A model of dynamic sacro–iliac joint instability from malrecruitment of gluteus maximus and biceps femoris muscles resulting in low back pain

Effects of pelvic tilt control using visual biofeedback on gluteus maximus, multifidus, and hamstring activities during three different bridge exercises

BACKGROUND

The effects of pelvic tilt control using visual biofeedback on gluteus maximus (GM), multifidus (MF), and hamstring (HAM) muscle activities during bridge exercises involving anterior pelvic tilt (APT), neutral pelvic tilt (NPT), and posterior pelvic tilt (PPT) were investigated.

METHODS

Twenty-five healthy participants were included (mean age, 24.6 ± 1.9 years). Visual biofeedback was used for the participants to self-control pelvic tilt during the bridge exercises. Pelvic tilt controls were performed in a random order (APT vs. NPT vs. PPT) following 30 minutes education program. GM, MF, and HAM muscle activities were measured by surface electromyography. One-way repeated analysis of variance and Bonferroni post hoc test were used.

RESULT

GM and MF muscle activities significantly differed among the different pelvic tilting controls (APT vs. NPT vs. PPT) (p < .017). GM muscle activity during the exercise involving PPT was significantly higher than that involving APT and NPT (p < .017). In contrast, MF muscle activity during the exercise involving PPT was significantly lower than that involving APT (p < .017). In addition, the GM/Right MF, GM/Left MF, and GM/HAM muscle activity ratios during the exercise involving PPT were significantly greater than those involving APT and NPT (p < .017).

CONCLUSIONS

The bridge exercise involving PPT using visual biofeedback can be recommended as a home exercise to selectively improve the muscle activity of the GM and the muscle activity ratio of the GM/HAM and GM/MF. This information may be valuable for clinicians seeking exercise programs to target specific muscles effectively.

Revisiting chronic low back pain: evidence that it is not non-specific

CONTEXT

There is a common symptom pattern with most chronic low back pain (CLBP), suggesting that there is a common underlying etiology, belying the term "nonspecific." Many studies of CLBP and its treatment have been conducted with the assumption of nonspecificity, and as a result, treatment has not been focused, thus there has not been a significant change in CLBP prevalence over the past several decades. It is the thesis of this study to show that there is an underlying, specific cause of CLBP and that the presumption that CLBP is nonspecific is misdirected. The lumbosacropelvic (LSP) region, including the sacroiliac joint (SIJ), is part of a neuromusculoskeletal (NMSK) feedback system, and it is proposed here that CLBP is the result of a change in the feedback (afferent) aspect in that system.

OBJECTIVES

The objectives of this study are to show that CLBP presents as a pattern of symptoms that actually represents the final common pathway for a dysfunctional LSP joint system. Rather than being "nonspecific," the majority of CLBP has an underlying cause that is quite specific and predictable.

METHODS

A total of 252 patients were seen for CLBP, 67% of whom were diagnosed with an SIJ dysfunction. The presence of pain was recorded from seven structures most closely associated with CLBP. The conditional probabilities of having each pain generator given a SIJ dysfunction and an SIJ dysfunction given the presence of the pain generator were estimated, and associations were analyzed utilizing chi-square tests. Phi coefficients and odds ratios were utilized to quantify the strength of the association. The multivariable logistic regression model was fit to relate the presence or absence of the SIJ dysfunction to the seven pain generators.

RESULTS

The associations between SIJ dysfunction and each pain generator were statistically significant. Phi coefficients indicated moderate strengths of these bivariate associations. Iliolumbar ligament (ILL) and psoas muscle (PSM) were significant predictors of SIJ dysfunction in the multivariable model.

CONCLUSIONS

Seven pain generators had a strong association with SIJ dysfunction. This empirical clinical evidence supports our hypothesis that LSP system dysfunction, as evidenced by SIJ dysfunction, is a common source of symptom patterning associated with CLBP and is most likely the causal element. This is evidence that most CLBP is not "nonspecific" but rather the result of changes made by the NMSK control system for the LSP region.

