STEP CHARACTERISTICS DURING LONG JUMP APPROACH: RELIANCE AND ASYMMETRY CONSIDERATIONS

This study's aim was to investigate step characteristic reliance and asymmetry during the long jump approach. Spatiotemporal data of the approach run were collected in national and international athletic competitions of 10 males (age 26.2 & 4.1 yrs, height 1.84 & 0.06 m, mass 72.77 i 3.23 kg, PB 7.96 i 0.30 m) and 9 females (26.3 i 2.19 yrs, 1.73 i 0.05 m, 55.75 * 3.79 kg, 6.68 * 0.20 m). Only two males showed step length reliance and only during late approach. Step frequency reliance was demonstrated during total, early and late approach, most prevalently during the latter (7110 male & 319 female). Four males and females displayed step length asymmetry whilst three males and two females were asymmetrical for frequency. No athletes showed step velocity asymmetry. In conclusion, asymmetrical demands of take-off were not consistently reflected in step characteristics

COMPARISON OF STEP CHARACTERISTIC INTERACTION AND ASYMMETRY BETWEEN FAILED AND SUCCESFUL ATTEMPTS IN POLE VAULT

The purpose of this study was to investigate step characteristics of high level pole vaulters during failed and successful jumps in terms of: a) the direction and magnitude of asymmetry between the pole carrying (PC) and non-pole carrying (NPC) foot and b) the reliance of step velocity (SV) on either step frequency (SF) or step length (SL). Eight male pole vaulters were recorded during competition with a panning video camera operating at 300 fps. Asymmetry was observed in four vaulters on either SF or SL both in successful and failed attempts but it was not consistent and its direction was not related to the athletes’ PC limb. No athletes demonstrated significant asymmetry for SV between failed and successful jumps. At the highest jump cleared, five out of eight vaulters demonstrated SF reliance. However, as the failed attempts progressed vaulters became less SF reliant

Prognostic Validity of Professional Soccer Status by Anthropometrics and Repeated Jump Testing

ABSTRACT Soccer is characterized by intermittent high-intensity actions interspersed with lower intensity ones. Soccer clubs invest time and money to early identify and nurture potential professional players in the premise to maximize the return of their investment. Multidimensional talent identification models are proposed as best practice but are difficult to be implemented in the field. Explosive lower limbs strength assessment by vertical jumping (VJ) is used as a single predictor for future player status. Alternative to VJ, the repeated vertical jump test (RVJ) has been proposed, but its prognostic ability is still unexplored. PURPOSE: To analyze the prognostic validity of the RVJ obtained variables within professional (PRO) and under 19 years old (U19) male soccer players. It was hypothesized that anthropometric and performance related variables modeled on U19 will fail to predict the PRO status. METHODS: Forty-four participants (PRO=24, U19=20), after the end of the preseason, performed 15 RVJ aiming for highest jump (hJUMP) with the minimum possible ground contact time. Group differences examined by t-test, binomial logistic regression (BLR) calculated the likelihood of each individual to be categorized as PRO or U19 and receiver operating characteristic (ROC) for prognostic validity of anthropometric and performance derivative values in predicting PRO status were used at p \u3c0.05. Statistical analyses were performed using the R-based software Jamovi version 2.3.3.0. RESULTS: PRO and U19 significantly differed in body height, mass, body mass index (BMI), hJUMP, average jump height, and relative jump power. The prediction model was significant (x2(2) = 17.12, p \u3c0.001). From the examined variables, only height and BMI were positive predictors of the PRO status (b = 21.66, SE = 8.20, p = 0.008 and b = 0.94, SE = 0.38, p = 0.014, respectively). The model was 73% accurate, 75% specific, and 71% sensitive, with acceptable area under the curve (AUC = 0.82). CONCLUSION: The RVJ test demonstrated acceptable discriminating prognostic validity between PRO and U19 soccer players. Until the applicability of the multidimensional models in predicting future player status is further established, field practitioners may use the simplistic and single dimensional RVJ testing to predict future status among male soccer players

INFLUENCE OF THE ANKLE JOINT DORSIFLEXION ON THE EXECUTION OF VERTICAL JUMPS

The purpose of the present study was to investigate the differences in the execution of vertical jumps between individuals with good and poor ankle dorsiflexion ability. Thirty (30) males and thirty (30) female P.E. students, after being evaluated for ankle dorsiflexion, formatted the flexible and inflexible groups (FG and IFG) and executed vertical jumps. In the SQJs the IFG exhibited more inclination of the trunk at the beginning of the jump, while in the CMJs and the DJs they applied greater forces and produced greater peak angular accelerations in all joints. The IFG, by leaning forward the trunk, underwent a greater injury risk for the low back while executing the SQJs. On the other hand, they underwent an increased injury risk for the achilles tendon by raising the heels off the ground and applying greater forces during the DJs

Biomechanical analysis of the late approach and the take off in the indoor women’s long jump

