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Featured Application: This training regimen can be used as a time-efficient protocol for people with lower levels of aerobic fitness to kickstart their fitness journey. The training loads applied can be used as initial mesocycle loads for untrained participants, noting that, through effective periodization, the HITT intensities will periodically increase to provide an ongoing adaptive stimulus. Further, for aerobically trained individuals (>40 mL/kg/min), we suggest that this program be modified by increasing the prescribed training intensities to induce a sufficient stimulus to increase their baseline strength and aerobic parameters. An alternative use of this intervention is as a short (off-/pre-season) training regimen within sports clubs to boost strength and endurance parameters through a brief, but intense, time-efficient training approach. Finally, the described intervention could be implemented in occupational settings (e.g., fly-in–fly-out work camp labour workers in mines), where the benefit from incorporating a systematic training regimen, especially when the time devoted to exercise is limited, can lead to general health benefits. There is conflicting evidence on whether concurrent aerobic endurance and resistance training (RT) leads to synergistic enhancements in aerobic capacity and muscular strength or causes interference, limiting performance gains. We developed a concurrent training (CT) intervention, including full-body dynamic RT combined with high-intensity interval training (HIIT), on a cycle ergometer to determine whether a brief CT intervention is beneficial to both muscular strength and aerobic capacity. In an exploratory pilot study, participants (n = 10; male = 4) undertook a four-week CT intervention consisting of RT, including six compound movements (bench press, squat, deadlift, Pendley row, squat jumps, and rack pulls), plus cycle HIIT. The pre-/post-intervention improvements were assessed via bench press and leg press 3RM testing, an isometric mid-thigh pull, a countermovement jump, and the change in the relative V ˙ O2max. We observed significant (p < 0.1) increases in the bench press (6.4%), leg press (6.7%), IMTP (11.1%), and relative V ˙ O2max (7%) results. Interestingly, the participants with the highest pre-intervention relative V ˙ O2max demonstrated no performance improvements. These pilot test results suggest that CT is an effective strategy that enables synergistic enhancements that can be observed with very low training volumes. This suggests that CT is an effective strategy for improving muscular strength and aerobic endurance in non-elite physically active individuals. [ABSTRACT FROM AUTHOR]

The objective of this research was to validate a single, trunk-mounted wearable sensor (Optimeye S5, Catapult Australia, Melbourne) to measure the cadence of swimming strokes, cycling pedals and running strides in a triathlon. While similar validations have been performed in swimming and running, it is a novel application in cycling, and thus, across a whole triathlon. Seven triathletes were recruited to participate in a sprint distance triathlon which was filmed and simultaneously measured by a single, trunk-mounted wearable sensor. To validate the wearable sensor, individual swimming strokes, cycling pedal strokes and running strides were manually counted by viewing the wearable sensor data and video footage. While analysing cycling data, changes in cycling subtask performances were noticed, thus, a secondary analysis in cycling was conducted to investigate. The 95% limits of agreement analysis indicated the sensor validly measured swimming strokes (mean bias = −0.034 strokes), cycling pedal strokes (mean bias = −0.09 strokes) and running strides (mean bias = 0.00 strides) with minimal to no bias (p > 0.05). Further analysis of cycling revealed the wearable sensor is an acceptably valid tool to measure the duration of out of saddle riding (mean bias = 0.08 s), however, significant differences in the duration of in saddle riding (mean bias = −0.5 s) and coasting were identified (mean bias = 0.39 s). A single trunk mounted wearable sensor is a valid tool to measure movement cadence in a triathlon, however, further validation is required to generate a full understanding of cycling subtask performances. [ABSTRACT FROM AUTHOR]

