Fig. 4. Representative electromyographic (EMG) activity from the lateral hypaxial muscles of Ambystoma tigrinum during swimming. (A) An example of locomotor strides with only the -bursts present in the TA, OEP and OES muscles. (B) Electromyographic activity recorded from the same individual as A with - and ß-bursts present in the OI and OES. A new locomotor cycle begins at each arrow. Filled and open bars represent our scoring of the - and ß-bursts, respectively, for the corresponding traces. OES, m. obliquus externus superficialis; OEP, m. obliquus externus profundus; OI, m. obliquus internus; TA, m. transversus abdominis.