The purpose of this study was to investigate the differences in muscle activity of the lumbar and pelvic extensor muscles during the hyperextension and reverse hyperextension exercises. Fifteen healthy and weight-trained volunteers (8 women, 7 men) were recruited from a university setting. Electromyographic (EMG) activity of selected hip and trunk extensor muscles was recorded during the execution of a hyperextension and a reverse hyperextension. Three muscles were analyzed: lumbar erector spinae (ES), biceps femoris (BF) and gluteus maximus (GM). The amount of external load used by each individual was determined by equating the amount of torque produced at the hip joint for both exercises. Participants performed two trials of each exercise, and completed at least three repetitions within the eight-second data collection period. Peak integrated EMG (iEMG) activity was expressed as a percentage of maximal voluntary isometric contraction (%MVC). A two-way repeated measures analysis of variance (ANOVA) failed to demonstrate significant differences in %MVC activity between the two exercises, (p>0.05). A comparison of the hyperextension and reverse hyperextension exercises revealed that under similar loading conditions, there is no significant difference in muscle activity of the lumbar and hip extensor muscles. / School of Physical Education

Thesis (M.S.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Vita. Bibliography: 115-118.