Our meta analysis of a homogeneous set of studies is the first to provide valuable LLNs for fiber CSA according to fiber type and gender .
Skeletal muscle atrophy is a major systemic impairment in chronic diseases .
Yet its determinants have been hard to identify because a clear research definition has not been agreed upon .
The reduction in muscle fiber cross-sectional area ( CSA ) is a widely acknowledged marker of muscle atrophy , but no reference values for the muscle fiber CSA at the age of the onset of chronic disease have ever been published .
Power output, isometric strength and steadiness in the leg muscles of pre- and postmenopausal women; the effects of hormone replacement therapy
There are conflicting reports of the effects of hormone replacement therapy ( HRT ) on strength preservation in postmenopausal women , while any effect on power output has received little attention . Decreased steadiness of force generation has been reported in older muscles and may be related to the hormonal changes associated with the menopause , but the effect of HRT has not been investigated . We have studied the effect of HRT on strength , power output and isometric force steadiness in healthy women . Sixteen young ( aged 27.4±1.4 years , mean ± SEM ) and 29 postmenopausal women were studied . Fifteen of the latter were taking HRT ( 68.1±1.4 years , HRT+  ) and 14 ( 70.5±1.5 years , HRT− ) had never done so . During isometric quadriceps contractions the force steadiness ( coefficient of variation of force ) was measured at 10 , 25 , 50 and 100 % maximum voluntary contraction ( MVC ) . The average power generated by an explosive leg extension was recorded . The HRT− group generated less power ( 110.2±7.2 W ) than both the HRT+ ( 136.5±10.9 W , P=0.027 ) and young ( 136.2±5.8 W , P=0.027 ) subjects . Power output was similar in the HRT+ and younger subjects . The HRT− subjects were weaker than the younger ones ( 241.3±14.0 N vs. 297.6±13 N , P=0.006 ) . The strength of the HRT+ group ( 255.5±14 N ) was not significantly different to the other two groups . There was no difference in steadiness between the three groups at any of the force levels . HRT appears to maintain power output to a greater extent than isometric strength in postmenopausal women . There was no evidence for an effect of either age or HRT  on isometric steadiness in the quadriceps
Our meta analysis of a homogeneous set of studies is the first to provide valuable LLNs for fiber CSA according to fiber type and gender .
Skeletal muscle atrophy is a major systemic impairment in chronic diseases .
Yet its determinants have been hard to identify because a clear research definition has not been agreed upon .
The reduction in muscle fiber cross-sectional area ( CSA ) is a widely acknowledged marker of muscle atrophy , but no reference values for the muscle fiber CSA at the age of the onset of chronic disease have ever been published .