Effects Of Sling Exercise Training With Different Vibration Parameters On The Activation Of Trunk Muscles In Patients With Chronic Non-specific Low Back Pain

Background: Chronic non-specific low back pain（CNLBP）is a musculoskeletal system disease with a high incidence rate.Patients with increased low back pain and lumbar spine dysfunction were associated with decreased core muscle strength and proprioception.Trunk muscle dysfunction interacts with decreased lumbar stability.Sling exercise training（SET）can improve spinal stability,increase lumbar and abdominal core muscle strength,and reduce pain.Vibration training can strengthen muscles strength and improve neuromuscular control.The vibration parameters that affect the training effects are frequency,amplitude.Objective: To compare the effects of four parameters（frequency-amplitude combination）of vibration stimulation in different sling exercise training methods on the activation of the trunk core muscles in patients with CNLBP.Methods: 25 patients with CNLBP were recruited for sling exercise training in four postures: supine bridging,prone bridging and left/right-side lying bridging.During the training process,vibration stimulation with four parameters（30 Hz frequency 2 mm amplitude,30 Hz frequency 4 mm amplitude,60 Hz frequency 2 mm amplitude,and60 Hz frequency 4 mm amplitude）were given.The s EMG system was used to evaluate the activity levels of rectus abdominis,transversus abdominis,erector spinae,and multifidus muscles.The signal values were standardized with the maximum voluntary contraction（MVC）s EMG values of the muscles,and the processed values were represented the degree of muscle activation.Repeated measures ANOVA was used to explore the effects of frequency and amplitude on muscle activation in different sling exercise training postures.Results:（1）Supine bridging sling exercise training: there were significant differences in different frequencies between erector spinae and multifidus muscles at 4 mm amplitude（P<0.05）;there were also differences in different frequencies of left multifidus muscle at 2 mm amplitude（P<0.05）,with the greatest degree of activation at 60 Hz frequency.At 60 Hz,there was a significant difference（P<0.05）for different amplitudes,with the greatest degree of activation at 4 mm amplitude.（2）Prone bridging sling exercise training: there were significant differences in different frequencies of left rectus muscle activation（P<0.05）,and the activation degree of 60 Hz frequency was the largest.There was a significant difference（P<0.05）between the right abdominal straight and bilateral abdominal transverse muscles at the two amplitudes,with the greatest degree of activation at 60 Hz.All rectus and transversus abdominis muscles showed significant differences（P<0.05）at different amplitudes at 60 Hz,with the greatest degree of activation at 4 mm amplitude.（3）Left-side lying bridging sling exercise training: there were significant differences in the activation frequencies of left transverse abdominal muscle and multifidus muscle（P<0.05）,and the activation degree of 60 Hz muscle was the largest.The activation of the left rectus abdominis and erector spinae muscles was significantly different at different frequencies at an amplitude of 4 mm（P<0.05）,with the greatest degree of activation in the 60 Hz muscle.All left muscles were significantly different（P<0.05）for different amplitudes at a frequency of 60 Hz,with the 4 mm amplitude muscle being the most activated.（4）Right-side lying bridging sling exercise training: there were significant differences in different frequencies of the right muscle at 4 mm amplitude（P<0.05）,and the degree of activation of the 60 Hz muscle was the greatest;there were also significant differences in different frequencies of the right abdominal transverse muscle and multifidus muscle at 2 mm amplitude（P<0.05）.All right muscles showed significant differences between amplitudes at 60 Hz（P<0.05）,with the 4 mm amplitude muscle being the most activated.Conclusion:In the vibration sling exercise training,the optimal frequency for activating the core muscles is 60 Hz,and the optimal amplitude is 4 mm.The 60 Hz and 4 mm amplitude vibration parameters are superior to the 60 Hz and 2 mm amplitude,30 Hz and 4 mm amplitude,and 30 Hz and 2 mm amplitude parameters in terms of activation of the trunk muscles.The results provide a basis for the practice of vibration sling exercise training in CNLBP patients.