Kinect and joint coordinates to get angles.

Hi, i have a problem with kinect v1 and matlab 2013, I need to acquire data from the joints when a person is walking but I get very few data because is very slow the sample of the "getdata" to get all the jointscoordinates each second, and thats give me only some angles and looses others that I need. This is the code. I hope someone could help me :(

depthVid = videoinput('kinect',2,'Depth_640x480');
preview(colorVid);
preview(depthVid );
triggerconfig(depthVid,'manual');
depthVid.FramesPerTrigger=1;
depthVid.TriggerRepeat=inf;
set(getselectedsource(depthVid),'TrackingMode','Skeleton')
start(depthVid);
himg = figure;
while ishandle(himg);          
  trigger(depthVid);
  [depthMap, ~, depthMetaData]= getdata(depthVid);
      if sum(depthMetaData.IsSkeletonTracked)>0
       cont=cont+1;
       skeletonJoints= depthMetaData.JointImageIndices(:,:,depthMetaData.IsSkeletonTracked);
       jointCoordinates=depthMetaData.JointWorldCoordinates(:,:,depthMetaData.IsSkeletonTracked);

       imshow (depthMap, [0 4096]);
  
       hold on;
       graficar_esqueleto(skeletonJoints)
       hold off; 

       i=i+1;
       %Angulos de articulación de rodillas 
       jointCoordinates
       %der
       ang1=Angulo(13,15,jointCoordinates);
       ang_rodilla1(i)=(180-ang1)
       
       %izq
       ang2=Angulo(17,19,jointCoordinates);
       ang_rodilla2(i)=(180-ang2)
      else
      imshow (depthMap, [0 4096]);
        end
      drawnow
end
stop(depthVid);
clear depthVid;