Latest research in football - week 51

#1. Effect of a single dose of green tea polyphenols on the blood markers of exercise-induced oxidative stress in soccer players

Authors: Jówko E, Sacharuk J, Balasinska B, Wilczak J, Charmas M, Ostaszewski P, Charmas R.

Reference: Int J Sport Nutr Exerc Metab. 2012 Dec;22(6):486-96.
Summary: The study evaluated the intake of a single dose of green tea polyphenols on blood markers of exercise-induced oxidative stress in soccer players. The randomized, double blind study was conducted utilizing a strength endurance protocol and measured blood variables pre-exercise, 5 min after the test and after 24 hours of recovery. The results showed no differences between the two groups except for a slight but significant increase in total plasma catechins. The authors concluded that a single dose of green tea polyphenols does not attenuate exercise induced oxidative stress and muscle damage.

#2. Repeated sprint and change-of-direction abilities in soccer players: effects of age group

Authors: Dellal A, Wong WD.
Reference: J Strength Cond Res. 2012 Dec 12. [Epub ahead of print]
Summary: The study assessed the repeated sprint and change-of-direction (COD) ability in youth soccer players aged U15, U17, U19 and professional soccer players. The tests were 10 x 20m straight sprints and a COD test with identical length and both regimes used an active recovery protocol. Results were a) all performance improved with age and b) repeated straight sprint and repeated COD performance are two distinct performances and as a consequence both need to be trained to improve performance of players.

#3. The effects of injury preventive warm-up programs on knee strength ratio in young male professional soccer players

Authors: Daneshjoo A, Mokhtar AH, Rahnama N, Yusof A.
Reference: PLoS One. 2012;7(12).
Summary: The purpose of the study was an evaluation of the effect of the FIFA 11+ and another warm-up protocol on thigh strength ratio (CSR), dynamic control ratio (DCR) and fast/slow ratio (FSR) in young professional soccer players. Strength was measured via an isokinetic device, included different speed of testing (60, 80 and 300 degrees/second) and the injury prevention part was performed 3 times per week for 2 month. Results showed that the FIFA 11+ showed differences in CSR and DCR and the authors stated that the FIFA 11+ has potential to alter strength ratios of knee muscles.

#4. Fatigue and rapid hamstring/quadriceps force capacity in professional soccer players

Authors: Greco CC, da Silva WL, Camarda SR, Denadai BS..
Reference: Clin Physiol Funct Imaging. 2013 Jan;33(1):18-23.
Summary: The purpose of the study was to examine the effect of fatigue, induced by an exhaustive laboratory-based soccer-specific exercise on different hamstrings/quadriceps (H:Q) ratios of soccer players. After performing eccentric and concentric knee flexion and extensions, 22 professional soccer players were measured for maximal muscle strength, rate of force development and strength ratios. There was a significant reduction in H:Q ratio for the concentric phase and in H:Q (eccentric to concentric) ratio. The authors also questioned if fatigue does reduce the potential for knee joint stabilization during the initial phase of voluntary muscle contraction.