Effects Of Signal Stimulation On The Hook Punch Movement And Brain Activation Characteristics Of Boxers

Purpose: At present,there is relatively little research on the biomechanics of hook punching,and it is difficult to reflect the true performance of boxing techniques in practical applications.This situation is highly inconsistent with the increasingly important role of swing boxing in competitions.In addition,no experimental research has been found to analyze the impact of external stimuli on boxing athletes’ punching and cortical activation from the perspective of simulated combat.The brain nervous system plays an important role in the process of exercise,so when analyzing the technical characteristics of athletes,the activation characteristics of the brain nerves cannot be ignored.Therefore,the purpose of this study is to analyze the differences in the characteristics of kinematics,dynamics,surface EMG and brain activation of boxers when they complete the swing boxing action after the completion of the swing boxing action under the two conditions of signal light stimulation hitting(simulating the boxers’ judgment on the timing of punching and the state of the opponent in real combat)and no signal stimulation autonomous hitting,and to explore the differences in the neural action control of athletes when they complete the swing boxing action under the simulated real combat conditions,To provide assistance for the training practice of coaches and athletes,and to provide a theoretical basis for better improvement and innovation in specialized technical training.Method: A total of 12 Shandong boxing team athletes were recruited as participants in this study(age: 21.5 ± 2.32 years old,height: 182.33 ± 6.28 cm,weight:73.91 ± 12.68 kg,training period: 8 ± 1.6 years,exercise level: 6 master athletes,4 first level athletes,and 2 second level athletes).Through motion capture system,force measuring fist bag,surface electromyography and portable functional near-infrared system,the indexes such as the speed of the hook punch,the hitting force value,the joint range of motion,the integrated electromyogram value,the IEMG contribution,and the concentration of oxyhemoglobin in the cerebral cortex were collected under the two hitting modes that signal lights stimulation and non-signal.The paired T test and paired Wilcoxon test were used to test the data that conform to and do not conform to the normal distribution,respectively.The differences of kinematics,hitting force value,surface electromyography and brain activation of the hook fist under the signal stimulation hitting and non-signal modes were compared,and p<0.05 was regarded as a significant difference.Results: This study mainly reported the results of kinematics,dynamics,surface electromyography and cerebral cortex activation of boxers using the hook technique under two conditions.(1)Kinematics results: compared with the non-signal hitting mode,boxers’ punching speed after signal hitting was significantly lower(p=0.034),and the joint range motion of ankle flexion and extension,shoulder adduction and abduction was significantly smaller(p=0.023,p=0.04).(2)Dynamics results: compared with the non-signal hitting mode,boxers have significantly lower hitting power values in the signal hitting(p=0.008).(3)Surface EMG results: there was no significant difference in the integral EMG values of all the tested muscles under the two hitting modes(p=0.117 for the lateral muscles of gastrocnemius muscle,p=0.738 for the biceps femoris muscle,p=0.275 for the rectus femoris,p=0.887 for the triceps brachii,p=0.547 for the biceps brachii,p=0.332 for the anterior bundle of the deltoid muscle),There was no significant difference in the IEMG contribution(lateral muscle of gastrocnemius muscle p=0.48,biceps femoris muscle p=0.201,rectus femoris p=0.875,triceps brachii p=0.355,biceps brachii p=0.527,anterior bundle of deltoid muscle p=1.000).(4)Cortical activation results: compared with non-signal hitting mode,boxers showed significantly lower activation levels in the left prefrontal lobe(channel 2,p=0.024)and left motor area(channel 8,p=0.03,channel 9,p=0.032)in signal hitting mode.Conclusion:(1)Signal hitting simulates a more complex technical usage environment,which can affect the posture of boxers’ hook fist movements and worsen the hitting effect;This type of exercise may serve as a training method for improving the effectiveness of boxers’ punching in complex environments.(2)The signal light,as a stimulus presentation method and the stimulus intensity given to boxers by this method,may not have caused significant differences in muscle performance.Therefore,when arranging exercises with signal stimuli,more diverse and high intensity presentation methods can be considered.(3)The signal hitting mode causes a relative decrease in the activation level of the left prefrontal and motor cortex of boxers,indicating that long-term fixed non-stimulation training may limit exercise in other brain regions,thereby affecting judgment and reaction in actual combat.The decrease in activation level of the motor area may be caused by a decrease in motor performance in this mode.