Electromyography Activation of Shoulder and Trunk Muscles is Greater During Closed Chain Compared to Open Chain Exercises

Background To compare the activation of shoulder and trunk muscles between six pairs of closed (CC) and open chain (OC) exercises for the upper extremity, matched for performance characteristics. The secondary aims were to compare shoulder and trunk muscle activation and shoulder activation ratios during each pair of CC and OC exercise. Methods Twenty-two healthy young adults were recruited. During visit 1, the 5-repetition maximum resistance was established for each CC and OC exercise. During visit 2, electromyography activation from the infraspinatus (INF), deltoid (DEL), serratus anterior (SA), upper, middle and lower trapezius (UT, MT, LT), erector spinae (ES) and external oblique (EO) muscles was collected during 5-repetition max of each exercise. Average activation was calculated during the concentric and eccentric phases of each exercises. Activation ratios (DEL/INF, UT/LT, UT/MT, UT/SA) were also calculated. Linear mixed models compared the activation by muscle collapsed across CC and OC exercises. A paired t-test compared the activation of each muscle and the activation ratios (DEL/INF, UT/LT, UT/MT, UT/SA) between each pair of CC and OC exercises. Results The INF, LT, ES, and EO had greater activation during both concentric (p = 0.03) and eccentric (p \u3c 0.01) phases of CC versus OC exercises. Activation ratios were lower in CC exercises compared to OC exercises (DEL/INF, 3 pairs; UT/LT, 2 pairs; UT/MT, 1 pair; UT/SA, 3 pairs). Conclusion Upper extremity CC exercises generated greater activation of shoulder and trunk muscles compared to OC exercises. Some of the CC exercises produced lower activation ratios compared to OC exercises

Supraspinatus tendon micromorphology in individuals with subacromial pain syndrome

Study Design: Cross-sectional cohort. Introduction: Tendon collagen organization can be estimated by peak spatial frequency radius (PSFR) on ultrasound images. Characterizing PSFR can define the contribution of collagen disruption to shoulder symptoms. Purpose of the Study: The purpose of this was to characterize the (1) supraspinatus tendon PSFR in participants with sub acromial pain syndrome (SPS) and healthy controls; (2) PSFR between participants grouped on a tendon visual quality score; and (3) relationship between PSFR with patient-reported pain, function, and shoulder strength. Methods: Participants with SPS (n ¼ 20) and age, sex, and arm-dominance matched healthy controls (n ¼ 20) completed strength testing in scaption and external rotation, and patient-reported pain, and functional outcomes. Supraspinatus tendon ultrasound images were acquired, and PSFR was calculated for a region of interest 15 mm medial to the supraspinatus footprint. PSFR was compared between groups using an independent t-test and an analysis of variance to compare between 3 groups for visually qualitatively rated tendon abnormalities. Relationships between PSFR with pain, function, and strength were assessed using Pearson correlation coefficient. Results: Supraspinatus tendon PSFR was not different between groups (P ¼ .190) or tendon qualitative ratings (P ¼ .556). No relationship was found between PSFR and pain, functional loss, and strength (P \u3e .05). Conclusions: Collagen disruption (PSFR) measured via ultrasound images of the supraspinatus tendon was not different between participants with SPS or in those with visually rated tendon defects. PSFR is not related to shoulder pain, function, and strength, suggesting that supraspinatus tendon collagen disorganization may not be a contributing factor to shoulder SPS. However, collagen disruption may not be isolated to a single region of interest. Level of Evidence: 3b: case-control study

