Back muscle fatigue during intermittent prone back extension exercise

The purpose of this study was to estimate the level of muscular activation and muscle fatigue of the low back muscles during the performance of an intermittent prone back extension (PBE) exercise. Forty-one healthy students (24 males and 17 females) lying prone on a bench with the legs fixed performed two maximal voluntary contractions (MVC) in extension, a maximum of 100 repetitions of an intermittent PBE exercise immediately followed by a final MVC in extension. In addition, 12 subjects (11 males and one female) repeated the PBE exercise but with the addition of a 45-N weight on the back. The PBE exercise consisted of a task broken into four 1-s segments, while lying prone on a bench (10 degrees below horizontal): (1) raising the trunk to a horizontal position; (2) holding the trunk in the static phase (10 degrees above horizontal); (3) returning to the original position; and (4) resting on the bench. Electromyography (EMG) was used to measure the level of muscle activity (erector spinae (ES), gluteus maximus (GM), hamstrings (HA)) relative to the maximum voluntary EMG (MVE). RESULTS: Most of the subjects (34 out of 41) completed the 100 repetitions without excessive muscle fatigue according to the post-exercise MVC values. The intermittent PBE increased fatigue in the lumbar and hip extensor muscles in terms of: (1) a decrease in the MVC; (2) an increase in the level of muscle activation; and (3) a decline of the median frequency (MF). There was no gender difference in all EMG measurements. The level of muscle activation in the hip extensors (GM and HA) was associated with task failure (number of repetitions <100) for some subjects and the addition of a weight of 45 N had more impact on HA than ES. In conclusion, the PBE exercise as performed in the present study (including rest intervals), although not very strenuous for our healthy subjects, seems an adequate exercise to measure and train the aerobic capacity of the back muscles. However, to train specifically the back muscles, the exercise must be adjusted to avoid task failure due to possible hip extensor fatigue.     

Estimated moments at L5/S1 level and muscular activation of back extensors for six prone back extension exercises in healthy individuals

The purpose of this study was to identify the prone back extension (PBE) exercises that offer the most resistance to the back extensor muscles. Twenty males with no previous history of low back injury performed two repetitions of eight exercises. These consisted of two maximal isometric voluntary activations (MVA) and six different PBE exercises. The participants, while lying prone on a bench, were asked to raise either their trunk or legs to the horizontal position and hold for one second (static phase) before returning to the original position. The exercises differed according to the particular segments that were raised into extension. To assess the PBE exercises, a biomechanical model was used to estimate the level of load resistance (%MVA) relative to the maximum voluntary activation strength (MVA). In addition, electromyography (EMG) was included to measure the level of muscle activity (%MVE) relative to the maximum voluntary activation EMG (MVE) value reached during the MVA. A significant relationship of 0.86 was found between the mass of the subject and the peak reaction moment during the MVA. Peak level of load resistance averaged around 50% MVA with the exception of exercise no. 5 where the subject had to raise in extension his trunk, legs and arms (65% MVA). The erector spinae (ES) activity level reached a peak value of 61% MVE for exercise no. 5. In the exercises where only the trunk was lifted, the peak level of ES was below 47% MVE and the average activity during the static phase reached approximately 26% MVE. For healthy individuals PBE exercises can be considered low intensity exercises (< 50% MVA; except exercise no. 5) and can be used to improve the endurance of the back muscles.     

Retraining motor control of abdominal muscles among elite cricketers with low back pain

The purpose of this study was to document the effect of a staged stabilization training program on the motor control of the anterolateral abdominal muscles in elite cricketers with and without low back pain (LBP). Changes in the cross‐sectional area of the trunk, the thickness of the internal oblique and transversus abdominis (TrA) muscles and the shortening of the TrA muscle in response to an abdominal drawing‐in task were measured at the start and completion of a 13‐week cricket training camp. Measures were performed using ultrasound imaging and magnetic resonance imaging. Participants from the group with LBP underwent a stabilization training program that involved performing voluntary contractions of the multifidus, TrA and pelvic floor muscles, while receiving feedback from ultrasound imaging. By the end of the training camp, the motor control of cricketers with LBP who received the stabilization training improved and was similar to that of the cricketers without LBP.     

