Table 2.

Correlations between hindlimb motor patterns and the use of more upright limb postures in Alligator



Individuals
EMG variable
r
P
r
P
r
P
Stance femoral retractors INDIVIDUAL 2      
   FTE REL ON —0.669 <0.001*     
   FTE REL OFF —0.768 <0.001*     
   FTE DUR —0.661 <0.001*     
   FTE DUR STANCE —0.193 0.306     
   FTE AREA 0.147 0.440     
   FTE AREA DUR 0.612 <0.001*     
   FTE AD STANCE 0.571 0.001*     
Stance femoral adductors       
   ADDFEM  No significant correlations (Individuals 1, 4 and 5)     
 INDIVIDUAL 1  INDIVIDUAL 2    
   PIFE3 REL ON —0.609 <0.001* —0.673 <0.001*   
   PIFE3 REL OFF —0.667 <0.001* —0.675 <0.001*   
   PIFE3 DUR —0.426 0.019 —0.514 <0.001*   
   PIFE3 DUR STANCE —0.105 0.582 —0.130 0.494   
   PIFE3 AREA 0.575 0.001* 0.679 <0.001*   
   PIFE3 AREA DUR 0.768 <0.001* 0.751 <0.001*   
   PIFE3 AD STANCE 0.719 <0.001* 0.679 <0.001*   
   PIT (a) REL ON 0.018 0.924     
   PIT (a) REL OFF 0.023 0.906     
   PIT (a) DUR 0.143 0.451     
   PIT (a) DUR STANCE 0.310 0.096     
   PIT (a) AREA 0.334 0.071     
   PIT (a) AREA DUR 0.474 0.008     
   PIT (a) AD STANCE 0.528 0.003*     
Stance knee extensors INDIVIDUAL 1  INDIVIDUAL 2  INDIVIDUAL 4  
   FEMTIB REL ON 0.051 0.789 —0.089 0.639 0.053 0.779 
   FEMTIB REL OFF —0.164 0.388 —0.222 0.239 0.208 0.271 
   FEMTIB DUR —0.203 0.282 —0.146 0.440 0.211 0.263 
   FEMTIB DUR STANCE 0.294 0.115 0.336 0.070 0.291 0.119 
   FEMTIB AREA 0.370 0.044 0.694 <0.001* 0.802 <0.001* 
   FEMTIB AREA DUR 0.668 <0.001* 0.723 <0.001* 0.719 <0.001* 
   FEMTIB AD STANCE 0.669 <0.001* 0.653 <0.001* 0.590 0.001* 
   ILTIBI  No significant correlations (Individual 5)     
 INDIVIDUAL 4  INDIVIDUAL 5    
   ILTIB2 REL ON 0.079 0.677 —0.287 0.123   
   ILTIB2 REL OFF 0.333 0.072 0.056 0.770   
   ILTIB2 DUR 0.128 0.500 0.197 0.296   
   ILTIB2 DUR STANCE 0.147 0.439 0.061 0.747   
   ILTIB2 AREA 0.863 <0.001* 0.840 <0.001*   
   ILTIB2 AREA DUR 0.774 <0.001* 0.774 <0.001*   
   ILTIB2 AD STANCE 0.622 <0.001* 0.651 <0.001*   
Stance ankle extensors INDIVIDUAL 3  INDIVIDUAL 4  INDIVIDUAL 5  
   GAST REL ON 0.169 0.363 0.116 0.540 —0.206 0.275 
   GAST REL OFF 0.118 0.529 —0.200 0.290 —0.041 0.828 
   GAST DUR —0.077 0.681 —0.157 0.408 0.335 0.071 
   GAST DUR STANCE —0.023 0.900 —0.086 0.652 0.178 0.347 
   GAST AREA 0.651 <0.001* 0.535 0.002* 0.760 <0.001* 
   GAST AREA DUR 0.702 <0.001* 0.643 <0.001* 0.790 <0.001* 
   GAST AD STANCE 0.640 <0.001* 0.602 <0.001* 0.518 0.003* 
Swing femoral protractors INDIVIDUAL 5      
   PIFI2 REL ON 0.289 0.122     
   PIFI2 REL OFF 0.421 0.021     
   PIFI2 DUR 0.296 0.112     
   PIFI2 DUR SWING 0.488 0.006*     
   PIFI2 AREA 0.412 0.024     
   PIFI2 AREA DUR 0.144 0.449     
   PIFI2 AD SWING 0.356 0.054     
Swing femoral abductors INDIVIDUAL 4      
   ILFEM REL ON 0.405 0.027     
   ILFEM REL OFF —0.212 0.261     
   ILFEM DUR —0.734 <0.001*     
   ILFEM DUR SWING —0.656 <0.001*     
   ILFEM AREA —0.586 0.001*     
   ILFEM AREA DUR 0.649 <0.001*     
   ILFEM AD SWING 0.540 0.002*     
Swing knee extensors       
   AMB 1 No significant correlations (Individuals 3 and 5)      
Swing knee flexors INDIVIDUAL 1      
   PIT (b) REL ON —0.288 0.122     
   PIT (b) REL OFF —0.494 0.005*     
   PIT (b) DUR —0.479 0.007*     
   PIT (b) DUR SWING —0.351 0.057     
   PIT (b) AREA —0.400 0.029     
   PIT (b) AREA DUR 0.382 0.037     
   PIT (b) AD SWING 0.335 0.070     
Swing ankle flexors INDIVIDUAL 3  INDIVIDUAL 4    
   TA REL ON 0.023 0.902 0.214 0.257   
   TA REL OFF 0.038 0.839 —0.046 0.808   
   TA DUR 0.137 0.462 —0.151 0.426   
   TA DUR SWING 0.062 0.742 0.048 0.800   
   TA AREA 0.634 <0.001* 0.875 <0.001*   
   TA AREA DUR 0.804 <0.001* 0.862 <0.001*   
   TA AD SWING 0.590 <0.001* 0.804 <0.001*   


