The overall purpose of this thesis was to validate the SRSS questionnaire. This was accomplished by conducting a single investigation using eleven well-trained weightlifters with at least one year of competition experience. These weightlifters completed five testing sessions over the course of five microcycles leading up to a competition. Every testing session took place on Monday morning prior to regular training and included: hydration testing, SRSS questionnaire, blood draws followed by a standardized warm-up protocol and squat jumps (SJ) with 0kg and 20kg. While the majority of SRSS recovery and stress items did not change with changes in VL or VLd, emotional balance and lack of activation did correlate with changes in VLd. Additionally, decreases in SRSS recovery items physical performance capability and emotional balance coincide with decreases in squat jump height and increases in cortisol following the first taper microcycle. The findings of this investigation partly support the SRSS as a monitoring tool for weightlifters.

This present study was intended to identify the reliability and validity of the Vert™ device when compared to a Switch mat. Vert is a wireless device intended to measure jump count and jump height through an application on a smartphone or tablet and the Switch mat provides jump height using wireless sensors. Jump height is an important factor in many sports such as volleyball and basketball and it is important to have devices that coaches and trainers can use for testing that they can rely on. If this device is found to be valid and reliable, coaches and trainers could potentially use it in more practical settings such as practice and games due to the portability and small size. This study consisted of 6 subjects who volunteered. The switch mat was connected to the device to display the jump height immediately after the jump. The Vert sensor was clipped onto the subject’s hip near the center of mass and the jump count and height were then displayed on an app. The subjects completed a series of warm-ups followed by 3 sets of 5 repetition countermovement jumps while using both devices to collect the data. The total 15 jump heights from these 3 sets of 5 were then analyzed using Pearson correlation analysis as well as a paired sample T-test. The jump height recorded from the Vert was consistently about 10 cm off from the jump height of the switch mat, which for a volleyball player, could be the difference between blocking and missing the ball. The results of this study showed that the Vert device is reliable but not practically valid. If technical improvements were made to the device to correct the height components the device could potentially be used in place of a force plate or switch mat when conducting athlete testing but the device is not currently valid for practical use.

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.