\begin{tikzpicture}[->,scale=0.7,auto,x=3cm, y=1.5cm, every node/.style={scale=0.7}]

  \node<1,3,4,5> (EEG) at (1.5,3) {EEG};
  \node<1,2,3,5> (EMG) at (3.5,-0.5) {EMG};
  \node (Syn) at (2.5,0.5) {Synergien};

  \node[align=center] (kin) at (0.55,0.5) {Geschwindig-\\keiten};
  \node (pos) at (-0.5,-0.5) {Positionen};

  \draw<1,2,5>[->,very thick] (EMG) -- (Syn);
  \draw<1,2,5>[->,very thick] (pos) -- (kin);

  \draw<1,3,5>[->] (EEG) -- (EMG);
  \draw<1,3,5>[->] (Syn) -- (kin);
  \draw<1,3,5>[->] (Syn) -- (pos);
  \draw<1,3,5>[->] (EEG) -- (kin);
  \draw<1,3,5>[->] (EEG) -- (pos);
  \draw<1,3,5>[->] (EEG) -- (Syn);
  \draw<1,3,5>[->] (EMG) edge[bend left,distance=1cm] (kin);
  \draw<1,3,5>[->] (EMG) edge[bend left,distance=1.5cm] (pos);

  \draw<1,4,5>[->,dashed] (EEG) .. controls (2.3,0.7) .. (pos);
  \draw<1,4,5>[->,dashed] (EEG) .. controls (2.3,0.7) .. (kin);


  %legend
  \node<1,3,5> (pred) at (-0.1,3) {vorhergesagt};
  \node<1,2,5> (comp) at (0,2.5) {berechnet};
  \node<1,4,5> (via) at (-0.25,2) {mit Zwischenschritt};

  \draw<1,2,5>[->, very thick] (comp) -- ++(0.5,0);
  \draw<1,3,5>[->] (pred) -- ++(0.6,0);
  \draw<1,4,5>[->, dashed] (via) -- ++(0.75,0);


\end{tikzpicture}