title: How to create individual lines on top of a boxplot with multiple groups
body: <p>In my study its important to show how each individual adapted to to the training, and not just the group mean and median change.
  As a beginner in R, im happy that ive got as far as my current boxplot with 3 groups, where I have via geom_point added individual dots, but I cant seem to get geom_line to connect lines between dots within each group. 
  All help highly appreciated. </p>
  
  <p>Ive tried to follow a similar posts advise but it did not respond to my data, <a href="https://stackoverflow.com/questions/36240695/connect-ggplot-boxplots-using-lines-and-multiple-factor">Connect ggplot boxplots using lines and multiple factor</a></p>
  
  <p>I dont know if i should be pasting my data.frame into here
  Basically column 1 is which "Group" (Heavy, Optimal, Control), column 2 "Time_point" is whether its pre or post measurements (F0_pre, F0_post) and column 3 "F0" are the values</p>
  
  <pre><code>ggplot(Studydata, aes(Group,F0,fill = Time_point)) + 
    geom_boxplot() +
    stat_summary(fun.y = mean, geom = "point", size=3, shape=23, 
                 position = position_dodge(width = .75)) +
    geom_point(position=position_dodge(width=0.75),aes(group=Time_point)) + 
    scale_y_continuous("F0 (N/kg)",limits=c(5,10),breaks=c(5,6,7,8,9,10),
                       expand = c(0,0)) +
    theme(axis.line = element_line(color = "black",size = 1, linetype = "solid"))+
    theme_classic() +
    scale_fill_manual(values=c("#999999", "#FFFFFF"), name = "Time point", labels = c("Pre", "Post"))
  
  structure(list(Group = structure(c(2L, 2L, 2L, 2L, 2L, 2L, 2L, 
  2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 1L, 1L, 1L, 1L, 1L, 
  1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 
  3L, 3L, 3L, 3L, 3L, 3L, 3L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
  1L), .Label = c("Control", "Heavy", "Optimal"), class = "factor"), 
      Time_point = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
      1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
      1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
      2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
      2L, 2L, 2L), .Label = c("F0_pre", "F0_post"), class = "factor"), 
      F0 = c(7.30353192, 7.16108594, 7.662873671, 7.319494415, 
      7.690339929, 6.640005807, 6.848095385, 6.1605622, 8.300462597, 
      6.906034443, 7.644367174, 7.021959506, 7.042100127, 7.375865657, 
      8.506645287, 6.373721759, 7.507468154, 7.057438325, 7.147624225, 
      7.958957761, 7.439431197, 7.974165294, 8.125949745, 6.532471264, 
      7.481686188, 7.542614257, 7.247552687, 6.91, 7.609185039, 
      7.809989766, 8.151059576, 7.847938658, 7.999819081, 7.935556724, 
      7.679970645, 6.761378005, 8.157705923, 7.545437794, 9.395395275, 
      7.455579962, 7.917317173, 7.465252201, 8.567501942, 7.786701877, 
      7.4971379, 7.649121924, 6.942119866, 7.466501673, 7.653161086, 
      8.220328678, 8.173918564, 7.431310356, 7.98999627, 7.529664586, 
      7.518519833, 6.905140493)), row.names = c(NA, -56L), class = "data.frame")
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/0v0aE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0v0aE.png" alt="enter image description here"></a></p>