Metabolic adaptation and related biomechanics in an ankle-based exoskeleton system during six sessions of steady state walking.

Ankle-based exoskeletons have demonstrated metabolic benefits during steady-state walking; however, variability exists in individual adaptation timelines necessary to achieve those benefits. This study assessed timelines for metabolic and gait-related adaptation while wearing an ankle-based exoskeleton while powered (EXOP) compared to unpowered (EXNP) and no device worn (NOEX). Metabolic (VO) and biomechanics data were collected while 14 participants walked on a treadmill at 1.

Characterizing Relationships Among the Cognitive, Physical, Social-emotional, and Health-related Traits of Military Personnel.

Introduction: Personnel engaged in high-stakes occupations, such as military personnel, law enforcement, and emergency first responders, must sustain performance through a range of environmental stressors. To maximize the effectiveness of military personnel, an a priori understanding of traits can help predict their physical and cognitive performance under stress and adversity. This work developed and assessed a suite of measures that have the potential to predict performance during operational scenarios.

Severity of Overuse Injury Impacts Self-Efficacy and Quality of Life in Runners: A 2-Year Prospective Cohort Study.

Context: While 55 million Americans incorporate running into their exercise routines, up to 65% of runners sustain an overuse injury annually. It has been consistently shown that regular physical activity positively impacts quality of life (QOL), an essential public health indicator; however, the impact of running-related injuries on QOL is unknown. This study seeks to determine whether overuse injury severity impacts QOL in recreational runners, and if self-efficacy mediates this relationship.

Spatiotemporal and Kinematic Comparisons Between Anthropometrically Paired Male and Female Soldiers While Walking With Heavy Loads.

Introduction: Limited work comparing the effect of heavier carried loads (greater than 30 kg) between men and women has attributed observed differences to sex with the possibility that anthropometric differences may have contributed to those discrepancies. With the recent decision permitting women to enter Combat Arms roles, knowledge of sex-based differences in gait response to load carriage is more operationally relevant, as military loads are absolute and not relative to body weight. The purpose of this study was to describe differences in gait parameters at light to heavy loads between anthropometrically similar male and female soldiers.

A 2-Year Prospective Cohort Study of Overuse Running Injuries: The Runners and Injury Longitudinal Study (TRAILS).

Background: The National Center for Injury Prevention and Control, noting flaws in previous running injury research, called for more rigorous prospective designs and comprehensive analyses to define the origin of running injuries.

Purpose: To determine the risk factors that differentiate recreational runners who remain uninjured from those diagnosed with an overuse running injury during a 2-year observational period.

Study Design: Cohort study; Level of evidence, 2.

Lower-Extremity Injury Increases Risk of First-Time Low Back Pain in the US Army.

Unlabelled: Low back pain (LBP) and lower-extremity injuries (LEI) are primary reasons for lost duty days and disability among military populations.

Purpose: This study examined acute LEI as a risk factor for developing LBP and examined the time to incident LBP between individuals with and without a history of LEI.

Methods: This retrospective cohort study examined U.

Spatiotemporal Parameters are not Substantially Influenced by Load Carriage or Inclination During Treadmill and Overground Walking.

Influences of load carriage and inclination on spatiotemporal parameters were examined during treadmill and overground walking. Ten soldiers walked on a treadmill and overground with three load conditions (00 kg, 20 kg, 40 kg) during level, uphill (6% grade) and downhill (-6% grade) inclinations at self-selected speed, which was constant across conditions. Mean values and standard deviations for double support percentage, stride length and a step rate were compared across conditions.

A history of low back pain affects pelvis and trunk coordination during a sustained manual materials handling task.

Purpose: The purpose of this study was to compare the coordination between the trunk and the pelvis during a sustained asymmetric repetitive lifting task between a group with a history of low back pain (LBP; HBP) and a group with no history of LBP (NBP).

Methods: Volunteers lifted a 11-kg box from ankle height in front to a shelf 45° off-center at waist height, and lowered it to the start position at 12 cycles/min for 10 min. Lifting side was alternated during the trial.

An integrative modeling approach for the efficient estimation of cross sectional tibial stresses during locomotion.

The purpose of this research was to utilize a series of models to estimate the stress in a cross section of the tibia, located 62% from the proximal end, during walking. Twenty-eight male, active duty soldiers walked on an instrumented treadmill while external force data and kinematics were recorded. A rigid body model was used to estimate joint moments and reaction forces.

Biomechanics of Load Carriage--Historical Perspectives and Recent Insights.

Loads carried by the warfighter have increased substantially throughout recorded history, with the typical U.S. ground soldier carrying external loads averaging 45 kg during operations in Afghanistan.

