Simplified marker sets for the calculation of centre of mass location during bend sprinting

Simplified marker sets for the calculation of whole body centre of mass (CoM) location and associated variables (velocity, touchdown distance and turn of CoM) used in the analysis of bend sprinting performance were examined. CoM related variables were compared between a whole-body (13 segment), lower limb and trunk and lower limb model. Both simplified models showed strong agreement with whole-body CoM (Intraclass correlation: 0.873 - 0.998). The lower limb and trunk model (LLT) was the most accurate representation of whole body calculations, with acceptably low differences in all variables examined. Therefore, the LLT model is recommended for future use

SIMPLIFIED MARKER SETS FOR THE CALCULATION OF CENTRE OF MASS LOCATION DURING BEND SPRINTING

Simplified marker sets for the calculation of whole body centre of mass (CoM) location and associated variables (velocity, touchdown distance and turn of CoM) used in the analysis of bend sprinting performance were examined. CoM related variables were compared between a whole-body (13 segment), lower limb and trunk and lower limb model. Both simplified models showed strong agreement with whole-body CoM (Intraclass correlation: 0.873 - 0.998). The lower limb and trunk model (LLT) was the most accurate representation of whole body calculations, with acceptably low differences in all variables examined. Therefore, the LLT model is recommended for future use

Measurement of bend sprinting kinematics with three-dimensional motion capture : a test-retest reliability study

Sprint velocity decreases on the bend when compared with the straight, therefore understanding technique during bend sprinting could have important implications for aiding race performance. Few bend sprinting studies have used optoelectronic cameras to investigate kinematic variables. Limited published evidence regarding the reliability of marker sets in conditions representative of elite bend sprinting makes model selection difficult. Therefore, a test-retest protocol was conducted to establish the reliability and minimum detectable difference of a lower limb and trunk marker set during bend sprinting (radius: 36.5 m). Six participants completed five, 60 m trials at maximum effort, with data collected at 38 - 45 m. This was repeated 2 - 7 days later. Spatio-temporal (e.g. contact time) and kinematic variables (e.g. peak joint angles) were evaluated. Intraclass correlation coefficients (ICC) were used to determine the between- and within-day reliability. Between-day reliability (ICC 3, k) was fair to excellent for all variables. Compared to between-day, within-day reliability demonstrated stronger agreement for the majority of variables. Thus, same-day data collection is preferable. It has been established that the marker set is reliable for future use. In addition, the minimal detectable difference was calculated which serves as useful reference for future research in bend sprinting

False-negative Histoplasma antigen in acute pulmonary histoplasmosis: the value of urinary concentration by ultrafiltration and heat denaturation of serum proteins in detection of Histoplasma antigen

We report an infant with localized pulmonary histoplasmosis in whom Histoplasma antibody assays, quantitative Histoplasma urine and serum antigen concentrations, and histopathologic findings of a mediastinal mass were nondiagnostic. A provisional diagnosis of histoplasmosis was established by using laboratory methods that increase the sensitivity of the antigen assay using ultrafiltration of urine and ethylenediaminetetraacetic acid/heat denaturation of serum proteins

Indigenous Case of Disseminated Histoplasmosis, Taiwan

We report the first indigenous case of disseminated histoplasmosis in Taiwan diagnosed by histopathology of bone marrow, microbiologic morphology, and PCR assay of the isolated fungus. This case suggests that histoplasmosis should be 1 of the differential diagnoses of opportunistic infections in immunocompromised patients in Taiwan

