The purpose of this study was to compare ground contact time between an optical measurement system and a force platform. Participants in this study included six collegiate level athletes who performed drop jumps and sprint strike steps for a total of 15 repetitions each. Ground contact data was simultaneously collected from an optical measurement system and a force platform, at a sampling frequency of 1000 Hz. Data was then analyzed with Pearson’s correlation and paired sample t-tests. The measures from the optical measurement system were found to be significantly higher (p < 0.001) than measures from the force platform in both conditions. Although significantly different, the extremely large relationships (0.979, 0.993) found between the two devices suggest the optical sensor is able to detect similar changes in performance to that of a force platform. Practitioners may continue to utilize optical sensors to monitor performance as it may provide a superior user-friendly alternative to more traditional based monitoring procedures, but must comprehend the inherent limitations due to the design of the optical sensors.

Syfte och frågeställning Syftet med studien är att studera hur svenska elitlöpares totaltider förhåller sig till de olika variablerna markkontakt, flygtid, hastighet, stegfrekvens och steglängd, med största fokus på hur markkontakterna påverkar hastigheten. Studiens två frågeställningar var: (1) Hur ser sambandet ut mellan de fyra variablerna markkontakt, flygtid, steglängd samt stegfrekvens vid den maximala hastigheten vid upprätt löpning hos elitlöpare verksamma inom sprintdistansen 100 meter? (2) Hur korrelerar markkontakt och hastighet hos elitlöpare verksamma inom sprintdistansen 100 meter? Metod En kvantitativ studie genomfördes där 33 manliga och 20 kvinnliga försökslopp på flygande 30 kartlades med mätutrustningen Optojump. Dessa mätvärden analyserades i SPSS för att jämföra korrelation mellan varje mätvärde, ett sambandsdiagram mellan markkontakt och hastighet gjordes samt den översiktliga statistiken analyserades. Resultat Resultaten visar att kortare markkontakter kan ge en högre hastighet, att flygtiden mellan män och kvinnor är lika, att genomsnittet av löparna i studien hade än lägre stegfrekvens och steglängd än litteraturen som presenteras i studien. Slutsatser Resultatet i studien visar att, i likhet med forskningsstudier, att en kortare markkontakt kan ge en höge horisontell löphastighet än en lång. Studien åskådliggör dock att betydligt fler variabler, än endast markkontakt, har stor inverkan på hastighet och totaltid. Jämfört visar detta att mer forskning inom området behövs för att kunna optimera träningsupplägg för löpare. / Purpose and question The purpose of the study is to show how Swedish elit runners total times relate to the different variables ground contact, flight time, speed, step rate and step length, with the main focus on how the ground contacts time affect speed. The study's two main questions were: (1) What is the relationship between the four variables: ground contact, flight time, step length and the velocity at the maximum speed at upright running (2) How do the variable ground contact and velocity correlate between elite runners competing within the track and field event 100 meters? Method A quantitative study was conducted in which 33 male and 20 female runs attempts were mapped with the measuring equipment Optojump. These measured values were analyzed in SPSS to compare correlation between each measurement value, a scatterplot between ground contact and speed, and the summary statistics were taken out. Results The results show that shorter ground contacts times can provide a faster running velocity, that the flight time between men and women is equal, the average of the runners in the study have lower step rate and step length then the literature presented in the study. Conclusions The result of the study shows that, like research studies, a shorter ground contact time can provide a higher horizontal running speed than a longer ground contact. However, the study illustrates that significantly more variables, than only ground contact, have a major impact on velocity and total time. In comparison, this shows that more research in the field is needed to optimize training for runners.