Age-Related Reduction of Foot Intrinsic Muscle Function and the Relationship with Postural Stability in Old Adults.

Introduction: The risk of falls among the elderly significantly increases, which has become a serious public health concern. Falls can not only lead to serious complications such as fractures and brain injuries but also limit their mobility function, reducing quality of life. Foot intrinsic muscles (FIMs) are an essential part of foot core stability even overall postural stability. This study aimed to investigate the effects of aging on the function of FIMs and to explore the influence of FIMs on postural control in the elderly. Materials and Methods: 56 healthy old participants (60-75 years) and 57 healthy young participants (18-29 years) joined this study. An ergoFet dynamometer was used to determine foot muscle strength (Doming, T1, T23 and T2345), and ankle muscle strength (plantarflexion and dorsiflexion). The morphology of FIMs and extrinsic foot muscle was determined using a Doppler ultrasound system, whereas the postural stability was assessed through Limits of Stability test. Independent samples t-test was used to determine the differences in strength and morphological parameters and Spearman correlation analysis was used to determine whether an association existed between muscle strength and postural stability parameters in the elderly. Results: Compared with young adults, foot muscle strength and ankle muscle strength (Doming, T1, T23, T2345, dorsiflexion, and plantarflexion, all p <0.05) and the morphology of foot muscles (all p <0.05) were significantly reduced in the elderly. The strength of FIMs and the limit of stability (r = 0.302-0.424, all p <0.05) were significantly correlated in the elderly. Conclusion: Compared with young adults, the weakness of strength as well as the morphological decline of the intrinsic and extrinsic foot muscles were found in the elderly. In addition, a correlation was observed between FIM's strength and postural stability in the elderly, suggesting their potential role in posture stability.

Difference in the recruitment of intrinsic foot muscles in the elderly under static and dynamic postural conditions.

Background: The effect of foot, especially intrinsic muscles, on postural control and its related mechanisms remain unclear due to the complex structure. Therefore, this study aims to investigate the activation of intrinsic foot muscles in the elderly under static and dynamic postural tasks. Methods: Twenty-one elderly participants were included to perform different postural tests (sensory organization test (SOT), motor control test (MCT), limit of stability test (LOS), and unilateral stance test) by a NeuroCom Balance Manager System. The participants were instructed to maintain postural stability under conditions with combined different sensory inputs (vision, vestibular, and proprioception) in SOT as well as conditions with translation disturbance in MCT, and to perform an active weight-shifting tasks in LOS. During these tasks, muscle activation were simultaneously acquired from intrinsic foot muscles (abductor halluces (AbH) and flexor digitorum brevis (FDB)) and ankle muscles (anterior tibialis, medial head of gastrocnemius, lateral head of gastrocnemius, and peroneus longus). The root-mean-square amplitude of these muscles in postural tasks was calculated and normalized with the EMG activity in unilateral stance task. Results: The activation of intrinsic foot muscles significantly differed among different SOT tasks (p < 0.001). Post-hoc tests showed that compared with that under normal condition 1 without sensory interference, EMGs increased significantly under sensory disturbance (conditions 2-6). By contrast, compared with that under the single-sensory disturbed conditions (conditions 2-4; 2 for disturbed vision, 3 for disturbed vestibular sensation, 4 for disturbed proprioception), activation was significantly greater under the dual-sensory disturbed postural tasks (conditions 5 and 6; 5 for disturbed vision and proprioception, 6 for disturbed vestibular sensation and proprioception). In MCT, EMGs of foot muscles increased significantly under different translation speeds (p < 0.001). In LOS, moderate and significant correlations were found between muscle activations and postural stability parameters (AbH, r = 0. 355-0.636, p < 0.05; FDB, r = 0.336-0.622, p < 0.05). Conclusion: Intrinsic foot muscles play a complementary role to regulate postural stability when disturbances occur. In addition, the recruitment magnitude of intrinsic foot muscles is positively correlated with the limit of stability, indicating their contribution to increasing the limits of stability in the elderly.