Immediate effect of trunk flexion and extension isometric exercise using an external compression device on electromyography of the hip extensor and trunk range of motion of healthy subjects

Background

Sacroiliac joints (SIJs) transmitted trunk load to lower extremities through the lumbopelvis. External compression devices across the SIJs could provide stability to the SIJs. A previous study established that using a device known as Active Therapeutic Movement version 2 (ATM^®2) has been developed to improve pain and joint range of motion (ROM) in patients with LBP. However, no study has examined the physiological change in the muscle through ATM®2-based exercise thus far. This study aimed to determine the immediate effects of ATM^®2 exercise on the contraction timing, back extension endurance, muscle fatigue, and trunk ROM of lumbar and lower limb muscles in healthy subjects.

Methods

Thirty-six healthy subjects (mean age = 23.16 ± 2.3) volunteered to participate in this study. Subjects were instructed to perform ROM test using sit and reach test, back extensor endurance test using Biering-Sorensen test, erector spinae (ES), lumbar multifidus (LM) fatigue and onset time of Gluteus maximus (GM) in prone hip extension using electromyography before and after trunk flexion and extension isometric exercises.

Results

The ROM in trunk flexion showed a significant increase of 7.9% after exercise compared to that before exercise (p < 0.05). Relative GM contraction onset timing significantly decreased after exercise (p < 0.05). The result of the Sorensen test after exercise showed a trend of increase in duration time. Muscle fatigue in the LM, however, showed a significant increase (p < 0.05), whereas muscle fatigue in the ES was reduced without statistical significance.

Conclusions

The results base on this study showed that exercise-based on ATM®2 is an effective exercise protocol with an effect on the biomechanics of healthy subjects.

Clinical trial registration numbers KCT0006728. Clinical trial registration date: 09/11/2021.

Electromyographic differences of the gluteus maximus, gluteus medius, biceps femoris, and vastus lateralis between the barbell hip thrust and barbell glute bridge

Hip extensor muscles are critical to sport performance as events requiring sprinting and forceful landings are highly dependent on these muscles. Despite biomechanical differences between the barbell hip thrust (BHT) and the barbell glute bridge (BGB), both are biomechanically efficient ways to load this musculature for training purposes. Research investigating the differences in muscular activity between the BHT and BGB has yet been conducted. The aim of this study was to investigate, through surface electromyography, if one exercise is more optimal than the other in producing greater muscle activation for specific hip extensor muscles. Ten male participants completed a two-part study protocol. Results revealed the BHT elicited significantly greater muscle activity within the vastus lateralis for peak and mean outcomes; however, the BGB elicited significantly greater muscle activity in the upper and lower gluteus maximus for peak and mean outcomes and mean outcome in the gluteus medius. Current findings suggest, the BGB is, at minimum, a superior substitute for the BHT for eliciting a larger magnitude of activity in the gluteus maximus. Future studies between the two exercises are warranted to discern which produces greater hypertrophy and whether adaption of the BHT or BGB transfers more optimally to sport performance.

Peak Power Output and Onset of Muscle Activation During High Pull Exercise

ABSTRACT

Barnes, MJ, Petterson, A, and Cochrane, DJ. Peak power output and onset of muscle activation during high pull exercise. J Strength Cond Res 35(3): 675-679, 2021-The aim of this study was to determine the percentage of 1 repetition maximum (1RM) at which peak power output occurred during the high pull (HP) exercise. In addition, the onset time of the biceps femoris (BF) and gluteus maximus (GM), across a range of loads, was investigated. Twelve resistance-trained men performed 1RM testing for the HP followed by lifts at 10% increments from 30 to 80% 1RM. During each load of power, output was measured using a linear potentiometer, whereas surface electromyography was recorded from the BF and GM. Peak power output occurred at 70% (1881.9 ± 296.1 W); however, there was no significant difference between loads at 60-80% (all p > 0.05). Loads between 40 and 80% 1RM produced significantly higher power outputs than 30% while 80% generated greater power than 100% 1RM (all p < 0.05). There was no significant (p > 0.05) main effect of muscle or load in the onset of BF (156.5-212.1 ms) or GM (112.1-158.1 ms). Therefore, these results suggest that training at a load between 60 and 80% 1RM may be useful in increasing power in the HP. In addition, activation of 2 of the hip extensors occurs in a relatively synchronous order irrespective of load.

Comparison of Glutues Maximus Activation to Flexion Bias Exercises Along with MET Technique in Subjects with Anterior Rotated Sacroiliac Joint Dysfunction-a Randomised Controlled Trial

BACKGROUND

Sacroiliac joint dysfunction (SIJD) is the primary source of low-back pain. Main muscles forming the force closure of sacroiliac joint are the biceps femoris and gluteus maximus which increase the stability through massive attachments via sacrotuberous ligament. However, there is a dearth of literature of the importance of activation of gluteus maximus in SIJD.

