The purpose of this study was to examine the effectiveness of an electronic muscle stimulator in strengthening normal quadriceps femoris muscle without the assistance of simultaneous isometric muscle contraction. The sample consisted of 58 subjects who were randomly divided into three independent groups. One group (n = 19) served as controls; one group (n = 20) underwent daily stimulation of th...

The aim of this study was to evaluate the effect of neuromuscular fatigue on vastus medialis and vastus lateralis co-contraction. Fifteen healthy young subjects performed an isometric leg extension test in two different condition phases: i) maximum test for determining the maximum voluntary isometric contraction, and ii) fatigue test for exercises executed at 50% of the maximum voluntary contra...

Balanced forces around the shoulder are important for normal function; however, rehabilitation guidelines are not well defined because the muscle contributions and optimal exercise technique to recruit them are poorly understood. This study aimed to determine (1) the conditions of resisted isometric external rotation that optimized the contribution of infraspinatus and (2) the load of external ...

BACKGROUND Frequent or chronic tension-type headache in children is a prevalent and debilitating condition for the child, often leading to medication overuse. To explore the relationship between physical factors and tension-type headache in children, the quality of repeated measures was examined. The aim of the present study was to determine the test-retest repeatability of parameters determini...

proprioceptive neuromuscular facilitation (pnf) training (contraction - relaxation method), in compared to the other methods of static and dynamic stretching exercises; has higher and safer effects on enhancement of hamstring muscle's flexibility, strength and endurance. achieving the optimal combination of contraction and stretching phases in pnf training that can increase these factors of phy...

STUDY DESIGN Controlled laboratory study, cross-sectional data. OBJECTIVES To investigate isometric knee flexion and extension strength, failure of voluntary muscle activation, and antagonist cocontraction of subjects with knee osteoarthritis (OA) compared with age-matched asymptomatic control subjects. BACKGROUND Quadriceps weakness is a common impairment in individuals with knee OA. Disus...

This study assessed changes in electrical impedance myography (EIM) at different levels of isometric muscle contraction as well as during exhaustive exercise at 60% maximum voluntary contraction (MVC) until task failure. The EIM was performed on the biceps brachii muscle of 19 healthy subjects. The results showed that there was a significant difference between the muscle resistance (R) measured...

To determine whether the asymptote of the torque-duration relationship (critical torque) could be estimated from the torque measured at the end of a series of maximal voluntary contractions (MVCs) of the quadriceps, eight healthy men performed eight laboratory tests. Following familiarization, subjects performed two tests in which they were required to perform 60 isometric MVCs over a period of...

During voluntary contractions, muscle sympathetic nerve activity (MSNA) to contracting muscles increases in proportion to force but the underlying mechanisms are not clear. To shed light on these mechanisms, particularly the influences of central command and muscle afferent feedback, the present study tested the hypothesis that MSNA is greater during voluntary compared with electrically-evoked ...

Ng, A. V., H. T. Dao, R. G. Miller, D. F. Gelinas, and J. A. Kent-Braun. Blunted pressor and intramuscular metabolic responses to voluntary isometric exercise in multiple sclerosis. J. Appl. Physiol. 88: 871–880, 2000.—To test the hypothesis that a lower mean arterial pressure (MAP) response during voluntary isometric exercise in multiple sclerosis (MS) is related to a dampened muscle metabolic...