Featured Application: Improving cornering skill has the potential to improve overall cycling performance. However, clinically used balance tests do not reflect cornering performance. More cycling-specific balance tests need to be developed to better assess cycling performance. Balance is paramount to safe and successful cycling, both in competition and recreation. Balance has been investigated in the return-to-cycling context, but its relationship to cycling performance is unknown. Our study aimed to analyse the relationship between balance, measured by common clinical balance tests, and cycling performance. Seven competitive cyclists participated in this cross-sectional correlational study. We collected field-based measures of cycling performance, including mean velocity, minimum and maximum velocity, mean corner speed, average lap time, and lean angle. Also, we measured balance via the balance error scoring system, the star excursion balance test, the lateral reach test, and the modified Bass test of dynamic balance. Strong correlations between cornering performance and cycling performance (r = 0.65–0.87, p < 0.01) were detected. Weak correlations between clinical balance tests and cycling performance (r = 0.33–0.53, p < 0.05) were observed. In conclusion, our study showed that improving cornering performance has the potential to improve overall cycling performance. We also found no clear correlations between our clinical balance tests and cycling performance. These weak correlations between postural control in standing and cycling performance suggest that standing balance and balancing during cycling are distinct motor control processes. [ABSTRACT FROM AUTHOR]

Sprinting plays a significant role in determining the results of road cycling races worldwide. However, currently, there is a lack of systematic research into the kinematics of sprint cycling, especially in an outdoor, environmentally valid setting. This study aimed to describe selected joint kinematics during a cycling sprint outdoors. Three participants were recorded sprinting over 60 meters in both standing and seated sprinting positions on an outdoor course with a baseline condition of seated cycling at 20 km/h. The participants were recorded using array-based inertial measurement units to collect joint excursions of the upper and lower limbs including the trunk. A high-rate GPS unit was used to record velocity during each recorded condition. Kinematic data were analyzed in a similar fashion to running gait, where multiple pedal strokes were identified, delineated, and averaged to form a representative (average ± SD) waveform. Participants maintained stable kinematics in most joints studied during the baseline condition, but variations in ranges of movement were recorded during seated and standing sprinting. Discernable patterns started to emerge for several kinematic profiles during standing sprinting. Alternate sprinting strategies emerged between participants and bilateral asymmetries were also recorded in the individuals tested. This approach to studying road cycling holds substantial potential for researchers wishing to explore this sport. [ABSTRACT FROM AUTHOR]

Australian aerial skiers are recruited from other acrobatic sports through a nationally coordinated transition program. However, there is limited understanding of how to train transferring athletes for both optimal performance and injury prevention. The aim of this study was to test whether an athletic profile could be used to identify which skills that gymnasts possess are more and less likely to transfer to aerial skiing based on similarities and differences in the athletes' physical attributes. Six elite female aerial skiers and five state- and national-level female gymnasts completed a test protocol involving drop-landing, countermovement jump, isokinetic strength of the knee flexors and extensors, flexibility and anthropometrical profile. Aerial skiers and gymnasts had an anthropometrical profile ideal for acrobatic efficiency, but gymnasts had smaller thigh girth and greater knee range of motion. These results suggest that gymnasts are more likely to succeed in transferring to aerial skiing's acrobatic skills than skiing and landing skills. We suggest that gymnasts transferring to aerial skiing undertake pretransfer training designed to improve hamstring isometric strength and dynamic stability of the knee to reduce the risk of knee injury and improve their ability to maintain a crouched position. [ABSTRACT FROM AUTHOR]

