How do I open multiple folders from one hdf5 file simultaneously?

I have 20 participants with all 4 trials. Every trial consists of a hdf5 file with 12 folders (different parameters). How can I open multiple folders (from the same hdf5 file) at the same time? I don't want to write 20*4*12 lines to open each parameter.

This is just a draft, but I would like to end up with a struct file for each participant with the 4 trials and 12 parameters in each trial.

for kk = 1:20
    for ii = 1:4
        for jj = 1:12
            participant_(kk).trial_(ii) = h5read('file_',sprintf('%d',i),'.h5','/Measures/Gait/Lower Limb/'foldernames(jj));
        end
    end
end