Problem Getting Motion History Image

I have problem for my MHI image. It is fixed on a frame and it doesn't have the motion sequence. Can anyone tell me how to fix it?

clear all

Video1 = VideoReader('C:\Users\User\Desktop\FYP\database\tumiitgait database\uploaded_video\Normal Walk\normal_id001_1.avi');

ii = 1;

for i=1:227 % keyboard data(:,:,i)=mean(readFrame(Video1),3); end

% data = uint8(255 * data);

 MHI = data;
    % Define MHI parameter T
    T = size(data,3)+20; % # of frames being considered; maximal value of MHI

    % Load the first frame
    frame1 = data(:,1);

    % Compute H(x,y,1,T) (the first MHI)
    fst = MHI(:,1);
    fst(fst>0) = T;
    MHI(:,1) = fst;

    % start global loop for each frame
    for frameIndex = 2 : size(data,3)
        %fprintf('Loading frame Index %d\n',frameIndex);

        % Load current frame from image array
        frame = data(:,frameIndex);
        frame_pre = MHI(:,frameIndex-1);

        MHI(:,frameIndex) = frame_pre - 1; 

        % Set of all non-zero value to T
        frame(frame > 0) = T;

        [y,x] = find(frame > 1);                

        for i = 1 : size(y,1)                    
            MHI(y(i,:), x(i,:), frameIndex) = frame(y(i,:), x(i,:));
        end

    end

    figure, imshow(MHI(:,:,227),[])