Physcial exercise and low back pain

Health care providers often prescribe exercises as treatment for nonspecific low back pain. However, the effectiveness of this treatment is poorly documented in the literature. While the evidence suggests that exercise in general is beneficial, there is a lack of knowledge about the types, frequency and duration of exercises that should be prescribed and at what stage of injury they are most helpful. In addition, few studies have dealt with exercise treatment alone rather than in combination with other treatments, making it hard to decipher the unique contribution of exercise. Inadequate study designs also make conclusions difficult. Conversely, the literature clearly shows that inactivity has detrimental effects (i.e. delayed return to normal activity, and negative physiological and psychological effects) for low back pain patients.     

Exercise programs for subjects with low back disorders

Exercise has played a central role in rehabilitation of subjects with low back pain. The research in this field has intensified since the 1980s. Low back pain has been associated with both physically stressful and sedentary occupations. There is no clear association between low back pain and physical activity during leisure time. Many studies have shown that subjects with back pain have impairments in muscular and connective tissue, functional limitations in muscular strength, endurance, speed, and neuromuscular functions, and physical, social and psychological disabilities. The ultimate aims of the exercise-based programs are to reduce and prevent these impairements, functional limitations and disabilities. The results of controlled studies with exercise programs have shown a positive effect on physical impairments and functional limitations for subjects with chronic low back pain. The outcome of exercise programs has not been so positive for disability, defined as an inability or a limitation in performance in social interactions including occupational activities.     

Clinical benefit of intensive dynamic exercises for low back pain

Over the years there has been an apparent contradiction between the widely utilized treatment of low back pain through exercise, and the often apparently disappointing results reported in the scientific literature. Recently published studies have shown that the most important factor regarding the training effects of chronic low back patients is the administration of a high training stimulus (number of repetitions of the exercise, exercise resistance, and the total number of sessions). This would explain why several of the previously published studies regarding training show insignificant results. Simply stated, in many low-dosage or short-time studies, the positive effects of training have not had adequate opportunity to take hold in the chronic low back pain patient. The patient group which has been operated on for disc prolapse often exhibits considerable functional deteriorations post-operatively. Rehabilitation studies have shown that many of these patients also benefit from post-operative rehabilitation including high dosage exercise programs. Exercise programs are generally free of side-effects.     

运动疗法对部队下腰痛病例的干预效果评价

目的 评价徒手核心肌力训练和悬吊运动疗法对下腰痛病例的干预效果.方法 以空军某场站部分下腰痛官兵为研究对象,采用抽签方式将144例下腰痛患者随机分成3组,第1组为徒手核心肌力组(徒手核心肌力训练+普通物理治疗),第2组为悬吊运动疗法组(悬吊运动疗法+普通物理治疗),第3组为对照组(普通物理治疗组),每组48例,开展6周干预试验.干预前、干预2周、4周、6周后分别对3组病例发放调查问卷,了解腰痛程度(VAS评分)、腰椎功能状况(Roland评分)及活动度(FFD评分),同步测量并观察3组病例的腰部肌力变化. 结果 全程参与的3组人数分别是:徒手核心肌力组43例,悬吊运动疗法组43例,对照组44例;徒手核心肌力组VAS评分为3.25、Roland评分为5.83、FFD评分为8.58;悬吊运动疗法组VAS评分为3.30、Roland评分为5.93、FFD评分为8.10;对照组VAS评分为2.41、Roland评分为3.03、FFD评分为7.40.3组下腰痛干预有效率分别为90.90%、85.13%和46.82%.试验组组间各项指标均无显著性差异(P>0.05),与对照组比较有显著性差异(P<0.05). 结论 徒手核心肌力训练和悬吊运动疗法对下腰痛病例均有明显疗效.在不同环境下,部队卫生机构可根据相应的设施条件对下腰痛病例选用徒手核心肌力训练或悬吊运动疗法进行干预,从而有效缓解下腰痛.     

Height changes among chronic low back pain patients during intense physical exercise

The possible effects of intense physical exercise on the total body stature of low back pain patients were monitored by circadian total body height measurements. The height was measured with a statiometer, and the change in height was correlated with the changes in the range of motion, pain and subjective disability and degree of disc degeneration seen on magnetic resonance imaging (MRI) pictures. The stature of 24 low back pain patients was measured during a 3-week period. There was an increase of about 3 mm in height after only 4 days of exercise, and by the end of the programme the morning height increased on average by 7.2 mm.
There were also 12 non-rehabilitated low back pain patients but no such increase was noted among them. The gain of height and reduction of pain were found to be statistically signigicantly correlated ( P =0.0001, r =−0.41), as did the gain of height and teh decrease of back disablity (Oswestry index) ( P <0.0001, r =−0.39). Circadian total height measures but not the MR images will change due to the active back rehabilitation programme.     

