Synergy of medial and lateral hamstrings at three positions of tibial rotation during maximum isometric knee flexion.

Rotation of the knee has been used to isolate the strength of the medial and lateral hamstrings during manual testing of the knee flexors. The purpose of this study was to determine if medial and lateral rotation of the knee during manual knee flexor strength testing increased the electromyographic activity of the respective hamstrings. Twenty-three women between 22 and 36 years old with no history of lower extremity injury or disease participated in the study.

Relationship between wire EMG activity, muscle length, and torque of the hamstrings.

Objective: To determine the effect of change of muscle length on the torque and wire electromyographic activity of six knee flexor muscles.

Design: Maximum isometric knee flexion torque and wire EMG data were collected at nine different positions.

Background: In vivo EMG-length-tension relationship is difficult to determine because of the interaction between muscle length and moment arm.

Are patellofemoral pain and quadriceps femoris muscle torque associated with locomotor function?

Background And Purpose: The purpose of this investigation was to determine the influence of pain and muscle weakness on gait variables in subjects with patellofemoral pain (PFP).

Subjects: Nineteen female subjects with a diagnosis of PFP and 19 female subjects without PFP participated in the study.

Methods: Subjects underwent gait analysis (stride characteristics and joint motion) during level walking, ascending and descending stairs, and ascending and descending ramps, in addition to isometric torque testing of the knee extensors of the involved limb.

Quadriceps force and myoelectric activity during flexed knee stance.

The purpose of this study was to determine the quadriceps demand during single limb stance with the knee in five positions of flexion (0 degree -60 degrees). Two variables were used to estimate the quadriceps demands: the integrated electromyogram (EMG) of three vasti and the torque about the knee joint. Ten normal subjects 23-29 years of age were tested.

Effects of feedback stimulation training and cyclical electrical stimulation on knee extension in hemiparetic patients.

Positional feedback stimulation training and cyclical electrical stimulation were used in combination as a treatment for facilitating knee extension in hemiparetic patients. Forty adult hemiparetic patients who demonstrated minimal active control of their quadriceps femoris muscles were randomly assigned to control or study groups. The control patients received a program of physical therapy, and the study patients received the positional feedback stimulation training in addition to their therapy program.