TECHNICAL CHANGES IN HURDLE CLEARANCES AT THE BEGINNING OF 110 M HURDLE EVENT - A PILOT STUDY

Practically in all hurdle studies, the analysis has been carried out over a single hurdle. The purpose of this study was to investigate individual differences in hurdle clearances at the first 4 hurdles. Two male athletes were videotaped and 3D analysis was carried out. Athlete A showed a more consistent pattern than athlete B in over a range of variables. Athlete A was also able to increase the mean horizontal velocity from hurdle to hurdle. From a coaching point of view the main issues for athlete A are to avoid drifting too close to the first hurdle and to try to take-off more aggressively forward. Subject A's lead leg worked very well before and after the hurdle. Subject B has most problems around the lead leg, i.e. it is not bent enough at the take-off and it is not working effectively at the landing contact

Verkko-opiskelu alokasjaksolla : palvelusmotivaation yhteys käyttäjäkokemuksiin PVMoodlesta

Digitalisaatio, uudet oppimiskäsitykset ja opetusmenetelmät luovat mahdollisuuksia varusmiespalveluksen kehittämiselle. Puolustusvoimien Koulutus 2020 -uudistuksen yhteydessä verkko-opetusta ja PVMoodle-verkko-oppimisalustaa hyödynnetään entistä enemmän varusmieskoulutuksessa. Yhtenä uudistuksen tavoitteena on edistää varusmiesten palvelukseen sopeutumista ja palvelusmotivaatiota. Kaikissa puolustushaaroissa toteutetaan yhtenäisesti alokasjakso, joka on tärkein koulutusjakso palvelusmotivaation muodostumisen kannalta. Tut-kielman tavoitteena oli selvittää, millaisia käyttäjäkokemuksia alokkailla oli PVMoodlesta ja miten käyttäjäkokemukset olivat yhteydessä alokkaiden palvelusmotivaatioon ja taustoihin. Tutkielma toteutettiin määrällisenä ja aineisto kerättiin informoituna verkkokyselynä Rannikkoprikaatin saapumiserän 2/2021 alokkailta. Alokasjakson viidennellä viikolla toteutettuun kyselyyn vastasi yhteensä 417 alokasta. Palvelusmotivaatiota koskevissa kysymyksissä hyödynnettiin odotusarvoteoriaa. PVMoodlen käyttäjäkokemuksia koskevissa kysymyksissä hyödynnettiin teknologian hyväksymismallia. Väittämät muodostettiin hyödyntämällä aiemmin validoituja kysymyssarjoja, Puolustusvoimien alkukyselyä sekä tätä tutkielmaa varten laadittuja kysymyksiä. Aineisto analysoitiin SPSS- ja Mplus-ohjelmilla. Tärkeimmät analyysit olivat konfirmatorinen ja eksploratiivinen faktorianalyysi, klusterianalyysi sekä eri varianssianalyysit. Alokkailla oli melko positiiviset käyttäjäkokemukset PVMoodlesta informaation laadun, hyödyllisyyden, helppokäyttöisyyden, teknisen toimivuuden ja yleisen tyytyväisyyden suhteen. Alokkaat suhtautuivat erityisen negatiivisesti PVMoodlen viestinnällisyyteen. Alokkaat jakautuivat kolmeen motivaatioryhmään odotusarvoprofiilien perusteella: motivoituneet, välinpitämättömät ja heikosti motivoituneet. Motivoituneilla oli positiivisimmat käyttäjäkokemukset, välinpitämättömät oli keskimmäinen ryhmä ja heikosti motivoituneilla oli negatiivisimmat käyttäjäkokemukset. Ryhmien väliset erot jäivät kuitenkin pieniksi. Omaehtoisella PVMoodlen käytöllä havaittiin positiivinen vaikutus käyttäjäkokemuksiin, ja sillä oli ryhmien välisiä eroja pienentävä vaikutus. Varusmiespalvelusta edeltävällä virtuaalisen oppimissalustan käytöllä ei havaittu vaikutusta motivaatioryhmien välisiin eroihin. Koulutustaustalla, johtajahalukkuudella ja sukupuolella havaittiin tilastollisesti merkittävä yhteys käyttäjäkokemuksiin. Alokkaat käyttävät PVMoodlea tyypillisesti muutaman kerran viikossa alle 30 minuuttia kerrallaan. Johtopäätöksenä voidaan todeta, että alokkailla on pääosin melko positiiviset käyttäjäkokemukset PVMoodlesta. Korkealla palvelusmotivaatiolla on heikko yhteys positiivisiin käyttäjäkokemuksiin PVMoodlesta. Ammattikoulutaustaisilla oli selkeästi positiivisimmat käyttäjäkokemukset. Johtajahalukkailla oli miehistöhalukkaita positiivisemmat käyttäjäkokemukset, ja naisilla oli miehiä positiivisemmat käyttäjäkokemukset

