Electromyographic Analysis of Core Muscles During front Plank Exercises Using the trx® System at Different Heights

Abstract

Abstract The importance and popularity of core training call for ongoing adjustments in exercise selection, overload, and progression to optimize workout outcomes. This study aimed to compare core muscle electromyographic activity during a 45-second isometric contraction under the front plank exercise with a Total-body Resistance Exercise (TRX®) system attached to the upper limbs at varying heights above the ground: a) 10 cm (FP-TRX10); b) 35 cm (FP-TRX35); c) 60 cm (FP-TRX60); and d) 85 cm (FP-TRX85). Twelve physically active male volunteers (mean age: 23.58 ± 2.58 years; mean weight: 75.29 ± 4.23 kg; mean height: 177.04 ± 4.96 cm; mean body fat: 11.57 ± 2.63%), without neuromuscular disorders, participated. Electromyographic signals were recorded from the rectus abdominis (RA), external oblique (EO), internal oblique (IO), erector spinae (ES), and multifidus muscles. Maximum values (root mean square [RMS]) were normalized to maximum voluntary isometric contraction. Statistical analysis was conducted using GraphPad Prism software. Results indicated significantly higher electromyographic activity in the RA, EO, IO, and ES muscles (p < 0.05) during the FP-TRX10 exercise compared to FP-TRX85, with ES muscle activity significantly higher (p < 0.05) in FP-TRX10 than FP-TRX60. Lower TRX® system heights (e.g., FP-TRX10) elicited greater electromyographic activity in most core muscles, highlighting height as a crucial exercise progression factor. FP-TRX10 could represent an advanced step in core training, transitioning from the highest (FP-TRX85) to the lowest point (FP-TRX10) for optimal progression.

Keywords

• Surface electromyography
• Exercise program
• Rectus abdominis