Abdominal muscle activity according to knee joint angle during sit-to-stand

Abstract

[Purpose] This study assessed the activity of the abdominal muscles according to the angle of the knee joints during sit-to-stand. [Subjects and Methods] Thirty healthy adult males participated in this study. Subjects initiated sit-to-stand at knee joint angles of 60°, 90°, or 120°. An electromyography system was used to measure the maximum voluntary isometric contraction of the rectus abdominis, external oblique, and internal oblique and transverse abdominis muscles. [Results] Percent contraction differed significantly among the three knee joint angles, most notably for the internal oblique and transverse abdominis muscles. [Conclusion] Wider knee joint angles more effectively activate the abdominal muscles, especially those in the deep abdomen, than do narrower angles.

Hip and trunk muscles activity during nordic hamstring exercise

“…Thus, it is very helpful for injury prevention to find how other muscles on hip and knee joints act ( Sahrmann, 2002 ). Change in knee joint angle from flexion to extension increases abdominal muscles activity to control of trunk ( Eom et al, 2016 ). Furthermore, antagonistic cocontraction of trunk muscles provides mechanical stability of lumbar spine in neutral postures ( Cholewicki et al, 1997 ).…”

Contributions of Muscle Elasticity and Lateral Slide of the Transversus Abdominis to Lumbar Stability

“…The functional contraction of the TrA was clarified to be 5% to 10% of the maximum contraction (5% to 10% maximum voluntary contraction), 18 and the activity of the TrA during stand-and-sit was about 10% maximum voluntary contraction. 23 Therefore, contraction of the TrA due to a load of 25% to 45% of the body weight is considered to be <5% of the maximum contraction of the TrA. Hodges et al 24 investigated that the thickness and activity of the abdominal muscle were linearly related up to 20% maximum voluntary contraction, but no association was observed above that; thus, they revealed a ceiling effect in TrA muscle thickness.…”