Brian Caulfield

Altered Neuromuscular Control and Ankle Joint Kinematics During Walking in Subjects With Functional Instability of the Ankle Joint

Background The ankle joint requires very precise neuromuscular control during the transition from terminal swing to the early stance phase of the gait cycle. Altered ankle joint arthrokinematics and muscular activity have been cited as potential factors that may lead to an inversion sprain during the aforementioned time periods. However, to date, no study has investigated patterns of muscle activity and 3D joint kinematics simultaneously in a group of subjects with functional instability compared with a noninjured control group during these phases of the gait cycle. Purpose To compare the patterns of lower limb 3D joint kinematics and electromyographic activity during treadmill walking in a group of subjects with functional instability with those observed in a control group. Study Design Controlled laboratory study. Methods Three-dimensional angular velocities and displacements of the hip, knee, and ankle joints, as well as surface electromyography of the rectus femoris, peroneus longus, tibialis anterior, and soleus muscles, were recorded simultaneously while subjects walked on a treadmill at a velocity of 4 km/h. Results Before heel strike, subjects with functional instability exhibited a decrease in vertical foot-floor clearance (12.62 vs 22.84 mm; P <. 05), as well as exhibiting a more inverted position of the ankle joint before, at, and immediately after heel strike (1.69°, 2.10°, and -0.09° vs -1.43°, -1.43°, and -2.78°, respectively [minus value = eversion]; P <. 05) compared with controls. Subjects with functional instability were also observed to have an increase in peroneus longus integral electromyography during the post–heel strike time period (107.91%[.dotmath]millisecond vs 64.53%[.dotmath]millisecond; P <. 01). Conclusion The altered kinematics observed in this study could explain the reason subjects with functional instability experience repeated episodes of ankle inversion injury in situations with only slight or no external provocation. It is hypothesized that the observed increase in peroneus longus activity may be the result of a change in preprogrammed feed-forward motor control.

Selection criteria for patients with chronic ankle instability in controlled research: a position statement of the international ankle consortium

The International Ankle Consortium is an international community of researchers and clinicians whose primary scholastic purpose is to promote scholarship and dissemination of research-informed knowledge related to pathologies of the ankle complex. The constituents of the International Ankle Consortium and other similar organizations have yet to properly define the clinical phenomenon known as chronic ankle instability (CAI) and its related characteristics for consistent patient recruitment and advancement of research in this area. Although research on CAI and awareness of its impact on society and healthcare systems have grown substantially in the last 2 decades, the inconsistency in participant/patient selection criteria across studies presents a potential obstacle to addressing the problem properly. This major gap within the literature limits the ability to generalize this evidence to the target patient population. Therefore, there is a need to provide standards for patient/participant selection criteria in research focused on CAI, with justifications using the best available evidence.

Biofeedback in rehabilitation.

This paper reviews the literature relating to the biofeedback used in physical rehabilitation. The biofeedback methods used in rehabilitation are based on biomechanical measurements and measurements of the physiological systems of the body. The physiological systems of the body which can be measured to provide biofeedback are the neuromuscular system, the respiratory system and the cardiovascular system. Neuromuscular biofeedback methods include electromyography (EMG) biofeedback and real-time ultrasound imaging (RTUS) biofeedback. EMG biofeedback is the most widely investigated method of biofeedback and appears to be effective in the treatment of many musculoskeletal conditions and in post cardiovascular accident (CVA) rehabilitation. RTUS biofeedback has been demonstrated effective in the treatment of low back pain (LBP) and pelvic floor muscle dysfunction. Cardiovascular biofeedback methods have been shown to be effective in the treatment of a number of health conditions such as hypertension, heart failure, asthma, fibromyalgia and even psychological disorders however a systematic review in this field has yet to be conducted. Similarly, the number of large scale studies examining the use of respiratory biofeedback in rehabilitation is limited. Measurements of movement, postural control and force output can be made using a number of different devices and used to deliver biomechanical biofeedback. Inertial based sensing biofeedback is the most widely researched biomechanical biofeedback method, with a number of studies showing it to be effective in improving measures of balance in a number of populations. Other types of biomechanical biofeedback include force plate systems, electrogoniometry, pressure biofeedback and camera based systems however the evidence for these is limited. Biofeedback is generally delivered using visual displays, acoustic or haptic signals, however more recently virtual reality (VR) or exergaming technology have been used as biofeedback signals. VR and exergaming technology have been primarily investigated in post-CVA rehabilitation, however, more recent work has shown this type of biofeedback to be effective in improving exercise technique in musculoskeletal populations. While a number of studies in this area have been conducted, further large scale studies and reviews investigating different biofeedback applications in different clinical populations are required.

