Which speed is most effective for ab training?
Defense Bodybuilders have always done reps in a slow
and controlled manner, because it better works the target
muscle rather than relying on momentum to “cheat”
on the exercise. Therefore, crunches should be
performed at a speed no faster than 2 seconds on
the positive (concentric) reps and 2 seconds
on the negative (eccentric) reps.
Prosecution Fast reps (at a speed of
1 second or less on the positive) can help to
recruit more muscle fibers, which can lead to
better muscle development, including the abs.
■ Spanish researchers tested the muscle activity of
subjects’ rectus abdominis, external obliques, internal
obliques and spinal erectors while they performed crunches
at a rep speed of 4 seconds, 2 seconds, 1.5 seconds, 1 second
or as fast as possible.
■ They reported that as the rep speed increased, the muscle
activity of all four muscles increased. The greatest boost
in muscle activity occurred in the external obliques, which
were hardly involved in the crunch at the slower speeds, but
rose by over six times at the fastest speed.
VERDICT FAST REP SPEED
The fast reps will help to recruit more muscle fibers in the
midsection and will particularly help to turn an ab exercise,
such as the crunch, into a fairly effective oblique exercise.
SENTENCING Be sure to mix up your rep speed during ab
exercises — such as the crunch — going slow and controlled
for some workouts, and as fast as possible for other
workouts. This can help you build better-developed abs that
are also strong and powerful.