This category of questions is directly answered by observing the raw EMG trace of any activity. It is answered on the nominal level by yes/no or on/off. Caution is needed to check that the quality of the EMG baseline allows a clear identification of active EMG. Noise may not be interpreted as “increased tonus”. The relevance of this fundamental question may be underestimated or misunderstood. Not only for neurological therapists asking if the patient can access to a certain muscle, but also for training professionals, this basic question can quickly receive relevance. E.g. the incorrectly
assumed “postural” role of the M. glutaeus maximus in regular upright standing, or the lumbar spinal/pelvic “stabilization” function of the M. rectus abdominis, two fundamental misunderstandings derived from pure functional anatomical considerations can quickly be cleared by simply asking and measuring, if these muscles are active or not in these given
tasks (Fig. 66). A healthy well organized muscle in regular conditions turns off if it is not needed anymore. If it still stays on, it is an indicator for active muscle spasm, reflex induced (e.g. pain) hypertonus, joint instability or behavioral
disuse (stress, bad muscle coordination).