Trouble with animation (getframe and movie)

I'm working on a project and I need to animate a simple line graph. I have a program set up to solve an ode45 and return a matrix. When I graph the 1st column vs. the 3rd column, it graphs perfectly, but I can't figure out how to convert the still image to an animation. Ideally, I'd like to have the existing line remain and have a ball animate along the trajectory. Here's the relevant coding. Any help would be greatly appreciated. Thanks

%%Set up and use ODE45 to evaluate
% 
timeint = linspace(0, 20, 200);
initialcond = [x0, xPrime0, y0, yPrime0];
[t x] = ode45('flowanalysis_func' , timeint , initialcond , [] , A , U , V);
% 
%%Plot Initial Figure
% 
f = figure(1);
plot(x(:,1), x(:,3)); % note this plots perfectly
grid on
xlabel('X (m)')
ylabel('Y (m)')
legend('Sphere')
title('Position of Sphere')
% 
%%Animation Loop
% 
for j=1:length(x(:,1)) % here's where I'm having trouble.  I can't seem to understand the help txt
    plot(x(j,:,1),x(j,:,3))
    M(j) = getframe;
end
movie(M,10,12)