Erratum: Williams et al (2013) A preliminary evaluation of surface electromyography as a tool to measure muscle fatigue in the National Hunt racehorse

In the article by Williams et al (2013) ‘A preliminary evaluation of surface electromyography as a tool to measure muscle fatigue in the National Hunt racehorse’ published in The Veterinary Nurse 4(9): 566–71, the data analysis protocol reported for mean frequency contained an error. The correct analysis protocol, subsequent amended results and conclusions are reported below. The authors apologise for this error.

Following application of the inbuilt Delsys’ filter to remove noise, initially the mean and median amplitude frequencies of the remaining signal were calculated via EMG Works™. Each of these parameters are considered valuable in the detection of fatigue, but as they are highly correlated, only one is required to assess fatigue changes (Kamen and Gabriel, 2010). Mean frequency was selected for analysis; a consistent decrease in mean frequency implies a reduction in muscle workload corresponding to fatigue (Hanon et al, 2005). Therefore the mEMGF for individual horses were calculated and were plotted over time at 0.125 s intervals with 0.0625 window overlap, for each piece of canter work to visually assess fitness and fatigue levels for the duration of the training periods that were recorded.