Corkery M1, Babigian J1, Bindert K1, Chen B1, Kuczmiec A1, Loweree B1, Yen S-C1
1Northeastern University, Department of Physical Therapy, Movement and Rehabilitation Sciences, Boston, United States
Background:
Static stretching (SS) and self-myofascial release (SMR) are commonly used by runners to increase gastrocnemius muscle (GA) flexibility and range of motion (ROM). However their effects on electromyographic (EMG) activity and ankle dorsiflexion (DF) ROM are inconclusive.
Purpose: To investigate the effects of SMR and SS on GA and tibialis anterior (TA) EMG activity during running, and on ankle DF ROM.
Methods: Sixteen runners with GA shortening (13 females, 3 males, 21.3 ±1.6 y), participated in this randomized comparison study. EMG surface electrodes were used to evaluate muscle activity of the GA and TA while running on a treadmill. Electrodes were placed on the skin over each muscle belly, aligned in parallel with the muscle fibers and in locations detailed by Seniam. Maximum voluntary isometric muscle contraction (MVIC) was established for each muscle group. Pre and post intervention weight bearing ankle DF ROM measurements were taken in a lunge position, using an inclinometer. An incline board and roller massager were used for SS and SMR respectively. A baseline pre-intervention EMG analysis was performed while each participant ran on a treadmill. Group (1) then completed a standing GA stretch. Group (2) performed SMR on the GA with a roller massager. A post-intervention EMG analysis was then performed during running. EMG signals were sampled at a frequency of 2000 Hz. The signals were band-pass filtered, rectified and linear-enveloped before normalization to MVIC. The processed signal was then evenly divided into 10 zones, and the values within each zone was averaged. A paired t-test was used to compare data within each group. Demographic data was analyzed using an independent t-test to ensure the two groups were similar.
Results: There was no significant difference between groups at baseline with regard to age and body mass index. In the SMR group, there was a significant reduction in TA activity post intervention, occurring between 40% and 50% of the running cycle (p=.03). The mean TA activity pre intervention was 20% MVIC ( ±6%) and the mean post intervention was 16% MVIC ( ±12%). A significant increase in ankle DF ROM was found post intervention in the SS group. Pre intervention DF was 33 ± 7°; post intervention DF was 42 ± 8°; p=.004. There were no other significant differences in EMG activity or ROM within groups.
Conclusion(s): This preliminary study found that SMR of the GA, performed immediately prior to running, resulted in a significant decrease in EMG activity of the TA during the transition from the stance to swing phase of running. SS was more effective than SMR for increasing ankle DF ROM.
Implications: While the effect size in this study was small, the findings suggest that GA SMR may have an effect on the antagonist muscle group. Additional research is needed to investigate if this change in EMG activity is associated with any change in force production of the GA or TA muscles, or alterations in ankle kinematics.
Keywords: Self-myofascial release, gastrocnemius stretch, electromyography
Funding acknowledgements: This work was not funded.
Purpose: To investigate the effects of SMR and SS on GA and tibialis anterior (TA) EMG activity during running, and on ankle DF ROM.
Methods: Sixteen runners with GA shortening (13 females, 3 males, 21.3 ±1.6 y), participated in this randomized comparison study. EMG surface electrodes were used to evaluate muscle activity of the GA and TA while running on a treadmill. Electrodes were placed on the skin over each muscle belly, aligned in parallel with the muscle fibers and in locations detailed by Seniam. Maximum voluntary isometric muscle contraction (MVIC) was established for each muscle group. Pre and post intervention weight bearing ankle DF ROM measurements were taken in a lunge position, using an inclinometer. An incline board and roller massager were used for SS and SMR respectively. A baseline pre-intervention EMG analysis was performed while each participant ran on a treadmill. Group (1) then completed a standing GA stretch. Group (2) performed SMR on the GA with a roller massager. A post-intervention EMG analysis was then performed during running. EMG signals were sampled at a frequency of 2000 Hz. The signals were band-pass filtered, rectified and linear-enveloped before normalization to MVIC. The processed signal was then evenly divided into 10 zones, and the values within each zone was averaged. A paired t-test was used to compare data within each group. Demographic data was analyzed using an independent t-test to ensure the two groups were similar.
Results: There was no significant difference between groups at baseline with regard to age and body mass index. In the SMR group, there was a significant reduction in TA activity post intervention, occurring between 40% and 50% of the running cycle (p=.03). The mean TA activity pre intervention was 20% MVIC ( ±6%) and the mean post intervention was 16% MVIC ( ±12%). A significant increase in ankle DF ROM was found post intervention in the SS group. Pre intervention DF was 33 ± 7°; post intervention DF was 42 ± 8°; p=.004. There were no other significant differences in EMG activity or ROM within groups.
Conclusion(s): This preliminary study found that SMR of the GA, performed immediately prior to running, resulted in a significant decrease in EMG activity of the TA during the transition from the stance to swing phase of running. SS was more effective than SMR for increasing ankle DF ROM.
Implications: While the effect size in this study was small, the findings suggest that GA SMR may have an effect on the antagonist muscle group. Additional research is needed to investigate if this change in EMG activity is associated with any change in force production of the GA or TA muscles, or alterations in ankle kinematics.
Keywords: Self-myofascial release, gastrocnemius stretch, electromyography
Funding acknowledgements: This work was not funded.
Topic: Musculoskeletal: lower limb; Sport & sports injuries
Ethics approval required: Yes
Institution: Northeastern University
Ethics committee: Institutional Review Board
Ethics number: 47135
All authors, affiliations and abstracts have been published as submitted.
