Statistical analysis
The original study was a double-blind randomised controlled trial and sample preparation and analysis for this work was carried out without any access to information that could identify the individuals involved. Statistical analysis was performed in Aabel 3.0 and SPSS with the exception of the Chi squared test. Normality was determined by Shapiro-Wilk test, with differences between groups determined by Mann-Whitney U test for data that was not normal distributed and Student’s T-test for normally distributed data. Changes in strength at baseline and follow-up were determined by Wilcoxon matched-pairs signed rank test in Aabel 3.0. Values are given as median (interquartile range) for non-parametric data or as mean ± SD for normally distributed data. The threshold for statistical significance (alpha) was taken as 0.05. All available data was used for each comparison and no manipulations were performed to include missing values for individual tests. As the analysis here is exploratory, no corrections have been made for multiple testing. Reasons for loss to follow-up is detailed in [