Effect of whole-body vibration on neuromuscular activation and explosive power of lower limb: A systematic review and meta-analysis.

OBJECTIVE: The review aimed to investigate the effects of whole-body vibration (WBV) on neuromuscular activation and explosive power. METHODS: Keywords related to whole-body vibration, neuromuscular activation and explosive power were used to search four databases (PubMed, Web of Science, Google Scholar and EBSCO-MEDLINE) for relevant studies published between January 2000 and August 2021. The methodology of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used. The eligibility criteria for the meta-analysis were based on PICOST principles. Methodological assessment used the Cochrane scale. Heterogeneity and publication bias were assessed by I2 index and funnel plots, respectively. The WBV training cycle is a random effect model. Publication bias was also assessed based on funnel plots. This study was registered in PROSPERO (CRD42021279439). RESULTS: A total of 156 participants data in 18 studies met the criteria and were included in the meta-analysis for quantitative synthesis. Results of the meta-analysis showed significant improvements in lower limb neuromuscular activation immediately after WBV compared with the baseline (SMD = 0.51; 95% CI: 0.26, 0.76; p<0.001), and no significant heterogeneity was observed (I2 = 38%, p = 0.07). In addition, the highest increase in lower limb explosive power was observed (SMD = 0.32; 95% CI: 0.11, 0.52; p = 0.002), and no significant heterogeneity (I2 = 0%, p = 0.80) was noted. CONCLUSIONS: WBV training could improve neuromuscular activation and explosive power of the lower limb. However, due to different vibration conditions, further research should be conducted to determine standardized protocols targeting performance improvement in athletes and healthy personnel experienced in training.

Electroencephalographic Measurement on Post-stroke Sensory Deficiency in Response to Non-painful Cold Stimulation.

Background: Reduced elementary somatosensation is common after stroke. However, the measurement of elementary sensation is frequently overlooked in traditional clinical assessments, and has not been evaluated objectively at the cortical level. This study designed a new configuration for the measurement of post-stroke elementary thermal sensation by non-painful cold stimulation (NPCS). The post-stroke cortical responses were then investigated during elementary NPCS on sensory deficiency via electroencephalography (EEG) when compared with unimpaired persons. Method: Twelve individuals with chronic stroke and fifteen unimpaired controls were recruited. A 64-channel EEG system was used to investigate the post-stroke cortical responses objectively during the NPCS. A subjective questionnaire of cold sensory intensity was also administered via a numeric visual analog scale (VAS). Three water samples with different temperatures (i.e., 25, 10, and 0°C) were applied to the skin surface of the ventral forearm for 3 s via glass beaker, with a randomized sequence on either the left or right forearm of a participant. EEG relative spectral power (RSP) and topography were used to evaluate the neural responses toward NPCS with respect to the independent factors of stimulation side and temperature. Results: For unimpaired controls, NPCS initiated significant RSP variations, mainly located in the theta band with the highest discriminative resolution on the different temperatures (P < 0.001). For stroke participants, the distribution of significant RSP spread across all EEG frequency bands and the temperature discrimination was lower than that observed in unimpaired participants (P < 0.05). EEG topography showed that the NPCS could activate extensive and bilateral sensory cortical areas after stroke. Significant group differences on RSP intensities were obtained in each EEG band (P < 0.05). Meanwhile, significant asymmetry cortical responses in RSP toward different upper limbs were observed during the NPCS in both unimpaired controls and participants with stroke (P < 0.05). No difference was found between the groups in the VAS ratings of the different temperatures (P > 0.05). Conclusion: The post-stroke cortical responses during NPCS on sensory deficiency were characterized by the wide distribution of representative RSP bands, lowered resolution toward different temperatures, and extensive activated sensory cortical areas.

Evaluating the Function of the Foot Core System in the Elderly.