Individuals
EMG variable
r
P
r
P
r
P
Stance femoral retractors INDIVIDUAL 2      
   FTE REL ON —0.669 <0.001*     
   FTE REL OFF —0.768 <0.001*     
   FTE DUR —0.661 <0.001*     
   FTE DUR STANCE —0.193 0.306     
   FTE AREA 0.147 0.440     
   FTE AREA DUR 0.612 <0.001*     
   FTE AD STANCE 0.571 0.001*     
Stance femoral adductors       
   ADDFEM  No significant correlations (Individuals 1, 4 and 5)     
 INDIVIDUAL 1  INDIVIDUAL 2    
   PIFE3 REL ON —0.609 <0.001* —0.673 <0.001*   
   PIFE3 REL OFF —0.667 <0.001* —0.675 <0.001*   
   PIFE3 DUR —0.426 0.019 —0.514 <0.001*   
   PIFE3 DUR STANCE —0.105 0.582 —0.130 0.494   
   PIFE3 AREA 0.575 0.001* 0.679 <0.001*   
   PIFE3 AREA DUR 0.768 <0.001* 0.751 <0.001*   
   PIFE3 AD STANCE 0.719 <0.001* 0.679 <0.001*   
   PIT (a) REL ON 0.018 0.924     
   PIT (a) REL OFF 0.023 0.906     
   PIT (a) DUR 0.143 0.451     
   PIT (a) DUR STANCE 0.310 0.096     
   PIT (a) AREA 0.334 0.071     
   PIT (a) AREA DUR 0.474 0.008     
   PIT (a) AD STANCE 0.528 0.003*     
Stance knee extensors INDIVIDUAL 1  INDIVIDUAL 2  INDIVIDUAL 4  
   FEMTIB REL ON 0.051 0.789 —0.089 0.639 0.053 0.779 
   FEMTIB REL OFF —0.164 0.388 —0.222 0.239 0.208 0.271 
   FEMTIB DUR —0.203 0.282 —0.146 0.440 0.211 0.263 
   FEMTIB DUR STANCE 0.294 0.115 0.336 0.070 0.291 0.119 
   FEMTIB AREA 0.370 0.044 0.694 <0.001* 0.802 <0.001* 
   FEMTIB AREA DUR 0.668 <0.001* 0.723 <0.001* 0.719 <0.001* 
   FEMTIB AD STANCE 0.669 <0.001* 0.653 <0.001* 0.590 0.001* 
   ILTIBI  No significant correlations (Individual 5)     
 INDIVIDUAL 4  INDIVIDUAL 5    
   ILTIB2 REL ON 0.079 0.677 —0.287 0.123   
   ILTIB2 REL OFF 0.333 0.072 0.056 0.770   
   ILTIB2 DUR 0.128 0.500 0.197 0.296   
   ILTIB2 DUR STANCE 0.147 0.439 0.061 0.747   
   ILTIB2 AREA 0.863 <0.001* 0.840 <0.001*   
   ILTIB2 AREA DUR 0.774 <0.001* 0.774 <0.001*   
   ILTIB2 AD STANCE 0.622 <0.001* 0.651 <0.001*   
Stance ankle extensors INDIVIDUAL 3  INDIVIDUAL 4  INDIVIDUAL 5  
   GAST REL ON 0.169 0.363 0.116 0.540 —0.206 0.275 
   GAST REL OFF 0.118 0.529 —0.200 0.290 —0.041 0.828 
   GAST DUR —0.077 0.681 —0.157 0.408 0.335 0.071 
   GAST DUR STANCE —0.023 0.900 —0.086 0.652 0.178 0.347 
   GAST AREA 0.651 <0.001* 0.535 0.002* 0.760 <0.001* 
   GAST AREA DUR 0.702 <0.001* 0.643 <0.001* 0.790 <0.001* 
   GAST AD STANCE 0.640 <0.001* 0.602 <0.001* 0.518 0.003* 
