS CURVE SPRINTING

The purpose of this study was to identify the effect of curve sprinting on the three dimensional joint kinetics and to specify the leg specific loading and functionality in the curve. Six male sprinters performed three submaximal curved and linear sprints. The findings point up different functionalities of the inner and outer leg. Peak knee and hip adduction moments were about twice as high at the inner leg compared to the outer leg during curve sprinting and compared to linear sprinting. Furthermore significantly higher peak external rotation moments in the knee and hip joints could be found during curve sprinting. In maximal sprinting these additional tasks may compromise propulsive force generation. These findings help to quantify the side specific load and provide information about involved muscles, which is helpful for the training process and injury prevention

AMPUTATION SIDE AND SITE DETERMINE PERFORMANCE CAPACITY IN PARALYMPIC CURVE SPRINTING

In the 2015 IPC world championships athletes with amputation at the inside leg were underrepresented in the finals of the 200 and 400 m sprinting events. Yet there is only very limited information on amputee curve sprinting and the influence of side and/or level of amputation on propulsion mechanisms. The aim of this study was to describe amputee curve sprinting kinetics and to it compare to able-bodied athletes. Three amputee athletes with different amputations of the lower limb and six able-bodied athletes performed curved runs. Results show differences between athletes in the ability to create high vertical and centripetal forces and suggest a dependence on site (above and below knee) and side (left or right) of amputation. Running specific prosthesis might benefit from design adaptation if used at the left limb in curve running

CONTRIBUTION OF THE LOWER EXTREMITY JOINTS TO MECHANICAL ENERGY IN ATHLETICS CURVE SPRINTING

The purposes of this study were to identify differences of the three-dimensional joint kinetics between linear and curve sprinting and to quantify the asymmetrical loading of both legs during curve sprinting. Six male sprinters performed three linear and curve sprints. The energies of the ankle, knee and hip joint were determined during the ground contact phase with the aid of an adjusted multibody human model. The ankle joint was the largest energy absorber and generator in the sagittal plane while the hip joint was the largest energy absorber and generator in the frontal and transversal plane. Asymmetric functions of the inside and outside leg were determined during curve sprinting. The hip joint of the inside leg might be highly loaded in sprinting on a bend track

MODELING AND OPTIMAL CONTROL OF ABLE-BODIED AND UNILATERAL AMPUTEE RUNNING

The remarkable performances of amputee athletes in sprint competitions aroused media and scientific interest and led to the question whether running-specific prostheses can be an advantage with respect to able-bodied running. The aim of this study was to bring together motion capture data and Scientific Computing methods to analyze the running motions of an able-bodied and a unilateral transtibial amputee athlete. For each of them a rigid multibody system model was created. By application of optimal control techniques, the dynamics of reference running movements from motion capture data was reconstructed for both models. The able-bodied and the transtibial amputee sprinters rely on dissimilar actuation strategies to perform similar running motions

MUSCULOSKELETAL MODELLING OF HANDCYCLING MOTION ON AN EROGOMETER: INFLUENCE OF CRANK POSITION ON TRAINING PURPOSES.

The objective of this study was to examine the influence of crank position during hand cycling on muscle forces and Glenohumeral joint reaction forces. Twelve male subjects performed 16 trials with variation in crank parameters. 3D motion capturing (Vicon) and custom made handlebars (Kistler force sensors) were used to determine kinematic and kinetic data. Musculoskeletal modelling (AnyBody) was used for calculations of joint contact and muscle forces. Significant difference was found between settings and muscle forces (p=0.006) and Glenohumeral joint reaction forces (p=0.000). For the m. Brachialis, the m. Latissimus Dorsi and the m. Deltoideus Scapularis, an optimal setting was found. The antero- posterior and distraction force are minimized with horizontal handlebars, a small crank width and long crank arms

