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Cug M.,Middle East Technical University | Ak E.,Middle East Technical University | Ozdemir R.A.,Center for Neuromotor and Biomechanics Research | Korkusuz F.,Middle East Technical University | Behm D.G.,Memorial University of Newfoundland
Journal of Sports Science and Medicine | Year: 2012

Although there are many studies demonstrating increased trunk activation under unstable conditions, it is not known whether this increased activation would translate into meaningful trunk strength with a prolonged training program. Additionally, while balance-training programs have been shown to improve stability, their effect on specific joint proprioception is not clear. Thus the objective of this study was to examine training adaptations associated with a 10-week instability-training program. Participants were tested pre-and post-training for trunk extension and flexion strength and knee proprioception. Forty-three participants participated in either a 10-week (3 days per week) instability- training program using Swiss balls and body weight as resistance or a control group (n = 17). The trained group increased (p < 0.05) trunk extension peak torque/body weight (23.6%) and total work output (20.1%) from pre- to post-training while the control group decreased by 6.8% and 6.7% respectively. The exercise group increased their trunk flexion peak torque/body weight ratios by 18.1% while the control group decreased by 0.4%. Knee proprioception (combined right and left joint repositioning) improved 44.7% from pre- to post-training (p = 0.0006) and persisted (21.5%) for 9 months post-training. In addition there was a side interaction with the position sense of the right knee at 9 months showing 32.1% (p = 0.03) less deviation from the reference angle than the right knee during pre-testing. An instability-training program using Swiss balls with body weight as resistance can provide prolonged improvements in joint proprioception and core strength in previously untrained individuals performing this novel training stress which would contribute to general health. © Journal of Sports Science and Medicine (2012). Source


Layne C.S.,University of Houston | Layne C.S.,Center for Neuromotor and Biomechanics Research | Layne C.S.,National Center for Human Performance | Chelette A.M.,University of Houston | And 5 more authors.
Somatosensory and Motor Research | Year: 2015

It has been proposed that proprioceptive input is essential to the development of a locomotor body schema that is used to guide the assembly of successful walking. Proprioceptive information is used to signal the need for, and promotion of, locomotor adaptation in response to environmental or internal modifications. The purpose of this investigation was to determine if tendon vibration applied to either the hamstrings or quadriceps of participants experiencing split-belt treadmill walking modified lower limb kinematics during the early adaptation period. Modifications in the adaptive process in response to vibration would suggest that the sensory-motor system had been unsuccessful in down weighting the disruptive proprioceptive input resulting from vibration. Ten participants experienced split-belt walking, with and without vibration, while gait kinematics were obtained with a 12-camera collection system. Bilateral hip, knee, and ankle joint angles were calculated and the first five strides after the split were averaged for each subject to create joint angle waveforms for each of the assessed joints, for each experimental condition. The intralimb variables of stride length, percent stance time, and relative timing between various combinations of peak joint angles were assessed using repeated measures MANOVA. Results indicate that vibration had very little impact on the split-belt walking adaptive process, although quadriceps vibration did significantly reduce percent stance time by 1.78% relative to the no vibration condition. The data suggest that the perceptual-motor system was able to down weight the disrupted proprioceptive input such that the locomotor body schema was able to effectively manage the lower limb patterns of motion necessary to adapt to the changing belt speed. Complementary explanations for the current findings are also discussed. © 2015 Informa UK Ltd. All rights reserved. Source


Dettmer M.,Memorial Bone and Joint Research Foundation | Dettmer M.,Center for Neuromotor and Biomechanics Research | Pourmoghaddam A.,Memorial Bone and Joint Research Foundation | Pourmoghaddam A.,Center for Neuromotor and Biomechanics Research | And 2 more authors.
Current Gerontology and Geriatrics Research | Year: 2016

Specific activities that require concurrent processing of postural and cognitive tasks may increase the risk for falls in older adults. We investigated whether peripheral receptor sensitivity was associated with postural performance in a dual-task and whether an intervention in form of subthreshold vibration could affect performance. Ten younger (age: 20-35 years) and ten older adults (70-85 years) performed repeated auditory-verbal 1-back tasks while standing quietly on a force platform. Foot sole vibration was randomly added during several trials. Several postural control and performance measures were assessed and statistically analyzed (significance set to α -levels of.05). There were moderate correlations between peripheral sensitivity and several postural performance and control measures (r =. 45 to.59). Several postural performance measures differed significantly between older and younger adults (p < 0.05); addition of vibration did not affect outcome measures. Aging affects healthy older adults' performance in dual-tasks, and peripheral sensitivity may be a contributor to the observed differences. A vibration intervention may only be useful when there are more severe impairments of the sensorimotor system. Hence, future research regarding the efficacy of sensorimotor interventions in the form of vibrotactile stimulation should focus on older adults whose balance is significantly affected. © 2016 Marius Dettmer et al. Source


Dettmer M.,University of Houston | Dettmer M.,Center for Neuromotor and Biomechanics Research | Pourmoghaddam A.,University of Houston | Pourmoghaddam A.,Center for Neuromotor and Biomechanics Research | And 4 more authors.
Human Movement Science | Year: 2013

Orchestration of sensory-motor information and adaptation to internal or external, acute or chronic changes is one of the fundamental features of human postural control. The postural control system is challenged on a daily basis, and displays a remarkable ability to adapt to both long and short term challenges. To explore the interaction between support surface stability and Achilles tendon vibration during a period of adaptation we used both a linear measure and a non-linear measure derived from center-of-pressure (COP) data. An equilibrium score (ES), based upon peak amplitude of anterior-posterior sway towards theoretical limits of stability was the linear measure used to assess postural performance. We observed early effects of vibration on postural stability, depending on support characteristics. Participants were able to decrease sway with extended practice over days, independent of support surface stability. Approximate entropy analysis of COP data provided additional information about control adaptation processes. © 2013 Elsevier B.V. Source

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