PURPOSE

To study the effect of gluteus maximus activation on Oswestry Disability Index (ODI), visual analog scale (VAS), and pelvic tilt angle in subjects with anterior rotated sacrolilac joint dysfunction.

SETTINGS

The study was conducted in outpatient Physiotherapy Department, Manipal Hospital, Bangalore, India.

PARTICIPANTS

Anterior rotated SIJD subjects were recruited in the study. They were divided into two groups (experimental and control groups) by block randomisation.

RESEARCH DESIGN

This is a randomised control trial.

CONTROLLED TREATMENT

Treatment order was determined by block randomisation. The subjects of both experimental and control group received Muscle Energy Technique (MET) technique on 1^st session to correct the anterior rotated SIJD. The experimental group received gluteus maximus activation protocol, whereas the control group received flexion bias exercises. The groups received the treatment of 20 mins per session. There were two supervised sessions per week for four weeks.

MAIN OUTCOME MEASURES

The primary outcome measure in the study is Oswestry Disability Index (ODI). The secondary outcome measures included visual analog scale (VAS) and Palpation Meter (PALM).

RESULTS

48 subjects (26 females, 22 males) were randomised into experimental and control groups having anterior rotation SIJD, and average age in groups was 38.83 ± 11.4 years and 34.96 ± 9.5 years, respectively. The within-group analysis showed significant improvements in only ODI outcome of both the groups (p = .001). The between-group analysis in both groups did not show any statistical significant difference in ODI, VAS, or PALM.

CONCLUSION

The flexion bias exercise and the gluteus maximus activation exercises used in this study were equally effective in improving physical function and reduction in pain, and maintaining the normal pelvic angle in subjects with anterior rotated SIJD.

Postural Stability in Individuals with and without Sacroiliac Joint Dysfunction Before and After Pelvic Belt Application

Background: Sacroiliac Joint Dysfunction (SIJD) is considered an origin of low-back pain. It can change the motor control strategy and postural control (PC). Objectives: We aimed to find any probable differences in PC between subjects with and without SIJD and determine the effects of the pelvic belt (PB) on PC. Methods: Thirty-eight subjects were assigned into two equal groups with and without SIJD. They started to walk from the place marked on a force plate for 10 seconds after hearing an auditory signal and performed three attempts for each foot. They repeated six more ones with PB. Raw data were imported to an excel software (version 2007) spreadsheet to calculate the reaction time (RT) and anticipatory postural adjustment (APA) as the components of PC. Results: Our results showed a significant difference in RT between the SIJD-affected and non-affected sides (P = 0.035), but there was no significant difference in APA (P = 0.057). There were significant differences in RT and APAs between the control and SIJD-affected side groups (P = 0.001 and P = 0.010, respectively). The PB application showed a significant difference in RT and APAs of the SIJD-affected side (P = 0.001 and P = 0.047, respectively). Conclusions: It seems pain could lead to the postural sway into instability and change the motor control strategy. The proprioception signals from the neuromuscular system of SIJ improved after PB. Therefore, PB, as a feasible tool, can be recommended for PC improvement.

Anticipatory postural control differs between low back pain and pelvic girdle pain patients in the absence of visual feedback

PURPOSE

The aim of this study was to examine the effect of vision on anticipatory postural control (APA) responses in two groups of clinically diagnosed chronic low back pain patients, those with Posterior Pelvic Girdle pain and those with Non-Specific Low Back Pain compared to a matched group of healthy controls during the modified Trendelenburg task.

METHODS

Seventy-eight volunteer participants (60 females and 18 males) gave informed consent to take part in this study. 39 with confirmed LBP or PGP lasting longer than 12 weeks and 39 healthy matched controls performed 40 single leg lift tasks (hip flexion to 90° as quickly as possible) with their non-dominant lower limb. A force plate was used to determine the medial-lateral displacement of the center of pressure, and the initiation of weight shift; kinematics was used to determine initiation of leg lift; and electromyography was used to determine onset times from the external oblique (EO), internal oblique (IO) and lumbar multifidus (MF), gluteus maximus (GM) and biceps femoris (BF).

