Charlotte Ganderton

The variable roles of the upper and lower subscapularis during shoulder motion.

BACKGROUND The varied roles of the subscapularis muscle as an internal rotator of the humerus, a shoulder abductor, a humeral head depressor and an anterior stabiliser may be a result of differing innervation and lines of torque between its superior and inferior components. The aims of the study were to investigate the differences in the level of muscle activation between the upper and lower subscapularis during abduction, flexion, internal and external rotation movements, and temporal characteristics during abduction and flexion. METHODS Intramuscular electrodes recorded electromyographic muscle activity from the upper and lower subscapularis muscles of the dominant throwing arm of twenty-four normal subjects. Participants completed ten repetitions of four shoulder movements - abduction, flexion, internal rotation and external rotation. Muscle activity was expressed as a percentage of maximum voluntary isometric contraction. FINDINGS The lower subscapularis was found to activate at a higher level than the subscapularis during abduction, flexion and external rotation movements and this was significant during concentric and eccentric phases of abduction and flexion (<0.001). During internal rotation, upper subscapularis muscle activity mirrored that of lower subscapularis, with a mean difference of 1.14%. Neither upper nor lower subscapularis had onset data commencing prior to the abduction movement; however upper subscapularis activated significantly later than lower subscapularis (P=0.018). INTERPRETATION The lower subscapularis has significantly higher muscle activity during shoulder elevation and this might reflect its greater role as a humeral head depressor and anterior stabiliser.

Development and validation of a VISA tendinopathy questionnaire for greater trochanteric pain syndrome, the VISA-G

BACKGROUND Greater trochanteric pain syndrome (GTPS) is common, resulting in significant pain and disability. There is no condition specific outcome score to evaluate the degree of severity of disability associated with GTPS in patients with this condition. OBJECTIVE To develop a reliable and valid outcome measurement capable of evaluating the severity of disability associated with GTPS. METHODS A phenomenological framework using in-depth semi structured interviews of patients and medical experts, and focus groups of physiotherapists was used in the item generation. Item and format clarification was undertaken via piloting. Multivariate analysis provided the basis for item reduction. The resultant VISA-G was tested for reliability with the inter class co-efficient (ICC), internal consistency (Cronbachs Alpha), and construct validity (correlation co-efficient) on 52 naïve participants with GTPS and 31 asymptomatic participants. RESULTS The resultant outcome measurement tool is consistent in style with existing tendinopathy outcome measurement tools, namely the suite of VISA scores. The VISA-G was found to be have a test-retest reliability of ICC2,1 (95% CI) of 0.827 (0.638-0.923). Internal consistency was high with a Cronbachs Alpha of 0.809. Construct validity was demonstrated: the VISA-G measures different constructs than tools previously used in assessing GTPS, the Harris Hip Score and the Oswestry Disability Index (Spearman Rho:0.020 and 0.0205 respectively). The VISA-G did not demonstrate any floor or ceiling effect in symptomatic participants. CONCLUSION The VISA-G is a reliable and valid score for measuring the severity of disability associated GTPS.

A systematic literature review of the resistance exercises that promote maximal muscle activity of the rotator cuff in normal shoulders

Background There are numerous resistance exercises that can be used to activate the rotator cuff. However, the optimal exercises to achieve maximal muscle activation in supraspinatus, infraspinatus, subscapularis and teres minor remain unclear. Thus, the aim of this systematic review is to identify the optimal resistance exercises for producing maximal muscle activation of the rotator cuff in normal shoulders. Methods A literature search was completed using six key databases - MEDLINE, EMBASE, CINAHL, PEDro, SPORTdiscus and Cochrane Library (from inception to January 2012). The search yielded 452 records using terms relating to rotator cuff, exercise, and electromyography. Eighteen papers remained after duplicates were removed and selection criteria applied. Quality assessment, data extraction and data synthesis of included papers was undertaken. Results Prone horizontal abduction at 90–100° with external rotation, push-up-plus, empty can and full can produced greatest activity in supraspinatus; prone horizontal abduction at 90–100° with full external rotation, standing external rotation at 0° abduction and the push-up-plus exercise produced greatest activity in infraspinatus and push-up-plus and shoulder flexion exercise in subscapularis. There was limited data for teres minor. Discussion Exercises to elicit maximal activity of supraspinatus, infraspinatus and subscapularis in normal shoulders were identified.