EMG-driven musculoskeletal modeling is a method in which loading on the active and passive structures of the cervical spine may be investigated. A model of the cervical spine exists; however, it has yet to be criterion validated. Furthermore, neck muscle morphometry in this model was derived from elderly cadavers, threatening model validity. Therefore, the overall aim of this study was to modify and criterion validate this preexisting graphically based musculoskeletal model of the cervical spine. Five male subjects with no neck pain participated in this study. The study consisted of three parts. First, subject-specific neck muscle morphometry data were derived by using magnetic resonance imaging. Second, EMG drive for the model was generated from both surface (Drive 1: N = 5) and surface and deep muscles (Drive 2: N=3). Finally, to criterion validate the modified model, net moments predicted by the model were compared against net moments measured by an isokinetic dynamometer in both maximal and submaximal isometric contractions with the head in the neutral posture, 20 deg of flexion, and 35 deg of extension. Neck muscle physiological cross sectional area values were greater in this study when compared to previously reported data. Predictions of neck torque by the model were better in flexion (18.2% coefficient of variation (CV)) when compared to extension (28.5% CV) and using indwelling EMG did not enhance model predictions. There were, however, large variations in predictions when all the contractions were compared. It is our belief that further work needs to be done to improve the validity of the modified EMG-driven neck model examined in this study. A number of factors could potentially improve the model with the most promising probably being optimizing various modeling parameters by using methods established by previous researchers investigating other joints of the body. Keywords: cervical spine, musculoskeletal modeling, neck, validity

The purpose of this study was to compare surface electromyography (EMG) activation levels of selected neck muscles for two common neck-training modalities (Thera-Band and Cybex). Seventeen asymptomatic subjects (eight men and nine women) with a mean age 23.4 years were recruited. EMG activation normalized to maximal voluntary isometric contraction (MVIC) was measured with subjects performing exercises with green, blue, and black Thera-Bands and 50%, 70%, and 90o/0 of 3RM for the Cybex modality. Four variables were used to depict exercise intensity: average and peak EMG activation in the concentric and eccentric phases. Significant differences (P [less than or equal to] 0.05) in EMG activation were evident when comparing intensities of the Cybex modality with each other and when comparing the Cybex intensities with Thera-Band intensities in most cases. Minimal differences were found among differing intensities of Thera-Band. Thera-Band exercise resulted in low-level EMG activation (range, flexion 3.8-15.7% MVIC; range, extension 20.2-34.8% MVIC); therefore, such exercise may be useful in rehabilitation programs. Cybex exercise (range, flexion 20.9-83.5% MVIC; range, extension 40.6-95.8% MVIC) may be useful for occupation-related injury prevention. However, exercise prescription should be undertaken with care as the mechanical loading on passive spinal structures is unknown. KEY WORDS Them-Band, Cybex, strength, rehabilitation, intensity

Optimal tuning of leg stiffness has been associated with better running economy. Running with a load is energetically expensive, which could have a significant impact on athletic performance where backpack carriage is involved. The purpose of this study was to investigate the impact of load magnitude and velocity on leg stiffness. We also explored the relationship between leg stiffness and running joint work. Thirty-one healthy participants ran overground at 3 velocities (3.0, 4.0, 5.0 m⋅s-1), whilst carrying 3 load magnitudes (0%, 10%, 20% weight). Leg stiffness was derived using the direct kinetic-kinematic method. Joint work data was previously reported in a separate study. Linear models were used to establish relationships between leg stiffness and load magnitude, velocity, and joint work. Our results found that leg stiffness did not increase with load magnitude. Increased leg stiffness was associated with reduced total joint work at 3.0 m⋅s-1, but not at faster velocities. The association between leg stiffness and joint work at slower velocities could be due to an optimal covariation between skeletal and muscular components of leg stiffness, and limb attack angle. When running at a relatively comfortable velocity, greater leg stiffness may reflect a more energy efficient running pattern. [ABSTRACT FROM AUTHOR]

The aim of this systematic review was to evaluate the impact of bilaterally symmetrical backpack systems borne on the posterior trunk on walking biomechanics, as backpacks represent the most prevalent method of load carriage in the military and civilian population. A search of electronic databases was performed for studies that only investigated posteriorly-borne backpack carriage during level-grade walking (treadmill and over ground). Methodology of studies was assessed, and both meta-analysis and qualitative synthesis were completed. Fifty-four studies were included in this review. In summary, the available literature showed that backpack carriage in walking was associated with an increased trunk flexion angle, increased hip and ankle range of motion, increased vertical and horizontal ground reaction force, increased cadence, and reduced stride length. Several variations in backpack carriage protocols could explain between-study variations in results, including: walking speed, backpack carriage skill level, the use of a hip belt, and posterior displacement of the load away from the trunk. The findings of this systematic review will inform backpack carriage practices in the area of injury risk assessment and physical performance enhancement. [ABSTRACT FROM AUTHOR]