RESULTS

The PGP group showed significantly longer muscle onset latencies in the BF, EO MF with visual occlusion (F_2,746 = 4.51, p < .0001).

CONCLUSION

The muscle onset delays identified between the two LBP sub-groups suggests that pain may not be the primary factor in alteration of APA response. The PGP group show a greater reliance on vision which may signal impairment in multiple feedback channels.

The effect of the trunk and gluteus maximus muscle activities according to support surface and hip joint rotation during bridge exercise

[Purpose] The purposes of this study were to strengthen gluteus maximus and trunk muscles depending upon the hip joint direction by bridging exercise on an unstable and stable surface, and to suggest an intervention method for efficient and selective exercise. [Participants and Methods] The test measured the muscle activities with the external rotation and internal rotation of 25 degrees and hip joint neutral position of 0 degree on a stable and unstable surface each exercise 3 times for 9 seconds. [Results] External oblique abdominis showed a higher muscle activity on the unstable surface and internal rotation. Erector spinae showed no significant difference on the surfaces and demonstrated the highest muscle activity at the internal rotation. Gluteus maximus showed a higher muscle activity on the stable surface and external rotation and the interaction effect between the surface and the angle indicated a statistical significance as well. [Conclusion] Muscle activities appear different depending upon the change of surface and joint angle, and it can be said that the correct mobilization of muscle fiber relying on the muscle arrangement direction and muscle contraction direction is the most important factor for gluteus maximus.

Hip joint torques in type II diabetes with and without neuropathy

Background

Patients with diabetes and peripheral neuropathy demonstrate significantly reduced peak torques at the peripheral joints.

Objectives

The aim of this study was to assess isometric and concentric peak torques of the hip joint in people with type II diabetes with and without peripheral neuropathy in comparison with healthy participants.

Methods

27 patients with type II diabetes including 15 patients without peripheral neuropathy, 12 patients with diabetes and peripheral neuropathy and 15 healthy people participated. Isometric and concentric peak torques of hip flexion, extension, adduction and abduction of the non-dominant leg were measured by motorized dynamometer.

Results

Peak and average peak concentric torques of the hip extension and abduction in patients with diabetes and peripheral neuropathy were lower than those patients with diabetes and control group. Angle of extension peak torque was significantly greater in patients with diabetes and peripheral neuropathy compared with other groups. Angle of flexion peak torque was lower in the patients with diabetes and peripheral neuropathy.

Conclusions

Torque related parameters in patients with type II diabetes with or without peripheral neuropathy, are different from healthy subjects. As a result, patients with diabetes especially with peripheral neuropathy are more susceptible of injury and disability in lower limbs.

Does short-term gluteal activation enhance muscle performance?

A reduction in gluteus maximus (GM) strength may contribute to the etiology of musculoskeletal impairments and lower-extremity injuries. Currently, there is a paucity of evidence regarding the efficacy of implementing a short-term gluteal activation programme to improving muscle performance. Twenty four semi-professional rugby males were assigned randomly to a gluteal activation group (GLUTE) or a control group (CON). During the 6-week training intervention, the GLUTE and CON groups performed the same training, however that GLUTE group performed seven gluteal activation exercises three times weekly prior to their normal training sessions. Whilst the CON group performed the conventional training with no gluteal activation exercises. Electromyography (EMG) was measured during a maximal isometric unilateral squat (MVIC) and unilateral hip extension force from the left and right vastus lateralis, gluteus maximus, and biceps femoris. After 6 weeks of training there was no significant main or interaction effect (p > 0.05) of EMG and peak force for MVIC and hip extension between GLUTE and CON. The current gluteal activation programme did not enhance EMG activity and hip extension force therefore, the body-weight exercises may not have been sufficient to elicit the appropriate changes.

Modifying the hip abduction angle during bridging exercise can facilitate gluteus maximus activity

PURPOSE

To investigate how the erector spinae (ES) and gluteus maximus (GM) muscle activity and the anterior pelvic tilt angle change with different hip abduction angles during a bridging exercise.

METHODS

Twenty healthy participants (10 males and 10 females, aged 21.6 ± 1.6) voluntarily participated in this study. Surface electromyography (EMG) signals were recorded from the ES and GM during bridging at three hip abduction angles: 0°, 15°, and 30°. Simultaneously, the anterior pelvic tilt angle was measured using Image J software.

