This study examined the relationship between energy expenditure and wrist accelerometer output during walking in persons with and without Down syndrome (DS). Energy expenditure in metabolic equivalent units (METs) and activity-count rate were respectively measured with portable spirometry and a uniaxial wrist accelerometer in 17 persons with DS (age: 24.7 ± 6.9 years; 9 women) and 21 persons without DS (age: 26.3 ± 5.2 years; 12 women) during six over-ground walking trials. Combined groups regression showed that the relationship between METs and activity-count rate differed between groups (p < .001). Separate models for each group included activity-count rate and squared activity-count rate as significant predictors of METs (p ≤ .005). Prediction of METs appeared accurate based on Bland-Altman plots and the lack of between-group difference in mean absolute prediction error (DS: 17.07%; Non-DS: 18.74%). Although persons with DS show altered METs to activity-count rate relationship during walking, prediction of their energy expenditure from wrist accelerometry appears feasible.
Prediction of Energy Expenditure From Wrist Accelerometry in People With and Without Down Syndrome
Stamatis Agiovlasitis, Robert W. Motl, John T. Foley, and Bo Fernhall
Stride Interval Dynamics Are Altered when Two Individuals Walk Side by Side
Jeff A. Nessler, Tomas Gonzales, Eric Rhoden, Matthew Steinbrick, and Charles J. De Leone
The purpose of this study was to examine the effects of interpersonal synchronization of stepping on stride interval dynamics during over-ground walking. Twenty-seven footswitch instrumented subjects walked under three conditions: independent (SOLO), alongside a partner (PAIRED), and side by side with intentional synchronization (FORCED). A subset of subjects also synchronized stepping to a metronome (MET). Stride time power spectral density and detrended fluctuation analysis revealed that the rate of autocorrelation decay in stride time was similar for both the SOLO and PAIRED conditions, but was significantly reduced during the FORCED and MET conditions (p=0.03 & 0.002). Stride time variability was also significantly increased for the FORCED and MET conditions (p<0.001). These data suggest that forced synchronization of stepping results in altered stride interval dynamics, likely through increased active control by the CNS. Passive side by side stepping, where synchronization is subconscious, does not appreciably alter stepping in this manner.
A Steps/Minute Value for Moderate Intensity Physical Activity in Adolescent Females
Deirdre M. Harrington, Kieran P. Dowd, Catrine Tudor-Locke, and Alan E. Donnelly
The number of steps/minute (i.e., cadence) that equates to moderate intensity in adolescents is not known. To that end, 31 adolescent females walked on a treadmill at 5 different speeds while wearing an ActivPAL accelerometer and oxygen uptake was recorded by indirect calorimetry. The relationship between metabolic equivalents (METs) and cadence was explored using 3 different analytical approaches. Cadence was a significant predictor of METs (r=.70; p<.001). Moderate intensity (3 METs) corresponded to 94 or 114 steps/minute based on the mixed model and ROC analysis, respectively. These two values, and a practical value of 100 steps/minute, were cross-validated on an independent sample of 33 adolescent females during over-ground walking at 3 speeds. The sensitivity and specificity of each value correctly identifying 3 METs were 98.5% and 87.2% for 94 steps/minute, 72.9% and 98.8 for 114 steps/minute and 96.5% and 95.7% for 100 steps/minute. Compromising on a single cadence of 100 steps/minute would be a practical value that approximates moderate intensity in adolescent females and can be used for physical activity interpretation and promotion.
Medial Unloader Braces and Lateral Heel Wedges Do not Alter Gait Biomechanics in Healthy Young Adults
Jonathan S. Goodwin, Robert A. Creighton, Brian G. Pietrosimone, Jeffery T. Spang, and J. Troy Blackburn
Context: Orthotic devices such as medial unloader knee braces and lateral heel wedges may limit cartilage loading following trauma or surgical repair. However, little is known regarding their effects on gait biomechanics in young, healthy individuals who are at risk of cartilage injury during physical activity due to greater athletic exposure compared with older adults. Objective: Determine the effect of medial unloader braces and lateral heel wedges on lower-extremity kinematics and kinetics in healthy, young adults. Design: Cross-sectional crossover design. Setting: Laboratory setting. Patients: Healthy, young adults who were recreationally active (30 min/d for 3 d/wk) between 18 and 35 years of age, who were free from orthopedic injury for at least 6 months, and with no history of lower-extremity orthopedic surgery. Interventions: All subjects completed normal over ground walking with a medial unloader brace at 2 different tension settings and a lateral heel wedge for a total of 4 separate walking conditions. Main Outcome Measures: Frontal plane knee angle at heel strike, peak varus angle, peak internal knee valgus moment, and frontal plane angular impulse were compared across conditions. Results: The medial unloader brace at 50% (−2.04° [3.53°]) and 100% (−1.80° [3.63°]) maximum load placed the knee in a significantly more valgus orientation at heel strike compared with the lateral heel wedge condition (−0.05° [2.85°]). However, this difference has minimal clinical relevance. Neither of the orthotic devices altered knee kinematics or kinetics relative to the control condition. Conclusions: Although effective in older adults and individuals with varus knee alignment, medial unloader braces and lateral heel wedges do not influence gait biomechanics in young, healthy individuals.