JOINT KINETICS IN MAXIMUM VELOCITY SPRINT RUNNING

The effect of variations in joint kinetics on step characteristics and velocity is not yet known. To investigate contributions from the ankle, knee and hip to maximum velocity sprint running, data were collected from four well-trained male sprinters performing maximum effort 60 m sprints. High-speed video (200 Hz) and ground reaction force (1000 Hz) data were collected at the 45 m mark. Horizontal velocity and joint kinetics, via inverse dynamics, were calculated for two trials in each athlete. The magnitude of positive work performed by the ankle joint during the propulsive phase of stance was closely linked to the velocity of the step, and thought to be the result of a coordinated leg action during the support phase. The study revealed the potential for athlete-specific biomechanical analyses to aid the technical work of athletes and their coaches

Bend sprinting performance : new insights into the effect of running lane

Athletes in inner lanes may be disadvantaged during athletic sprint races containing a bend portion because of the tightness of the bend. We empirically investigated the veracity of modelled estimates of this disadvantage and the effect of running lane on selected kinematic variables. Three-dimensional video analysis was conducted on nine male athletes in lanes 8, 5 and 2 of the bend of an outdoor track (radii: 45.10, 41.41 and 37.72 m, respectively). There was over 2% (p < 0.05) reduction in mean race velocity from lane 8 (left step 9.56 ± 0.43 m/s, right step: 9.49 ± 0.41 m/s) to lane 5 (left step: 9.36 ± 0.51 m/s, right step: 9.30 ± 0.51 m/s), with only slight further reductions from lane 5 to lane 2 (left step: 9.34 ± 0.61 m/s, right step: 9.30 ± 0.63 m/s). Race velocity decreased mainly because of reductions in step frequency as radius decreased. These unique data demonstrate the extent of the disadvantage of inner lane allocation during competition may be greater than previously suspected. Variations in race velocity changes might indicate some athletes are better able to accommodate running at tighter radii than others, which should have implications for athletes' training

Kinetic factors differentiating mid-to-late sprint acceleration performance in sprinters and soccer players

High-speed running in soccer is an important skill, however, the underlying kinetic factors are not fully understood. Ground reaction forces from steps 8 to 24 of maximal-effort sprints were captured for 24 soccer players and 28 track and field athletes using 54 force plates. Correlations between discrete force variables and horizontal acceleration were assessed, and statistical parametric mapping revealed performance associations across entire waveforms. Track and field athletes produced higher forces (mean anteroposterior: 1.56 N•kg-1) across shorter contacts (0.101 s) than soccer players (1.27 N•kg-1, 0.110 s). Interestingly, the technical ability to apply force and the performance-differentiating parts of stance were similar across groups. Thus, practitioners should perhaps target physical (force production) rather than technical factors to improve soccer players’ sprint abilities

A NEW METHOD FOR EVALUATING THE BALANCE BETWEEN THE DIFFERENT PHASES IN 100 M SPRINTING

The aim of this paper was to investigate, whether it is possible to objectively evaluate the relationship between three different phases of 100 m sprint running. Following correlation analyses from six major athletics championships, a linear regression based scoring system was created for the acceleration, maximum velocity and velocity maintenance phases. The scoring system can be used for athletes from international level down to moderate national level. Tests for two female juniors showed that the maximum velocity phase was the weakest part of their performance. Therefore, recommendations can be made to coaches for changes to be made in training. This strategy has already resulted in improved balance between different phases for a specific athlete. Current studies are expanding the analysis into the area of individual running gait variables