As a complex structure to link the body and the ground, the foot contributes to postural control in human static and dynamic activities. The foot core is rooted in the functional interdependence of the passive, active, and neural subsystems, which combine into the foot core system controlling foot motion and stability. The foot arch (passive subsystem), responsible for load, is considered the functional core of the foot, and its stability is necessary for normal foot functions. The functional abnormalities of the foot have been widely reported in the elderly, such as weakness of toe flexor muscles, abnormal foot postures, and decreased plantar sensory sensitivity. In this paper, a comprehensive approach is introduced for evaluating the foot function based on foot core subsystems. The strength and morphology of the foot intrinsic and extrinsic muscles were used to evaluate the foot muscle (active subsystem) function. The doming strength test was applied to determine the function of foot intrinsic muscles, while the toe flexion strength test focused more on the function of extrinsic muscles. The navicular drop test and foot posture index were applied to evaluate foot arch (passive subsystem) function. For the neural subsystem, the plantar light touch threshold test and two-point discrimination test were used to assess plantar tactile sensitivity at nine regions of the foot. This study provides new insights into the foot core function in the elderly and other populations.

Effects of intrinsic-foot-muscle exercise combined with the lower extremity resistance training on postural stability in older adults with fall risk: study protocol for a randomised controlled trial.

BACKGROUND: Falls are one of the most common accidents in older adults, often leading to injury, disability and quality-of-life declines. Foot core function contributes to postural stability in most static postures and dynamic activities. As efficient foot core training, the intrinsic-foot-muscle exercise has been proposed to improve postural control. However, the effects of the exercise on postural stability in the elderly remain unclear. Therefore, this study attempts to investigate the effect of 12-week intrinsic-foot-muscle exercise on postural stability in older adults with fall risk. METHODS: We will conduct a prospective, single-blind randomised controlled trail on 120 older adults with fall risk. Participants will be randomly assigned to an intrinsic-foot-muscle exercise combining the lower extremity resistance training group (IFM group), an extrinsic-foot-muscle exercise combining the lower extremity resistance training group (EFM group) and a control group. The control group will perform lower extremity resistance training. The IFM and EFM groups will be given additional short-foot exercise or towel-curl exercise training, respectively. After the intervention, participants will be followed up for another 12 weeks with no active intervention. The outcome measures will include the postural stability measurements, self-reported postural stability, number of falls, intrinsic-foot-muscle strength and foot arch function. Furthermore, adverse events will be recorded and analysed. If any participant withdraws from the trial, an intention-to-treat analysis will be performed. DISCUSSION: The trial is designed to investigate the efficacy of a 12-week intrinsic foot muscle training combined with the lower extremity resistance training on postural stability outcomes in elderly people with fall risk. The trial will also examine the comprehensive outcomes of postural stability during static standing and dynamic movements. The function of intrinsic foot muscle to support the arch will also be evaluated. Important features of this trial mainly include intervention setting, outcome measure selection and study duration. The results of this study will determine the effectiveness and provide scientific evidence to establish comprehensive fall prevention intervention. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2000033623. Registered on 7 June 2020. http://www.chictr.org.cn/showproj.aspx?proj=54741.

Effects of overground surfaces on running kinematics and kinetics in habitual non-rearfoot strikers.

This study aimed to investigate the effects of different overground surfaces on running biomechanics of non-rearfoot strikers. Thirty-one male habitual non-rearfoot strikers were required to run at 3.3 ± 0.2 m/s on a customized runway with artificial grass, concrete, or synthetic rubber surfaces in a random order. Vertical loading rates, three-dimensional ground reaction forces (GRFs), and lower-limb joint angles and moments were compared among surfaces. Regarding kinematics, significances were only detected in maximum knee flexion angle, with greater values when running on artificial grass compared to synthetic rubber or concrete. Regarding kinetics, changes were demonstrated in GRF peaks and lower-limb joint moments. GRF peaks were significantly greater when running on synthetic rubber or artificial grass compared to concrete; lower-limb joint moments were significantly lower when running on synthetic rubber compared to concrete; these changes were inconsistent when running on artificial grass compared to concrete. Significant differences were demonstrated in running kinetics when habitual non-rearfoot strikers ran on different overground surfaces. Running on artificial grass or synthetic rubber caused greater GRFs than running on concrete. However, only synthetic rubber could reduce joint loads.