Ankle Bracing Alters Coordination and Coordination Variability in Individuals With and Without Chronic Ankle Instability
Adam E. Jagodinsky, Christopher Wilburn, Nick Moore, John W. Fox, and Wendi H. Weimar
Context: Ankle bracing is an effective form of injury prophylaxis implemented for individuals with and without chronic ankle instability, yet mechanisms surrounding bracing efficacy remain in question. Ankle bracing has been shown to invoke biomechanical and neuromotor alterations that could influence lower-extremity coordination strategies during locomotion and contribute to bracing efficacy. Objective: The purpose of this study was to investigate the effects of ankle bracing on lower-extremity coordination and coordination dynamics during walking in healthy individuals, ankle sprain copers, and individuals with chronic ankle instability. Design: Mixed factorial design. Setting: Laboratory setting. Participants: Forty-eight recreationally active individuals (16 per group) participated in this cross-sectional study. Intervention: Participants completed 15 trials of over ground walking with and without an ankle brace. Main Outcome Measures: Coordination and coordination variability of the foot–shank, shank–thigh, and foot–thigh were assessed during stance and swing phases of the gait cycle through analysis of segment relative phase and relative phase deviation, respectively. Results: Bracing elicited more synchronous, or locked, motion of the sagittal plane foot–shank coupling throughout swing phase and early stance phase, and more asynchronous motion of remaining foot–shank and foot–thigh couplings during early swing phase. Bracing also diminished coordination variability of foot–shank, foot–thigh, and shank–thigh couplings during swing phase of the gait cycle, indicating greater pattern stability. No group differences were observed. Conclusions: Greater stability of lower-extremity coordination patterns as well as spatiotemporal locking of the foot–shank coupling during terminal swing may work to guard against malalignment at foot contact and contribute to the efficacy of ankle bracing. Ankle bracing may also act antagonistically to interventions fostering functional variability.
Jill Pawlowski, E. Andrew Pitchford, Daniel W. Tindall, and Seo Hee Lee
Edited by ZáNean McClain
controlled assistance group, utilizing a robotic system, a load assisted swing was applied to both legs starting from the toe-off to mid-swing phase of gait. The treadmill speed and the resistance/assistance load were gradually increased during 6 weeks of treadmill training in both groups. Over ground
Weighted Vest Loads Do Not Elicit Changes in Spatial-Temporal Gait Parameters in Children and Adolescents With Autism
Alyssa N. Olivas, Emily A. Chavez, and Jeffrey D. Eggleston
sensory integration . J Autism Dev Disord . 2016 ; 46 ( 3 ): 853 – 861 . doi:10.1007/s10803-015-2621-4 10.1007/s10803-015-2621-4 13. Eggleston JD , Harry JR , Hickman RA , Dufek JS . Analysis of gait symmetry during over-ground walking in children with autism spectrum disorder . Gait
Trunk Postural Control Strategies Among Persons With Lower-Limb Amputation While Walking and Performing a Concurrent Task
Courtney M. Butowicz, Julian C. Acasio, and Brad D. Hendershot
. 17 Trunk local stability increases during treadmill versus over ground walking 17 ; however, the extent to which changes in visual and proprioceptive information influence local stability during treadmill walking is unknown and should be considered. Finally, different prioritization strategies may
Accelerometer Calibration: The Importance of Considering Functionality
Scott J. Strath, Taylor W. Rowley, Chi C. Cho, Allison Hyngstrom, Ann M. Swartz, Kevin G. Keenan, Julian Martinez, and John W. Staudenmayer
, Sandroff et al. ( 2014 ) categorized a sample of 54 individuals with MS into those with a mild, moderate, or severe diagnosis using a neurological exam and Expanded Disability Status Scale. In this study, the sample performed different over-ground walking speeds, and the results revealed decreases in
Dominant vs. Non-Dominant Wrist Placement of Activity Monitors: Impact on Steps per Day
Susan Park, Lindsay P. Toth, Paul R. Hibbing, Cary M. Springer, Andrew S. Kaplan, Mckenzie D. Feyerabend, Scott E. Crouter, and David R. Bassett
higher step counts. Previous studies ( Chen et al., 2016 ; Chow et al., 2017 ; Modave et al., 2017 ) focused on treadmill and over-ground walking and running, and found similar step counts between dominant and non-dominant wrists. While one study examined the differences between wrists during