Retraction Note: Performance improvement in sport through vitamin D - a narrative review.

The article "Performance improvement in sport through vitamin D - a narrative review" by K. Weiss, A. Devrim-Lanpir, Z.

Sex Differences in Participation and Performance Trends in Time-Limited Ultramarathon Events.

We aimed to analyze sex differences in time-limited ultramarathon participation, while also identifying trends in participation, age, and performance across different formats of events, from 1990 to 2020. This is an exploratory study, using data obtained from the official event web pages. We downloaded information regarding the year of the event, athletes' year of birth, sex, race event, ranking, and mean running speed (km/h).

Analysis of the 10-day ultra-marathon using a predictive XG boost model.

Objective: Ultra-marathon running races are held as distance-limited or time-limited events, ranging from 6 h to 10 days. Only a few runners compete in 10-day events, and so far, we have little knowledge about the athletes' origins, performance, and event characteristics. The aim of the present study was to investigate the origin and performance of these runners and the fastest race locations.

The influence of origin and race location on performance in IRONMAN® age group triathletes.

Background: The IRONMAN® (IM) triathlon is a popular multi-sport, where age group athletes often strive to qualify for the IM World Championship in Hawaii. The aim of the present study was to investigate the location of the fastest IM racecourses for age group IM triathletes. This knowledge will help IM age group triathletes find the best racecourse, considering their strengths and weaknesses, to qualify.