Comparison of whole-body vibration training and quadriceps strength training on physical function and neuromuscular function of individuals with knee osteoarthritis: A randomised clinical trial.

BACKGROUND: Knee osteoarthritis (KOA) is one of the leading causes of global disability, which causes knee pain, stiffness and swelling. Impaired neuromuscular function may cause joint instability, alignment changes and knee stress, which leads to the progression of KOA. Whole-body vibration (WBV) training is considered to improve pain and functional mobility effectively. However, few studies have investigated the therapeutic effect of WBV on neuromuscular function in KOA. MATERIAL AND METHODS: A single-blinded, randomised, controlled trial was performed on 81 participants diagnosed with KOA. The participants were randomised into three groups: (1) WBV group, in which participants performed strength training (ST) with vibration exposure for 8 weeks; (2) ST group, in which participants performed ST without vibration for 8 weeks; and (3) health education (HE) group, in which participants received a HE for 8 weeks. The visual analogue scale for knee pain, isokinetic muscle strength test, proprioception test, Timed Up and Go test (TUG) and 6-min Walk Distance test (6MWD) were performed before and after the interventions. RESULTS: No significant difference was found on pain, proprioception, TUG and 6MWD. A significant interaction effect was found in isokinetic muscle strength between groups. Further analysis showed that compared with the HE group, the WBV group exhibited significantly greater improvement in isokinetic muscle strength (peak torque [PT] of extensors, p < 0.01, 95% CI = 0.11-0.33 Nm/kg; PT of flexors, p = 0.01, 95% CI = 0.02-0.19 Nm/kg; peak work [PW] of extensors, p < 0.01, 95% CI = 0.12-0.75 W/kg). In addition, compared with the ST group, the muscle strength of the WBV group (PT of extensors, p < 0.01, 95% CI = 0.10-0.32 Nm/kg; PW of extensors, p < 0.01, 95% CI = 0.09-0.71 W/kg) improved significantly. CONCLUSION: Our findings suggested that adding WBV training to ST might benefit muscle strength around the knee joint in patients with KOA.

Impairments of cortico-cortical connectivity in fine tactile sensation after stroke.

BACKGROUND: Fine tactile sensation plays an important role in motor relearning after stroke. However, little is known about its dynamics in post-stroke recovery, principally due to a lack of effective evaluation on neural responses to fine tactile stimulation. This study investigated the post-stroke alteration of cortical connectivity and its functional structure in response to fine tactile stimulation via textile fabrics by electroencephalogram (EEG)-derived functional connectivity and graph theory analyses. METHOD: Whole brain EEG was recorded from 64 scalp channels in 8 participants with chronic stroke and 8 unimpaired controls before and during the skin of the unilateral forearm contacted with a piece of cotton fabric. Functional connectivity (FC) was then estimated using EEG coherence. The fabric stimulation induced FC (SFC) was analyzed by a cluster-based permutation test for the FC in baseline and fabric stimulation. The functional structure of connectivity alteration in the brain was also investigated by assessing the multiscale topological properties of functional brain networks according to the graph theory. RESULTS: In the SFC distribution, an altered hemispheric lateralization (HL) (HL degree, 14%) was observed when stimulating the affected forearm in the stroke group, compared to stimulation of the unaffected forearm of the stroke group (HL degree, 53%) and those of the control group (HL degrees, 92% for the left and 69% for the dominant right limb). The involvement of additional brain regions, i.e., the distributed attention networks, was also observed when stimulating either limb of the stroke group compared with those of the control. Significantly increased (P < 0.05) global and local efficiencies were found when stimulating the affected forearm compared to the unaffected forearm. A significantly increased (P < 0.05) degree of inter-hemisphere FC (interdegree) mainly within ipsilesional somatosensory region and a significantly diminished degree of intra-hemisphere FC (intradegree) (P < 0.05) in ipsilesional primary somatosensory region were observed when stimulating the affected forearm, compared with the unaffected forearm. CONCLUSIONS: The alteration of cortical connectivity in fine tactile sensation post-stroke was characterized by the compensation from the contralesional hemisphere and distributed attention networks related to involuntary attention. The interhemispheric connectivity could implement the compensation from the contralateral hemisphere to the ipsilesional somatosensory region. Stroke participants also exerted increased cortical activities in fine tactile sensation.

