european college of sport science

PP-TT09 Training and Testing 9
Changes in insulin concentrations were significantly related to changes in fat mass (r=0.630) and lean body mass (r=0.725). It was concluded
that severe energy restriction to extremely low body energy reserves decreases significantly the concentrations of hormones of the
three anabolic pathways despite relatively high protein intake. Monitoring of insulin and IGF-1 concentration is suggested in order to
prevent losses in muscle mass in energy restricted conditions.
References
Newton, LE, Hunter, G, Bamman, M, Roney, R. Changes in psychological state and self-reported diet during various phases of training in
competitional bodybuilders. J Strength Cond Res 7: 153-158, 1993
CHANGES IN MUSCLE POWER FATIGUE AND SEMG PARAMETERS DURING DYNAMIC FATIGUING CONTRACTIONS
GONZALEZ-IZAL, M., MALANDA, A., NAVARRO-AMEZQUETA, I., GOROSTIAGA, E., MALLOR, F., IBAÑEZ, J., IZQUIERDO, M.
PUBLIC UNIVERSITY OF NAVARRE AND RESEARCH, STUDIES AND SPORT MEDICINE CENTER, GOVERMENT OF NAVARRA
Introduction: Several surface electromyography (sEMG) techniques have been applied to assess muscle fatigue. Although dynamic contractions
are more relevant to daily function, many of the studies have used isometric ones due to the technical limitations of sEMG (2).
The purpose of this study was to examine changes on muscle power output and sEMG parameters during a dynamic fatiguing protocol.
Methods: 15 physically active males performed 5 sets consisting of 10 repetition maximum leg press, with 2 minutes of rest between sets.
Mechanical power output and bipolar sEMG from vastus medialis (VM), and lateralis (VL) and biceps femoris (BF) were recorded. Different
sEMG parameters were obtained: Mean average voltage (MAV), median spectral frequency (Fmed), Dimitrov’s spectral index (FInsm5) (1),
negentropy index to describe the non-gaussianity of a distribution and others obtained from a time-frequency analysis (Choi-Williams
distributions) such as mean (MFM) and variance (MFV) of the instantaneous frequency and frequency variance (FV). FInsm5 was logtransformed
because it did not follow a normal distribution.
Results: Significant (P