The Relationships between Age and Running Biomechanics.

Unlabelled: Running has high injury rates, especially among older runners. Most aging literature compares young with old runners without accounting for the progression of biomechanics throughout the lifespan. We used age as a continuous variable to investigate the continuum of age-related gait adaptations in running along with determining the chronology and rate of these adaptations.

Characterization of Foot-Strike Patterns: Lack of an Association With Injuries or Performance in Soldiers.

Objectives: Characterize the distribution of foot-strike (FS) patterns in U.S. Army Soldiers and determine if FS patterns are related to self-reported running injuries and performance.

Lower extremity biomechanical changes associated with symmetrical torso loading during simulated marching.

The dose-response relationship between biomechanical variables and the magnitude of external loads is unclear. The use of different load distributions (e.g.

Trunk bend and twist coordination is affected by low back pain status during running.

Recent literature has related differences in pelvis-trunk coordination to low back pain (LBP) status. In addition, repetitive motions involving bending and twisting have been linked to high incidence of LBP. The purpose of this study was to examine trunk sagittal motion - axial rotation ('bend and twist') coordination during locomotion in three groups of runners classified by LBP status (LBP: current low back pain; RES: resolved low back pain and CTR: control group with no history of LBP).

A history of low back pain affects pelvis and trunk mechanics during a sustained lift/lower task.

Unlabelled: This study compared three-dimensional trunk and pelvis range of motion (ROM) during a sustained asymmetric box lift/lower task between a group with a history of low back pain (HBP, n = 9) and a group with no history of low back pain (NBP, n = 9). Participants lifted an 11-kg box for 10 min at 12 cycles/min from ankle height in front to shelves 45 deg off-centre at waist height. Kinematic data were collected at the beginning (min1), middle (min5) and end of the bout (min9).

Lower extremity mechanics during marching at three different cadences for 60 minutes.

During group marches, soldiers must walk in step with one another at the same imposed cadence. The literature suggests that shorter trainees may be more susceptible to injury due to overstriding that can occur when taller recruits dictate marching cadence. This study assessed the effects of fixed cadence simulated marching at cadences above and below preferred step rate (PSR) on lower extremity joint mechanics in individuals who were unaccustomed to marching.

Hypohydration does not alter standing balance.

We examined the effect of body water deficits on standing balance and sought to determine if plasma hyperosmolality (P(osm)) and/or volume reduction (%ΔV(plasma)) exerted independent effects. Nine healthy volunteers completed three experimental trials which consisted of a euhydration (EUH) balance test, a water deficit session and a hypohydration (HYP) balance test. Hypohydration was achieved both by exercise-heat stress to 3% and 5% body mass loss (BML), and by a diuretic to 3% BML.

Low back pain status affects pelvis-trunk coordination and variability during walking and running.

Background: The purpose of this study was to compare pelvis-trunk coordination and coordination variability over a range of walking and running speeds between three groups of runners; runners with low to moderate low back pain; runners who had recovered from a single bout of acute low back pain; and runners who had never experienced any symptoms of low back pain.

Methods: Pelvis and trunk kinematic data were collected as speed was systematically increased on a treadmill. Coordination between pelvis and trunk in all three planes of motion was measured using continuous relative phase, and coordination variability was defined as the standard deviation of this measure.

Influence of low back pain status on pelvis-trunk coordination during walking and running.

Study Design: Two-way repeated-measures analysis of variance.

Objective: To assess pelvis and trunk three-dimensional segmental excursions and coordination differences during walking and running between runners with low back pain (LBP), runners with resolved LBP, and a control group with no history of LBP.

Summary Of Background Data: Studies have documented differences in pelvis and trunk coordination between those with moderate to severe LBP during walking.

Carrying a rifle with both hands affects upper body transverse plane kinematics and pelvis-trunk coordination.

The purpose of this study was to assess how carrying a rifle in both hands affects upper body motion and coordination during locomotion. In total, 11 male soldiers walked (1.34 m/s) and ran (2.

Coordination variability around the walk to run transition during human locomotion.

Increases in movement variability have previously been observed to be a hallmark property of coordination changes between coupled oscillators that occur as movement frequency is scaled. Prior research on the walk-run transition in human locomotion has also demonstrated increases in variability around the transition region, supporting predictions of nonequilibrium phase transitions (Diedrich & Warren, 1995). The current study examined the coordinative patterns of both intra- and inter-limb couplings around the walk-run transition using two different temporal manipulations of locomotor velocity as a control parameter in healthy young participants (N = 11).