Leg Stiffness and Vertical Stiffness of Habitual Forefoot and Rearfoot Strikers during Running.

Foot strike patterns influence the running efficiency and may be an injury risk. However, differences in the leg stiffness between runners with habitual forefoot (hFFS) and habitual rearfoot (hRFS) strike patterns remain unclear. This study aimed at determining the differences in the stiffness, associated loading rate, and kinematic performance between runners with hFFS and hRFS during running. Kinematic and kinetic data were collected amongst 39 runners with hFFS and 39 runners with hRFS running at speed of 3.3 m/s, leg stiffness (Kleg), and vertical stiffness (Kvert), and impact loads were calculated. Results found that runners with hFFS had greater Kleg (P = 0.010, Cohen's d = 0.60), greater peak vertical ground reaction force (vGRF) (P = 0.040, Cohen's d = 0.47), shorter contact time(t c ) (P < 0.001, Cohen's d = 0.85), and smaller maximum leg compression (ΔL ) (P = 0.002, Cohen's d = 0.72) compared with their hRFS counterparts. Runners with hFFS had lower impact peak (IP) (P < 0.001, Cohen's d = 1.65), vertical average loading rate (VALR) (P < 0.001, Cohen's d = 1.20), and vertical instantaneous loading rate (VILR) (P < 0.001, Cohen's d = 1.14) compared with runners with hRFS. Runners with hFFS landed with a plantar flexed ankle, whereas runners with hRFS landed with a dorsiflexed ankle (P < 0.001, Cohen's d = 3.35). Runners with hFFS also exhibited more flexed hip (P = 0.020, Cohen's d = 0.61) and knee (P < 0.001, Cohen's d = 1.15) than runners with hRFS at initial contact. These results might indicate that runners with hFFS were associated with better running economy through the transmission of elastic energy.

Evaluating Postural Control and Lower-extremity Muscle Activation in Individuals with Chronic Ankle Instability.

Computerized dynamic posturography (CDP) is an objective technique for the evaluation of postural stability under static and dynamic conditions and perturbation. CDP is based on the inverted pendulum model that traces the interrelationship between the center of pressure and the center of gravity. CDP can be used to analyze the proportions of vision, proprioception, and vestibular sensation to maintain postural stability. The following characters define chronic ankle instability (CAI): persistent ankle pain, swelling, the feeling of "giving way," and self-reported disability. Postural stability and fibular muscle activation level in individuals with CAI decreased due to lateral ankle ligament complex injuries. Few studies have used CDP to explore the postural stability of individuals with CAI. Studies that investigate postural stability and related muscle activation by using synchronized CDP with surface electromyography are lacking. This CDP protocol includes a sensory organization test (SOT), a motor control test (MCT), and an adaption test (ADT), as well as tests that measure unilateral stance (US) and limit of stability (LOS). The surface electromyography system is synchronized with CDP to collect data on lower limb muscle activation during measurement. This protocol presents a novel approach for evaluating the coordination of the visual, somatosensory, and vestibular systems and related muscle activation to maintain postural stability. Moreover, it provides new insights into the neuromuscular control of individuals with CAI when coping with real complex environments.

Neuro-perceptive discrimination on fabric tactile stimulation by Electroencephalographic (EEG) spectra.

