Three-dimensional kinematics of the lumbar spine during gait using marker-based systems: a systematic review.

To review the current scientific literature on the assessment of three-dimensional movement of the lumbar spine with a focus on the utilisation of a 3D cluster. Electronic databases PubMed, OVID, CINAHL, The Cochrance Library, ScienceDirect, ProQuest and Web of Knowledge were searched between 1966 and March 2015. The reference lists of the articles that met the inclusion criteria were also searched. From the 1530 articles identified through an initial search, 16 articles met the inclusion criteria. All information relating to methodology and kinematic modelling of the lumbar segment along with the outcome measures were extracted from the studies identified for synthesis. Guidelines detailing 3D cluster construction were limited in the identified articles and the lack of information presented makes it difficult to assess the external validity of this technique. Scarce information was presented detailing time-series angle data of the lumbar spine during gait. Further developments of the 3D cluster technique are required and it is essential that the authors provide clear instruction, definitions and standards in their manuscript to improve clarity and reproducibility

COMPARISON OF MARKERLESS AND MARKER-BASED MOTION CAPTURE FOR ESTIMATING EXTERNAL MECHANICAL WORK IN TENNIS: A PILOT STUDY

This pilot study assessed the accuracy of markerless motion capture to estimate the external mechanical work performed during tennis serves. One tennis player performed 9 serves whilst motion data were captured concurrently with a criterion marker-based and a custom markerless system (utilising HRNet and OpenPose). Centre of mass kinetic and potential energy were calculated and used to compute external mechanical work for all 3 approaches. Markerless methods yielded differences of 2-3% (HRNet) and 6-9% (OpenPose) for external work compared to the criterion measure, with the former regarded as a high level of agreement. Our markerless system, paired with HRNet, shows promise for accurately estimating external work during the tennis serve and has potential to provide players and coaches with a non-invasive tool for monitoring training ‘load’ in the field

Public Shelter Admission Rates in Philadelphia and New York City: The Implications of Turnover for Sheltered Population Counts

Previous estimates of the size and composition of the U.S. homeless population have been based on cross-sectional survey methodologies. National enumeration efforts have yielded point-prevalence estimates ranging from 0.11 to 0.25 percent of the population. This study reports data from shelter databases in Philadelphia and New York City that record identifiers for all persons admitted and so make possible unduplicated counts of users. Unduplicated counts of shelter users yield annual rates for 1992 of about 1 percent for both cities and rates near 3 percent over three years in Philadelphia (1990–92) and over five years (1988–92) in New York City. The annual rates are three times greater than rates documented by point-prevalence studies. Shelter bed turnover rates are reported, as are average monthly first admission and readmission counts over a two-year period. Implications for future research and public policy are discussed

Individual Characteristics Associated with PBDE Levels in U.S. Human Milk Samples

BackgroundReported polybrominated diphenyl ether (PBDE) concentrations in human samples in the United States have been higher than in Europe and Asia. Little is known about factors that contribute to individual variability in body burden.ObjectiveIn this large study we measured PBDE concentrations in human milk from the United States during 2004–2006. We assessed characteristics associated with concentrations in milk and change in milk concentration between 3 and 12 months postpartum.MethodsWe analyzed 303 milk samples obtained 3 months postpartum for PBDEs. A second sample was analyzed for 83 women still lactating 12 months postpartum. PBDE concentrations in milk and variability by individual characteristics such as age, parity, and prepregnancy body mass index (BMI) were evaluated using generalized linear models.ResultsPBDE congeners BDEs 28, 47, 99, 100, and 153 were detected in > 70% of samples. BDE-47 concentrations were the highest, ranging from below the limit of detection to 1,430 ng/g lipid, with a median of 28 ng/g lipid. Concentrations of most individual PBDE congeners and the sum of BDEs 28, 47, 99, 100, and 153 (∑PBDE) were lower among mothers > 34 years of age compared with those 25–29 years of age and higher among mothers with high compared with normal BMI, after adjustment for other covariates. Parity was not associated with PBDE concentration. The change in ∑PBDE concentration in milk between 3 and 12 months postpartum was highly variable (median increase, 14%; interquartile range, −26% to 50%).ConclusionsPBDEs were detected in nearly all human milk samples, varying by maternal weight and age and over the course of breast-feeding

Validity of energy expenditure estimation methods during 10 days of military training

