Whiplash injury is a common neck injury caused by frontal collisions during sports. While muscle activation patterns during impact are critical to injury mechanisms, how cervical and lumbar electromyographic (EMG) responses scale with collision intensity remains unclear. This investigation compares neck and low-back EMG profiles under incremental impact intensities, providing biomechanical insights to optimize protective strategies for high-risk populations exposed to dynamic acceleration environments. 35 male subjects were selected. Age range: 19-22 years old; height: 173. 6 ± 4. 1cm; weight: 70. 2 ± 6. 4kg. Front impact was simulated on a specific testing apparatus by applying forward traction along the head with three different loads: 2. 5 kg, 5 kg, and 7. 5 kg. The height of vertical collision is 10cm. An electromyographic (EMG) system (Delsys, USA) was used for recording the muscle-- bilateral Erector Spinae (ES), Trapezius (TR), sternocleidomastoid (SCM), splenius capitis (SC) -- activity at a rate of 2000 Hz. Python 3. 1. 1 was used to analyze the EMG data. A bandpass filter was used (20–450 Hz, 4-pole Butterworth). Maximum voluntary isometric contractions (MVC) were used for data standardization. The indicators were the root mean square (RMS), mean power frequency (MPF), and integral electromyographic (iEMG). SC：2. 5kg：RMS=2. 75±4. 17, MPF=62. 99±10. 4, iEMG=1. 75±2. 99; 5kg：RMS=3. 38±5. 71, MPF=67. 14±8. 24, iEMG=2. 53±4. 6;7. 5kg：RMS=4. 06±5. 62, MPF=69. 82±7. 01; iEMG=2. 71±3. 93. TR：2. 5kg: RMS=0. 48±0. 5, MPF=69. 74±11. 68, iEMG=0. 32±0. 51; 5kg: RMS=0. 46±0. 43, MPF=73. 09±9. 34, iEMG=0. 34±0. 42; 7. 5kg: RMS=0. 5±0. 38, MPF=73. 13±11. 61, iEMG=0. 41±0. 43. SCM-L: 2. 5kg: RMS=5. 74±5. 83, MPF=64. 62±9. 42, iEMG=3. 67±3. 91; 5kg: RMS=6. 79±7. 1, MPF=63. 38±10. 1, iEMG=4. 62±5. 43; 7. 5kg: RMS=6. 04±5. 7, MPF=69. 82±12. 68, iEMG=4. 57±4. 67. ES：2. 5kg: RMS=0. 99±1. 34，MPF=65. 67±10. 18, iEMG=0. 56±0. 67; 5kg: RMS=1. 17±2. 37, MPF=65. 99±7. 83, EMG=0. 75±1. 3; 7. 5kg: RMS=1. 88±4. 42, MPF=65. 33±9. 41, iEMG=1. 73±5. 5. Repeated measures ANOVA is used to assess muscle metrics across various positions and intensities. RMS (load: p=0. 001, η²=0. 011; muscle: p < 0. 001, η²=0. 168; load*muscle: p=0. 219, η²=0. 010), MPF (load: p=0. 001, η²=0. 028; muscle: p=0. 025, η²=0. 036; load*muscle: p=0. 181, η²=0. 027). iEMG (load: p < 0. 001, η²=0. 016; muscle: p < 0. 001, η²=0. 135; load*muscle: p=0. 206, η²=0. 015). 1) Within a certain range of collision intensity, the activation response characteristics of the human neck and waist increase with increasing intensity. 2) There is no interaction effect between muscle position and load.
Tang et al. (Thu,) studied this question.