This study aimed to validate an array-based inertial measurement unit to measure cricket fast bowling kinematics as a first step in assessing feasibility for tele-sportand-exercise medicine. We concurrently captured shoulder girdle relative to the pelvis, trunk lateral flexion, and knee flexion angles at front foot contact of eight cricket medium-fast bowlers using inertial measurement unit and optical motion capture. We used one sample t-tests and 95% limits of agreement (LOA) to determine the mean difference between the two systems and Smallest Worth-while Change statistic to determine whether any differences were meaningful. A statistically significant (p < 0.001) but small mean difference of -4.7° ± 8.6° (95% Confidence Interval (CI) [-3.1° to -6.4°], LOA [-22.2 to 12.7], SWC 3.9°) in shoulder girdle relative to the pelvis angle was found between the systems. There were no statistically significant differences between the two systems in trunk lateral flexion and knee flexion with the mean differences being 0.1° ± 10.8° (95% CI [-1.9° to 2.2°], LOA [-22.5 to 22.7], SWC 1.2°) and 1.6° ± 10.1° (95% CI [-0.2° to 3.3°], LOA [-19.2 to 22.3], SWC 1.9°) respectively. The inertial measurement unit-based system tested allows for accurate measurement of specific cricket fast bowling kinematics and could be used in determining injury risk in the context of tele-sportand-exercise-medicine. [ABSTRACT FROM AUTHOR]

The musculoskeletal load in waste collection has been examined through simulated assessment of pulling and pushing bins as well as lifting and throwing rubbish bags. With the onset of mechanization, many of these tasks do not exist and workers are faced with other loads not previously assessed. The purpose of this study was to quantify the postures and muscle activity during mechanized waste collection work. Three subtasks of mechanized waste collection were identified, namely driving, bin collection, and egress and access of the vehicle. Spinal, shoulder, and upper limb kinematics along with surface electromyography from three muscles were collected during these tasks in a typical work shift. During driving and bin collection, participants adopted a head-extended, torso forward-flexed posture with frequent rotations of the head and neck. Egress and access of the vehicle produced substantially larger ranges of movement compared with driving and bin collection. The forward-flex, sitting posture can increase the risk of low back pain if there are undulations in the terrain and if this posture is adopted for prolonged periods. The frequent head and neck rotations can increase the incidence and severity of neck pain. Prolonged driving has been linked with an increased cardiometabolic risk and egress and access has increased risk of trips and falls from a height. Managers of waste collection workers should consider implementing interventions to reduce the exposure of this important workforce to the deleterious demands of their work. [ABSTRACT FROM AUTHOR]

Context: Accelerometer peak impact accelerations are being used to measure player physical demands in contact sports. However, their accuracy to do so has not been ascertained. Purpose: To compare peak-impact-acceleration data from an accelerometer contained in a wearable tracking device with a 3-dimensional motion-analysis (MA) system during tackling and bumping. Methods: Twenty-five semielite rugby athletes wore a tracking device containing a 100-Hz triaxial accelerometer (MinimaxX S4, Catapult Innovations, Australia). A single retroreflective marker was attached to the device, with its position recorded by a 12-camera MA system during 3 physical-collision tasks (tackle bag, bump pad, and tackle drill; N = 625). The accuracy, effect size, agreement, precision, and relative errors for each comparison were obtained as measures of accelerometer validity. Results: Physical-collision peak impact accelerations recorded by the accelerometer overestimated (mean bias 0.60 g) those recorded by the MA system (P < .01). Filtering the raw data at a 20-Hz cutoff improved the accelerometer's relationship with MA data (mean bias 0.01 g; P > .05). When considering the data in 9 magnitude bands, the strongest relationship with the MA system was found in the 3.0-g or less band, and the precision of the accelerometer tended to reduce as the magnitude of impact acceleration increased. Of the 3 movements performed, the tackle-bag task displayed the greatest validity with MA. Conclusions: The findings indicate that the MinimaxX S4 accelerometer can accurately measure physical-collision peak impact accelerations when data are filtered at a 20-Hz cutoff frequency. As a result, accelerometers may be useful to measure physical collisions in contact sports. [ABSTRACT FROM AUTHOR]