肌内效胶贴联合运动训练治疗慢性下腰痛的疗效

 目的 评价肌内效胶贴联合运动训练治疗慢性下腰痛的疗效。方法 某训练基地非特异性下腰痛患者113例, 按照就诊顺序分为肌内效胶贴组(A组, n=58)和肌内效胶贴联合训练组(B组, n=53), 于治疗1周后和4 周后分别应用视觉模拟评分(visual analogue scale, VAS)、Oswestry功能障碍指数(oswestry disability index, OSW)评价治疗效果。结果 B组治疗1和4 周后, VAS评分(5.05±1.98)分、OSW(64.73±7.92)分与治疗前相比明显改善, 差异有统计学意义(P<0.01)。A组治疗1周后, 疼痛症状和残疾指数较治疗前无明显改善, 治疗4周后明显好转。治疗后1周和4周B组的VAS 评分及OSW指数较A组明显下降, 差异有统计学意义(P<0.01)。结论 肌内效胶贴与运动训练联合应用能显著缓解慢性非特异性下腰痛的疼痛症状, 明显减轻残疾程度, 值得临床推广。
     

Muscular performance after a 3 month progressive physical exercise program and 9 month follow-up in subjects with low back pain. A controlled study

The purpose of this study was to assess, in subjects with low back pain, the changes and their permanence in muscular performance after a 3 month progressive physical exercise program. Ninety subjects with chronic low back pain participated in the study. The study design was controlled and it was carried out in three groups: intensive training, home exercise, and control group. Isometric and dynamic muscle strength of the trunk and lower limb were measured, at the beginning of the study and after the 3 months exercise program, and then during each of the follow-up sessions. The Oswestry Index and back pain intensity were also determined. Both exercise groups received benefit from the progressive exercise program. Their muscular performance improved and their back pain intensity decreased significantly. Among the home exercise group, the Oswestry Index also changed positively. The results demonstrate that the home exercise program could be as effective as the intensive training program in increasing muscle strength, as well as decreasing back pain and functional disability among low back pain patients with mild functional limitations.     

Adolescent flexibility, endurance strength, and physical activity as predictors of adult tension neck, low back pain, and knee injury: a 25 year follow up study

Objective

To examine whether adolescent flexibility, endurance strength, and physical activity can predict the later occurrence of recurrent low back pain, tension neck, or knee injury.

Methods

In 1976, 520 men and 605 women participated in a sit and reach test (flexibility) and a 30 second sit up test (endurance strength). In 1976 and 2001 (aged 37 and 42 years) they completed a questionnaire. Lifetime occurrence and risk of self reported low back pain and self reported, physician diagnosed tension neck and knee injury were calculated for subjects divided into tertiles by baseline results of strength and flexibility tests.

Results

Men from the highest baseline flexibility tertile were at lower risk of tension neck than those from the lowest tertile (odds ratio (OR) 0.51, 95% confidence interval (CI) 0.28 to 0.93). Women from the highest baseline endurance strength tertile were at lower risk of tension neck than those from the lowest tertile (OR 0.60, 95% CI 0.40 to 0.91). Men from the highest baseline endurance strength tertile were at higher risk of knee injury than those from the lowest tertile (OR 1.96, 95% CI 1.05 to 3.64). Men who at school age participated in physical activity were at lower risk of recurrent low back pain (OR 0.61; 95% CI 0.42 to 0.88) than those who did not.

Conclusions

Overall good flexibility in boys and good endurance strength in girls may contribute to a decreased risk of tension neck. High endurance strength in boys may indicate an increased risk of knee injury.     