Bioavailability and Pharmacokinetics of Oral Meloxicam in Llamas

South American camelids in the United States have rapidly developed into an important agricultural industry in need of veterinary services. Pain management is challenging in camelids because there are no drugs currently approved by the U.S. Food and Drug Administration for use in these species. Dosage regimens used for many therapeutic drugs have been extrapolated from other ruminants; however, the pharmacokinetics, in camelids, may differ from those of other species. Studies investigating the pharmacokinetics of cyclooxygenase-2 (COX-2) selective non-steroidal anti-inflammatory drugs in camelids are deficient in the published literature. Six adult llamas (121- 168 kg) were administered either a 1 mg/kg dose of oral or a 0.5 mg/kg dose of IV meloxicam in a randomized cross-over design with an 11 day washout period between treatments. Plasma samples collected up to 96 hours post-administration were analyzed by high pressure liquid chromatography and mass spectrometry detection (HPLC-MS) followed by non-compartmental pharmacokinetic analysis. A mean peak plasma concentration (CMAX) of 1.314 μg/mL (Range: 0.826 – 1.776 μg/mL) was recorded at 21.4 hours (Range: 12.0 – 24.0 hours) with a half-life (T ½ λz) of 22.7 hours (Range: 18.0 – 30.8 hours) after oral meloxicam administration. In comparison, a half-life (T ½ λz) of 17.4 hours (Range: 16.2 – 20.7 hours) was demonstrated with IV meloxicam administration. The oral bioavailability (F) of meloxicam (dose normalized) was 76% (Range: 48 – 92%). No adverse effects associated with either treatment modality were observed in the llamas. The mean bioavailability (F) of oral meloxicam was 76% indicating a high degree of gastrointestinal absorption. Plasma meloxicam concentrations >0.2 μg/mL were maintained for up to 72 h after oral administration; >0.2 μg/mL is considered to be the concentration of meloxicam required for analgesic effects in other species such as the horse. These data suggest that a single dosage of oral meloxicam at 1 mg/kg could potentially maintain therapeutic concentrations in plasma for up to 3 days in adult llamas.This article is from BMC Veterinary Research 8 (2012): 85, doi:10.1186/1746-6148-8-85. Posted with permission.</p

Hip Abduction Strength: Relationship to Trunk and Lower Extremity Motion During A Single-Leg Step-Down Task in Professional Baseball Players

# Background The single-leg step down task (SLSD) is a clinical tool to assess movement and control of the lower extremity and trunk. Hip abduction weakness may impact movement quality during the SLSD, however the relationships between movement and strength are unclear. # Purpose To determine the relationship between hip abduction isometric strength and movement during the SLSD of trunk lean, pelvic drop, knee valgus, and hip flexion. # Study Design Cross sectional, cohort study # Methods One hundred-eighteen Minor League baseball players (age=21.6 ± 2.0 years; n=68 pitchers, n=50 position players) participated. Bilateral hip abduction isometric strength was measured using a handheld dynamometer (HHD), and then multiplied by distance from the greater trochanter to the HHD and expressed as hip abduction torque. Video cameras captured the SLSD, with participants standing on one leg while lowering their contralateral heel to touchdown on the floor from a 0.203m (8in.) step. Trunk lean, trunk flexion, pelvic drop, knee valgus, and hip flexion were measured using Dartfish at heel touchdown. A value of 180° indicated no knee valgus. Pearson correlations examined the relationships between hip abduction torque and SLSD motions. # Results There were no significant correlations for position players. For pitchers, on the lead leg increased hip abduction torque weakly correlated with a decrease in knee valgus (r= 0.24, p=0.049). Also for pitchers on the trail leg, increased hip abduction torque weakly correlated with decreased pelvic drop (r= -0.28, p=0.021). # Conclusion Hip abduction strength contributes to dynamic control of the trunk and legs. Specifically in pitchers, hip abduction weakness was related to increased movement of the lower extremity and lumbopelvic regions during the dynamic SLSD task. These deficits could translate to altered pitching performance and injury. # Levels of Evidence 2\

Case Report: Cerebral Revascularization in a Child With Mucopolysaccharidosis Type I

Mucopolysaccharidosis (MPS) type I is a rare lysosomal storage disorder caused by an accumulation of glycosaminoglycans (GAGs) resulting in multisystem disease. Neurological morbidity includes hydrocephalus, spinal cord compression, and cognitive decline. While many neurological symptoms have been described, stroke is not a widely-recognized manifestation of MPS I. Accordingly, patients with MPS I are not routinely evaluated for stroke, and there are no guidelines for managing stroke in patients with this disease. We report the case of a child diagnosed with MPS I who presented with overt stroke and repeated neurological symptoms with imaging findings for severe ventriculomegaly, infarction, and bilateral terminal carotid artery stenosis. Direct intracranial pressure evaluation proved negative for hydrocephalus. The patient was subsequently treated with cerebral revascularization and at a 3-year follow-up, the patient reported no further neurological events or new ischemia on cerebral imaging. Cerebral arteriopathy in patients with MPS I may be associated with GAG accumulation within the cerebrovascular system and may predispose patients to recurrent strokes. However, further studies are required to elucidate the etiology of cerebrovascular arteriopathy in the setting of MPS I. Although the natural history of steno-occlusive arteriopathy in patients with MPS I remains unclear, our findings suggest that cerebral revascularization is a safe treatment option that may mitigate the risk of future strokes and should be strongly considered within the overall management guidelines for patients with MPS I

