The purpose of this study was to examine the extent of activation in various trunk muscles during dynamic weight-training and isometric instability exercises. Sixteen subjects performed squats and deadlifts with 80% 1 repetition maximum (1RM), as well as with body weight as resistance and 2 unstable calisthenic-type exercises (superman and sidebridge). Electromyographic (EMG) activity was measu...

OBJECTIVES The objectives of this study were to determine the psychological fatigue and analyze muscle activity of production workers who are performing processes jobs while standing for prolonged time periods. METHODS The psychological fatigue experienced by the workers was obtained through questionnaire surveys. Meanwhile, muscle activity has been analyzed using surface electromyography (sE...

OBJECTIVE The aim of this study was to investigate the effects of an EMG-based feedback device on the human musculoskeletal system by assessing the kinematics of the lumbar and cervical regions during computer operation. METHODS Using an EMG device, measurements were collected under four conditions: with feedback from the upper trapezius muscle, from the L4-erector spinae muscles and from bot...

BACKGROUND Changes in activation of the trunk and hip extensor muscles can result in excessive stress on the lumbar spinal structures, predisposing them to lesions and pain. OBJECTIVES To compare electromyographic activity of the gluteus maximus, semitendinosus and the erector spinae muscles between asymptomatic and individuals with low back pain during active prone hip extension exercises. ...

In people with a history of low back pain (LBP), structural and functional alterations have been observed at several peripheral and central levels of the sensorimotor pathway. These existing alterations might interact with the way the sensorimotor system responds to pain. We examined this assumption by evaluating the lumbar motor responses to experimental nociceptive input of 15 participants du...

[Purpose] This study compared the effects of sling exercises with and without vibration on the muscular activity of the internal oblique (IO), rectus abdominis (RA), multifidus (MF), and erector spinae (ES) muscles of healthy adults. [Methods] Eleven healthy university students (11 men) with a mean age of 22.8 years were enrolled in this study. Subjects performed supine and prone bridge exercis...

[Purpose] The effect of duration of smartphone use on neck and shoulder muscle fatigue and pain was investigated in adults with forward head posture. [Subjects and Methods] Thirty-four adults with forward head posture were classified into groups by duration of smartphone use: 11 used a smartphone for 10 minutes each (group 1), 12 for 20 minutes each (group 2), and 11 for 30 minutes each (group ...

We examined the effects of changing target distance from within arm's length (AL) to beyond arm's length on the onsets of electromyographic (EMG) activity of non-focal muscles for a reaching task performed while standing. Two questions were addressed. First, do changes in target distance result in consistent changes in the onsets of non-focal anticipatory muscle activity of the trunk and legs i...

To evaluate the effect of short-duration, high-load resistive exercise, with and without whole body vibration on lumbar muscle size, intervertebral disk and spinal morphology changes, and low back pain (LBP) incidence during prolonged bed rest, 24 subjects underwent 60 days of head-down tilt bed rest and performed either resistive vibration exercise (n = 7), resistive exercise only (n = 8), or ...