The article discusses a study that tested the effectiveness of a rhythmic gymnastics-based supplementary training program on lower limb flexibility and power of contemporary dancers. Highlights include the association of muscular power with improved aesthetic qualities of dance and dancers' jumping ability, the need for dance-specific training interventions and testing, and the use of an isokinetic dynamometer to measure hip flexor peak torque during dance kicks.

Greater functional knee valgus (FKV) is thought to contribute to a greater risk of sustaining overuse running injuries. The hip is commonly implicated in greater functional knee valgus, but no studies have investigated the effects of hip taping on running kinematics. The present study investigated whether or not hip taping altered hip and knee kinematics compared to sham and no taping in female runners demonstrating excessive functional knee valgus. Lower limb stance-phase kinematics were collected from 23 female runners using three-dimensional motion capture. Participants performed over ground running at 3.5 m/s and 5.0 m/s. Three taping conditions (no tape; sham tape; hip tape) were tested. Statistical inference was performed using Statistical Parametric Mapping Hotelling's paired t-tests, with post-hoc paired t-tests. Hip taping significantly decreased hip adduction and internal rotation angles throughout stance phase by up to 7°, compared to sham and no taping. Hip taping significantly increased knee adduction, internal rotation, flexion, and reduced peak knee flexion angles, compared to no tape. Hip taping reduced excessive hip motion by clinically meaningful magnitudes, and also benefited knee frontal and transverse plane kinematics at the slower running speed. Hip taping may provide an immediate solution in correcting FKV in running. [ABSTRACT FROM AUTHOR]

Agricultural operations routinely expose farm workers to high levels of soil dust and other airborne particulate matter that have been linked to adverse health outcomes. The main objective of this study was to investigate exposure to agricultural dust during seeding operations of Western Australian farm workers. Twenty-one wheat-belt farms were recruited to participate in the study. Data were collected over the 6-week seeding period of April-June 2014. Each farm was visited once, and workers were asked to complete a workplace survey that asked questions related to minimizing exposure to agricultural dusts and occupational health and safety issues on their farm. Farmers were also asked to simultaneously participate in monitoring of personal exposure to inhalable or respirable dust along with real-time monitoring for particulate air pollution in their tractor cabin. Sampling was undertaken for 4 hr. The results showed that, on average, Western Australian farmers were exposed to personal respirable dust concentrations above the Australian Institute of Occupational Hygienists recommended guideline values, with some farmers being exposed to concentrations up to seven times higher than the value for respirable dusts. In comparison, in-cabin dust concentrations were lower, although some individual tractors recorded intermittently higher levels, which might be attributed to the type of work activity or process being undertaken. Remaining in tractor cabins with closed doors and windows with properly maintained seals might minimize the infiltration of hazardous dusts and may provide some protection from dust exposures. Future research should focus on educating and providing farm owners and workers with more information on adopting work processes and procedures related to minimizing harmful exposures to agricultural dusts. [ABSTRACT FROM AUTHOR]

