An electromyographical evaluation of the validity of the 2-minute sit-up section of the Army Physical Fitness Test in measuring abdominal strength and endurance.
OBJECTIVE
The aim was to evaluate electromyographically the validity of the sit-up section of the Army Physical Fitness Test as a way to assess abdominal endurance.


METHODS
Twenty-eight Reserve Officer Training Corps students at the University of Scranton (Scranton, PA) performed the test while eight electromyography surface electrodes picked up the activity of the rectus abdominus and rectus femoris muscles. The researchers analyzed three groups of five contractions from the beginning, middle, and the end of the test. The percentage area of each group of five contractions for each channel and for each of the 28 participants was averaged.


RESULTS
Two paired sample t tests were used to analyze the change in area for the left hip flexor and left abdominal muscle (t = 5.951, p < 0.001) and right hip flexor and right abdominal muscle (t = 5.025, p < 0.001). Results for both right and left sides indicate a statistically significant increase in the use of hip flexors as compared with abdominal muscles.


CONCLUSIONS
Hip flexors can compensate for fatigued abdominal muscles, causing sit-ups to be performed unsafely, yet are still counted as correct according to Army Physical Fitness Test standards.
Szasz
Anna
A
Department of Physical Therapy, University of Scranton, PA 18510, USA.
Zimmerman
Amy
A
Frey
Erin
E
Brady
Danielle
D
Spalletta
Robert
R
D000009:Abdominal Muscles / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008889:Military Personnel; D010809:Physical Fitness; D015203:Reproducibility of Results