STUDY DESIGN: Validation study. OBJECTIVES: To investigate the association between changes in electromyographic (EMG) signal amplitude and sonographic measures of muscle thickness of 4 abdominal muscles, during 2 clinical tests, in adults with and without lumbopelvic pain (LPP). BACKGROUND: There is a trend in rehabilitation to use ultrasound imaging (USI) to determine the extent of abdominal muscle contraction. However the literature investigating the relationship between abdominal muscle thickness change and level of activation is inconclusive, and has not included clinically relevant tasks. METHODS: Simultaneous recording from fine-wire EMG and USI was performed for 4 abdominal muscles in 7 adults (mean ± SD age, 29.7±12.0 years) with and 7 adults (32.0±10.6 years) without LPP, during an active straight leg raise  (ASLR) test and an abdominal drawing in manoeuvre (ADIM). Cross-correlation functions and linear regression analyses were used to describe the relationship between the 2 measures. Analyses of variance (ANOVA) were used to compare individuals with and without LPP, with a set at 0.05. RESULTS: Across all muscles, peak cross-correlation values were low (ASLR; r=0.28±0.09, ADIM; r=0.35±0.11) and there was large variability in associated time lags (ASLR; τ=0.69s±2.56s, ADIM; τ=0.53s±3.75s). Regression analyses did not detect a systematic pattern of association between EMG signal amplitude and RUSI measurements and ANOVAs revealed no differences between cohorts. CONCLUSION: These results suggest a weak relationship between EMG amplitude and abdominal muscle thickness change measured with USI during the ADIM and ASLR, and raises question about using thickness change derived from USI as a measure of muscular activity for the abdominal musculature.

J Orthop Sports Phys Ther, Epub 30 April 2013. doi:10.2519/jospt.2013.4440

KEY WORDS: EMG, external oblique, internal oblique, rectus abdominis, transversus abdominis, ultrasound imaging

STUDY DESIGN: Clinical measurement. OBJECTIVES: To cross-culturally adapt the questionnaire Shoulder Pain and Disability Index (SPADI) into Brazilian-Portuguese and test the measurement properties of the Brazilian-Portuguese versions of the SPADI, Quick Disabilities of the Arm Shoulder and Hand (QuickDASH), Patient-Specific Functional Scale (PSFS), Pain Numerical Rating Scale (Pain NRS), and Global Perceived Effect scale (GPE) in patients with shoulder disorders. BACKGROUND: Most instruments for shoulder disorders were developed in English. To be used in Brazil, translation into Brazilian-Portuguese, cross-cultural adaptation, and testing of measurement properties of these instruments is required. METHODS: The SPADI was translated and cross-culturally adapted consistent with current guidelines. Measurement properties of internal consistency, reproducibility, construct validity, ceiling and floor effects, and responsiveness of all instruments were tested in 100 patients with shoulder disorders. The patients filled out the questionnaires on 3 occasions: at baseline 24 to 48 hours after baseline, and 4 weeks after baseline. RESULTS: The instruments showed adequate internal consistency (Cronbach's alpha between 0.78 and 0.93) and a good level of agreement as reflected by low standard error of measurements and minimal detectable change. The reliability (Intraclass Correlation Coefficients) of the instruments varied from 0.82 to 0.96. Most instruments presented good levels of construct validity. All instruments showed acceptable levels of internal and external responsiveness. CONCLUSION: The Brazilian versions of the SPADI, QuickDASH, Pain NRS, PSFS, and GPE are reproducible, valid, and responsive instruments for assessing patients with shoulder disorders.

J Orthop Sports Phys Ther, Epub 18 March 2013. doi:10.2519/jospt.2013.4441

KEY WORDS: ceiling and floor effects, cross-cultural adaptation, reliability, responsiveness, validity

STUDY DESIGN: Measurements, descriptive. OBJECTIVES: To describe a weight bearing method to assess bilateral hip abductor & external rotator muscle performance. BACKGROUND: The hip abductors and external rotators are important in maintaining lower extremity alignment during weight bearing tasks. As such, there is a need for a method to assess hip muscle performance in weight bearing. METHODS: The weight bearing method utilized a force transducer connected to a non-stretchable fabric strap positioned around the distal ends of both thighs (proximal to the lateral epicondyles). The force generation capacity was recorded with the participants in a semi-squat position (30° of hip and 50° of knee flexion). To establish the reliability of the measurement, 20 participants were tested on 2 separate days. Intraclass correlation coefficient (ICC_3,1) and Standard Error of Measurement were calculated to evaluate the test-retest reliability and inter-session consistency. The level of agreement between the muscle performance values obtained using the weight bearing method and the traditional non-weight bearing test in side-lying (dynamometer) was assessed using a linear correlation model. RESULTS: The weight bearing hip muscle performance assessment was reliable (ICC=0.99, 95% CI=0.97-0.99), and consistent (SEM = 0.02 N/kg). The measured strength using the weight bearing method was moderately associated with the strength values measured in non-weight bearing (r=0.75, p<0.01). CONCLUSIONS: The proposed weight bearing method to assess hip abductor & external rotator muscle performance can be used as a simple, economic, and reliable method to assess hip muscle strength.

