An EMG Study Analysis Between Upper and Lower Rectus Abdominis Muscles in Asymptomatic and Chronic Low Back Pain Patients

The aim of this study is to compare the EMG activity of upper and lower rectus abdominis in normal subjects and chronic low back pain patients.

A convenience sample of 30 male subjects were participated in the study. In group A 15 healthy male subjects of mean age (24±1.7) year, height (162.6±3.5cm.) and weight (65.9±5.6) kg participated and they were not having any history of low back pain and abdominal surgery. In group B 15 patients having chronic low back pain from at least past 3 months were participated who scored more than 50% disability according to the Oswestry disability index with mean age (24.3±2.6year), height (163.6±4.8) cm and weight (67.2±6.3) kg. All the subjects were selected according to the inclusion and exclusion criteria and were divided into two groups. The subject in both the groups were performed two exercises i.e. curl-ups and leg raise. The EMG activity was recorded from URA and LRA muscles sites during curl-ups and leg raise exercise after proper placement of electrode.

Analysis of activity of URA & LRA between group A & B was showing no significant difference of URA & LRA activity during curl-ups & leg raise (P>0.05). Analysis of EMG activity within exercises for group A during Curlups and Leg-raises showed no significant difference (P>0.05). Analysis of the EMG activity of URL & LRA within exercises for group B showed no significant difference (P>0.05). Analysis of the amplitude of EMG activity of URA during leg raise and curl ups showed significant difference. The activity of URA during curls-up was more than during leg raise (P<0.05).Analysis of the activity of LRA also shows significant difference between the exercises i.e. curl- up & leg raise. The activity of LRA was also less during leg raise & more during curlups (P<0.05). Analysis of EMG activity of URA and LRA between exercises in group B also showed significant difference. The URA and LRA activity more in curl-ups than in leg raise exercise (P<0.05).

The result of this study showed that there was no significant difference in EMG activity of URA & LRA between healthy subjects and chronic low back pain patients. The URA & LRA showed equal activity within the exercise in both groups, but EMG activity of URA & LRA showed significant difference between the exercises i.e. during curl-ups the URA & LRA showed more EMG activity/amplitude than during leg raise exercise. Clinical Relevance In this present study we have seen that there was no significant difference in EMG activity of URA & LRA between healthy individuals and low back pain patient, but URA & LRA showed more EMG amplitude during curl ups than in the leg raise. So curl-up exercise was more strenuous on rectus abdominis than leg raise. So curl-ups exercise can be used to strength the Rectus abdominis.