There has been a prevalence of long-distance running footwear incorporating carbon-fiber plates within their midsoles, effectively increasing their longitudinal bending stiffness (LBS). This modification of modern racing footwear has occurred concurrently with large improvements in running times (Bermon et al., 2021), putting into question how these footwear components affect performance (Muniz-Pardos et al., 2021). The current literature has investigated this at level running, but with the increasing popularity of trail running, it is of interest to investigate whether the benefits found during level running translate to graded running. Therefore, the overall aim of this study was to investigate the effects of increased footwear midsole longitudinal bending stiffness (i.e. carbon-fiber plates) on running energetics and biomechanics at various inclines. The effects of high LBS (Nike Vaporfly 4% with midsole intact) and low LBS (Nike Vaporfly 4% with mediolateral cuts made at the forefoot of the midsole through the carbon-fiber plate) footwear conditions were compared for running at 0°, 6°, and 12° inclines. Running energetics and biomechanics data were quantified by measuring metabolic rate and lower leg joint mechanics (from motion capture and ground reaction force measurements). Results from this study suggest that increasing longitudinal bending stiffness within the footwear midsoles has limited influence on running energetics (small non-significant improvements of metabolic power at all inclines), but has considerable effects on the biomechanics of the ankle and MTP joints. However, the most important between shoe differences were independent of grade, suggesting that the benefits of modern racing shoe observed for level running can be expected to translate to steep uphill running. Nevertheless, it should be noted that this study was only able to collect and use data for analysis from a limited number of participants (n=7), and therefore is underpowered, so there may be significant differences that go undetected

Background and aim The pace of development of distance running shoes has been fast-forward since 2016 when Nike introduced their model Nike Zoom Vaporfly, with an imbedded carbon fiber plate and an advanced newly developed Pebax®-foam. The shoe-development has continued to track events, with the introduction of carbon fiber plate in several shoe-models for running and sprint- events. The research area for track events has not reached the level as for distance running shoes, therefore the aim of this study was to examine the effects on long jump performance when using long jump spikes with (AFT) compared to without (non-AFT) a carbon fiber plate.  Method Nine experienced male (n=6, age 22 ± 4.8 years, body mass 76.4 ± 3.5 kg, height 182 ± 4.9 cm), and female (n=3, age 20.3 ± 3.5 years, body mass 64.8 ± 6.0 kg, height 172 ± 2.0 cm) Swedish long jumpers performed three maximal effort long jumps in AFT and non-AFT long jump shoes. Three-dimensional kinematic data was captured with eight markerless motion capture cameras, and the take-off was performed from a force plate. Run-up velocity was measured using a lidar laser and step characteristics using an optical contact grid. Pearson’s correlation coefficient was calculated for jump distance and maximal run-up velocity and paired samples t-tests and a Wilcoxon rank sum test were conducted to examine differences between the shoes.  Results Peak run-up velocity correlated with jump distance both for AFT (Pearson’s r=0.919, p<0.001) and non-AFT shoes (Pearson’s r=0.910, p<0.001). At a group-level no statistical differences were found between the shoes for the run-up variables. The AFT shoes showed significantly greater horizontal velocity at touchdown (p=0.046) and vertical velocity difference from touchdown to toe-off (p=0.029) compared to the non-AFT shoes. No other significant difference was found on group level for the take-off variables. Conclusion The results in this study did not show a longer jump distance in long jump specific AFT shoes compared to non-AFT on a group level, but individual differences were seen. To further understand the effect of AFT shoes on long jump performance, more studies on different individual characteristics and their relation to long jump performance is needed. Keywords Long jump, super spikes, AFT-shoes, carbon fiber plate, biomechanics. / Bakgrund och syfte Sedan Nike 2016 introducerade sin skomodell Nike Zoom Vaporfly har utvecklingen av löparskor med en