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Biomedical subjects

J J Lykkegaard

Publications and source records attributed to J J Lykkegaard.

4 recordsLinked to original sources
PubMed2003

Postural sway in normal subjects aged 20-70 years.

So far, no population-based reference material of postural sway has been presented in the literature. This study evaluated postural control by measuring posturographic parameters, with the aim of establishing useful standards with regard to gender, age, body weight, cigarette smoking, alcohol consumption and articular hypermobility. This was performed in an age-stratified random sample of 195 subjects from the Copenhagen City Heart Study, of whom, 133 agreed to participate. Measurement of postural sway was performed the Balance Master Pro(R). Outcome parameters were average angular velocity, target sway area, per cent maximum stability and per cent ankle strategy. Using SAS Proc Mixed, backward stepwise elimination was performed and 95% prediction intervals were obtained. Sway increased with increasing difficulty of the test (P<0.001) and with increasing age (P<0.001). No differences were found between the sexes. Ankle-strategy did not change with age, but decreased with increasing body weight, and increased in subjects reporting a consumption of modest amounts of alcohol (P<0.001), or with the finding of increased hypermobility (P = 0.006). The present material may be used as a reference in further studies of postural control.

Adult↗
PubMed1997

The twitch interpolation technique for the estimation of true quadriceps muscle strength.

The aim of this study was to examine the reliability of the twitch interpolation technique when used to estimate the true isometric knee extensor muscle strength. This included an examination of whether submaximal activation causes any bias in the estimation of the true muscle strength and an examination of the precision of the method. Twenty healthy subjects completed three contraction series, in which the subjects were told to perform as if their voluntary strength was 60%, 80% or 100% of that determined by a maximal voluntary contraction (MVC). Electrical muscle stimulations were given at each of five different contraction levels in each series. At torque levels above 25% of MVC the relationship between torque and twitch size could be approximated to be linear. The true muscle strength (TMS) could therefore be estimated using linear regression of the twitch-torque relationship to the torque point of no twitch in each of the three series, termed TMS60, TMS80 and TMS100. The TMS80 was slightly lower (P < 0.01), median 94% (IQ range 87-101%) of the TMS100. The TMS60 was median 99% (IQ range 83-125%) (NS) of TMS100, but a few severe outliers were observed. In conclusion, we found the reliability of the method acceptable for many research purposes, if series with estimated central activation of below 40-50% were excluded. The only moderate precision and the slightly lower estimations in subjects applying submaximal does, however, limit its usefulness.

Adult↗
PubMed1997

Muscle strength, working capacity and effort in patients with fibromyalgia.

The objective of the study was to evaluate the physical capacity and effort in patients with fibromyalgia. Muscle strength and the coefficient of variation of the strength measurements of 181 female fibromyalgia patients and 126 healthy females were compared. These measurements and ergometer exercise capacity, work status and psychometric scoring (SCL-90-R) were correlated. The fibromyalgia patients exhibited significant reduction in voluntary muscle strength of the knee and elbow, flexors and extensors in the order of 20-30%. However, the coefficient of variation was higher among patients, thus indicating lower effort. The physical performance during an ergometer test corresponded to a maximal oxygen consumption of 21 ml/kg-1 x min-1. The maximal increase in heart rate was only 63% (44-90%) of the predicted increase. Degree of effort or physical capacity did not correlate to psychometric scores. Work status was related to psychometric scoring, but not to physical capacity or effort. In conclusion, we found a low degree of effort but near normal physical capacity in the fibromyalgia patients.

Elbow Joint↗