Background. The effects of resistance training on a muscle's neural, architectural, and mechanical properties are well established. However, whether resistance training can positively change the coordination of multiple motor elements in the control of a well-defined lower limb motor performance objective remains unclear. Such knowledge is critical given that resistance training is an essential and ubiquitous component in gait rehabilitation. This study aimed to investigate if strength gains of the ankle and knee extensors after resistance training increases kinematic motor abundance in hopping. Methods. The data presented in this study represents the pooled group results of a sub-study from a larger project investigating the effects of resistance training on load carriage running energetics. Thirty healthy adults performed self-paced unilateral hopping, and strength testing before and after six weeks of lower limb resistance training. Motion capture was used to derive the elemental variables of planar segment angles of the foot, shank, thigh, and pelvis, and the performance variable of leg length. Uncontrolled manifold analysis (UCM) was used to provide an index of motor abundance (IMA) in the synergistic coordination of segment angles in the stabilization of leg length. Bayesian Functional Data Analysis was used for statistical inference, with a non-zero crossing of the 95% Credible Interval (CrI) used as a test of significance. Results. Depending on the phase of hop stance, there were significant main effects of ankle and knee strength on IMA, and a significant ankle by knee interaction effect. For example at 10% hop stance, a 1 Nm/kg increase in ankle extensor strength increased IMA by 0.37 (95% CrI [0.14-0.59]), a 1 Nm/kg increase in knee extensor strength decreased IMA by 0.29 (95% CrI [0.08-0.51]), but increased the effect of ankle strength on IMA by 0.71 (95% CrI [0.10-1.33]). At 55% hop stance, a 1 Nm/kg increase in knee extensor strength increase IMA by 0.24 (95% CrI [0.001-0.48]), but reduced the effect of ankle strength on IMA by 0.71 (95% CrI [0.13-1.32]). Discussion. Resistance training not only improves strength, but also the structure of coordination in the control of a well-defined motor objective. The role of resistance training on motor abundance in gait should be investigated in patient cohorts, other gait patterns, and its translation into functional improvements. [ABSTRACT FROM AUTHOR]

Background. There is convincing evidence for the benefits of resistance training on vertical jump improvements, but little evidence to guide optimal training prescription. The inability to detect small between modality effects may partially reflect the use of ANOVA statistics. This study represents the results of a sub-study from a larger project investigating the effects of two resistance training methods on load carriage running energetics. Bayesian statistics were used to compare the effectiveness of isoinertial resistance against speed-power training to change countermovement jump (CMJ) and squat jump (SJ) height, and joint energetics. Methods. Active adults were randomly allocated to either a six-week isoinertial (n= 16; calf raises, leg press, and lunge), or a speed-power training program (n = 14; countermovement jumps, hopping, with hip flexor training to target pre-swing running energetics). Primary outcome variables included jump height and joint power. Bayesian mixed modelling and Functional Data Analysis were used, where significance was determined by a non-zero crossing of the 95% Bayesian Credible Interval (CrI). Results. The gain in CMJ height after isoinertial training was 1.95 cm (95% CrI [0.85- 3.04] cm) greater than the gain after speed-power training, but the gain in SJ height was similar between groups. In the CMJ, isoinertial training produced a larger increase in power absorption at the hip by a mean 0.018% (equivalent to 35 W) (95% CrI [0.007-0.03]), knee by 0.014% (equivalent to 27 W) (95% CrI [0.006-0.02]) and foot by 0.011% (equivalent to 21 W) (95% CrI [0.005-0.02]) compared to speed-power training. Discussion. Short-term isoinertial training improved CMJ height more than speed- power training. The principle adaptive difference between training modalities was at the level of hip, knee and foot power absorption. [ABSTRACT FROM AUTHOR]

The present study aimed to quantify the demand of seven generic, closed agility drills. Twenty males with experience in invasion sports volunteered to participate in this study. They performed seven, closed agility drills over a standardised 30-m distance. Physical demand measures of peak velocity, total foot contacts, peak impacts, completion time, and maximum heart rate were obtained via the use of wearable sensor technologies. A subjective rating of perceived exertion (RPE) was also obtained. All measures, with the exception of maximum heart rates and RPE were able to delineate drills in terms of physical and physiological demand. The findings of this study exemplify the differences in demand of agility-type movements. Drill demand was dictated by the type of agility movement initiated with the increase in repetitiveness of a given movement type also contributing to increased demand. Findings from this study suggest agility drills can be manipulated to vary physical and physiological demand. This allows for the optimal application of training principles such as overload, progression, and periodisation. [ABSTRACT FROM AUTHOR]