inbäddad kolfiberplatta och nyutvecklade med energiåtergivande material snabbt fortskridit. Utvecklingen av skor har fortsatt från löparspåren till friidrottsbanan för flera grenar. Forskningsområdet för grenspecifika skor har inte kommit lika långt som för distanslöparskor, därför var syftet med denna studie att undersöka effekterna på längdhoppsprestation av att använda längdhoppsspecifika spikskor med (AFT) jämfört med utan (non-AFT) kolfiberplatta. Metod Nio erfarna manliga (n=6, ålder 22 ± 4,8 år, kroppsvikt 76,4 ± 3,5 kg, längd 182 ± 4,9 cm) och kvinnliga (n=3, ålder 20,3 ± 3,5 år, kroppsvikt 64,8 ± 6 kg, längd 172 ± 2 cm) svenska längdhoppare gjorde tre maximala längdhopp i AFT och non-AFT längdhoppsskor. Tredimensionell kinematisk data samlades in med åtta markörlösa motion capture-kameror och uthoppet skedde från en kraftplatta. Ansatshastigheten mättes med en laserkamera och steg-specifik data med ett optiskt kontaktnät. Pearson’s korrelations koefficient beräknades for hopplängd och maximal ansatshastighet samt så genomfördes paired samples t-test och Wilcoxon rank sum test för att undersäka skillnaderna mellan skorna. Resultat Maximal ansatshastighet korrelerade med maximal hopplängd både för AFT skor (Pearsons r=0,919, p<0,001) och non-AFT skor (Pearsons r=0,910, p<0,001). På gruppnivå hittades ingen statistisk skillnad mellan skorna vad gäller ansatslöpningens variabler. AFT skorna visade en signifikant högre horisontell hastighet vid första markkontakt med kraftplatta (p=0,046) och vertikal hastighetsdifferens från första markkontakt med kraftplatta till sista markkontakt med kraftplatta (p=0,029) jämfört med non-AFT-skor. Ingen annan signifikant skillnad hittades på gruppnivå vad gäller uthoppsvariabler. Slutsats Resultaten i denna studie visade inte på en längre hopplängd i längdhoppsspecifika AFT skor jämfört med icke-AFT skor på gruppnivå men skillnader sågs på individnivå. För att ytterligare förstå effekten av AFT skor på längdhoppsprestation behövs fler studier om olika individuella egenskaper och dess relation till längdhoppsprestation. Nyckelord Längdhopp, super spikes, AFT-skor, karbonfiberplatta, biomekanik.

Syftet med aktuellt arbete var att kalibrera en kamera i MATLAB, med hjälp av tillägget Computer Vision Toolbox, samt utforma ett skript som kan konvertera pixelkoordinater i MATLAB till rumskoordinater. Resultatet av arbetet agerar som ett komplement till en studie på Gymnastik- och idrottshögskolan, där kompression av skosulor undersöks med hjälp av kamera och MATLAB-skript. Flertalet tester utfördes för att säkerställa kalibreringens tillförlitlighet samt kompatibiliteten mellan de två MATLAB-skripten. Kalibreringen anses tillförlitlig, och kompatibiliteten mellan skripten anses god. Vidare utfördes en mindre kompressionsstudie på löpband. Resultaten från denna studie är ej tillförlitliga, eftersom väldigt stora fel behövde tillåtas för att möjliggöra skriptets så kallade pixelspårning. Detta anses vara på grund av ljussättningen vid testerna, samt att kamerans videoupptagning ej hade hög nog bildupptagning per sekund till att följa skornas höga hastighet på löpbandet. Vidare studier av kompression rekommenderas att utföras på stilla underlag, där foten är huvudsakligen stilla i bildens synfält under markkontakt. / The purpose of this work was to calibrate a camera in MATLAB using the Computer Vision Toolbox add-on and to design a script to convert pixel coordinates in MATLAB into spatial coordinates in the room. The result of this work serves as a complement to a study conducted at Gymnastik- och idrottshögskolan in Stockholm, where they are investigating the compression of shoe soles with a camera and a MATLAB-script. Several tests were conducted to ensure the reliability of the calibration along with the compatibility of the two MATLAB scripts. The calibration is considered reliable, and the compatibility of the two scripts is considered satisfactory. Furthermore, a smaller compression study was performed on a treadmill. The results from this study are considered unreliable, as large errors were allowed in the so-called pixel tracking of the MATLAB script. This is considered to be due to bad lighting, and because the video recording did not have a high enough frames-per-second to follow the high velocity of the shoes on the treadmill. Further compression studies are recommended to be performed on stable, non-moving surfaces, where the foot is principally still in the camera’s field of view during ground contact.