Effects Of Two Dumbbell Exercises On Muscle And Brain Activation Patterns

Background:In the past,the research on human motor control was mostly analyzed from the perspective of biomechanics.There are few studies on how the cerebral cortex participates in motor control during exercise.Therefore,we aim to explore the effects of two dumbbell exercises on muscle and brain activation patterns with surface electromyography(sEMG)and functional near infrared spectroscopy(fNIRS).Method:11 healthy male undergraduate or postgraduate students participated in this experiment.All subjects completed the momentum-based dumbbells and traditional dumbbells exercise,respectively.Each dumbbell exercise was maintained for 10 seconds,and 10 groups were completed,with an interval of 60 seconds between groups.The momentum-based dumbbell and the traditional dumbbell need to be separated by 5 minutes.During the exercise,we use the Delsys wireless surface electromyography,JVC high-speed camera and functional near infrared spectroscopy to collect the activation of upper limbs,core muscles,upper limb trajectories and cerebral cortex activation pattern in real time.The sampling frequency was 2000 Hz,50Hz and 3.91 Hz.We use the paired sample T test and repeated measures analysis of variance to analyse the activation pattern of the muscles and cerebral cortex of the two dumbbells,the significance level was p<0.05.Result:1 surface electromyography:(1)Within 10 s,the biceps muscle activation in traditional dumbbell exercise is greater than momentum-based dumbbell,but there is no significant difference.The levels of triceps activation was similar(p>0.05);The activation level of the trapezius,anterior deltoid,posterior deltoid,flexor carpi radialis and extensor carpi radialis longus in momentum-based dumbbell exercise is significantly greater than that of traditional dumbbells(p<0.05);the levels of activation of the rectus abdominis and erector spinae in momentum-based dumbbell exercise is greater than that of the traditional dumbbell(p>0.05).(2)Comparing the contribution rate of upper limb muscles during the two dumbbell exercise,we found that the contribution rate of the momentum-based dumbbell flexion exercise is biceps brachii,extensor carpi radialis longus,anterior deltoid,flexor carpi radialis,triceps brachii and posterior deltoid in turn.The contribution rate of the traditional dumbbell flexion exercise is biceps brachii,flexor carpi radialis,triceps brachii,extensor carpi radialis longus,anterior deltoid and posterior deltoid.The contribution rate of the momentum-based dumbbell extension exercise is flexor carpi radialis,anterior deltoid,biceps brachii,extensor carpi radialis longus,triceps brachii and posterior deltoid.The contribution rate of the traditional dumbbell extension exercise is biceps brachii,flexor carpi radialis,anterior deltoid,flexor carpi radialis,triceps brachii and posterior deltoid.(3)In the two dumbbell flexion exercises,the shoulder joint co-activation of the momentum-based dumbbell is significantly greater than that of the traditional dumbbell(p<0.05).The elbow joint co-activation of the momentum-based dumbbellis greater than the traditional dumbbell,but there are no significant differences(p>0.05).The wrist joint co-activation of the momentum-based dumbbell was significantly greater than that of the traditional dumbbell(p<0.05).In the two dumbbell extension exercises,the shoulder joint co-activation of the momentum-based dumbbell is greater than the traditional dumbbell,but there was no significant difference(p>0.05).Traditional dumbbell elbow joints and wrist joints were activated more than momentum-based dumbbell,but there are no significant difference(p>0.05).2 brain activation:(1)The HbO concentration of ROI-1 and ROI-2 during the momentum-based dumbbell is significantly greater than in traditional dumbbell exercise and resting state(p<0.05),the HbO concentration of ROI-1 or ROI-2 during traditional dumbbell exercise is greater than resting state,but the difference was not significant(p>0.05).(2)The activation level of left cortex is significantly higher than the right cortex during dumbbell exercise(p<0.05).Conclusion:Compared with traditional dumbbell exercises,momentum-based dumbbell can activate the upper limbs and core muscles effectively;the two kinds of dumbbells have different contribution rate patterns of upper limb muscles;in general,compared with momentum-based dumbbell,traditional dumbbell exercises have better coordinated control ability.In addition,momentum-based dumbbell can better mobilize the involvement of the prefrontal and parietal cortex of the brain,and activation has the characteristics of lateralization.In summary,momentum-based dumbbell can be used as a new type of exercise to exercise upper limbs and core muscles and improve brain activation.Since this study is only a preliminary exploration of the effects of momentum-based dumbbell on muscle and brain activation patterns,large samples and further optimized experimental protocols are needed in the future.