Effect of feedback techniques for lower back pain on gluteus maximus and oblique abdominal muscle activity and angle of pelvic rotation during the clam exercise

ObjectivesThis study was conducted in order to determine the effect of feedback tools on activities of the gluteus maximus (Gmax) and oblique abdominal muscles and the angle of pelvic rotation during clam exercise (CE).DesignComparative study using repeated measures.SettingUniversity laboratory.ParticipantsSixteen subjects with lower back pain.Main outcome measuresEach subject performed the CE without feedback, the CE using a pressure biofeedback unit (CE-PBU), and the CE with palpation and visual feedback (CE-PVF). Electromyographic (EMG) activity and the angles of pelvic rotation were measured using surface EMG and a three-dimensional motion-analysis system, respectively. One-way repeated-measures ANOVA followed by the Bonferroni post hoc test were used to compare the EMG activity in each muscle as well as the angle of pelvic rotation during the CE, CE-PBU, and CE-PVF.ResultsThe results of post-hoc testing showed a significantly reduced angle of pelvic rotation and significantly more Gmax EMG activity during the CE-PVF compared with during the CE and CE-PBU.ConclusionThese findings suggest that palpation and visual feedback is effective for activating the Gmax and controlling pelvic rotation during the CE in subjects with lower back pain.     

Low back pain investigations and prognosis: a review

Low back pain is reviewed in terms of when investigations are useful and its clinical course. Despite the extensive evaluation of the accuracy of investigations such as radiography, magnetic resonance imaging, and myelography, there is a surprising dearth of research to inform their use in primary care. There is no clear evidence on which to base judgments for selection of appropriate tests to confirm or exclude low back pain pathology. It appears that investigations are rarely necessary for low back pain. Specific investigations should be ordered to identify a particular pathology but should not be ordered routinely for general screening. In the absence of pathology, low back pain and its associated disability improve rapidly in the first weeks after onset, but, in contradiction to all guidelines, both commonly persist and the best evidence suggests that recurrences are common.     

稳定肌群压力反馈仪对腰部稳定性测试的重测信度及其对iQ脉冲枪干预的敏感性

 目的 探讨稳定肌群压力反馈仪对腰部稳定性测试的重测信度及其对iQ脉冲枪干预的敏感性。方法 选择2018年5－9月某校教师22名,分别进行俯卧位和仰卧位的稳定肌群压力反馈仪测试,每名教师均需进行间隔3 d的2组重复测试和1组iQ脉冲枪干预后的测试,共计3组测试;每次测试均要求受试者达到最大压强值并维持10 s,记录压强的变化情况(上限值和下限值)。结果 (1)俯卧位测试中,重测试验上限值和下限值测试前后比较均没有统计学差异,相关系数分别为0.734和0.798(P<0.01);干预试验上限值和下限值测试前后比较均没有统计学差异,相关系数分别为0.866和0.870(P<0.01)。(2)仰卧位测试中,重测试验上限值和下限值测试前后比较均没有统计学差异,相关系数分别为0.798和0.767(P<0.01);干预试验上限值和下限值测试前后比较均有统计学差异(P<0.05),相关系数分别为0.955和0.956(P<0.01)。结论 仰卧位稳定肌群压力反馈仪测试有较高的重测信度,对于干预刺激有较好的敏感性;而俯卧位测试虽有一定的重测信度,但不能反映干预的变化;因此,稳定肌群压力反馈仪仰卧位测试法是一种简单实用的腰部功能评估方法。     

Electromyography of the trunk and abdominal muscles in golfers with and without low back pain

Twelve male golfers who experienced low back pain (LBP) whilst playing or practicing golf and 18 asymptomatic golfers were recruited and divided into handicap-specific groups; low-handicap golfers, with a handicap between 0 and 12 strokes; and high-handicap golfers, with a handicap of between 13 and 29 strokes. The myoelectric activity of the lumbar erector spinae (ES) and the external obliques (EO) was recorded via surface electromyography (EMG), whilst the golfers performed 20 drives. The root mean square (RMS) was calculated for each subject and the data for the ES and EO were normalised to the EMGs recorded whilst holding a mass equal to 5% of the subjects' body mass at arms length and whilst performing a double-leg raise, respectively. The results showed that the low-handicap LBP golfers tended to demonstrate reduced ES activity at the top of the backswing and at impact and greater EO activity throughout the swing. The high-handicap LBP golfers demonstrated considerably more ES activity compared with their asymptomatic counterparts, whilst EO activity tended to be similar between the high-handicap groups. The reduced ES activity demonstrated by the low-handicap LBP group may be associated with a reduced capacity to protect the spine and its surrounding structures at the top of the backswing and at impact, where the torsional loads are high. When considering this with the increased EO activity demonstrated by these golfers, it is reasonable to suggest that these golfers may be demonstrating characteristics/mechanisms that are responsible for or are a cause of LBP.     

