Excessive pronation, because of its coupling with tibial internal rotation (TIR), has been implicated as a risk factor in the development of anterior knee pain (AKP). Traditionally, this coupling has been expressed as a ratio between the eversion range of motion and the TIR range of motion (Ev/TIR) that occurs during stance. Currently, this technique has not been used to evaluate specific injuries or the effects of sex. In addition, Ev/TIR is incapable of detecting coupling changes that occur throughout stance. Therefore, the purpose of this study was to compare the coupling between eversion and TIR in runners with (n = 19) and without AKP (n = 17) and across sex using the Ev/TIR ratio, and more continuously using vector coding. When using vector coding, significant coupling differences were noted in runners with AKP (34% to 38% stance), with runners with AKP showing relatively more TIR than eversion. Similarly significant differences were noted across sex (14%–25% and 36%–47% stance), with males transitioning from a loading to propulsive coordination pattern using a proximal to distal strategy, and female runners using a distal to proximal strategy. These differences were only detected when evaluating this coupling relationship using a continuous technique such as vector coding.
Pedro Rodrigues, Ryan Chang, Trampas TenBroek, Richard van Emmerik and Joseph Hamill
Jaclyn B. Caccese and Thomas W. Kaminski
The Balance Error Scoring System (BESS) is the current standard for assessing postural stability in concussed athletes on the sideline. However, research has questioned the objectivity and validity of the BESS, suggesting that while certain subcategories of the BESS have sufficient reliability to be used in evaluation of postural stability, the total score is not reliable, demonstrating limited interrater and intrarater reliability. Recently, a computerized BESS test was developed to automate scoring.
To compare computerderived BESS scores with those taken from 3 trained human scorers.
Interrater reliability study.
Athletic training room.
NCAA Division I student athletes (53 male, 58 female; 19 ± 2 y, 168 ± 41 cm, 69 ± 4 kg).
Subjects were asked to perform the BESS while standing on the Tekscan (Boston, MA) MobileMat® BESS. The MobileMat BESS software displayed an error score at the end of each trial. Simultaneously, errors were recorded by 3 separate examiners. Errors were counted using the standard BESS scoring criteria.
Main Outcome Measures:
The number of BESS errors was computed for the 6 stances from the software and each of the 3 human scorers. Interclass correlation coefficients (ICCs) were used to compare errors for each stance scored by the MobileMat BESS software with each of 3 raters individually. The ICC values were converted to Fisher Z scores, averaged, and converted back into ICC values.
The double-leg, single-leg, and tandem-firm stances resulted in good agreement with human scorers (ICC = .999, .731, and .648). All foam stances resulted in fair agreement.
Our results suggest that the MobileMat BESS is suitable for identifying BESS errors involving each of the 6 stances of the BESS protocol. Because the MobileMat BESS scores consistently and reliably, this system can be used with confidence by clinicians as an effective alternative to scoring the BESS.
Saunders N. Whittlesey and Joseph Hamill
An alternative to the Iterative Newton-Euler or linked segment model was developed to compute lower extremity joint moments using the mechanics of the double pendulum. The double pendulum model equations were applied to both the swing and stance phases of locomotion. Both the Iterative Newton-Euler and double pendulum models computed virtually identical joint moment data over the entire stride cycle. The double pendulum equations, however, also included terms for other mechanical factors acting on limb segments, namely hip acceleration and segment angular velocities and accelerations Thus, the exact manners in which the lower extremity segments interacted with each other could be quantified throughout the gait cycle. The linear acceleration of the hip and the angular acceleration of the thigh played comparable roles to muscular actions during both swing and stance.
M. Monda, A. Goldberg, P. Smitham, M. Thornton and I. McCarthy
To study mobility in older populations it can be advantageous to use portable gait analysis systems, such as inertial measurement units (IMUs), which can be used in the community. To define a normal range, 136 active subjects were recruited with an age range of 18 to 97. Four IMUs were attached to the subjects, one on each thigh and shank. Subjects were asked to walk 10 m at their own self-selected speed. The ranges of motion of thigh, shank, and knee in both swing and stance phase were calculated, in addition to stride duration. Thigh, shank, and knee range of movement in swing and stance were significantly different only in the > 80 age group. Regressions of angle against age showed a cubic relationship. Stride duration showed a weak linear relationship with age, increasing by approximately 0.1% per year.
