Backseat Inclination Affects the Myoelectric Activation During the Inclined Leg Press Exercise in Recreationally Trained Men

Marchetti, PH, Gomes, WA, Da Silva, JJ, Magalhaes, RA, Teixeira, LFM, and Whiting, WC. Backseat inclination affects the myoelectric activation during the inclined leg press exercise in recreationally trained men. J Strength Cond Res 37(10): e541-e545, 2023-Changes in the angle between the seat and backrest during the inclined leg press (ILP) exercise may influence myoelectric activity. The purpose of this study was to evaluate the myoelectric activity between 2 different angles between the seat and backrest (90 degrees and 125 degrees) during the ILP exercise in recreationally trained men. Fifteen young, resistance-trained men (age: 26.8 +/- 5.3 years, height: 173.8 +/- 6.6 cm, total body mass: 81.6 +/- 7.6 kg) performed 1 set of 10 repetitions at 70% of their body mass during the ILP exercise using 2 different angles between the seat and backrest (ILP90 degrees and ILP125 degrees). Surface electromyography (peak RMS90 and iEMG) was used to measure the myoelectric activity of the vastus lateralis (VL), biceps femoris (BF), and gluteus maximus (GM). A paired t test was used to measure differences in knee and hip joint displacement, peak RMS90, and iEMG between ILP90 and ILP125. The hip angle presented a greater displacement during the ILP125 when compared with ILP90 (p < 0.001), considering a similar knee joint displacement. For the VL, there was observed greater myoelectric activation (peak RMS90 and iEMG) during ILP125 when compared with ILP90 (p < 0.05). For the BF, there was observed greater myoelectric activation (peak RMS90 and iEMG) during ILP90 when compared with ILP125 (p < 0.05). However, GM did not present differences between ILP90 and ILP125. In conclusion, the angle between the seat and backrest (ILP90 or ILP125) altered the myoelectric activation of the VL and BF with no difference for the GM.