Abdominal strengthening using the AbVice machine as measured by surface electromyographic activation levels.

Twenty-four college students served as subjects in a study that examined the effect of a prototypical abdominal muscle strengthening device (AbVice) compared with other devices currently on the market. The purpose of the present study was to investigate a prototypical device (AbVice) that incorporates contraction of the hamstring and gluteal musculature in conjunction with the abdominals, which may assist in decreasing activation of the hip flexors by allowing greater activity levels of the abdominal musculature via the theory of reflex inhibition, compared with other devices currently available on the market (AbRoller and AbRocker). The repeated-measures study included 17 women and 7 men who ranged in age from 20-23 years (mean +/- SD age, 21.3 +/- 1.5 years). Each subject underwent a single session of data collection during which they completed 10 repetitions of abdominal crunches per device. Subjects completed 4 different crunch sets (AbRocker, AbRoller, standard crunch, AbVice). Counterbalancing of the device was used to negate the effect of fatigue. Speed of repetitions was ensured via use of a metronome set at 40 b.min(-1) to permit similar contraction times and rest periods between repetitions. Rest between conditions was 3 minutes. Mean activation levels of surface electromyography (EMG) were recorded for each condition at the following locations on the right side of the body: rectus abdominis 2.5 cm superior to the umbilicus, rectus abdominis 2.5 cm inferior to the umbilicus, external oblique abdominis 1.0 cm medial to the anterior superior iliac spine, and external oblique abdominis less than 1.0 cm superior to the inguinal ligament. Mean (SD) activation was 1,165.21 mV (634.60 mV) with the AbVice, 242.92 mV (263.03 mV) with the AbRocker, 753.29 mV (514.80 mV) with the standard crunch, and 757.67 mV (542.85 mV) with the AbRoller. Broken down by sex, women had the following mean (SD) EMG values: 1,079.76 mV (705.02 mV) with the AbVice, 680.35 mV (535.35 mV) with the standard crunch, 262.70 mV (305.89 mV) with the AbRocker, and 636.88 mV (502.82 mV) with the AbRoller. Men demonstrated mean (SD) values of 1,372 mV (383.87 mV) with the AbVice, 1,051 mV (560.09 mV) with the AbRoller, 930.43 mV (447.17 mV) with the standard crunch, and 194.86 mV (109.05 mV) with the AbRocker. Two-way analysis of variance with factor 1 (person) and factor 2 (condition) had F values of 11.73 and 36.04, respectively. Post hoc analysis using the Tukey test indicated that all comparisons between conditions were significant at the p = 0.01 level except for the standard crunch vs. the AbRoller. The AbVice activated the selected abdominal musculature more effectively than the other conditions.