Lower Extremity Muscle Recruitment Following Concussion Using Electromyography: A Pilot Study

Athletes who sustain sports-related concussions (SRC) are up to 3.5x more likely to sustain a lower extremity musculoskeletal injury within a year post injury. This increased risk may be caused by disruptions in neuromuscular connections. PURPOSE: Investigate differences in muscle activation during the Buffalo Concussion Treadmill Test (BCTT) in athletes at two time points: within 48 hours of injury (AC) and when >24 hours symptom-free (SF) using surface electromyography (sEMG). METHODS: 5 healthy collegiate athletes (3 male, age = 19.4 yrs) with a physician diagnosed SRC performed the BCTT at AC and SF. Participants were fitted with sEMG sensors (2000 Hz, Delsys, Natick, MA) attached to their anterior tibialis (AT), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), the medial head (GM) and the lateral head (GL) of the gastrocnemius. Athletes performed the BCTT, a graded exercise test to assess exercise tolerance during SRC. sEMG data for consecutive minutes was normalized to each participant’s muscle activation during minute 0 (normal gait). sEMG was filtered using a bandpass filter of 30-450 Hz, rectified, and then normalized. Participants’ data was truncated to the lowest minute completed by the participants. Paired samples t-tests analyzed the relationships between muscle activation at AC and SF for each muscle at each minute. RESULT: There were no significant differences in muscle activation when comparing each muscle, from AC to SF; however some trended towards significance (Table 1.) CONCLUSION: Muscle activation is not statistically different throughout the progression of SRC, however, there are some greater normalized activation values in AC than SF. Table 1. - Mean, standard deviations, and normalized proportions of muscle activation (to normal gait at minute 0) for each muscle, at minutes 1 through 4. BF = biceps femoris, GM = medial gastrocnemius, GL = lateral gastrocnemius, AT = anterior tibialis, VM = vastus medialis, RF = rectus femoris Minute 1 AC SF p d BF 0.99 ± 0.16 1.36 ± 0.78 0.18 0.66 GM 1.12 ± 0.16 0.98 ± 0.69 0.32 -0.28 GL 1.07 ± 0.39 2.09 ± 1.7 0.11 0.83 AT 1.14 ± 0.14 1.09 ± 0.22 0.34 -0.27 VM 1.08 ± 0.08 1.94 ± 1.21 0.12 1.00 RF 1.14 ± 0.1 1.18 ± 0.48 0.43 0.12 Minute 2 AC SF p d BF 0.89 ± 0.31 1.37 ± 0.99 0.17 0.65 GM 0.98 ± 0.19 0.98 ± 0.73 0.50 0.00 GL 0.91 ± 0.4 1.87 ± 1.54 0.11 0.85 AT 1.01 ± 0.12 1.17 ± 0.45 0.23 0.49 VM 0.99 ± 0.03 1.92 ± 1.42 0.15 0.93 RF 1.13 ± 0.24 1.15 ± 0.5 0.46 0.05 Minute 3 AC SF p d BF 0.99 ± 0.38 1.47 ± 1.14 0.21 0.56 GM 1 ± 0.41 1.15 ± 1.05 0.37 0.19 GL 0.89 ± 0.37 2.01 ± 1.76 0.10 0.88 AT 1 ± 0.12 1.3 ± 0.77 0.21 0.54 VM 1.01 ± 0.1 2.2 ± 1.78 0.13 0.94 RF 1 ± 0.35 1.19 ± 0.58 0.22 0.00 Minute 4 AC SF p d BF 1 ± 0.38 13.38 ± 27.98 0.19 0.63 GM 0.92 ± 0.26 1.66 ± 2.06 0.23 0.50 GL 0.85 ± 0.32 1.98 ± 2.05 0.14 0.77 AT 0.98 ± 0.14 1.38 ± 0.66 0.12 0.84 VM 1.03 ± 0.08 2.28 ± 1.83 0.14 0.97 RF 0.91 ± 0.29 1.26 ± 0.7 0.13 0.65