Aim of the study was to provide evidence concerning the biomechanical parameters of contemporary Women’s long jump in indoor competition. The final six steps and the take-off of 11 jumps (6.88 ± 0.23 m) were recorded (panning camera; sampling frequency: 300 fps) in an indoor competition. The examined parameters were a) the step parameters, the percentage distribution of adjustment (ADJ%) and the inter-limb symmetry angle (θSYM) in the late approach, b) the joint angles and the take-off parameters. Pearson’s correlation analysis revealed that approach velocity (9.8 ± 0.3 m/s) was significantly correlated (r = .86, p = .001) with effective distance (6.96 ± 0.23 m). The largest ADJ% (57.6 %) was executed at the penultimate step which was 12.2 ± 2.8 % larger than the last step. An inter-limb difference was revealed for step frequency (t10 = 6.965, p < .001) due to the large asymmetry observed (θSYM = 5.54 deg). The knee angle of the push-off leg at take-off was 171.2 ± 4.7deg. Resultant velocity (8.3 ± 0.4 m/s), height (1.15 ± 0.05 m) and angle (20.7 ± 2.3 deg) of take-off significantly predicted effective distance (F3,7 = 12.671, p = .003, R2 = .844). The present findings are in reasonable agreement with previous research. Future studies should examine the possible reliance and asymmetry for the step parameters in the final approach

Colour contrast and regulation of the long jump approach run

Research has shown that visual perception of the take-off board and the subsequent regulation of the approach run occur 4-5 strides prior to take-off. Contrast in visual perception is determined by the difference in colour and occurs when a surface of one colour induces its antagonist colour in an adjoining surface. The aim of the present study was to investigate if colour contrast between the track surface and the board affects the stride regulation pattern at the long jump approach run. Four long jumpers performed long jumps in two different occasions: 6 from a runway track coloured blue, with a white take-off board and 6 from a modified yellow board. The runway was marked and the approach runs were recorded with a panning camera. Toeboard distance (TBD) for each support phase in every run-up and the percentage distribution of adjustment of the regulated strides was calculated. With the white take-off board, the average TBD variability reached its peak value (21.74cm) on the 5th stride from the board and at a distance of 9.77m from take-off point. With the yellow take-off board the average TBD variability culminated (24.80cm) on the 7th stride from the board and at a distance of 13.40m from take-off point. With the white board, 80% of the adjustment was distributed during the last two strides as opposed to 61% with the yellow board. When a take-off board of a colour complementary to the runway’s blue track surface is used, athletes initiated their regulation 2 strides earlier. This may be attributed to an enhanced visual perception of the approaching target allowing a more uniform distribution of adjustments during the last two strides of the approach

Vertical jump kinetic parameters on sand and rigid surfaces in young female volleyball players with a combined background in indoor and beach volleyball

Little is known about the differences in vertical jump biomechanics executed on rigid (RJS) and sand (SJS) surfaces in female indoor and beach volleyball players. Eleven young female beach volleyball players with a combined indoor and beach volleyball sport background performed squat jumps, countermovement jumps with and without an arm swing, and drop jumps from 40 cm on a RJS (force plate) and SJS (sand pit attached to the force plate). The results of the 2 (surface) × 4 (vertical jump test) repeated-measure ANOVA revealed a significant (p 0.05), was observed for the other examined biomechanical parameters. The only significant (p < 0.05) jump height gain difference between RJS and SJS was observed for the utilization of the stretch-shortening cycle, which was higher in SJS (15.4%) compared to RJS (7.5%). In conclusion, as the testing was conducted during the beach volleyball competitive season, the examined female players showed adaptations relating the effective utilization of the pre-stretch and enhanced stability during the execution of the vertical jump tests on a SJS compared to RJS

THE USE OF UPPER LIMB PROSTHESIS OPTIMIZES LONG JUMP APPROACH KINEMATICS: A CASE STUDY OF AN ELITE T47 ATHLETE

This study aimed to investigate approach run kinematics using an upper limb prosthesis. A European Τ47 long- and triple- jump champion with right upper-limb congenital deficiency was analyzed in simulated approach run-ups wearing prosthesis (PW) or not (NP). Two attempts in each condition were recorded (300 fps). Step characteristics and kinematic parameters were extracted for the deficient (DLS) and intact (HLS) sides with a 2D-DLT analysis during the early (EA) and late (LA) approach. Results revealed systematic asymmetry for step frequency and length in NP, with the latter reduced in PW. Horizontal velocity in both EA and LA was larger by 0.3 m/s in PW than NP. These results suggest that asymmetry of NP reduces approach run performance compared to PW

TECHNIQUE ASSESSMENT OF THE JAVELIN RELEASE PERFORMED BY YOUNG SERBIAN ATHLETES

The purpose of the present study was to indicate the biomechanical parameters of the delivery phase associated with performance in young javelin throwers. Seven right-handed young Serbian club level javelin throwers (19.0±1.0 yrs; 1.84±0.08 m; 81.0±5.2 kg) were recorded at 100 fps sampling frequency during competition. Spatial parameters (delivery stride length, distance to foul line, javelin grip height) and body configuration (joint angles, inclination of body segments) were extracted with a 2D-DLT kinematical analysis method. Model Technique Analysis Charts were used for the qualitative assessment of the throwing technique of the examined athletes. The relationship between the extracted biomechanical parameters and the official throwing distance was examined with a correlation analysis. The results revealed that the official throwing distance (46.43 ± 4.89 m) significantly (p.78) with release velocity (16.0±1.4 m/s), release angle (36.4±1.4 deg), javelin grip height (1.21±0.07 m) and the braking leg knee angle at its final touchdown (153.0±11.4 deg). The most common technique errors observed during the delivery phase were the flexed elbow of the throwing arm, the large knee flexion of the braking leg and the lack of the braking leg’s knee extension at the instant of release. The quantitative assessment revealed less favorable values in key biomechanical parameters compared to the results of other studies investigating elite young athletes. It is suggested that young javelin throwers’ training should focus on performing the release of the javelin with a proximal to distal joint sequencing that optimizes the transfer of the kinetic energy along the body