Differences in ground reaction waveforms between elite senior and junior academy sprinters during the block phase and first two steps

The block start and initial steps following block exit are fundamental aspects of sprinting and their development is key to junior athletes’ progression. This study assessed the difference in force production between elite senior (including two sub-10 s 100-m sprinters) and junior academy sprinters during the block phase and the first two steps of a sprint. Thirty-seven male sprinters (17 senior, 20 junior) performed a series of maximal effort 20–40 m acceleration from blocks on an indoor track, with the ground reaction forces produced during the block phase and first two steps measured using force platforms. Senior athletes produced better block-phase performances (average horizontal external power; 15.52 ± 1.48 W/kg, M ± SD) compared with the juniors (12.37 ± 2.21 W/kg; effect size ± 90% confidence interval = 1.28 ± 0.38). However, force production during the initial two steps was comparable across groups. Specifically, senior athletes exhibited higher relative force production and ratio of forces during the early (∼15–35%) block phase and higher anteroposterior forces during the transition from bilateral to unilateral pushing (58–62% of the block phase). Front foot force production was also found to differentiate senior and junior groups at rear block exit (∼55% of the block phase). This may be a required response to the greater centre of mass displacement in order to prevent over-rotation in the senior athletes during the front block pushing phase. Collectively, these results indicate that the progression of junior athletes is non-uniform across the block phase and subsequent two contacts, which should be considered when attempting to progress junior athletes towards senior ranks.</p

Understanding the effect of touchdown distance and ankle joint kinematics on sprint acceleration performance through computer simulation

This study determined the effects of simulated technique manipulations on early acceleration performance. A planar seven-segment angle-driven model was developed and quantitatively evaluated based on the agreement of its output to empirical data from an international-level male sprinter (100 m personal best = 10.28 s). The model was then applied to independently assess the effects of manipulating touchdown distance (horizontal distance between the foot and centre of mass) and range of ankle joint dorsiflexion during early stance on horizontal external power production during stance. The model matched the empirical data with a mean difference of 5.2%. When the foot was placed progressively further forward at touchdown, horizontal power production continually reduced. When the foot was placed further back, power production initially increased (a peak increase of 0.7% occurred at 0.02 m further back) but decreased as the foot continued to touchdown further back. When the range of dorsiflexion during early stance was reduced, exponential increases in performance were observed. Increasing negative touchdown distance directs the ground reaction force more horizontally; however, a limit to the associated performance benefit exists. Reducing dorsiflexion, which required achievable increases in the peak ankle plantar flexor moment, appears potentially beneficial for improving early acceleration performance

THE EFFECT OF THE BEND ON TECHNIQUE AND PERFORMANCE DURING MAXIMAL SPEED SPRINTING

For 200 and 400 m races half of the race is run around the bend. This study aimed to understand the changes in kinematics that occur during maximal effort bend sprinting. Velocity reduction (5%) on the bend compared to the straight was, for the left step, mainly due to increased (20%) touchdown distance and some angular kinematics changes which led to increased contact time and reduced step frequency. During the right step, performance dropped mainly due to a reduction in step length. It is likely that changes caused by inward lean, to counteract moments caused by centripetal forces, on the bend contributed to detrimental changes in sagittal plane kinematics (e.g. knee flexion at touchdown) normally associated with superior performance in sprinting. Similar to straight sprinting, reduced touchdown distance could hold the key to improve bend performance

FORCE PRODUCTION IN THE FIRST FOUR STEPS OF SPRINT RUNNING

The purpose of this investigation was to understand how the athlete produces acceleration during the first steps of sprint running. One athlete performed four starts from starting blocks over a series of four force plates. Horizontal impulse (which directly relates to the acceleration of the athlete) gradually decreased after leaving the blocks, while this decrease was transferred to a gradual increase in vertical force production to support the small but required vertical movement of CM in order to increase flight time (to gain longer steps). It also seems that the body can compensate for some technical mistakes during the performance, as the results revealed that an extended braking time in one step yielded a reduced braking time in the next step. This implied that the increased time in the contact was used to get other body parts into more favourable positions for the next step