J Orthop Sports Phys Ther, Epub 18 March 2013. doi:10.2519/jospt.2013.4412

KEY WORDS: abductor, external rotator, gluteus maximus, gluteus medius, hip, strength

STUDY DESIGN: Controlled laboratory study: cross-sectional. OBJECTIVE: To determine if proprioception, measured by the threshold to detection of passive movement (TDPM), differed in individuals who regularly participate in moderate intensity exercise for fitness as compared to individuals involved in high intensity skilled exercise. BACKGROUND: Previous research has been equivocal as to whether exercise training is associated with superior proprioceptive acuity, in particular, exercise that includes dynamic postural challenges such as cutting/pivoting. METHODS: Two groups of 25 healthy individuals (18 to 32 years old) were recruited.  One group consisted of individuals who performed moderate activity level exercises for 5 to 10 hours per week.  Participants in the other group performed high activity level exercises, including high speed cutting and pivoting activities, at least 10 hours per week.  Proprioception was determined using TDPM, in which the knee was slowly extended or flexed at an angular velocity of 0.5°/second or less from a starting position of 40° of knee flexion. An average of TDPM measures of both limbs was determined. RESULTS: Individuals participating in competitive high intensity skilled exercise demonstrated better acuity (average of both limbs) of TDPM, (mean ± SD, 0.81±0.38°; P<.001) than those participating in moderate intensity exercise for fitness (1.53 ± 0.58°).  A low but statistically significant association (r = -0.38; P=.006) was found between weekly duration of exercise and proprioceptive threshold as measured by TDPM. CONCLUSION: These results suggest that perceptual thresholds of passive movement may be enhanced dependent on activity level and associated postural challenge, and that higher level and increased amount of exercise may promote enhanced neurosensory processing in these individuals.  Consequently, high intensity skilled training may deserve further emphasis in orthopedic rehabilitation.

J Orthop Sports Phys Ther, Epub 18 March 2013. doi:10.2519/jospt.2013.4403

KEY WORDS: joint proprioception, somatosensation, threshold to detection of passive motion

STUDY DESIGN: Cross-sectional study. OBJECTIVES: To compare pressure pain thresholds (PPT) between adolescent females diagnosed with patellofemoral pain syndrome (PFPS) and gender- and age-matched controls without musculoskeletal pain. BACKGROUND: PFPS is prevalent among adolescents. PFPS may be associated with reduced PPT both locally and remotely from the site of reported pain. This may indicate altered central processing of nociceptive information. However this has never been investigated in adolescents with PFPS. METHODS: Adolescents with PFPS and a comparison group without musculoskeletal pain were recruited from a population-based cohort that consisted of students aged 15 to 19 years from 4 upper secondary schools. All 2846 students within that age range were invited to answer an online questionnaire regarding musculoskeletal pain. The students who reported knee pain were contacted by telephone and offered a clinical examination by an experienced rheumatologist who made a diagnosis. PPTs were measured at 4 sites around the knee and 1 site on the tibialis anterior in 57 female adolescents with PFPS and 22 female adolescents without musculoskeletal pain. RESULTS: At each of the 4 the sites around the knee, adolescents with PFPS had a significantly 26-37% (100-178 kPa) lower PPT (localised hyperalgesia) compared with controls. On the tibialis anterior, adolescents with PFPS had a 33% (159 kPa) lower PPT (distal hyperalgesia) compared with controls. CONCLUSION: These findings suggest that adolescent females with PFPS have localised and distal hyperalgesia. These findings may have implications for treating PFPS as both peripheral and central mechanisms may be driving the pain.

J Orthop Sports Phys Ther, Epub 18 March 2013. doi:10.2519/jospt.2013.4383

KEY WORDS: adolescents, anterior knee pain, hyperalgesia, pressure pain thresholds