A cross-sectional comparison between cardiorespiratory fitness, level of lesion and red blood cell distribution width in adults with chronic spinal cord injury

Objectives: To assess; (1) differences in red blood cell distribution width between individuals with chronic (&gt;1 year), motor-complete cervical (n = 21), upper-thoracic (n = 27) and thoracolumbar (n = 15) spinal cord injury and, (2) associations between red blood cell distribution width and cardiorespiratory fitness. Design: Prospective multi-center, cross-sectional study. Methods: Peak oxygen uptake was determined using an upper-body arm-crank exercise test to volitional exhaustion and red blood cell distribution width was measured using an automated hematology system. Results: There were significant (p &lt; 0.009) differences between groups classified by level of injury in absolute and relative peak oxygen uptake, peak power output and red blood cell distribution width. A significant (p &lt; 0.001) large negative association (r = −0.524) was found between relative peak oxygen uptake and red blood cell distribution width. Unbiased recursive partitioning, while revealing study site specific differences in red blood cell distribution width, identified homogenous subgroups based specifically on cardiorespiratory fitness irrespective of additional demographic and injury characteristics. Conclusion: The strong negative association between cardiorespiratory fitness and red blood cell distribution width in individuals with paraplegia parallel those previously observed in non-disabled individuals. Higher red blood cell distribution width values are an independent risk factor for increased cardiovascular mortality, heart failure, and coronary heart disease and may reflect several underlying exacerbated metabolic responses such as oxidative stress and systemic inflammation. These data emphasize the importance of maintaining a high aerobic capacity following spinal cord injury.</p

Validity and Reliability of Firefighting Simulation Test Performance

To assess the validity and reliability of a firefighting simulation test (FFST). Sixty-nine operational firefighters completed a best-effort FFST on one occasion and twenty-two participants completed a further FFST. All participants completed a maximal treadmill test to determine cardiorespiratory fitness (VO2max). Time to complete the FFST demonstrated a strong inverse relationship with VO2max (r = -0.73), although the prediction error was high. Reliability of the FFST was high (r = 0.84, p = 0.01), demonstrating a coefficient of variation of 4.5%. The FFST demonstrated reasonable validity as a surrogate assessment of cardiorespiratory fitness for firefighting. The FFST also demonstrated good reliability. Given the apparent magnitude of the prediction error, the FFST would be best used as a training tool, rather than as a primary means of assessing cardiorespiratory fitness for firefighting

Predicting ambulatory energy expenditure in lower limb amputees using multi-sensor methods

PurposeTo assess the validity of a derived algorithm, combining tri-axial accelerometry and heart rate (HR) data, compared to a research-grade multi-sensor physical activity device, for the estimation of ambulatory physical activity energy expenditure (PAEE) in individuals with traumatic lower-limb amputation.MethodsTwenty-eight participants [unilateral (n = 9), bilateral (n = 10) with lower-limb amputations, and non-injured controls (n = 9)] completed eight activities; rest, ambulating at 5 progressive treadmill velocities (0.48, 0.67, 0.89, 1.12, 1.34m.s-1) and 2 gradients (3 and 5%) at 0.89m.s-1. During each task, expired gases were collected for the determination of and subsequent calculation of PAEE. An Actigraph GT3X+ accelerometer was worn on the hip of the shortest residual limb and, a HR monitor and an Actiheart (AHR) device were worn on the chest. Multiple linear regressions were employed to derive population-specific PAEE estimated algorithms using Actigraph GT3X+ outputs and HR signals (GT3X+HR). Mean bias±95% Limits of Agreement (LoA) and error statistics were calculated between criterion PAEE (indirect calorimetry) and PAEE predicted using GT3X+HR and AHR.ResultsBoth measurement approaches used to predict PAEE were significantly related (Pr = 0.92, bilateral; r = 0.93, and control; r = 0.91, and AHR; unilateral; r = 0.86, bilateral; r = 0.81, and control; r = 0.67). Mean±SD percent error across all activities were 18±14%, 15±12% and 15±14% for the GT3X+HR and 45±20%, 39±23% and 34±28% in the AHR model, for unilateral, bilateral and control groups, respectively.ConclusionsStatistically derived algorithms (GT3X+HR) provide a more valid estimate of PAEE in individuals with traumatic lower-limb amputation, compared to a proprietary group calibration algorithm (AHR). Outputs from AHR displayed considerable random error when tested in a laboratory setting in individuals with lower-limb amputation.</div

