SLOW VS. FAST CRUNCHES which are better

SLOW VS. FAST CRUNCHES

Which speed is most effective for ab training?

by Jim Stoppani, PhD

Which speed is most effective for ab training?

OPENING ARGUMENTS

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.

EVIDENCE

■ 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.