RESULTS

The EMG amplitude of the GM muscle and the GM/ES EMG ratio were greatest at 30° hip abduction, followed by 15° and then 0° hip abduction during the bridging exercise. In contrast, the ES EMG amplitude at 30° hip abduction was significantly lesser than that at 0° and 15° abduction. Additionally, the anterior pelvic tilt angle was significantly lower at 30° hip abduction than at 0° or 15°.

CONCLUSIONS

Bridging with 30° hip abduction can be recommended as an effective method to selectively facilitate GM muscle activity, minimize compensatory ES muscle activity, and decrease the anterior pelvic tilt angle.

Electromyographic Analysis of the Hip Extension Pattern in Visually Impaired Athletes

The objective of the study was to determine the order of muscle recruitment during the active hip joint extension in particular positions in young visually impaired athletes. The average recruitment time (ART) of the gluteus maximus (GM) and the hamstring muscle group (HMG) was assessed by the means of surface electromyography (sEMG). The sequence of muscle recruitment in the female and male group was also taken into consideration. This study followed a prospective, cross - sectional, randomised design, where 76 visually impaired athletes between the age of 18-25 years were enrolled into the research and selected on chosen inclusion and exclusion criteria. Finally, 64 young subjects (32 men and 32 women) were included in the study (age: 21.1 ± 1.05 years; body mass: 68.4 ± 12.4 kg; body height: 1.74 ± 0.09 m; BMI: 22.20 ± 2.25 kg/m2). All subjects were analysed for the ART of the GM and HMG during the active hip extension performed in two different positions, as well as resting and functional sEMG activity of each muscle. Between gender differences were comprised and the correlations between the ART of the GM and HMG with their functional sEMG activity during hip extension in both positions were shown. No significant differences between the ART of the GM and HMG were found (p>0.05). Furthermore, there was no significant difference of ART among both tested positions, as well in male as female subjects (p>0.05).

Characteristics of stabilizer muscles: a systematic review

PURPOSE

To identify the main characteristics, based on available evidence, of stabilizer muscles to inform the development of a definition of stabilizer muscles.

METHODS

Electronic databases were systematically searched for relevant literature from the databases' inception to June 2013 using keywords related to stability, muscles, and characteristics of stabilizer muscles. Studies that provided at least one characteristic of a stabilizer muscle were included. For the quality assessment, all included articles were categorized as either experimental or opinion-based studies. Methodological quality was assessed using a customized checklist, and data were analyzed with a narrative synthesis involving content analysis. The number of articles providing either direct evidence supporting a link between the characteristic and joint stability or indirect evidence that a muscle considered to be a stabilizer has that characteristic determined the level of significance of that characteristic for stabilizer muscles.

RESULTS

A total of 77 studies met the inclusion criteria. The highest number of articles providing supporting evidence that a particular muscle characteristic plays a stabilizing role related to biomechanical characteristics (27 articles), followed by neurological characteristics (22 articles) and anatomical/physiological characteristics (4 articles).

CONCLUSION

Based on a synthesis of supporting evidence from the literature, stabilizer muscles can be defined as muscles that contribute to joint stiffness by co-contraction and show an early onset of activation in response to perturbation via either a feed-forward or a feedback control mechanism. These results may guide researchers to investigate which muscles exhibit these characteristics to determine whether particular muscles have a stabilizer rather than a prime mover role during normal functioning.

Muscle Activation and Onset Times of Hip Extensors during Various Loads of a Closed Kinetic Chain Exercise

The aim of this study was to determine the muscle activity and onset time of hip extensors during a closed kinetic chain exercise (deadlift) at sub-maximal loads of 30%, 40%, 50%, and 75% of one repetition maximum (1RM). Twelve healthy males with at least three years of resistance training experience volunteered for the study. Biceps femoris (BF) and gluteus maximus (GM) muscle activity, onset time, peak and mean power were measured during the concentric phase of the deadlift. There was no main effect (p > 0.05) or no interaction effect for the onset time in BF and GM and for each load BF and GM had similar muscle activity. Increasing the external load during deadlift had no adverse effect on the relative onset time and it did not promote BF onset to occur before GM onset, thus both muscles were simultaneously activated, which should not compromise a delay in GM.