Wearable physical activity (PA) monitors have improved the ability to estimate free-living total energy expenditure (TEE) but their application during arduous military training alongside more well-established research methods has not been widely documented. This study aimed to assess the validity of two wrist-worn activity monitors and a PA log against doubly-labelled water (DLW) during British Army Officer Cadet (OC) training. For 10 days of training, twenty (10 male and 10 female) OCs (mean ± SD: age 23 ± 2 years, height 1.74 ± 0.09 m, body mass 77.0 ± 9.3 kg) wore one research-grade accelerometer (GENEActiv, Cambridge, UK) on the dominant wrist, wore one commercially-available monitor (Fitbit SURGE, USA) on the non-dominant wrist and completed a self-report PA log. Immediately prior to this 10-day period, participants consumed a bolus of DLW and provided daily urine samples, which were analysed by mass spectrometry to determine TEE. Bivariate correlations and limits of agreement (LoA) were employed to compare TEE from each estimation method to DLW. Average daily TEE from DLW was 4112 ± 652 kcal·day against which the GENEActiv showed near identical average TEE (mean bias ± LoA: -15 ± 851 kcal day ) while Fitbit tended to underestimate (-656 ± 683 kcal·day ) and the PA log substantially overestimate (+1946 ± 1637 kcal·day ). Wearable physical activity monitors provide a cheaper and more practical method for estimating free-living TEE than DLW in military settings. The GENEActiv accelerometer demonstrated good validity for assessing daily TEE and would appear suitable for use in large-scale, longitudinal military studies

Association between external training loads and injury incidence during 44 weeks of military training

Military training is physically arduous and associated with high injury incidence. Unlike in high-performance sport, the interaction between training load and injury has not been extensively researched in military personnel. Sixty-three (43 men, 20 women; age 24 ± 2 years; stature 1.76 ± 0.09 m; body mass 79.1 ± 10.8 kg) British Army Officer Cadets undergoing 44 weeks of training at the Royal Military Academy Sandhurst volunteered to participate. Weekly training load (cumulative 7-day moderate-vigorous physical activity [MVPA], vigorous PA [VPA] and the ratio between MVPA and sedentary-light PA [SLPA; MVPA:SLPA]) was monitored using a wrist-worn accelerometer (GENEActiv, UK). Self-report injury data were collected and combined with musculoskeletal injuries recorded at the Academy medical centre. Training loads were divided into quartiles with the lowest load group used as the reference to enable comparisons using Odds Ratios (OR) and 95% confidence intervals (95% CI). Overall injury incidence was 60% with the most common injury sites being the ankle (22%) and knee (18%). High (load; OR; 95% CI [>2327 mins; 3.44; 1.80–6.56]) weekly cumulative MVPA exposure significantly increased odds of injury. Similarly, likelihood of injury significantly increased when exposed to low-moderate (0.42–0.47; 2.45 [1.19–5.04]), high-moderate (0.48–0.51;2.48 [1.21–5.10]) and high MVPA:SLPA loads (>0.51; 3.60 [1.80–7.21]). High MVPA, and high-moderate MVPA:SLPA increased odds of injury by ~2.0–3.5 fold, suggesting that the ratio of workload to recovery is important for mitigating injury occurrence

Nutrition and Physical Activity in British Army Officer Cadet Training Part 2 - Daily Distribution of Energy and Macronutrient Intake

Dietary intake and physical activity impact performance and adaptation during training. The aims of this study were to compare energy and macronutrient intake during British Army Officer Cadet training with dietary guidelines and describe daily distribution of energy and macronutrient intake and estimated energy expenditure (EE). Thirteen participants (seven women) were monitored during three discrete periods of military training for nine days on-camp (CAMP), five days’ field exercise (FEX) and nine days of a mixture of the two (MIX). Dietary intake was measured using researcher-led food weighing and food diaries and EE was estimated from wrist-worn accelerometers. Energy intake was below guidelines for men (4600kcal·d-1) and women (3500kcal·d-1) during CAMP (men: -16%; women -9%), FEX (men: -33%; women: -42%) and MIX (men and women both -34%). Carbohydrate intake of men and women were below guidelines (6g·kg·d-1) during CAMP (men: -10%; women: -9%), FEX (men: -18%; women: -37%), and MIX (men: -3%; women: -39%), respectively. Protein intake was above guidelines (1.2kcal·kg·d-1) for men and women during CAMP (men: 48%; women: 39%) and MIX (men: 9%; women: 3%), but below guidelines during FEX (men: -13%; women: -27%). Energy and macronutrient intake during CAMP centred around mealtimes with a discernible sleep/wake cycle for EE. During FEX, energy and macronutrient intake were individually variable and EE was high throughout the day and night. These findings could be used to inform evidenced-based interventions to change the amount and timing of energy and macronutrient intake around physical activity to optimise performance and adaptations during military training