Innervation zone location of the biceps brachii, a comparison between genders and correlation with anthropometric measurements.
Avoiding the innervation zone (IZ) is important when collecting surface electromyographic data. The purposes of this study were threefold: (1) to examine the precision of two different techniques for expressing IZ location for the biceps brachii, (2) to compare these locations between men and women, and (3) to determine if IZ movement with changes in elbow joint angle is related to different anthropometric measures. Twenty-four subjects (mean+/-SD ages=21.8+/-3.5yr) performed isometric contractions of the right forearm flexors at each of three separate elbow joint angles (90 degrees, 120 degrees, and 150 degrees between the arm and forearm). During each contraction, the location of the IZ for the biceps brachii was visually identified using a linear electrode array. These IZ locations were expressed in both absolute (i.e. as a distance (mm) from the acromion process) and relative (i.e. as a percentage of humerus length) terms. The results suggested that the estimations of IZ location were more precise when expressed in relative versus absolute terms, and were generally different for men and women. The shift in IZ location with changes in elbow joint angle was not, however, related to height, weight, or humerus length.
DeFreitas
Jason M
JM
Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA.
Costa
Pablo B
PB
Ryan
Eric D
ED
Herda
Trent J
TJ
Cramer
Joel T
JT
Beck
Travis W
TW
D000886:Anthropometry / Q000379:methods; D049628:Body Size / Q000502:physiology*; D004576:Electromyography / Q000379:methods*; D005260:Female; D005542:Forearm / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology*; D012680:Sensitivity and Specificity; D012737:Sex Factors; D013223:Statistics as Topic; D055815:Young Adult