Supraspinatus tendon micromorphology in individuals with subacromial pain syndrome

Study Design: Cross-sectional cohort. Introduction: Tendon collagen organization can be estimated by peak spatial frequency radius (PSFR) on ultrasound images. Characterizing PSFR can define the contribution of collagen disruption to shoulder symptoms. Purpose of the Study: The purpose of this was to characterize the (1) supraspinatus tendon PSFR in participants with sub acromial pain syndrome (SPS) and healthy controls; (2) PSFR between participants grouped on a tendon visual quality score; and (3) relationship between PSFR with patient-reported pain, function, and shoulder strength. Methods: Participants with SPS (n ¼ 20) and age, sex, and arm-dominance matched healthy controls (n ¼ 20) completed strength testing in scaption and external rotation, and patient-reported pain, and functional outcomes. Supraspinatus tendon ultrasound images were acquired, and PSFR was calculated for a region of interest 15 mm medial to the supraspinatus footprint. PSFR was compared between groups using an independent t-test and an analysis of variance to compare between 3 groups for visually qualitatively rated tendon abnormalities. Relationships between PSFR with pain, function, and strength were assessed using Pearson correlation coefficient. Results: Supraspinatus tendon PSFR was not different between groups (P ¼ .190) or tendon qualitative ratings (P ¼ .556). No relationship was found between PSFR and pain, functional loss, and strength (P \u3e .05). Conclusions: Collagen disruption (PSFR) measured via ultrasound images of the supraspinatus tendon was not different between participants with SPS or in those with visually rated tendon defects. PSFR is not related to shoulder pain, function, and strength, suggesting that supraspinatus tendon collagen disorganization may not be a contributing factor to shoulder SPS. However, collagen disruption may not be isolated to a single region of interest. Level of Evidence: 3b: case-control study

Bioavailability and Pharmacokinetics of Oral Meloxicam in Llamas

South American camelids in the United States have rapidly developed into an important agricultural industry in need of veterinary services. Pain management is challenging in camelids because there are no drugs currently approved by the U.S. Food and Drug Administration for use in these species. Dosage regimens used for many therapeutic drugs have been extrapolated from other ruminants; however, the pharmacokinetics, in camelids, may differ from those of other species. Studies investigating the pharmacokinetics of cyclooxygenase-2 (COX-2) selective non-steroidal anti-inflammatory drugs in camelids are deficient in the published literature. Six adult llamas (121- 168 kg) were administered either a 1 mg/kg dose of oral or a 0.5 mg/kg dose of IV meloxicam in a randomized cross-over design with an 11 day washout period between treatments. Plasma samples collected up to 96 hours post-administration were analyzed by high pressure liquid chromatography and mass spectrometry detection (HPLC-MS) followed by non-compartmental pharmacokinetic analysis. A mean peak plasma concentration (CMAX) of 1.314 μg/mL (Range: 0.826 – 1.776 μg/mL) was recorded at 21.4 hours (Range: 12.0 – 24.0 hours) with a half-life (T ½ λz) of 22.7 hours (Range: 18.0 – 30.8 hours) after oral meloxicam administration. In comparison, a half-life (T ½ λz) of 17.4 hours (Range: 16.2 – 20.7 hours) was demonstrated with IV meloxicam administration. The oral bioavailability (F) of meloxicam (dose normalized) was 76% (Range: 48 – 92%). No adverse effects associated with either treatment modality were observed in the llamas. The mean bioavailability (F) of oral meloxicam was 76% indicating a high degree of gastrointestinal absorption. Plasma meloxicam concentrations >0.2 μg/mL were maintained for up to 72 h after oral administration; >0.2 μg/mL is considered to be the concentration of meloxicam required for analgesic effects in other species such as the horse. These data suggest that a single dosage of oral meloxicam at 1 mg/kg could potentially maintain therapeutic concentrations in plasma for up to 3 days in adult llamas.This article is from BMC Veterinary Research 8 (2012): 85, doi:10.1186/1746-6148-8-85. Posted with permission.</p