How to store values of iterations

I have a for loop with an if condition. I want to store all the values of 'i' for which the codition is met. Right now it only stores the last value of i.

for i=1:length(data)
    x = i+1;
    if i == length(data)
        x = length(data);
    end
    if (magnitude_velocity(x,1)<0.01) && (magnitude_velocity(i,1)>0.01)
           index = i;
    end
end

Answer 1

[Wouter]

index = [];
for i=1:length(data)
    x = i+1;
    if i == length(data)
        x = length(data);
    end
    if (magnitude_velocity(x,1)<0.01) && (magnitude_velocity(i,1)>0.01)
           index = [index i];
    end
end

[Wouter]

And this is a bit shorter:

index = [];
for i=1:length(data)-1
    if (magnitude_velocity(i+1,1)<0.01) && (magnitude_velocity(i+1,1)>0.01)
           index = [index i];
    end
end