Effect of abduction and external rotation of the hip joint on muscle onset time during prone hip extension with knee flexion

[Purpose] This study investigated the effect of hip position on muscle onset time during prone hip extension with knee flexion. [Subjects] The study included 21 healthy male volunteers. [Methods] Muscle onset times of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and bilateral lumbar multifidus were measured using surface electromyography during right hip extension with knee flexion in the prone position. Measurements were made with the hip in 3 positions: (1) neutral, (2) abduction, and (3) abduction and external rotation. [Results] Gluteus maximus onset relative to the hamstrings was significantly earlier with hip abduction and with hip abduction and external rotation compared with that with the hip in the neutral position. Gluteus maximus onset relative to the hamstrings was significantly earlier with hip abduction and external rotation compared with that with hip abduction. The bilateral multifidus and left lumbar erector spinae onset times relative to the hamstrings were significantly earlier with hip abduction and external rotation compared with those with hip abduction and with the hip in the neutral position. [Conclusion] Abduction and external rotation of the hip during prone hip extension with knee flexion is effective for advancing the onset times of the gluteus maximus, bilateral multifidus, and contralateral lumbar erector spinae.

Influence of Hip Joint Position on Muscle Activity during Prone Hip Extension with Knee Flexion

[Purpose] This study investigated the selective activation of the gluteus maximus during a prone hip extension with knee flexion exercise, with the hip joint in different positions. [Subjects] The subjects were 21 healthy, male volunteers. [Methods] Activities of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and bilateral lumbar multifidus were measured using surface electromyography during a prone hip extension with knee flexion exercise. Measurements were made with the hip joint in each of 3 positions: (1) a neutral hip joint position, (2) an abduction hip joint position, and (3) an abduction with external rotation hip joint position. [Results] Gluteus maximus activity was significantly higher when the hip was in the abduction with external rotation hip joint position than when it was in the neutral hip joint and abduction hip joint positions. Gluteus maximus activity was also significantly higher in the abduction hip joint position than in the neutral hip joint position. Hamstring activity was significantly lower when the hip was in the abduction with external rotation hip joint position than when it was in the neutral hip joint and abduction hip joint positions. [Conclusion] Abduction and external rotation of the hip during prone hip extension with knee flexion exercise selectively activates the gluteus maximus.

Isometric hip abduction using a Thera-Band alters gluteus maximus muscle activity and the anterior pelvic tilt angle during bridging exercise

The purpose of this study was to investigate the effects of bridging with isometric hip abduction (IHA) using the Thera-Band on gluteus maximus (GM), hamstring (HAM), and erector spinae (ES) muscle activity; GM/HAM and GM/ES ratios; and the anterior pelvic tilt angle in healthy subjects. Twenty-one subjects participated in this study. Surface EMG was used to collect EMG data of GM, HAM, and ES muscle activities, and Image J software was used to measure anterior pelvic tilt angle. A paired t-test was used to compare GM, HAM, and ES muscle activity; the GM/HAM and GM/ES ratios; and the anterior pelvic tilt angle with and without IHA during the bridging exercise. GM muscle activity increased significantly and the anterior pelvic tilt angle decreased significantly during bridging with IHA using the Thera-Band (p < 0.05). However, there were no significant differences in the activity of the HAM and ES and the GM/HAM and GM/ES ratios between bridging with and without IHA (p > 0.05). The results of this study suggest that bridging with IHA using the Thera-Band can be implemented as an effective method to facilitate GM muscle activity and reduce the anterior pelvic tilt angle.

How different knee flexion angles influence the hip extensor in the prone position

[Purpose] The present study examined the effects of knee flexion angle on hip extensor muscle activity. [Subjects and Methods] Twenty healthy subjects maintained knee flexion angles of 0°, 30°, 60°, 90° and 110° in the prone position and performed maximal voluntary contraction in hip extension. Maximum torque in hip extension at the different angles was measured, and surface electromyogram activities of the gluteus maximus (GM), biceps femoris (BF) and semitendinosus (ST) were recorded and normalized by the maximum voluntary isometric contraction (MVIC). [Results] The maximum torque of the hip extensor showed significant decreases between 0°and 60°, 90° and 110° of knee flexion. The muscle activity of BF was significantly high at 0°, and GM showed a significantly higher activity than both BF and ST at 60°, 90°and 110° of knee flexion. [Conclusion] The maximum torque in hip extension and muscle activities of BF and ST were significantly high at 0° but they decreased at knee flexion angles of more than 60°. Therefore, we consider that more than 60° of knee joint flexion is required to increase GM activity, and to reduce the muscle activities of BF and ST.

