create_map_rep_rpe_to_pct
                        Create a mapping from reps and rpe to pct_1rm
e1rm                    Estimated one rep max
hard_sets               Number of hard sets
pct1rm_rts              Mapping from reps and rpe to pct_1rm.
pct_lookup_brzycki      Percentage lookup from Brzycki.
pct_lookup_helms        Percentage lookup from Helms and colleagues.
pct_lookup_rts          Percentage lookup from reactive training
                        systems (RTS)
rpe_tab_brzycki         RPE table from Brzycki.
rpe_tab_helms           RPE table Helms and colleagues.
rpe_tab_rts             RPE table RTS
rpe_tab_to_lookup       RPE table to lookup table