Swing femoral protractors INDIVIDUAL 5      
   PIFI2 REL ON 0.289 0.122     
   PIFI2 REL OFF 0.421 0.021     
   PIFI2 DUR 0.296 0.112     
   PIFI2 DUR SWING 0.488 0.006*     
   PIFI2 AREA 0.412 0.024     
   PIFI2 AREA DUR 0.144 0.449     
   PIFI2 AD SWING 0.356 0.054     
Swing femoral abductors INDIVIDUAL 4      
   ILFEM REL ON 0.405 0.027     
   ILFEM REL OFF —0.212 0.261     
   ILFEM DUR —0.734 <0.001*     
   ILFEM DUR SWING —0.656 <0.001*     
   ILFEM AREA —0.586 0.001*     
   ILFEM AREA DUR 0.649 <0.001*     
   ILFEM AD SWING 0.540 0.002*     
Swing knee extensors       
   AMB 1 No significant correlations (Individuals 3 and 5)      
Swing knee flexors INDIVIDUAL 1      
   PIT (b) REL ON —0.288 0.122     
   PIT (b) REL OFF —0.494 0.005*     
   PIT (b) DUR —0.479 0.007*     
   PIT (b) DUR SWING —0.351 0.057     
   PIT (b) AREA —0.400 0.029     
   PIT (b) AREA DUR 0.382 0.037     
   PIT (b) AD SWING 0.335 0.070     
Swing ankle flexors INDIVIDUAL 3  INDIVIDUAL 4    
   TA REL ON 0.023 0.902 0.214 0.257   
   TA REL OFF 0.038 0.839 —0.046 0.808   
   TA DUR 0.137 0.462 —0.151 0.426   
   TA DUR SWING 0.062 0.742 0.048 0.800   
   TA AREA 0.634 <0.001* 0.875 <0.001*   
   TA AREA DUR 0.804 <0.001* 0.862 <0.001*   
   TA AD SWING 0.590 <0.001* 0.804 <0.001*   

Correlation coefficients (r) and significance levels (P)for regressions of electromyographic variables on femoral posture, based on N=30 strides per individual spanning the femoral posture ranges given in Table 1 (positive correlations indicate increases in the variable with more upright posture).

The prefix of each variable name is the abbreviation for the muscle (see Myology), and the suffix describes the EMG variable: REL ON, burst onset relative to foot-down; REL OFF, burst offset relative to foot-down; DUR, burst duration; DUR STANCE, burst duration normalized by stance duration; DUR SWING,burst duration normalized by swing duration; AREA, rectified burst area; AREA DUR, rectified area normalized by burst duration (i.e. mean burst amplitude);AD STANCE, mean burst amplitude normalized by stance duration; AD SWING, mean burst amplitude normalized by swing duration. For PIT, letters denote the stance (a) and swing (b) phase activity bursts for this muscle.

*

Significant (P<0.05) with sequential Bonferroni correction, N=7 variables per muscle

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