This study was undertaken to evaluate the influence of weight shift over the affected leg of standing hemiplegic patients on the electromyographic responses of the medial gastrocnemius and tibialis anterior muscles during continuous anterior-posterior movements of the base of support. Recordings were taken from 10 hemiplegic subjects and from 9 healthy subjects of comparable age. Each subject w...

Changes in electromyographic (EMG) parameters are used to evaluate timing, amplitude, and fatigue of muscle actions during movement. Little published data describe the reliability and precision of multiple EMG parameters, how these parameters compare to one another, and how these parameters vary between muscles. The purpose of this study was to determine the reliability and precision of four EM...

PURPOSE The purpose of this investigation was to determine the effect of stable and unstable conditions on one repetition maximum strength and muscle activity during dynamic squatting using absolute and relative loading. METHODS Ten recreationally weight-trained males participated in this study (age = 24.1 +/- 2.0 y, height = 178.0 +/- 5.6 cm, body mass = 83.7 +/- 13.4 kg, 1RM/body mass = 1.5...

The aim of this critical appraisal and hazards of surface electromyography (SEMG) is to enhance the data acquisition quality in voluntary but complex movements, sport and exercise in particular. The methodological and technical registration strategies deal with telemetry and online data acquisition, the placement of the detection electrodes and the choice of the most adequate normalization mode...

AIM Sledge jump systems (SJS) are often employed to examine the underlying mechanical and neuromuscular mechanisms of the stretch-shortening cycle (SSC) as they allow the systematic variation of impact velocity and energy. However, in existing SJS the jumps are not very comparable to natural jumps because of the long contact times (∼200%), which prevent the storage of kinetic energy. The aim of...

Injuries from slips, falls and overexertion during ladder cfimbing activities are common in both occupational and non-occupational environments. Little is known, however, about the task, equipment, and user parameters which may cause these injuries. In order to evaluate the hazards assocmted with ladder climbing, ten male subjects were tested under combinations of ladder rung separation, ladder...

This study analysed the effect of different electromyographic (EMG) capture rates during maximal voluntary contraction, submaximal and maximal dynamic cycling activity on EMG amplitude and signal characteristics. Ten healthy subjects participated in this study. Peak power output (PPO) and maximal isometric force output (MVC) were measured, followed by a progressive cycle ride on a cycle ergomet...

BACKGROUND The purpose was to investigate the effect of double-leg semisquat with hip adduction on the activation of vastus medialis oblique (VMO) and vastus lateralis (VL) in patients with patellofemoral pain syndrome (PFPS). METHODS Thirty patients with PFPS were designated to the study group, while 30 healthy matched subjects were enrolled in the control group. The activation of VL and VMO...

Nitrate (NO3-) supplementation may enhance fatigue resistance and recovery, possibly because its additive effect on muscle blood flow (BF) during contraction. During submaximal contractions, there are numerous ways in which the decrease performance can be compensated for, such as motor unit (MU) recruitment, or increasing firing rate (MUFR). Given that changes BF correlates with MUFR, increased...