Trunk And Lower Extremity Muscle Activation During Yoga

PURPOSE: Yoga is a mind-body practice that includes postures, relaxation, breathwork, and meditation. Yoga can improve balance and mobility. This study investigated the activation levels of trunk and lower extremity muscles during yoga poses. METHODS: Thirty-one university students participated in this study. All participants were healthy with varying experience in chair yoga. The investigators explained the benefits and risks of this study to all participants, who then signed an informed consent form approved by the IRB. Participants were led through a pre-recorded chair yoga warm-up video from a certified yoga instructor. The video allowed subjects to warm up and practice the chair yoga poses that were tested. Electrodes were placed on the subject’s dominant side over the following muscles: Rectus Abdominis, Erector Spinae, Rectus Femoris, Tibialis Anterior, and Gastrocnemius. Electrode placement was determined by the SENIAM (Surface Electromyography for Non-Invasive Assessment of Muscles) Protocol. Investigators performed manual muscle testing (MMT) for five seconds on each muscle being tested to elicit a maximum voluntary contraction. Each subject was then instructed to maintain five different yoga poses for ten seconds. Between postures, subjects had a fifteen-second rest period. The percent of muscle activation was determined per muscle, per pose, per participant. The mean percent of muscle activation during each pose was calculated. RESULTS: The following yoga poses were determined to elicit the greatest average percent muscle activation. The rectus abdominis muscle was most active during the Chair Staff pose (23% ± 21 MVC). The erector spinae muscle was most active during the Chair Mountain pose (29% ± 24 MVC). The rectus femoris was most active during the Chair Staff pose (33% ± 22 MVC). The tibialis anterior was most active during the Chair Staff Pose (38% ± 25 MVC). The gastrocnemius was most active during the Lower Staff pose (43% ± 24 MVC). CONCLUSIONS: In a healthy population, several chair yoga poses were seen to elicit significant muscle activation (>25% MVC) for muscles necessary for balance and stability. These findings indicate that yoga can add value to existing physical therapy practices as a means of improving functional fitness and daily life activities.