Shane R. Wurdeman, Jessie M. Huisinga, Mary Filipi and Nicholas Stergiou
Patients with multiple sclerosis (MS) have less-coordinated movements of the center of mass resulting in greater mechanical work. The purpose of this study was to quantify the work performed on the body’s center of mass by patients with MS. It was hypothesized that patients with MS would perform greater negative work during initial double support and less positive work in terminal double support. Results revealed that patients with MS perform less negative work in single support and early terminal double support and less positive work in the terminal double support period. However, summed over the entire stance phase, patients with MS and healthy controls performed similar amounts of positive and negative work on the body’s center of mass. The altered work throughout different periods in the stance phase may be indicative of a failure to capitalize on passive elastic energy mechanisms and increased reliance upon more active work generation to sustain gait.
Jay Hertel, Craig R. Denegar, W.E. Buckley, Neil A. Sharkey and Wayne L. Stokes
To identify changes in sagittal- and frontal-plane center of pressure (COP) excursion length and velocity during single-leg stance under 6 orthotic conditions.
1 × 6 repeated-measures.
University biomechanics laboratory.
Fifteen healthy young adults without excessive forefoot, arch, or rear-foot malalignments.
Selected variables of COP length and velocity were calculated in both the frontal and sagittal planes during three 5-second trials of quiet unilateral stance.
Postural control was assessed under 6 conditions: shoe only and 5 orthotics.
The medially posted orthotic caused the least frontal COP length and velocity, and the Cramer Sprained Ankle Orthotic® caused the greatest frontal-plane sway. No significant differences were found between the different orthotic conditions in sagittal-plane measures.
Differently posted rear-foot orthotics had various effects on frontal-plane postural control in healthy participants. Further research is needed on pathological populations.
Nicolas Vuillerme, Ludovic Marin and Bettina Debû
This study evaluated stance control in 24 teenagers with and without Down syndrome (DS) by (a) assessing center of foot pressure variables under different conditions of availability of visual and somatosensory inputs and (b) analyzing postural perturbation and adaptation following abrupt changes in visual information. Results showed no gender-related differences in either group. Group comparison revealed similar strategies in adolescents with and without DS, although quantitative differences may exist in the ability to integrate sensory inputs to control stance. Adaptation to changing environmental conditions varied greatly from one individual to another in the two groups. Finally, comparison of the two experiments suggests that the increased postural oscillations reported for the sample with DS on long lasting recordings could be related to insufficient allocation of cognitive resources in stable environments.
Kristen K. Maughan, Kristin A. Lowry, Warren D. Franke and Ann L. Smiley-Oyen
A 6-wk group balance-training program was conducted with physically active older adults (based on American College of Sports Medicine requirements) to investigate the effect of dose-related static and dynamic balance-specific training. All participants, age 60–87 yr, continued their regular exercise program while adding balance training in 1 of 3 doses: three 20-min sessions/wk (n = 20), one 20-min session/wk (n = 21), or no balance training (n = 19). Static balance (single-leg-stance, tandem), dynamic balance (alternate stepping, limits of stability), and balance confidence (ABC) were assessed pre- and posttraining. Significant interactions were observed for time in single-leg stance, excursion in limits of stability, and balance confidence, with the greatest increase observed in the group that completed 3 training sessions/wk. The results demonstrate a dose-response relationship indicating that those who are already physically active can improve balance performance with the addition of balance-specific training.
Daniel S. Rooks, Bernard J. Ransil and Wilson C. Hayes
The aim of this study was to determine the efficacy and safety of 16 weeks of self-paced resistance training or walking protocols on neuromotor and functional parameters in active, community-dwelling older adults. Twenty-two sequentially recruited older adults were randomly assigned to one of two exercise groups: self-paced resistance training and self-paced walking. Static and dynamic balance, upper and lower extremity reaction times, muscle strength, and stairclimbing speed were measured before and immediately after 16 weeks of exercise. Preliminary data showed that 16 weeks of self-paced. progressive, lower body resistance training improved balance (one-legged stance with eyes open, 68%). reaction time (10%), muscle strength (160%), and stair climbing speed (28%), while a self-paced walking program improved balance (one-legged stance with eyes open, 51%), stair climbing speed (16%), and in certain circumstances muscle strength (25%), in active, community-dwelling older adults.
Monika Thomas and Michael Kalicinski
The present study investigated whether slackline training enhances postural control in older adults. Twenty-four participants were randomized into an intervention and a control group. The intervention group received 6 weeks of slackline training, two times per week. Pre–post measurement included the time of different standing positions on a balance platform with and without an external disturbance and the acceleration of the balance platform. Results showed significantly improved standing times during one-leg stance without external disturbance and a significantly reduced acceleration of the balance platform for the intervention group after the training period during tandem stance with and without an external disturbance. We conclude that slackline training in older adults has a positive impact on postural control and thus on the reduction of fall risk.