Comparison of Posterior Oblique Sling Activity during Hip Extension in the Prone Position on the Floor and on a Round Foam Roll

[Purpose] The aim of this study was to compare muscle activity of the posterior oblique sling during prone hip extension (PHE) on the floor and on a round foam roll. [Subjects] Twenty-two (11 male, 11 female) healthy volunteers were recruited for this study. [Methods] The participants performed PHE on the floor and on a round foam roll. Surface electromyography (EMG) was recorded from the contralateral latissimus dorsi (LD), contralateral erector spinae (ES), ipsilateral ES, ipsilateral gluteus maximus (GM), and ipsilateral biceps femoris (IBF). A paired t-test was used to compare muscle activity under the floor and round foam roll conditions. [Results] EMG activity of the contralateral LD, ipsilateral ES, and ipsilateral GM was significantly greater when PHE was performed on the round foam roll than on the floor. [Conclusion] Performing PHE on the round foam roll induced greater posterior oblique sling EMG activity than did exercise on the floor. These results suggest that the activation pattern of the posterior oblique sling during PHE is differs according to the type of surface (stable vs. unstable) on which it is performed.

Closed internal degloving associated with a thoracolumbar burst fracture: a case report

Internal degloving injuries are rare in association with thoracolumbar fractures. A high index of suspicion is warranted to identify and debride such lesions to prevent infection, which can be disastrous in the presence of spinal hardware. Whether such lesions should be routinely repaired is probably dependent on the extent of avulsion.

Multi-factorial causative model for back pain management; relating causative factors and mechanisms to injury presentations and designing time- and cost effective treatment thereof

Back pain resolution has not statistically improved over many years with some literature suggesting chronic back pain to be increasing. From a search of literature on causes, events, mechanisms, factors and treatment for back pain, a model is developed that relates causes of back injury to factors that result in pain through two primary mechanisms; muscle fatigue and muscle/tendon/connective tissue strain or sprain with other main mechanisms being diminished reactivity and strength, changes in tendon/tissue mechanical properties and fear of back pain recurrence/fear of movement following a back pain episode. The model highlights the fact that back pain/injury is multi-factorial with numerous circular relationships. Therefore treatment should also be multi-factorial; a combination of physical and psychological therapy with attention to mechanisms at work or in daily living that exacerbate the injury and delay recovery thereof. Exercise is one method that can reduce muscle imbalance, improve resilience to muscle fatigue, and address reactivity and strength. More importantly, eccentric exercise can rectify musculotendinous or connective tissue injury which plays a role in prolonging the back injury cycle. Posture is identified as a causative factor for back pain with the time exposure for posture representing the largest portion of daily activities. From literature and from clinical observation, treatment methods can be improved and incorporated into integrated multi-modal programs. An integrated exercise program that commences with motor control exercise and progresses into functional movement is suggested. Furthermore a modification of the McKenzie extension movement may benefit back injury rehabilitation for a majority of lower back pain patients. Otherwise the sit-to-stand movement is a regular and frequent exacerbating mechanism of back pain and likely continuously tears connective tissue during the movement thus prolonging the cycle of back pain and can be addressed instantly with a modification in sit-to-stand technique.

Muscular activation patterns during active prone hip extension exercises

BACKGROUND

Changes in activation patterns of hip extensors and pelvic stabilizing muscles are recognized as factors that cause low back disorders and these disturbances could have an impact on the physiological loading and alter the direction and magnitude of joint reaction forces.

OBJECTIVE

To investigate activation patterns of the gluteus maximus, semitendinosus and erector spinae muscles with healthy young individuals during four different modalities of therapeutic exercise.

METHODS

Thirty-one volunteers were selected: (16 men and 15 women), age (24.5+/-3.47years), body mass of 66.89+/-11.89kg and a height of 1.70+/-0.09m). They performed four modalities of therapeutic exercise while the electromyographic activity of the investigated muscles was recorded to determine muscle pattern activation for each exercise.

