NutriAnd
2007-04-26, 20:16
En ny studie som inte visar några direkta fördelar med högre proteinintag under 12 veckors styrketräning på tränade individer.
The effect of protein supplementation on athletic performance
and hormonal changes was examined in 21 experienced collegiate
strength/power athletes participating in a 12-week resistance
training program. Subjects were randomly assigned to
either a protein supplement (PR; n = 11) or a placebo (PL; n =
10) group. During each testing session subjects were assessed
for strength (one repetition maximum [1-RM] bench press and
squat), power (Wingate anaerobic power test) and body composition.
Resting blood samples were analyzed at weeks 0 (PRE),
6 (MID) and 12 (POST) for total testosterone, cortisol, growth
hormone, and IGF-1. No difference was seen in energy intake
between PR and PL (3034 ± 209 kcal and 3130 ± 266 kcal,
respectively), but a significant difference in daily protein intake
was seen between PR (2.00 g·kg body mass[BM]-1·d-1) and PL
(1.24 g·kgBM-1·d-1). A greater change (p < 0.05) in the Δ 1-RM
squat was seen in PR (23.5 ± 13.6 kg) compared to PL (9.1 ±
11.9 kg). No other significant strength or power differences
were seen between the groups. Cortisol concentrations were
significantly lower at MID for PL and this difference was significantly
different than PR. No significant changes were noted
in resting growth hormone or IGF-1 concentrations in either
group. Although protein supplementation appeared to augment
lower body strength development, similar upper body strength,
anaerobic power and lean tissue changes do not provide clear
evidence supporting the efficacy of a 12-week protein supplementation
period in experienced resistance trained athletes.
Effects of protein supplementation on muscular performance and resting
hormonal changes in college football players. (http://www.jssm.org/vol6/n1/11/v6n1-11pdf.pdf) Journal of Sports Science and Medicine (2007) 6, 85-92
The effect of protein supplementation on athletic performance
and hormonal changes was examined in 21 experienced collegiate
strength/power athletes participating in a 12-week resistance
training program. Subjects were randomly assigned to
either a protein supplement (PR; n = 11) or a placebo (PL; n =
10) group. During each testing session subjects were assessed
for strength (one repetition maximum [1-RM] bench press and
squat), power (Wingate anaerobic power test) and body composition.
Resting blood samples were analyzed at weeks 0 (PRE),
6 (MID) and 12 (POST) for total testosterone, cortisol, growth
hormone, and IGF-1. No difference was seen in energy intake
between PR and PL (3034 ± 209 kcal and 3130 ± 266 kcal,
respectively), but a significant difference in daily protein intake
was seen between PR (2.00 g·kg body mass[BM]-1·d-1) and PL
(1.24 g·kgBM-1·d-1). A greater change (p < 0.05) in the Δ 1-RM
squat was seen in PR (23.5 ± 13.6 kg) compared to PL (9.1 ±
11.9 kg). No other significant strength or power differences
were seen between the groups. Cortisol concentrations were
significantly lower at MID for PL and this difference was significantly
different than PR. No significant changes were noted
in resting growth hormone or IGF-1 concentrations in either
group. Although protein supplementation appeared to augment
lower body strength development, similar upper body strength,
anaerobic power and lean tissue changes do not provide clear
evidence supporting the efficacy of a 12-week protein supplementation
period in experienced resistance trained athletes.
Effects of protein supplementation on muscular performance and resting
hormonal changes in college football players. (http://www.jssm.org/vol6/n1/11/v6n1-11pdf.pdf) Journal of Sports Science and Medicine (2007) 6, 85-92