Abstract
This study examined the impact of different inter-repetition rest (IRR)
configurations (zero seconds [IRR0], three seconds [IRR3], and self-selected
less than five seconds [SSIRR]) on estimating the number of repetitions (Nrep)
and the percentage of completed repetitions relative to the maximum number of
repetitions possible to failure (%rep) after reaching 10%,
20%, and 30% velocity loss thresholds (VLT). Eighteen men
completed three sessions, each with a different IRR configuration, separated by
48–72 hours. Single sets of repetitions to momentary muscular
failure were performed against 65%, 75%, and 85% of the
one-repetition maximum during free-weight back squat and bench press exercises.
No significant differences were reported between IRR configurations for the Nrep
(P≥0.089) and %rep (P≥0.061), except
for %rep after reaching the 20–30%VLT against
65%1RM and the 10–20%VLT against 75%1RM in the
bench press exercise (P≤0.048). Additionally, both Nrep and
%rep exhibited high interindividual variability (between-subject
CV=14–79%) across the different IRR configurations. The
individual %rep-%VLT relationships were slightly stronger than
the general %rep-%VLT relationships (median
R
2
=0.914–0.971 vs.
0.698–0.900). Overall, regardless of the IRR configuration, this novel
velocity-based approach does not guarantee the same effort levels across
subjects in the free-weight back squat and bench press sets.
Key word
exercise prescription - level of effort - strength training - velocity-based training
