The electromyogram is a recording of the ionic potential associated with the muscle action potentials. The emg is not a recording of tension produced by the muscle, but there is a good correlation between the magnitude of the emg and tension under many conditions. For example, when a subject is required to hold heavier and heavier weights, which subjects the muscle to increasingly higher loads, the integrated emg increases. This increase in emg is linear for some muscle (e. g. soleus) and demonstrates a non-linearity at lower loads for other muscles (e. g. muscle (e. g. soleus) and demonstrates a non-linearity at lower loads for other muscles (e. g. biceps brachii). This higher level of neural activation normally results in a higher level of electrical activity in muscle, which is reflected in the emg. Most of the emg signal lies in the 30-200hz frequency.