improve commentary in Limbs2.m

dat/Limbs2.m

@@ -13,7 +13,9 @@ t = 0 : 1 : END;
 q = 0 : 0.001: END;
 
 % vars starting with tr_ are "tracks", or arrays of unprocessed positions
-% over a period of time
+% over a period of time. The rotational position of a joint is measured
+% in radians. Each array corresponds to a degree of freedom. The length
+% of each array is to be equal to the value of END plus 1.
 
 % TRACKS: Left Leg Joints X, Y, Z
 tr_LHipY = [0, 0, 0, 0, 0]; % positive: move foot back