RESULTS

Repeated measure ANOVA revealed that muscle activation patterns were similar for the four analyzed exercises, starting with the semitendinosus, followed by the erector spinae, and then, the gluteus maximus. The gluteus maximus was the last activated muscle during hip extension associated with knee flexion (p<0.0001), knee extension (p<0.0001), and with lateral rotation and knee flexion (p<0.05).

CONCLUSION

Findings of the present study suggested that despite individual variability, the muscle firing order was similar for the four therapeutic exercises.

Common errors and clinical guidelines for manual muscle testing: "the arm test" and other inaccurate procedures

BACKGROUND

The manual muscle test (MMT) has been offered as a chiropractic assessment tool that may help diagnose neuromusculoskeletal dysfunction. We contend that due to the number of manipulative practitioners using this test as part of the assessment of patients, clinical guidelines for the MMT are required to heighten the accuracy in the use of this tool.

OBJECTIVE

To present essential operational definitions of the MMT for chiropractors and other clinicians that should improve the reliability of the MMT as a diagnostic test. Controversy about the usefulness and reliability of the MMT for chiropractic diagnosis is ongoing, and clinical guidelines about the MMT are needed to resolve confusion regarding the MMT as used in clinical practice as well as the evaluation of experimental evidence concerning its use.

DISCUSSION

We expect that the resistance to accept the MMT as a reliable and valid diagnostic tool will continue within some portions of the manipulative professions if clinical guidelines for the use of MMT methods are not established and accepted. Unreliable assessments of this method of diagnosis will continue when non-standard MMT research papers are considered representative of the methods used by properly trained clinicians.

CONCLUSION

Practitioners who employ the MMT should use these clinical guidelines for improving their use of the MMT in their assessments of muscle dysfunction in patients with musculoskeletal pain.

Structural and biomechanical aspects of equine sacroiliac joint function and their relationship to clinical disease

Pain originating from the sacroiliac joint (SIJ) in horses has long been associated with poor performance, yet specific diagnosis of sacroiliac dysfunction (SID) has been difficult to achieve. Clinical presentation of SID appears to fall into two categories. The first, presenting as pain and poor performance, is responsive to local analgesia of periarticular structures with poorly defined pathology. The second presents primarily as poor performance with bony pathological changes as a result of chronic instability. Diagnostic tests based on biomechanics as well as manual provocation for SIJ pain have formed the basis of tests currently used to diagnose SIJ dysfunction in humans. This review summarises the anatomy and biomechanics of the equine SIJ and current biomechanical, innervation and motor control concepts in human SID. The relationship between abnormal SIJ motion and altered neuromotor control with clinical disease of the equine SIJ are discussed. Future utilisation of these principles to develop new diagnostic and management tools for the equine SID is promising.

On the reliability and validity of manual muscle testing: a literature review

INTRODUCTION

A body of basic science and clinical research has been generated on the manual muscle test (MMT) since its first peer-reviewed publication in 1915. The aim of this report is to provide an historical overview, literature review, description, synthesis and critique of the reliability and validity of MMT in the evaluation of the musculoskeletal and nervous systems.

METHODS

Online resources were searched including Pubmed and CINAHL (each from inception to June 2006). The search terms manual muscle testing or manual muscle test were used. Relevant peer-reviewed studies, commentaries, and reviews were selected. The two reviewers assessed data quality independently, with selection standards based on predefined methodologic criteria. Studies of MMT were categorized by research content type: inter- and intraexaminer reliability studies, and construct, content, concurrent and predictive validity studies. Each study was reviewed in terms of its quality and contribution to knowledge regarding MMT, and its findings presented.

RESULTS

More than 100 studies related to MMT and the applied kinesiology chiropractic technique (AK) that employs MMT in its methodology were reviewed, including studies on the clinical efficacy of MMT in the diagnosis of patients with symptomatology. With regard to analysis there is evidence for good reliability and validity in the use of MMT for patients with neuromusculoskeletal dysfunction. The observational cohort studies demonstrated good external and internal validity, and the 12 randomized controlled trials (RCTs) that were reviewed show that MMT findings were not dependent upon examiner bias.

CONCLUSION

The MMT employed by chiropractors, physical therapists, and neurologists was shown to be a clinically useful tool, but its ultimate scientific validation and application requires testing that employs sophisticated research models in the areas of neurophysiology, biomechanics, RCTs, and statistical analysis.