The effects of 12 weeks of functional strength training on muscle strength,volume and activity upon exposure to elevated Gz forces in high-performance aircraft personnel

Background:Technological advancements in modern military and acrobatic jet planes have resulted in extraordinary psychophysiological loads being exerted upon flying personnel,including inducing neck and back pain.The purpose of this study was to examine the effects of 12 weeks of functional strength training on 1)the volume and strength of the neck and shoulder muscles and 2)muscular activity upon exposure to helmets of different masses and elevated Gz forces in a long-arm centrifuge in high-performance aircraft personnel.Methods:Eighteen participants underwent 12 weeks of functional strength training(n=12)or the control protocol(n=6)without additional strength training.Pre-and post-intervention tests included evaluations of isometric strength of the head extensor muscles,flexion,and lateral flexion and rotation,as well as magnetic resonance imaging(MRI)to measure the volume of the m.sternocleidomastoideus,m.trapezius,and deep neck muscles.Furthermore,during a long-arm centrifuge(+1.4 and+3Gz)protocol,the muscular activity levels of the m.sternocleidomastoideus,m.trapezius and m.erector spinae muscles were assessed without a flight helmet,with a helmet,and with a helmet and night vision goggles.Each participant’s perception of muscular strain was noted immediately after the long-arm centrifuge protocol.Results:The maximal isometric strength in all exercises and muscle volumes increased in the training group but not the control group(P<0.05).Relative muscle activity(%MVC)with a helmet decreased after the intervention in the training but not the control group(P=0.01).Relative muscle activity while wearing a helmet and night vision goggles was higher after intervention in the control group than in the training group(P<0.01).The perceived muscular strain of the neck muscles induced by the long-arm centrifuge did not differ between the groups.Conclusions:Twelve weeks of functional strength training improves the maximal isometric strength and volume of neck and shoulder muscles and leads to lower relative muscle activation upon exposure to elevated Gz forces in a long-arm centrifuge.

Changes in sternocleidomastoid and descending portion of trapezius muscles in terms of electromyography and pressure pain threshold: women with chronic neck pain after acupuncture treatment

OBJECTIVE:To evaluate the sternocleidomastoid and the descending portion of the trapezius muscles in terms of electromyographic activity and pressure pain threshold in women with chronic cervical pain after acupuncture treatment.METHODS:Twenty-five women,aged 18-50 years[(31±3)years],with chronic neck and temporomandibular disorder participated in the study.The electromyographic activity of the sternocleidomastoid muscle and the descending portion of the trapezius muscle were recorded at rest,during shoulder elevation,(left and right)rotation of the neck and crucifix position.Maximum voluntary contraction was used to normalize the electromyographic activity data.The points used for acupuncture were Jiache(ST 6),Xiaguan(ST 7),Quanliao(SI 18),Tinggong(SI 19),Yifeng(TE-17),Fengchi(GB 20),Renzhong(GV 26),Yangbai(GB-14),and points of the lower and upper limbs:Tai chong(LV 3),Zusanli(ST 36),Sanyinjiao(SP 6),Kunlun(BL 60),He Gu(LI4)and Yanglingquan(GB 34).The treatment course was 10 sessions,30 min long per session,and twice a week.The final electromyographic activity and pressure pain threshold data collection were performed 15 d after treatment completion.RESULTS:The normalized electromyographic activity and pressure pain threshold data were tabulated and submitted to statistical analysis using t-test(P<0.05).Significant difference was observed during shoulder elevation for the left trapezius muscle,during neck rotation from the right side to the left,and pressure pain threshold for the trapezius and sternocleidomastoid muscles,bilaterally,after the acupuncture treatment.CONCLUSION:The acupuncture treatment improved the neck muscles in terms of electromyographic activity and increased the tolerance to chronic pain in women.

Tendon-regulating and bone-setting manipulation plus endurance resistance exercises for female with chronic neck pain

Objective:To observe the clinical efficacy of tendon-regulating and bon e-setting manipulation combined with en dura nee resistance exercises in treating female with chronic neck pain,and explore the mechanism.Methods:A total of 57 female patients with chronic neck pain who met the inclusion criteria were randomly divided into a manipulation group(29 cases)and a medium-frequency electrotherapy group(28 cases).Patients in both groups received the same endura nee exercise therapy,while those in the man ipulation group received additi onalten don-regulating and bone-setting manipulation,and those in the medium-frequency electrotherapy group received additional medium-frequency electrotherapy.Both groups were treated for 5 weeks.Before and after treatment,the neck function of patients was evaluated by visual analog scale(VAS),Analgesy-Meter,Northwick Park questionnaire(NPQ),root mean square(RMS)and median frequency(MF)of surface electromyography of sternocleidomastoid muscle and posterior cervical extensor muscle,and the patients were followed up at a month after treatment.Results:All patients completed the treatment and were followed up.Compared with the same group before treatmerrt,the VAS scores of both groups decreased,the tenderness values increased,the RMS and MF values increased,and the NPQ scores decreased after treatment(all P<0.05).The improvement of manipulation group was more notable than that of medium-frequency electrotherapy group(all P<0.05).At one-month follow-up,the VAS and NPQ scores of the manipulation group were lower than those before and after treatment,and the VAS and NPQ scores of the mediumfreq ue ncy electrotherapy group were only lower than those before treatment;the two scores of the manipulation group were lower than those of the medium-frequency electrotherapy group(both P<0.05).Conclusion:Tendon-regulating and bone-setti ng man ipulati on combi ned with endurance resista nee exe rcises can relieve neck pain and cervical dysfunction in female patients with chronic neck pain.The efficacy of this method is more durable and better than that of medium-frequency electrotherapy combined with enduranee exercises.