I am currently working on publishing an article from my Masters thesis. I had real trouble with the statistics section which was also pointed out by the markers. I was hoping to get some advice on how I could make this section clearer, concise, and overall of a better quality.

Briefly, the experiment involved each of the participants attending 5 exercise sessions. These exercise sessions were of 5 different durations that were performed on different days; these were 30mins, 20mins, 10mins, 6mins, and 2mins. Before and immediately after the exercise, and then after 30mins of rest after exercise, electrical stimulation was delivered to look at neuromuscular function.

With regards to analysis, the electrical activity recorded immediately after exercise and 30mins post exercise was normalised to the one recorded before exercise (the one recorded before exercise was therefore used as a reference), therefore we get data that shows the change relative to before exercise at the two testing points.

I am using SigmaStats 3.5 for statistics. I used two factor ANOVA with repeated measures. The two factors were ‘when electrical stimulation was applied’ and ‘exercise duration’. When a main effect or interaction was detected, significant differences were located using Tukey’s post hoc analysis. Basically we were looking to see how the different durations of exercise effects muscle activity after exercise.

My first question is whether the correct statistical measure has been used? Would it be better to use one way ANOVA? If two factor ANOVA is the correct statistical analysis to use I have a few questions about analysis and interpretation please. For one variable, it says that the mean values among the different levels of Condition is not great enough to exclude the possibility that the difference is just due to random sampling variability after allowing for the effects of differences in Time, and that There is a statistically significant difference between the different times, and that there is no interaction. So for this example does it mean that yes at the different exercise durations there is a sig difference but this can’t be determined for each of the two times stimulation was applied? So then how do you know at which point the difference exists, whether its straight after exercise or after 30min rest?

My next question is to do with interactions. When an interaction is detected, what does it mean? For example, if there is a significant difference for a variable measured 30 minutes post exercise compared to straight after exercise, for all exercise durations, what does it mean by saying there is an interaction between the two? Similarly, if significant differences occur between different exercise durations for each of the two conditions (the two points of neuromuscular function tests) what would that mean in terms of the interaction? Oh and also why isn’t the main effect analysed when there is an interaction, like would it not be useful to analyse the main effect for each factor even when there is an interaction?

As you can probably tell my stats knowledge is extremely limited. Any help or direction would be much appreciated. Thank you so much in advance for any help or advice that can be given