HANDLE REACTION FORCES IN HANDCYCLING ON AN ERGOMETER

The purpose of this study was to develop a three dimensional sensitive dynamometric handcycling grip and to examine the influence of grip positioning on hand contact forces during low resistance arm cranking. Contact forces of ten male subjects were measured at a neutral grip position, increased crank arm length and increased grip width. The findings suggest a pushdown-pull cranking pattern. Therefore shoulder extensors and elbow flexors may have an important role in force generation. Changes at the grip position have a clear effect on grip contact forces, thus the interaction is complex due to subject specific variations. The data sets the basis for an inverse dynamic model and provides information about involved muscles which is helpful for the training process and injury prevention

NO DATASET TOO SMALL! ANIMATING 3D MOTION DATA TO ENLARGE 2D VIDEO DATABASES

This study outlines a technique to leverage the wide availability of high resolution three-dimensional (3D) motion capture data for the purpose of synthesising two-dimensional (2D) video camera views, thereby increasing the availability of 2D video image databases for training machine learning models requiring large datasets. We register 3D marker trajectories to generic 3D body-shapes (hulls) and use a 2D pose estimation algorithm to predict joint centre and anatomical landmark keypoints in the synthesised 2D video views – a novel approach that addresses the limited data available in elite sport settings. We use 3D long jump data as an exemplar use case and investigate the influence of; 1) varying anthropometrics, and 2) the 2D camera view, on keypoint estimation accuracy. The results indicated that 2D keypoint determination accuracy is affected by body-shape. Frontal plane camera views result in lower accuracy than sagittal plane camera views

FREE MOMENT APPLICATION BY ATHLETES WITH AND WITHOUT AMPUTATIONS IN LINEAR AND CURVED SPRINTING

The purpose of the present study was to describe free moment (FM) application to the ground in high speed linear and curved running in athletes with unilateral amputations and non-amputee athletes. The results indicate that peak FM amplitudes are about three times higher in sprinting compared to running at distance running speeds. Curved running decreases internal rotation FM amplitudes of the right (outside) leg in nonamputee runners. The use of running specific prostheses (RSPs) is related to lower FM application in sprinters with unilateral amputations. This might be related to inertial asymmetries between legs or to constraints imposed at the RSP attachment interface. Monitoring FM patterns in sprint diagnostics might help athletes and coaches in the improvement of running and sprinting performance and overuse injury prevention

BLADE KINETICS OF A UNILATERAL PROSTHETIC ATHLETE IN CURVE SPRINTING

In athletics sprinting longer than 100 m, athletes will run more than 50% in a curve. No data on ground reaction forces or joint kinetics of prosthetic curve sprinting can be found in the scientific literature. The purpose of this study was to analyze GRFs and moments acting on the prosthesis’ blade using a 3D motion capture system and four force plates. A left sided unilateral amputee athlete (knee exarticulation) of highest international level, ran 30 m straight and curved clockwise and counter clockwise. GRFs show differences between curve and straight running. Results show different loading applied to the blade of a prosthesis when curve running in comparison with straight running. The study gives an inside into the kinetics of amputee curve running and might affect the construction and design of future prosthesis generations as well as performance diagnostics

FORCE PROFILE OF FUNCTIONAL LEG MUSCLE GROUPS IN CURVE SPRINTING - PRELIMINARY RESULTS

Research on lower extremity joint and muscle kinetics in athletic curve sprinting is under-represented in the scientific literature. This is an issue due to its importance for training and rehabilitation protocols as well as for injury prevention. In this study, we analysed six male sprinters regarding their force profile of functional lower extremity muscle groups in curve sprinting. Three-dimensional motion capture (Vicon) and four force plates (Kistler) were used to capture kinematic and kinetic data. Inverse dynamic calculations (Anybody), including muscle forces, provide first insights into potential side differences of leg muscle group force profiles between the inside and the outside leg in submaximal curve sprinting (9.48 ± 0.26 m/s). However, a differentiated analysis of individual muscles is necessary in the future as grouping might overlay the side-specific effects in particular muscles