Generalized linear mixed model fit by maximum likelihood (Laplace
  Approximation) [glmerMod]
 Family: Negative Binomial(2.2932)  ( log )
Formula: Duration ~ Sex + Bodymass + Starttime + Trainingsday * Trial +  
    Age + (1 | ID)
   Data: data

     AIC      BIC   logLik deviance df.resid 
  7079.6   7135.4  -3527.8   7055.6      757 

Scaled residuals: 
       Min         1Q     Median         3Q        Max 
-1.2947718 -0.7483967 -0.3957172  0.3201434  7.7330845 

Random effects:
 Groups Name        Variance   Std.Dev. 
 ID     (Intercept) 0.08788219 0.2964493
Number of obs: 769, groups:  ID, 52

Fixed effects:
                                      Estimate    Std. Error  z value
(Intercept)                       4.224786e+00  3.511176e-01 12.03239
Sexm                              8.922473e-03  9.860779e-02  0.09048
Bodymass                          1.662017e-03  2.698944e-03  0.61580
Starttime                        -1.687625e+02  2.502621e+01 -6.74343
TrainingsdayFirst Training        3.161601e+00  2.382200e-01 13.27177
TrainingsdayLast Training        -2.362062e-01  1.439731e-01 -1.64063
Trial                             5.471144e-02  2.477593e-02  2.20825
Age                              -7.242481e-03  3.930602e-03 -1.84259
TrainingsdayFirst Training:Trial -7.673016e-01  1.177027e-01 -6.51898
TrainingsdayLast Training:Trial   1.011348e-01  3.167830e-02  3.19256
                                   Pr(>|z|)    
(Intercept)                      < 2.22e-16 ***
Sexm                              0.9279022    
Bodymass                          0.5380247    
Starttime                        1.5469e-11 ***
TrainingsdayFirst Training       < 2.22e-16 ***
TrainingsdayLast Training         0.1008748    
Trial                             0.0272269 *  
Age                               0.0653892 .  
TrainingsdayFirst Training:Trial 7.0787e-11 ***
TrainingsdayLast Training:Trial   0.0014102 ** 
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Correlation of Fixed Effects:
            (Intr) Sexm   Bdymss Strttm TrnnFT TrnnLT Trial  Age    TrFT:T
Sexm        -0.224                                                        
Bodymass    -0.339 -0.119                                                 
Starttime   -0.348  0.002 -0.001                                          
TrnngsdyFrT -0.497  0.063  0.058  0.019                                   
TrnngsdyLsT -0.553  0.084 -0.102  0.006  0.455                            
Trial       -0.250  0.032  0.068  0.005  0.318  0.510                     
Age         -0.576  0.173 -0.474  0.053  0.388  0.530 -0.021              
TrnngsdFT:T  0.081  0.006 -0.113 -0.002 -0.802 -0.093 -0.218  0.059       
TrnngsdLT:T  0.198 -0.018 -0.060  0.000 -0.245 -0.730 -0.783  0.016  0.165
fit warnings:
Some predictor variables are on very different scales: consider rescaling
optimizer (Nelder_Mead) convergence code: 0 (OK)
Model is nearly unidentifiable: very large eigenvalue
 - Rescale variables?
Model is nearly unidentifiable: large eigenvalue ratio
 - Rescale variables?