Demystifying the clinical diagnosis of greater trochanteric pain syndrome in women

OBJECTIVE To evaluate the diagnostic accuracy of 10 clinical tests that can be used in the diagnosis of greater trochanteric pain syndrome (GTPS) in women, and to compare these clinical tests to magnetic resonance imaging (MRI) findings. MATERIALS AND METHODS Twenty-eight participants with GTPS (49.5 ± 22.0 years) and 18 asymptomatic participants (mean age ± standard deviation [SD], 52.5 ± 22.8 years) were included. A blinded physiotherapist performed 10 pain provocation tests potentially diagnostic for GTPS-palpation of the greater trochanter, resisted external derotation test, modified resisted external derotation test, standard and modified Obers tests, Patricks or FABER test, resisted hip abduction, single-leg stance test, and the resisted hip internal rotation test. A sample of 16 symptomatic and 17 asymptomatic women undertook a hip MRI scan. Gluteal tendons were evaluated and categorized as no pathology, mild tendinosis, moderate tendinosis/partial tear, or full-thickness tear. RESULTS Clinical test analyses show high specificity, high positive predictive value, low to moderate sensitivity, and negative predictive value for most clinical tests. All symptomatic and 88% of asymptomatic participants had pathological gluteal tendon changes on MRI, from mild tendinosis to full-thickness tear. CONCLUSIONS The study found the Patricks or FABER test, palpation of the greater trochanter, resisted hip abduction, and the resisted external derotation test to have the highest diagnostic test accuracy for GTPS. Tendon pathology on MRI is seen in both symptomatic and asymptomatic women.

A comparison of gluteus medius, gluteus minimus and tensor facia latae muscle activation during gait in post-menopausal women with and without greater trochanteric pain syndrome

The effect of greater trochanteric pain syndrome (GTPS) on gluteus medius (GMed) and minimus (GMin) activation in post-menopausal women is unknown. The aim of this study was to compare segmental muscle activation and variability of the GMed, GMin and tensor fascia latae (TFL) during gait in post-menopausal women with and without GTPS. Intramuscular electrodes were inserted into segments of GMin (x2) and GMed (x3) and a surface electrode placed on TFL. Ten control participants and 8 with GTPS completed six walking trials. Peak amplitude, average amplitude and time to peak from each phase of the gait cycle (0-30%, 30%- toe off (TO), total stance and swing) were compared between groups using independent t-tests and effect-size (ES) calculations. Variability of muscle activation was calculated using the mean coefficient of variation (CV). Reversal of anterior GMin electromyographic burst pattern and greater average muscle activity was found in the GTPS group compared to controls: 0-TO for anterior GMin (p<0.05), anterior and middle GMed (p<0.01); 0-30% for posterior GMin (p<0.01) and GMed (p<0.05). No significant differences were identified in TFL. Overall, this study found increased segmental gluteal muscle activation, decreased hip abduction strength, and reduced variability in muscle activation in post-menopausal women with GTPS, compared with controls.

Differentials in Turnout Among Professional Classical Ballet Dancers.

BACKGROUND Screening and training of professional dancers is commonly based around beliefs that a large range of turnout is more advantageous in the ballet industry. This belief leads dancers who have limited hip external rotation to compensate by forcing turnout at the knee and ankle, which has been linked to injury. OBJECTIVE To examine if there is a difference in degree of turnout between three levels of dancers (corps, soloist, principal) in a professional classical ballet company. An additional aim was to establish average values for the range of turnout and hip rotation present in the dancers. METHODS Forty-five professional dancers from The Australian Ballet (25 female, 20 male) participated in the study. Active and passive hip external rotation (hip ER) was measured in supine using inclinometers, and functional turnout in ballet first position (lower limb external rotation, LLER) was measured using foot traces utilising bony landmarks. Below-hip external rotation (BHER) was also calculated. RESULTS No relationship was found among level of dancer and passive hip ER, active hip ER, LLER, and BHER. Professional dancers had on average 50.2° of passive hip ER range, 35.2° of active hip ER, and 133.6° of functional turnout position. In addition, no correlation was found between LLER and hip ER, but significant correlations were found between LLER and BHER. CONCLUSIONS Hip rotation range of motion is similar across all levels of professional dancers. Average values for passive and active hip ER and functional turnout were established.

Gluteus Minimus and Gluteus Medius Muscle Activity During Common Rehabilitation Exercises in Healthy Postmenopausal Women

STUDY DESIGN: Controlled laboratory study, cross‐sectional. BACKGROUND: The gluteus medius (GMed) and gluteus minimus (GMin) provide dynamic stability of the hip joint and pelvis. These muscles are susceptible to atrophy and injury in individuals during menopause, aging, and disease. Numerous studies have reported on the ability of exercises to elicit high levels of GMed activity; however, few studies have differentiated between the portions of the GMed, and none have examined the GMin. OBJECTIVES: To quantify and rank the level of muscle activity of the 2 segments of the GMin (anterior and posterior fibers) and 3 segments of the GMed (anterior, middle, and posterior fibers) during 4 isometric and 3 dynamic exercises in a group of healthy, postmenopausal women. METHODS: Intramuscular electrodes were inserted into each segment of the GMed and GMin in 10 healthy, postmenopausal women. Participants completed 7 gluteal rehabilitation exercises, and average normalized muscle activity was used to rank the exercises from highest to lowest. RESULTS: The isometric standing hip hitch with contralateral hip swing was the highest‐ranked exercise for all muscle segments except the anterior GMin, where it was ranked second. The highest‐ranked dynamic exercise for all muscle segments was the dip test. CONCLUSION: The hip hitch and its variations maximally activate the GMed and GMin muscle segments, and may be useful in hip muscle rehabilitation in postmenopausal women.