Background: In recent years, athletes have ventured into ultra-endurance and adventure racing events, which tests their ability to race, navigate, and survive. These events often require race participants to carry some form of load, to bear equipment for navigation and survival purposes. Previous studies have reported specific alterations in biomechanics when running with load which potentially influence running performance and injury risk. We hypothesize that a biomechanically informed neuromuscular training program would optimize running mechanics during load carriage to a greater extent than a generic strength training program. Methods: This will be a two group, parallel randomized controlled trial design, with single assessor blinding. Thirty healthy runners will be recruited to participate in a six weeks neuromuscular training program. Participants will be randomized into either a generic training group, or a biomechanically informed training group. Primary outcomes include self-determined running velocity with a 20 % body weight load, jump power, hopping leg stiffness, knee extensor and triceps-surae strength. Secondary outcomes include running kinetics and kinematics. Assessments will occur at baseline and post-training. Discussion: To our knowledge, no training programs are available that specifically targets a runner's ability to carry load while running. This will provide sport scientists and coaches with a foundation to base their exercise prescription on. [ABSTRACT FROM AUTHOR]

Musculoskeletal injuries are reported as burdening the military. An identified risk factor for injury is carrying heavy loads; however, soldiers are also required to wear their load as body armour. To investigate the effects of body armour on trunk and hip kinematics during military-specific manual handling tasks, 16 males completed 3 tasks while wearing each of 4 body armour conditions plus a control. Three-dimensional motion analysis captured and quantified all kinematic data. Average trunk flexion for the weightiest armour type was higher compared with control during the carry component of the ammunition box lift (p < 0.001) and sandbag lift tasks (p < 0.001). Trunk rotation ROM was lower for all armour types compared with control during the ammunition box place component (p < 0.001). The altered kinematics with body armour occurred independent of armour design. In order to optimise armour design, manufacturers need to work with end-users to explore how armour configurations interact with range of personal and situational factors in operationally relevant environments. Practitioner Summary:Musculoskeletal injuries are reported as burdening the military and may relate to body armour wear. Body armour increased trunk flexion and reduced trunk rotation during military-specific lifting and carrying tasks. The altered kinematics may contribute to injury risk, but more research is required. [ABSTRACT FROM AUTHOR]

The purpose of this study was to validate peak acceleration data from an accelerometer contained within a wearable tracking device while walking, jogging and running. Thirty-nine participants walked, jogged and ran on a treadmill while 10 peak accelerations per movement were obtained (n = 390). A single triaxial accelerometer measured resultant acceleration during all movements. To provide a criterion measure of acceleration, a 12-camera motion analysis (MA) system tracked the position of a retro-reflective marker affixed to the wearable tracking device. Peak raw acceleration recorded by the accelerometer significantly overestimated peak MA acceleration (P < 0.01). Filtering accelerometer data improved the relationship with the MA system (P < 0.01). However, only the 10 Hz and 8 Hz cut-off frequencies significantly reduced the errors found. The walk movement demonstrated the highest accuracy, agreement and precision and the lowest relative errors. Linear increases in error were observed for jog compared with walk and for run compared to both other movements. As the magnitude of acceleration increased, the strength of the relationship between the accelerometer and the criterion measure decreased. These results indicate that filtered accelerometer data provide an acceptable means of assessing peak accelerations, in particular for walking and jogging. [ABSTRACT FROM AUTHOR]

