ACCURACY AND PRECISION OF THE KINETIC ANALYSIS OF DROP JUMP PERFORMANCE

The aims of this study were to quantify (a) the accuracy and precision of measuring drop jump (DJ) performance kinetically and (b) the influence of the starting technique on those values. A 14-camera 3D motion analysis system and the double force plate technique were used simultaneously to obtain vertical displacements of centre of mass (CM) for comparison. Ten physically active male subjects performed DJs with 3 different techniques: stepping forward, with a small jump upwards, and flexing one knee before dropping. In total, 90 DJs were analyzed, 30 of each type. Small bias was obtained showing good accuracy as well as small typical error for jump height in all starting techniques. Our data indicates that double force plate technique can be used confidently for DJ analysis regardless of the starting technique

BILATERAL CMJ ASSYMETRIES IN YOUNG MALE ATHLETES: A STUDY ACROSS DIFFERENT AGE GROUPS AND SPORTS

The purpose of this study was to investigate bilateral countermovement jump asymmetries on a sample of 232 male student-athletes of 10 different sports, on a cross sectional approach over one year duration. Asymmetry in a number of force-related variables during the concentric and eccentric phases of a countermovement jump was defined as the absolute difference in performance between limbs expressed as a percentage of the total performance. Thresholds based on those asymmetries’ means plus standard deviations of the whole sample were set. Our study indicates that regardless of the sport, asymmetries defined in this way are more likely to occur in active boys from 13 to 15 years old

DIFFERENCES IN PERFORMANCE CHARACTERISTICS IN SPRINT HURDLES BETWEEN HURDLERS AND DECATHLETES IN ASIAN GAMES 2006

Hurdling technique may not be the main factor to explain the differences in race performance between world-class hurdlers (Brüggemann et al. 1999). However, it is likely that technical factors play a more important role in hurdling performance in less skilled athletes. Therefore, we examined the differences in hurdling performance between the specialized (hurdlers, HRDS) and non-specialized (decathletes, DECS) athletes

ACCURACY AND PRECISION OF THE KINETIC ANALYSIS OF COUNTER MOVEMENT JUMP PERFORMANCE

The purpose of this study was to quantify the accuracy and precision of measuring counter movement jump (CMJ) performance kinetically (i.e. measuring impulse using a force plate). A 14-camera 3D motion analysis system and a force plate were used simultaneously to obtain vertical trajectories of centre of mass (CM) for comparison. Fifty-eight CMJs were analyzed from eleven physically active males. Jump height differences were trivial, and small bias was obtained thereby showing good accuracy as well as small typical errors for performance. Our study indicates that force plates can be used confidently for CMJ analysis

Change of direction speed in soccer: how much braking is enough?

The aims of the present study were to examine: 1) the validity and reliability of a new timing system to assess running kinematics during change of direction (COD), and 2) the determinants of COD-speed. Twelve young soccer players performed three 20-m sprints, either in straight line or with one 45º- or 90º- COD. Sprints were monitored using timing gates and two synchronized 100-Hz laser guns, to track players’ velocities before, during and after the COD. The validity analysis revealed trivial-to-small biases and small-to-moderate typical errors of the estimate with the lasers compared with the timing gates. The reliability was variable-dependent, with trivial- (distance at peak speed) to-large (distance at peak deceleration) typical errors. Kinematic variables were angle-dependent, with likely lower peak speed, almost-certainly slower minimum speed during the COD and almost-certainly greater deceleration reached for 90º-COD vs. 45º- COD sprints. The minimum speed during the COD was largely correlated with sprint performance for both sprint angles. Correlations with most of the other independent variables were unclear. The new timing system showed acceptable levels of validity and reliability to assess some of the selected running kinematics during COD sprints. The ability to maintain a high speed during the COD may be the determinant of COD-speed

CENTRE OF PRESSURE DURING COUNTERMOVEMENT JUMP: IS IT RELATED TO EXPERTISE OR PERFORMANCE?

The purpose of this study was to investigate how specific variables related to the centre of pressure (CoP) trajectory during a countermovement jump (CMJ) carry information related to expertise and performance. The variables investigated were: lengths and average velocities during eccentric (Ecc) and concentric (Con) phases, medio-lateral (ML) and antero-posterior (AP) ranges of movement, and ML bias. In terms of expertise, the curves were tracked and compared over four jump sessions conducted by both experienced and inexperienced jumpers to investigate adaptive changes towards a more efficient way of jumping. Links between performance and those characteristics were also investigated. Our study indicated that no useful information related to either expertise or performance can be extracted from the CoP trajectory during a CMJ

KINETIC COMPARISON OF THE SPRINT STARTS BETWEEN YOUTH AND SENIOR ELITE ATHLETES

The purpose of this study was to identify differences in force, impulse and power characteristics in block starts and first two contacts between youth academy (n=20) and elite senior male sprinters (n=17). Senior sprinters were significantly faster out of the blocks with a horizontal velocity of 3.35m/s ±0.15 compared to 3.14 ±0.16m/s, leading to 10m times of 1.64±0.045s and 1.706±0.06s respectively. Force application time of the arms, rear leg and front leg were significantly lower in the senior athletes (all

KINEMATIC DIFFERENCES BETWEEN ‘ONE-FOOTED’ AND ‘TWO-FOOTED’ YOUNG SOCCER PLAYERS KICKING WITH THE NON-PREFERRED LEG

The purpose of this study was to examine kinematic differences between ‘one-footed’ and ‘two-footed’ players when kicking with the non-preferred leg at a target and with maximal effort. Eighteen highly-trained young soccer players were categorised as one-footed (n=9) and two-footed (n=9) based on results of a kicking test. Motion analysis data showed that two-footed players run-up straighter and have less pelvic rotation at ball-foot impact than one-footed players and the differences are likely to be meaningful (ES differences of 0.89 and 0.99 respectively). Run-up angle and pelvic rotation angle are significantly correlated (P < 0.1). The study found that two-footed players are significantly smaller in stature than one-footed players (P < 0.1). Practical implications for soccer coaches arose from the study

Multi-scale transport and exchange processes in the atmosphere over mountains. Programme and experiment

TEAMx is an international research programme that aims at improving the understanding of exchange processes in the atmosphere over mountains at multiple scales and at advancing the parameterizations of these processes in numerical models for weather and climate prediction–hence its acronyms stands for Multi-scale transport and exchange processes in the atmosphere over mountains – Programme and experiment. TEAMx is a bottom-up initiative promoted by a number of universities, research institutions and operational centres, internationally integrated through a Memorandum of Understanding between inter- ested parties. It is carried out by means of coordinated national, bi-national and multi-national research projects and supported by a Programme Coordination Office at the Department of Atmospheric and Cryospheric Sciences of the University of Innsbruck, Austria. The present document, compiled by the TEAMx Programme Coordination Office, provides a concise overview of the scientific scope of TEAMx. In the interest of accessibility and readability, the document aims at being self-contained and uses only a minimum of references to scientific literature. Greyboxes at the beginning of chapters list the literature sources that provide the scientific basis of the document. This largely builds on review articles published by the journal Atmosphere between 2018 and 2019, in a special issue on Atmospheric Processes over Complex Terrain. A few other important literature pieces have been referenced where appropriate. Interested readers are encouraged to examine the large body of literature summarized and referenced in these articles. Blue boxes have been added to most sub-chapters. Their purpose is to highlight key ideas and proposals for future collaborative research

Reliability of some metabolic power variables collected with the new timing methodology and timing gates during sprints with and without change of direction.

<p>Reliability of some metabolic power variables collected with the new timing methodology and timing gates during sprints with and without change of direction.</p