The precise evaluation of sensory perceptions during fabric-skin interactions is still poorly understood in neuroscience. This study aims to investigate the cortical sensory response to fabric stimuli with different textiles by Electroencephalographic (EEG) spectral intensities, and evaluate the relationships between EEG frequency bands, traditional subjective questionnaires, and the materials' physical properties. Twelve healthy adult participants were recruited to test three fabrics with different textile compositions of 1) cotton, 2) nylon, and 3) polyester and wool. The physical properties of the fabrics were quantitatively evaluated by a Fabric Touch Tester (FTT). Subjects were invited to rate the sensory perception of the fabric samples via a subjective questionnaire and objective EEG recording. Significant differences in the EEG relative spectral power of Theta and Gamma bands were acquired in response to the different fabric stimuli (P<0.05). The Theta and Gamma powers demonstrated a significant correlation with the most of the subjective sensations evaluated by questionnaire and the fabrics' physical properties by FTT (P<0.05). The EEG spectral analysis could feasibly be used for the discrimination of fabric stimuli with different textile compositions and further indicates sensory perceptions during fabric stimulation. This finding may provide evidence for further exploratory research of sensory perceptions via EEG spectral analysis, which could be applied to the study of brain generators of skin tactility in future prostheses and the automatic detection of sensory perception in industries.

Measurement of sensory deficiency in fine touch after stroke during textile fabric stimulation by electroencephalography (EEG).

Objective: Sensory deficiency of fine touch limits the restoration of motor functions after stroke, and its evaluation was seldom investigated from a neurological perspective. In this study, we investigated the cortical response measured by electroencephalography (EEG) on the fine touch sensory impairment during textile fabric stimulation after stroke. Approach: Both participants with chronic stroke (n = 12, stroke group) and those unimpaired (n = 15, control group) were recruited. To investigate fine touch during textile fabric stimulations, full brain EEG recordings (64-channel) were used, as well as the touch sensation questionnaires based on the American Association of Textile Chemists and Colorists (AATCC) Evaluation Procedure 5. During the EEG measurement, relative spectral power (RSP) and EEG topography were used to evaluate the neural responses toward the fabric stimuli. In the subjective questionnaire, the fine touch for fabric stimuli was rated and represented by 13 different sensation parameters. The correlation between the fine touch evaluated by the EEG and the questionnaire was also investigated. Main results: The neural responses of individuals with fine touch impairments after stroke were characterized by a shifted power spectrum to a higher frequency band, enlarged sensory cortical areas and higher RSP intensity (P < 0.05). Asymmetric neural responses were obtained when stimulating different upper limbs for both unimpaired participants and stroke participants (P < 0.05). The fine touch sensation of the stroke participants was impaired even in the unaffected limb. However, as a result of different neural processes, the correlation between the EEG and the questionnaire was weak (r < 0.2). Significance: EEG RSP was able to capture the varied cortical responses induced by textile fabric fine touch stimulations related to the fine touch sensory impairment after stroke.

Effects of Taichi exercise on knee and ankle proprioception among individuals with knee osteoarthritis.

The study aimed to investigate the effects of 24 weeks Taichi intervention on knee and ankle proprioception amongst individuals with knee osteoarthritis (KOA). Ninety-two patients with KOA were included in the current study, involving 52 participants in the intervention group and 40 participants in the control group. The intervention group performed Taichi exercise for 24 weeks, the control group accepted the health education lectures. The main outcome of this study was the proprioception of the knee and ankle which was measured by an electric-driven movable frame. Between- and within-group differences were evaluated through the repeated-measurement ANOVA. For the Taichi group, the differences in the changes in ankle proprioception were significant on ankle plantarflexion (p = 0.03), ankle dorsiflexion (p = 0.043), ankle varus (p = 0.019) and knee flexion (p = 0.01) between the baseline and post-test measures. Twenty-four weeks Taichi exercise may improve the ankle and knee proprioception of patients with KOA.

Effect of adding whole-body vibration training to squat training on physical function and muscle strength in individuals with knee osteoarthritis.