Detection of (1,3)-β-d-Glucan in Cerebrospinal Fluid in Histoplasma Meningitis

The diagnosis of central nervous system (CNS) histoplasmosis is often difficult. Although cerebrospinal fluid (CSF) (1,3)-β-d-glucan (BDG) is available as a biological marker for the diagnosis of fungal meningitis, there are limited data on its use for the diagnosis of Histoplasma meningitis. We evaluated CSF BDG detection, using the Fungitell assay, in patients with CNS histoplasmosis and controls. A total of 47 cases and 153 controls were identified. The control group included 13 patients with a CNS fungal infection other than histoplasmosis. Forty-nine percent of patients with CNS histoplasmosis and 43.8% of controls were immunocompromised. The median CSF BDG level was 85 pg/ml for cases, compared to <31 pg/ml for all controls (P < 0.05) and 82 pg/ml for controls with other causes of fungal meningitis (P = 0.27). The sensitivity for detection of BDG in CSF was 53.2%, whereas the specificity was 86.9% versus all controls and 46% versus other CNS fungal infections. CSF BDG levels of ≥80 pg/ml are neither sensitive nor specific to support a diagnosis of Histoplasma meningitis

Blastomyces Antigen Detection for Monitoring Progression of Blastomycosis in a Pregnant Adolescent

Although disseminated blastomycosis is a rare complication in pregnancy, delay in diagnosis and treatment can be fatal. We investigate the use of the Blastomyces urine antigen in diagnosis following disease progression in the intrapartum, postpartum, and neonatal periods. We describe a case of disseminated blastomycosis in a pregnant adolescent and review the pertinent literature regarding treatment and monitoring blastomycosis in pregnancy and the neonatal periods. This is the first reported case in which the Blastomyces urine antigen is utilized as a method of following disease activity during pregnancy confirming absence of clinically evident disease in a neonate. Urine antigen detection for blastomycosis can be useful for following progression of disease in patients with disseminated blastomycosis in both the intrapartum and postpartum periods

Joint moments and power in the acceleration phase of bend sprinting

Joint kinetics of the lower limb (hip, knee, ankle, midfoot and metatarsophalangeal joints) were investigated during the acceleration phase of bend sprinting and straight-line sprinting. Within the bend sprinting literature, it is generally accepted that sprint performance on the bend is restricted by moments in the non-sagittal plane preventing the production of force in the sagittal plane. However, there is limited evidence in conditions representative of elite athletics performance that supports this hypothesis. Three-dimensional kinematic and ground reaction force data were collected from seven participants during sprinting on the bend (36.5 m radius) and straight, allowing calculation of joint moment, power and energy. No changes in extensor moment were observed at the hip and knee joints. Large effect sizes (g = 1.07) suggest a trend towards an increase in left step peak ankle plantarflexion moment. This could be due to a greater need for stabilisation of the ankle joint as a consequence of non-sagittal plane adaptations of the lower limb. In addition, the observed increase in peak MTP joint plantar-flexor moment might have implications for injury risk of the fifth metatarsal. Energy generation, indicated by positive power, in the sagittal plane at the MTP and ankle joints was moderately lower on the bend than straight, whilst increases in non-sagittal plane energy absorption were observed at the ankle joint. Therefore, energy absorption at the foot and ankle may be a key consideration in improving bend sprinting performance

Kinematic modifications of the lower limb during the acceleration phase of bend sprinting.

A decrease in speed when sprinting on the bend compared with the straight has been attributed to kinetic, kinematic and spatiotemporal modifications. Although maximal speed is dependent on an athlete's ability to accelerate, there is limited research investigating the acceleration phase of bend sprinting. This study used a lower limb and trunk marker set with 15 optoelectronic cameras to examine kinematic and spatiotemporal variables of the lower limb during sprinting on the bend and straight. Nine sprinters completed up to six 30 m maximal effort trials in bend (radius 36.5 m, lane one) and straight conditions. An increase in body lateral lean at touchdown resulted in a number of asymmetric kinematic modifications. Whilst the left limb demonstrated a greater peak hip adduction, peak hip internal rotation and peak ankle eversion on the bend compared with the straight, the right limb was characterised by an increase in peak hip abduction. These results demonstrate that kinematic modifications start early in the race and likely accumulate, resulting in greater modifications at maximal speed. It is recommended that strength and conditioning programmes target the hip, ankle and foot in the non-sagittal planes. In addition, sprint training should prioritise specificity by occurring on the bend