Renza Perini

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The contracting muscle generates a low frequency sound detectable at the belly surface, ranging from 11 to 40 Hz. To study the relationship between the muscular sound and the intensity of the contraction a sound myogram (SMG) was recorded by a contact sensor from the biceps brachii of seven young healthy males performing 4-s isometric contractions from 10%(More)
The frequency content of muscular sound (MS), detected by placing a contact sensor transducer over the belly of the biceps brachii during 10 isometric contractions of 4 s each [10-100% of maximal voluntary contraction (MVC)] in seven sedentary men, was analyzed by the maximum entropy spectral estimation and the fast Fourier transform methods. With(More)
The power spectral analysis of R-R interval variability (RRV) has been estimated by means of an autoregressive method in seven sedentary males at rest, during steady-state cycle exercise at 21 percent maximal oxygen uptake. (% V O 2max), SEM 2%, 49% VO 2max, SEM 2% and 70% VO 2max, SEM 2% and during recovery. The RRV, i.e. the absolute power of the(More)
The changes in the soundmyogram (SMG) and electromyogram (EMG) frequency content during exhausting contractions at 20070, 40%, 60070 and 80% of the maximal voluntary contraction (MVC) were investigated by the spectral analysis of the SMG and EMG detected from the biceps brachii muscles of 13 healthy men The root mean squares (rms) of the two signals were(More)
The ROX1 gene encodes a heme-induced repressor of hypoxic genes in yeast. Using RNA blot analysis and a ROX1/lacZ fusion construct that included the ROX1 upstream region and only the first codon, we discovered that Rox1 represses its own expression. Gel-retardation experiments indicated that Rox1 was capable of binding to its own upstream region.(More)
PURPOSE The effects of an intense 8-wk aerobic training program on cardiovascular responses at rest and during exercise, including heart rate variability (HRV) as an expression of autonomic modulation, were evaluated in subjects over 70 yr (mean: 73.9 +/- 3.5 yr). METHODS Before and after training in 7 men and 8 women: a) heart rate (HR), blood pressures(More)
The rhythmic components of heart rate variability (HRV) can be separated and quantitatively assessed by means of power spectral analysis. The powers of high frequency (HF) and low frequency (LF) components of HRV have been shown to estimate cardiac vagal and sympathetic activities. The reliability of these spectral indices, as well as that of LF/HF ratio as(More)
The sound (SMG) generated by the biceps muscle during isometric exercise at 20, 40, 60, and 80% of maximum voluntary contraction (MVC) up to exhaustion has been recorded by a contact transducer and integrated (iSMG), together with the surface electromyogram (EMG) in eight young untrained men. At the onset of exercise, iSMG and integrated surface EMG (iEMG)(More)
The time course of heart rate (HR) and venous blood norepinephrine concentration [NE], as an expression of the sympathetic nervous activity (SNA), was studied in six sedentary young men during recovery from three periods of cycle ergometer exercise at 21%±2.8%, 43%±2.1% and 65%±2.3% of $$\dot V_{o_{2max} } $$ respectively (mean±SE). The HR decreased(More)
Oxygen uptake ( $$\dot V$$ O2) at steady state, heart rate and perceived exertion were determined on nine subjects (six men and three women) while walking (3–7 km · h−1) or running (7–14 km · h−1) on sand or on a firm surface. The women performed the walking tests only. The energy cost of locomotion per unit of distance (C) was then calculated from the(More)