Assessment instruments of movement quality in patients with non-specific low back pain: A systematic review and selection of instruments

BackgroundObserving and analyzing movement quality (MQ) in patients with non-specific low back pain (NS-LBP) is important in the clinical reasoning of primary care physiotherapists and exercise therapists. However, there is no standardized form of assessment. Research question: which MQ domains are measured with which instruments, and which activities are relevant, appropriate and methodologically sound for assessing MQ in patients with NS-LBP?MethodsThe study had three phases. In phase 1 we conducted a systematic review in PubMed, CINAHL and SPORTDiscus of literature published until October 2018. The selected studies measured MQ domains with instruments that enabled us to 1) compare MQ in self-paced dynamic activities of patients with NS-LBP and healthy controls, and/or 2) determine change over time of MQ in patients with NS-LBP. In phase 2 we established relevant dynamic activities to assess in patients with NS-LBP. In phase 3 we determined appropriateness and methodological qualities of the selected instruments.ResultsThirty cross-sectional and three pre-post-test studies were eligible. The instruments consisted of complex (n = 19) and simple (n = 7) instrumented motion analysis systems and standardized observational tests (n = 7). We identified three domains representative for MQ: range of motion (ROM), inter-segmental coordination, and whole-body movements. In these domains, patients with NS-LBP significantly differed from healthy controls, respectively 7/12, 12/13 and 13/20 studies. Moreover, ROM and whole-body movements significantly improved over time in patients with NS-LBP (3/3 studies). Based on phase 3, we concluded that none of the instruments are appropriate to assess MQ in patients with NS-LBP in primary care.SignificanceForward bending, lifting, and walking seem the most relevant activities to evaluate in patients with NS-LBP. However, we found no suitable instruments to measure ROM, inter-segmental coordination, or whole-body movements as determinants of MQ in these activities in daily practice. We therefore recommend such an instrument be developed.     

八段锦锻炼法对慢性精神分裂症患者精神康复的促进作用

 目的 探讨八段锦锻炼对慢性精神分裂症患者精神康复的促进作用.方法 选取44例符合CCMD-3精神分裂症诊断标准的住院患者作为研究对象,采用简单随机法分为研究组和对照组,两组患者均保持抗精神病药物治疗不变,研究组进行八段锦锻炼并给予常规护理,对照组给予常规护理.在八段锦锻炼前和锻炼12周后分别用护士用住院患者观察量表(NOSIE)和阴性症状量表(SANS)进行评定.结果 八段锦锻炼12周后,研究组在NOSIE病情总分、总积极分、社会能力、社会兴趣、个人整洁等因子分明显高于研究前评分,而激惹、迟缓、抑郁等因子分明显低于研究前评分,差异均具有统计学意义(P＜0.01);而对照组研究前后各因子分评分无显著差异.八段锦锻炼组12周后SANS评分各因子分均明显低于研究前,差异均具有统计学意义(P≤0.01).结论 八段锦锻炼可改善慢性精神分裂症患者的社会功能,减轻阴性症状,对患者的精神康复有一定辅助作用.     

Neuromuscular response differences to power vs strength back squat exercise in elite athletes

The study's aim was to establish the neuromuscular responses in elite athletes during and following maximal ‘explosive’ regular back squat exercise at heavy, moderate, and light loads. Ten elite track and field athletes completed 10 sets of five maximal squat repetitions on three separate days. Knee extension maximal isometric voluntary contraction (MIVC), rate of force development (RFD) and evoked peak twitch force (Pt) assessments were made pre‐ and post‐session. Surface electromyography [root mean square (RMS)] and mechanical measurements were recorded during repetitions. The heavy session resulted in the greatest repetition impulse in comparison to moderate and light sessions (P < 0.001), while the latter showed highest repetition power (P < 0.001). MIVC, RFD, and Pt were significantly reduced post‐session (P < 0.01), with greatest reduction observed after the heavy, followed by the moderate and light sessions accordingly. Power significantly reduced during the heavy session only (P < 0.001), and greater increases in RMS occurred during heavy session (P < 0.001), followed by moderate, with no change during light session. In conclusion, this study has shown in elite athletes that the moderate load is optimal for providing a neuromuscular stimulus but with limited fatigue. This type of intervention could be potentially used in the development of both strength and power in elite athletic populations.