Muscle activity in upper and lower rectus abdominus during abdominal exercises.
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.


METHODS
Nonrandomized control trial.


METHODS
Kinesiology laboratory in a university medicine faculty.


METHODS
Convenience sample of 33 healthy volunteers. 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).


METHODS
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 (t = 2.14302, 95%) and low (t = 2.35875, 95%) activity groups. Only the cp subgroup of the high activity group showed that PT was significantly more strenuous than CU exercise on lower RA (t = -2.06467, 95%).


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.
Sarti
M A
MA
Unidad de Ivestigación de Cinesiología, Departamento CC Morfológicas, Universidad de Valencia, Spain.
Monfort
M
M
Fuster
M A
MA
Villaplana
L A
LA
D000009:Abdominal Muscles / Q000502:physiology*; D000200:Action Potentials; D000328:Adult; D000704:Analysis of Variance; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D012494:Sampling Studies