OBJECTIVES: This study aims to investigate the effects of adding whole-body vibration (WBV) exercise to squat training (ST) on the physical function and muscle strength of patients with knee osteoarthritis (KOA). METHODS: 41 participants completed the intervention and measurements (ST group; n=21, age=65.00±4.39 years, BMI=23.01±2.95 kg/m2; WBV+ST group; n=20, age=64.10±4.95 years, BMI=24.79±3.12 kg/m2). The supervised eight-week intervention was performed three times per week with the intensity and duration increased gradually. Visual analog scale, Timed Up and Go test (TUG), 6-min Walk Distance test, and isokinetic measurements were performed at baseline and post-intervention. RESULTS: The peak torque (PT) of the extensors at 180°/s increased significantly in the WBV+ST group compared with the ST group (p = 0.046). The peak work of the extensors and the PT of the flexors at 180°/s improved only in the WBV+ST group (p<0.0125). However, no significant changes in these variables were found between groups (p>0.05). CONCLUSIONS: Adding 8 weeks of WBV training to ST can more effectively improve the muscular strength of knee extensors compared with ST in patients with KOA.

Effects of strength exercise on the knee and ankle proprioception of individuals with knee osteoarthritis.

This study aims to investigate the effects of 8-week strength exercise on knee and ankle proprioception of individuals with knee osteoarthritis (KOA). Forty participants were randomly divided into control and strength exercise groups. Strength exercise group underwent squat training of three times a week for 8 weeks, while control group received an education programme. Threshold for detection of passive movement of knee and ankle joint was tested using an electrically driven movable frame. Between- and within-group differences were evaluated through repeated-measurement analysis of variance. After intervention, passive motion sense in knee flexion of participants in strength exercise group significantly improved (p = 0.033, 95% confidence interval of mean difference: 0.019-1.478) with significant difference between groups. No significant differences of passive motion senses were found in knee extension and ankle between strength exercise and control groups. Eight-week squat training significantly improves the motion sense of knee flexion in patients with KOA.

Effects of whole body vibration exercise on neuromuscular function for individuals with knee osteoarthritis: study protocol for a randomized controlled trial.

BACKGROUND: Knee osteoarthritis (KOA) is a leading cause of public disability. Neuromuscular function contributes to the development and/or progression of KOA. Whole body vibration (WBV) exercise improve the neuromuscular function of patients with neurological disorders and even that of older patients with limited exercise options. Therefore, WBV exercise may offer an efficient and alternative treatment for individuals with KOA. However, the effects of WBV training on the neuromuscular function of individuals with KOA remain unclear. Therefore, this study attempts to investigate the effect of a 12-week WBV exercise on the neuromuscular function of individuals with KOA. METHODS/DESIGN: We will conduct a prospective, single-blind randomized controlled trial on 180 KOA patients. Participants will be randomly assigned to the WBV exercise, lower extremity resistance training, and health education groups. The WBV exercise group will participate in a 12-week WBV training. The lower extremity resistance training group will undergo a 12-week lower extremity resistance training of both lower limbs. The control group will receive health education for 12 weeks. After the intervention, the participants will be followed up for 3 months with no active intervention. Primary outcome measures will include anthropometric measurements, gait analysis during walking and stair climbing, muscle strength test of the knee and ankle, proprioception test of the knee and ankle, and neuromuscular response of the leg muscles. Secondary outcome measures will include self-reported pain and physical functional capacity, and physical performance measures. Furthermore, adverse events will be recorded and analyzed. If any participant withdraws from the trial, intention-to-treat analysis will be performed. DISCUSSION: Important features of this trial mainly include intervention setting, outcome measure selection, and study duration. This study is intended for estimating the effect of WBV intervention on neuromuscular control outcomes. Study results may provide evidence to support the beneficial effects of WBV exercise on the physical performance and neuromuscular control of individuals with KOA to fill the research gap on the efficacy of WBV. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ID: ChiCTR-IOR-16009234 . Registered on 21 September 2016.