Abstract
Using exercise to enhance occupational performance and injury prevention is well documented. In recent years the use of labile suspension exercise devices (i.e. TRX) has become a popular means of exercise used in both performance enhancement and rehabilitative settings. Firefighting is known to be a physically demanding occupation that is associated with a high prevalence of lower back injury. Exercise intervention, namely the inclusion of core training, is a commonly used strategy for injury prevention, performance enhancement, and rehabilitation of the low back. Biomechanical analysis can provide insight to the efficacy of several different dynamic labile suspension exercises. The purpose of this study was to measure the kinematics and electromyographical differences in (EMG) activity of the rectus abdominis (RA), external obliques (EO), and lumbar erector spinae (LES) of firefighters when comparing a TRX Straight Arm Plank to several different TRX core exercise conditions. Six healthy male firefighters were recruited from local fire departments. Each subject performed several different TRX core exercises in randomized order. Mean ± SD EMG activity at the peak phase (p-phase) and Peak EMG was recorded bilaterally for the RA, EO, and LES and compared between a control condition and several other exercise conditions. Dependent samples t-tests were used to detect differences between the exercise conditions. The results indicated that there were significant differences (p < 0.015) identified in the %MVC at the p-phase of the right EO between the control and both the TRX Alternating Knee Tuck (p = 0.007) and TRX Pike (p = 0.0008). Additionally, each TRX suspension exercise elicited significant differences (p < 0.015) in Peak %MVC between left EO (KT, p = 0.006; AKT, p = 0.005; Pike, p = 0.003) and right EO (KT, p = 0.008; AKT, p = 0.006; Pike, p = 0.0002) when compared to the control condition. The TRX pike elicited the highest mean Peak %MVC for the LE (19% ± 12%), LO (64% ± 19%), RO (84% ± 30%), and RRA (58% ± 17%). The findings of this study support the notion that labile suspension exercises in general produce moderate to high levels of abdominal challenge, particularly in the EO. Exercise prescription should take into account and match an individual’s level of fitness, injury history, and training goals. The data collected in this study can help govern exercise selection for the firefighter. The information provided in this research indicates that the TRX suspension exercises can be used as a viable means for strengthening the abdominal wall of firefighters.