Journal of Sports Science and Physical Education 5(2): 9-14, 2016 - Jump squat tests can be
used to investigate the differences in the force - velocity (f-v) profile in movement that is
more a sport-specific than isolated exercises such as open chain leg extension. However,
squat jumps involve multi-joint movement, making it questionable which muscle is the main
contributor for the movement. The main aim of this study is to develop a test of isolated knee
extension that encompasses the entire range of human f-v relationship and to investigate the
correlation between linear encoder and kinematic measurement of angular velocity using a
camera system during unloaded kicking. One healthy male subject volunteered to participate
in the study and performed 10 unloaded kicks (knee extension). A cuff was strapped around
the lower leg, approximately 2 cm above the medial malleoli and connected to a linear
velocity encoder (MuscleLab Ergotest version 4010, Norway). During the test sessions, threedimensional
motion analysis was performed with an Oqus Motion Capture System (Qualisys,
Sweden). Data were transferred to Windows-based data acquisition software (Qualisys Track
Manager). There was a positive linear relationship (r = 0.94). The unloaded kicking test to
determine maximum angular velocity at knee extension measured using the QTM showed
that the mean angular velocity was 362˚.s-1, with the highest value being 528˚.s-1. This
preliminary study suggests isokinetic dynamometry (IKD) can be used to investigate the
entire range of velocities (i.e isometric – velocity maximum) of knee extension in normal
human subjects. Further studies can examine the use of IKD in measuring higher velocities.