TY  - JOUR
A1  - Chaouachi, Mehdi
A1  - Granacher, Urs
A1  - Makhlouf, Issam
A1  - Hammami, Raouf
A1  - Behm, David G.
A1  - Chaouachi, Anis
T1  - Within Session Sequence of Balance and Plyometric Exercises Does Not Affect Training Adaptations with Youth Soccer Athletes
JF  - Journal of sports science & medicine
N2  - The integration of balance and plyometric training has been shown to provide significant improvements in sprint, jump, agility, and other performance measures in young athletes. It is not known if a specific within session balance and plyometric exercise sequence provides more effective training adaptations. The objective of the present study was to investigate the effects of using a sequence of alternating pairs of exercises versus a block (series) of all balance exercises followed by a block of plyometric exercises on components of physical fitness such as muscle strength, power, speed, agility, and balance. Twenty-six male adolescent soccer players ( 13.9 +/- 0.3 years) participated in an 8-week training program that either alternated individual balance (e. g., exercises on unstable surfaces) and plyometric (e. g., jumps, hops, rebounds) exercises or performed a block of balance exercises prior to a block of plyometric exercises within each training session. Pre- and post-training measures included proxies of strength, power, agility, sprint, and balance such as countermovement jumps, isometric back and knee extension strength, standing long jump, 10 and 30-m sprints, agility, standing stork, and Y-balance tests. Both groups exhibited significant, generally large magnitude (effect sizes) training improvements for all measures with mean performance increases of approximately > 30%. There were no significant differences between the training groups over time. The results demonstrate the effectiveness of combining balance and plyometric exercises within a training session on components of physical fitness with young adolescents. The improved performance outcomes were not significantly influenced by the within session exercise sequence.
KW  - Power
KW  - strength
KW  - jumps
KW  - sprints
KW  - balance
KW  - children
Y1  - 2017
SN  - 1303-2968
VL  - 16
SP  - 125
EP  - 136
PB  - Department of Sports Medicine, Medical Faculty of Uludag University
CY  - Bursa
ER  - 
TY  - JOUR
A1  - Matuschek, Hannes
A1  - Kliegl, Reinhold
A1  - Vasishth, Shravan
A1  - Baayen, Harald R.
A1  - Bates, Douglas
T1  - Balancing Type I error and power in linear mixed models
JF  - Journal of memory and language
N2  - Linear mixed-effects models have increasingly replaced mixed-model analyses of variance for statistical inference in factorial psycholinguistic experiments. Although LMMs have many advantages over ANOVA, like ANOVAs, setting them up for data analysis also requires some care. One simple option, when numerically possible, is to fit the full variance covariance structure of random effects (the maximal model; Barr, Levy, Scheepers & Tily, 2013), presumably to keep Type I error down to the nominal a in the presence of random effects. Although it is true that fitting a model with only random intercepts may lead to higher Type I error, fitting a maximal model also has a cost: it can lead to a significant loss of power. We demonstrate this with simulations and suggest that for typical psychological and psycholinguistic data, higher power is achieved without inflating Type I error rate if a model selection criterion is used to select a random effect structure that is supported by the data. (C) 2017 The Authors. Published by Elsevier Inc.
KW  - Power
KW  - Linear mixed effect model
KW  - Hypothesis testing
Y1  - 2017
U6  - https://doi.org/10.1016/j.jml.2017.01.001
SN  - 0749-596X
SN  - 1096-0821
VL  - 94
SP  - 305
EP  - 315
PB  - Elsevier
CY  - San Diego
ER  -