Seren, with this type of study you can never have enough. Therefore by re-posting this request it is not an indication of the lack of participants it is an indication of the more numbers the stronger the study.
Dear All, we are currently conducting research in to the injury type and rate of barefoot and/or minimalist footwear runners training for a marathon. This study is designed to look at the location, type of injuries as well as their rates that occur in runners who are training for a 2013 marathon barefoot and/or in minimalist footwear. The study will start in January 2013 and carry on until July 2013 (the study will start 3 months prior to your specific marathon). The data collected will hopefully give a better understanding of whether this type of running has fewer injury rates and types than conventional heel strike running (shod), and whether running barefoot or in minimalist footwear has a similar injury rate. This data may also help improve the way people are taught to run barefoot and/or in minimalist footwear. As we are still recruiting participants, the more the better as far as results are concerned, and you would like to take part, please email firstname.lastname@example.org