This article examined differences between upper and lower abdominal
activation in skilled and less skilled subjects. Interestingly, one
conclusion was that, among incorrect performers of abdominal exercises,
either exercise indistinctly activates the muscle portions - and this is
precisely the sort of finding that is frequently reported by various
researchers who are adamant that there can be no differentiated mucsle
activity over the length of rectus abdominis.
In other words, though various abdominal exercises may appear to be very
similar as performed by different individuals, the pattern of muscle and
recruitment and kinesiology may differ significantly. One again, we note the
fundamental role played by the superordinate cortical and subcortical neural
patterns in determining motor output even in apparently rather gross
activities.
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Sarti M et al Muscle activity in upper and lower rectus abdominis during
abdominal exercises. Arch Phys Med Rehabil 1996 Dec; 77(12):1293-7
OBJECTIVE: To compare the intensity of the upper versus lower rectus
abdominis (RA) muscle activity provoked by each of two different abdominal
exercises and to contrast the intensity of contraction elicited by two
different abdominal exercises on each RA muscle portion. PARTICIPANTS:
Subjects who had practiced endurance or strength training activities (1.5
hours 3 days a week for 3 years) and those who had not accomplished that
criterion comprised a high and a low physical activity group, respectively.
Each of these two groups was divided by the ability to perform the exercises
into two subgroups: correct and incorrect performers (cp, ic). MAIN
MEASURE: Average surface iEMG was compared between upper and lower RA and on
each muscle portion performing curl-up (CU) and posterior pelvic tilt (PT)
exercises. The coefficient of variation, a two-way analysis of variance, and
the t test were calculated.
RESULTS: The upper RA showed significantly greater activity during performance
of CU exercise by the cp subgroups of both high and low activity groups.
Only the cp subgroup of the high activity group showed that PT was
significantly more strenuous than CU exercise on lower RA.
CONCLUSIONS: Among correct performers, CU produces greater activity on upper
RA. For persons who have a high level of activity, PT is more strenuous than
CU on lower RA. Among incorrect performers, either exercise indistinctly
activates the muscle portions.
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Dr Mel C Siff
Denver, USA
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