The study examined the hypothesis that altered synergistic activation of the knee extensors leads to cyclic modulation of the force fluctuations. To test this hypothesis, the force fluctuations were investigated during sustained knee extension at 2.5% of maximal voluntary contraction force for 60 min in 11 men. Surface electromyograms (EMG) were recorded from the rectus femoris (RF), vastus lat...

OBJECTIVE To evaluate whether using surface electromyography to assess skeletal muscle fatigue during an isometric exercise has the potential to be clinically useful in patients with coronary artery disease (CAD). DESIGN Double sample comparative study. SETTING Cardiac rehabilitation service in France. PARTICIPANTS Sixteen men with documented CAD and 9 age-matched healthy men. INTERVENT...

The purpose of this study was to examine the effects of diverting activities on electromyographic amplitude and mean frequency. On three separate occasions, eleven men and eight women performed two bouts of fifty consecutive maximal concentric isokinetic muscle actions of the dominant leg extensors. Between these bouts, the subjects either solved math problems, performed contralateral dynamic c...

Objective: To identify integrated EMG (I-EMG) activity of 6 lower-extremity muscles during the 8 Star Excursion Balance Tests (SEBTs). Design and Setting: Repeated measures, laboratory setting. Subjects: 10 healthy young adults. Interventions: The SEBTs require the subject to balance on the stance leg and maximally reach with the contralateral foot along each of 8 lines extending from a common ...

[Purpose] This study compared the activity of the quadriceps femoris muscle according to the angle of ankle abduction during a lunge exercise. [Subjects and Methods] Fifteen male healthy volunteers participated in the study. All participants performed the lunge exercise with different angles of ankle abduction (0°, 20°, 40°, 60°). The activity of the rectus femoris (RF), vastus lateralis (VL) a...

Patellofemoral pain syndrome (PFPS) is usually due to weakness of vastus medialis obliquus (VMO) resulting in abnormal patellar tracking. One of the objectives of rehabilitation is to strengthen the VMO so as to counterbalance the vastus lateralis (VL) action during normal activities. This study compared the effects of an 8-week exercise program with and without EMG biofeedback on the relative ...

PURPOSE Leg muscle strength and power are increased after whole-body vibration (WBV) exercise. These effects may result from increased neuromuscular activation during WBV; however, previous studies of neuromuscular responses during WBV have not accounted for motion artifact. METHODS Sixteen healthy adults performed a series of static and dynamic unloaded squats with and without two different ...

BACKGROUND It has been proposed that high-heeled shoes may contribute to the development and progression of knee pain. However, surprisingly little research has been carried out on how shoe heel height affects muscle activity around the knee joint. The purpose of this study was to investigate the effect of differing heel height on the electromyographic (EMG) activity in vastus medialis (VM) and...

This study explored motor adaptations in response to an acute noxious stimulation during three tasks that differed in the number of available degrees of freedom. Fifteen participants performed three isometric force-matched tasks (single leg knee extension, single leg squat, and bilateral leg squat) in three conditions (Control, Pain, and Washout). Pain was induced by injection of hypertonic sal...

[Purpose] The purpose of this study was to examine the correlation between quadriceps muscle activity and balance and gait in stroke patients. [Subjects and Methods] Fifty-five stroke patients (30 males 25 females; mean age 58.7 years; stroke duration 4.82 months; Korean mini-mental state examination score 26.4) participated in this study. MP100 surface electromyography, BioRescue, and LUKOtron...