Abstract
This study investigated the acute effects of seated and supine knee extension
exercise on muscle swelling, torque, and work output. Twelve resistance-trained
men performed two isokinetic concentric-only knee-extension training protocols
at different hip positions in a counter-balanced order. They completed the knee
extension exercise in the seated (hip angle at 85°) and supine (hip
angle at 180°) positions. The torque and work output were assessed
during each set. Moreover, muscle thickness of the middle and proximal vastus
lateralis and rectus femoris were evaluated before and after each protocol and
used as an indicator of muscle swelling. Middle rectus femoris and proximal
vastus lateralis thickness increased significantly (p=0.01) with no
difference between exercise variations. However, the middle vastus lateralis
thickness increased (p=0.01) only after the seated knee extension
exercise (~7%). Knee extensors’ peak torque and work
output were approximately 8% higher (p=0.04) in the seated when
compared to the supine hip position. There was a similar decrease in torque and
work output throughout both protocols (p=0.98). In conclusion, seated
knee extension exercises produced greater torque, work output, and muscle
swelling in the vastus lateralis when compared to the supine knee extension
exercise.
Key words
total work - muscle swelling - resistance training - fatigue index - torque