Trovato un altro studio.
"J Int Soc Sports Nutr. 2006; 3(2): 12–18.
Published online 2006 December 13. doi: 10.1186/1550-2783-3-2-12
PMCID: PMC2129168
Effect of Protein Intake on Strength, Body Composition and Endocrine Changes in Strength/Power Athletes
Jay R Hoffman,corresponding author1 Nicholas A Ratamess,1 Jie Kang,1 Michael J Falvo,1 and Avery D Faigenbaum1
Abstract
Comparison of protein intakes on strength, body composition and hormonal changes were examined in 23 experienced collegiate strength/power athletes participating in a 12-week resistance training program.
Subjects were stratified into three groups depending upon their daily consumption of protein; below recommended levels (BL; 1.0 – 1.4 g·kg-1·day-1; n = 8), recommended levels (RL; 1.6 – 1.8 g·kg-1·day-1; n = 7) and above recommended levels (AL; > 2.0 g·kg-1·day-1; n = 8). Subjects were assessed for strength [one-repetition maximum (1-RM) bench press and squat] and body composition.
Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, and insulin-like growth factor. No differences were seen in energy intake (3,171 ± 577 kcal) between the groups, and the energy intake for all groups were also below the recommended levels for strength/power athletes. No significant changes were seen in body mass, lean body mass or fat mass in any group. Significant improvements in 1-RM bench press and 1-RM squat were seen in all three groups, however no differences between the groups were observed. Subjects in AL experienced a 22% and 42% greater change in Δ 1-RM squat and Δ 1-RM bench press than subjects in RL, however these differences were not significant.
No significant changes were seen in any of the resting hormonal concentrations. The results of this study do not provide support for protein intakes greater than recommended levels in collegiate strength/power athletes for body composition improvements, or alterations in resting hormonal concentrations."
Effect of Protein Intake on Strength, Body Composition and Endocrine Changes in Strength/Power Athletes - PMC
23 atleti esperti di college (grosso modo l’università) in sport di forza/potenza sono stati sottoposti a tre diete: il primo gruppo meno proteine di quanto in genere raccomandato (1-1,4 g x Kg di peso corporeo); un alto il livello raccomandato ( 1,6-1,8); infine il terzo gruppo, superiore ai 2 g. L’esperimento è durato 12 settimane e alla fine nessuna differenza nei livelli ormonali, aumenti di forza o massa muscolare è stato osservato nei diversi gruppi.
E’ interessante notare che gli autori, che forse non si aspettavano un risultato del genere, fanno l’ipotesi che la mancanza di migliori risultati nei gruppi alimentati con più proteine sia dovuta al basso consumo calorico in tutti e tre i gruppi; il che è un pò contraddittorio, se già mangi poco in generale la carenza di proteine dovrebbe produrre differenze ancora più evidenti.