A task analysis methodology for the development of minimum physical employment standards

Objective: The aim of this study was to develop a systematic task analysis process for determination of minimum acceptable job performance in arduous safety-related occupations. Methods: A task analysis using modifications on established methods was completed in UK firefighters. Subject-matter experts (all male) identified critical, physically arduous tasks generic to all UK firefighters and developed individual, role-specific task simulations. Video footage and blinded voting were used to determine minimum acceptable task performance. Results: Eight tasks were identified in combination with role-specific variations, task simulations suitable for use in a physical demands analysis, and corresponding minimum acceptable performance. Conclusions: The bespoke steps highlighted here allow structured identification of task-specific minimum performance standards and simulations from which physical employment standards could be based. However, including a more divergent expert panel with respect to age, sex, and race would strengthen the applicability of this framework in future practice.</p

Validity and Reliability of Firefighting Simulation Test Performance

OBJECTIVE: To assess the validity and reliability of a firefighting simulation test (FFST). METHODS: Sixty-nine operational firefighters completed a best-effort FFST on one occasion and 22 participants completed a further FFST. All participants completed a maximal treadmill test to determine cardiorespiratory fitness (VO2max). RESULTS: Time to complete the FFST demonstrated a strong inverse relationship with VO2max (r = -0.73), although the prediction error was high. Reliability of the FFST was high (r = 0.84, P = 0.01), demonstrating a coefficient of variation of 4.5%. CONCLUSIONS: The FFST demonstrated reasonable validity as a surrogate assessment of cardiorespiratory fitness for firefighting. The FFST also demonstrated good reliability. Given the apparent magnitude of the prediction error, the FFST would be best used as a training tool, rather than as a primary means of assessing cardiorespiratory fitness for firefighting.</p

Training-related changes in force-power profiles:Implications for the skeleton start

Purpose: Athletes' force-power characteristics influence sled velocity during the skeleton start, which is a crucial determinant of performance. This study characterized force-power profile changes across an 18-month period and investigated the associations between these changes and start performance. Methods: Seven elite- and 5 talent-squad skeleton athletes' (representing 80% of registered athletes in the country) force-power profiles and dry-land push-track performances were assessed at multiple time points over two 6-month training periods and one 5-month competition season. Force-power profiles were evaluated using an incremental leg-press test (Keiser A420), and 15-m sled velocity was recorded using photocells. Results: Across the initial maximum strength development phases, increases in maximum force (Fmax) and decreases in maximum velocity (Vmax) were typically observed. These changes were greater for talent (23.6% and-12.5%, respectively) compared with elite (6.1% and-7.6%, respectively) athletes. Conversely, decreases in Fmax (elite-6.7% and talent-10.3%) and increases in Vmax (elite 8.1% and talent 7.7%) were observed across the winter period, regardless of whether athletes were competing (elite) or accumulating sliding experience (talent).When the training emphasis shifted toward higher-velocity, sprint-based exercises in the second training season, force-power profiles seemed to becomemore velocity oriented (higher Vmax andmore negative force-velocity gradient), which was associated with greater improvements in sled velocity (r = .42 and-.45, respectively). Conclusions: These unique findings demonstrate the scope to influence force-power-generating capabilities in well-trained skeleton athletes across different training phases. To enhance start performance, it seems important to place particular emphasis on increasing maximum muscle-contraction velocity.</p