Coronary heart disease (CHD) is a major problem for firefighters, even when considering the healthy worker effect (HWE). Although volunteer firefighters outnumber paid personnel, previous research has focused on paid US firefighters. By contrast, no CHD data for Australian firefighters exist. Risk factor data were collected from 2,943 Australian volunteer firefighters and CHD risk was compared with reference “low-risk” and Australian population data. Predicted CHD risk for male and female firefighter was 19.2% and 5.1%, respectively. Female firefighters high blood pressure and fasting glucose was significantly lower than the general population, whereas all other risk factors was similar to the general population. Firefighters’ CHD risk was greater than other volunteer and paid emergency services, but the prevalence for most risk factors was similar to the general population. Therefore, Australian volunteer firefighters may not benefit from the HWE. [ABSTRACT FROM PUBLISHER]

Eleven recreationally active males performed 11 circuits of military work, wearing torso armor on one occasion, and full armor on another. Performance was measured by the time taken to complete individual tasks, and the overall time to completion (TTC) for each circuit. Heart rate, intestinal temperature, ratings of perceived exertion (RPE), and thermal sensation were recorded after each circuit. Participants' circuit TTC was no different between conditions; however, specific tasks were differentially impeded by the two armor configurations. Vaulting and crawling were significantly slower (0.28 ± 0.06 and 0.55 ± 0.26 seconds) in full armor; however, box lifting and shooting were significantly slower (0.36 ± 0.18 and 0.86 ± 0.23 seconds) when wearing torso armor. Heart rate and core temperature were significantly higher during the full armor trial (5 ± 1 beats · min(-1) and 0.22 ± 0.03 °C). Similarly, RPE and thermal sensation were significantly higher (1 ± 0 and 0.5 ± 0.0) during the full armor condition. Military tasks were differentially impaired by the armor configurations used, which suggests a need to explore role-specific armor for military personnel. Physiological and perceptual responses were elevated in full armor, which could be exacerbated during longer periods of work or in hot conditions. [ABSTRACT FROM AUTHOR]

This study examined the trunk postures and upper-body muscle activations during four physically demanding wildfire suppression tasks. Bilateral, wireless surface electromyography was recorded from the trapezius and erector spinae muscles of nine experienced, wildfire fighters. Synchronised video captured two retroreflective markers to allow for quantification of two-dimensional sagittal trunk flexion. In all tasks, significantly longer time was spent in the mild and severe trunk flexion (p≤  0.002) compared to the time spent in a neutral posture. Mean and peak muscle activation in all tasks exceeded previously established safe limits. These activation levels also significantly increased through the performance of each task (p<  0.001). The results suggest that the wildfire suppression tasks analysed impose significant musculoskeletal demand on firefighters. Fire agencies should consider developing interventions to reduce the exposure of their personnel to these potentially injurious musculoskeletal demands. Practitioner Summary:Wildfire fighters adopt high-risk trunk postures and utilise high levels of upper-body muscle activity to perform wildfire suppression tasks. This combination places these workers at elevated risk of musculoskeletal injury. Interventions should be developed to manage the injury exposure risk of this vital workforce. [ABSTRACT FROM AUTHOR]

This study assessed the validity of a tri-axial accelerometer worn on the upper body to estimate peak forces during running and change-of-direction tasks. Seventeen participants completed four different running and change-of-direction tasks (0°, 45°, 90°, and 180°; five trials per condition). Peak crania-caudal and resultant acceleration was converted to force and compared against peak force plate ground reaction force (GRF) in two formats (raw and smoothed). The resultant smoothed (10 Hz) and crania-caudal raw (except 180°) accelerometer values were not significantly different to resultant and vertical GRF for all running and change-of-direction tasks, respectively. Resultant accelerometer measures showed no to strong significant correlations (r = 0.00–0.76) and moderate to large measurement errors (coefficient of variation [CV] = 11.7–23.9%). Crania-caudal accelerometer measures showed small to moderate correlations (r = − 0.26 to 0.39) and moderate to large measurement errors (CV = 15.0–20.6%). Accelerometers, within integrated micro-technology tracking devices and worn on the upper body, can provide a relative measure of peak impact force experienced during running and two change-of-direction tasks (45° and 90°) provided that resultant smoothed values are used. [ABSTRACT FROM PUBLISHER]