Ankle function during hopping in subjects with functional instability of the ankle joint

A common mechanism of inversion injury involves a lateral movement producing a hypersupination of the ankle joint. To date, no study has investigated patterns of muscle activity, three‐dimensional (3D) joint kinematics and kinetics simultaneously in a group of subjects with functional instability (FI) compared with a non‐injured control group during a lateral hopping test. Twenty‐six subjects with the subjective complaint of FI of the ankle joint and 24 non‐injured healthy control subjects volunteered to participate in the study. We measured 3D lower limb kinematics, kinetics and surface electromyography (EMG) of the rectus femoris, tibialis anterior, peroneus longus and soleus muscle in all subjects during a lateral hop task for the period 200 ms pre‐ and post‐initial contact (IC). FI subjects were observed to have a less‐everted position of the ankle joint during the time period from 45 ms pre‐IC to 95 ms post‐IC (P<0.05). FI subjects were also found to have an increase in pre‐ and post‐IC rectus femoris, tibialis anterior and solues EMG activity. The results suggest that subjects with FI exhibit changes in ankle joint movement and neuromuscular control that could predispose to further injury.

Characteristics of people with recurrent ankle sprains: a systematic review with meta-analysis

Objective To examine whether people with recurrent ankle sprain, have specific physical and sensorimotor deficits. Design A systematic review of journal articles in English using electronic databases to September 2009. Included articles compared physical or sensorimotor measures in people with recurrent (≥2) ankle sprains and uninjured controls. Main outcome groups Outcome measures were grouped into: physical characteristics, strength, postural stability, proprioception, response to perturbation, biomechanics and functional tests. A meta-analysis was undertaken where comparable results within an outcome group were inconsistent. Results Fifty-five articles met the inclusion criteria. Compared with healthy controls, people with recurrent sprains demonstrated radiographic changes in the talus, changes in foot position during gait and prolonged time to stabilisation after a jump. There were no differences in ankle range of motion or functional test performance. Pooled results showed greater postural sway when standing with eyes closed (SMD=0.9, 95% CI 0.4 to 1.4) or on unstable surfaces (0.5, 0.1 to 1.0) and decreased concentric inversion strength (1.1, 0.2 to 2.1) but no difference in evertor strength, inversion joint position sense or peroneal latency in response to a perturbation. Conclusion There are specific impairments in people with recurrent ankle sprain but not necessarily in areas commonly investigated.

A Comparison Between Performance on Selected Directions of the Star Excursion Balance Test and the Y Balance Test

CONTEXT The Star Excursion Balance Test (SEBT) is a widely accepted method of assessing dynamic postural stability. The Y Balance Test (YBT) is a commercially available device for measuring balance that uses 3 (anterior, posteromedial, and posterolateral) of the 8 SEBT directions and has been advocated as a method for assessing dynamic balance. To date, no studies have compared reach performance in these tests in a healthy population. OBJECTIVE To determine whether any differences exist between reach distance performance for the anterior, posteromedial, and posterolateral directions of the SEBT and the YBT. DESIGN Descriptive laboratory study. SETTING University motion analysis laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 20 healthy active male participants (age = 22.50 ± 3.05 years, height = 1.78 ± 0.82 m, weight = 79.48 ± 11.32 kg, body mass index = 24.96 ± 2.56 kg/m²). INTERVENTION(S) Participants carried out 3 trials in each reach direction on each leg on the SEBT and the YBT a minimum of 1 week apart. MAIN OUTCOME MEASURE(S) The means of the 3 trials in each direction on each leg on both tests were calculated. Data were collected after 4 practice trials in each direction. Paired t tests and Bland-Altman plots were used to compare reach distances between the SEBT and the YBT. RESULTS Participants reached farther in the anterior direction on the SEBT than on the YBT. No differences were observed in the posteromedial and posterolateral directions. CONCLUSIONS Differing postural-control strategies may be used to complete these tasks. This finding has implications for the implementation and interpretation of these dynamic balance tests.

Prolonged Electrical Muscle Stimulation Exercise Improves Strength, Peak VO2, and Exercise Capacity in Patients With Stable Chronic Heart Failure

BACKGROUND Exercise training can help patients with chronic heart failure but may be limited in its applicability due to age and other comorbidities. This investigation evaluated training responses to prolonged electrical muscle stimulation (EMS) in patients with stable chronic heart failure. METHODS AND RESULTS In a crossover designed study, 10 patients (age 66 +/- 6.5 years, 9 male) were randomized to 8 weeks of training or habitual activity before crossing over to the other limb after a washout period of 2 weeks. Training consisted of electrical muscle stimulation of the major leg muscles for a minimum of 1 hour, 5 days a week. Peak oxygen consumption, 6-minute walking distance test, body mass index, and quadriceps muscle strength were the end points. At baseline the mean values for peak oxygen consumption (VO(2)), 6-minute walking distance, quadriceps strength, and body mass index were 19.5 +/- 3.5 mL x kg x min, 415.1 +/- 56.6m, 377.9 +/- 110.4N, and 27.9 +/- 3.1 kg/m(2), respectively. After training, peak VO(2) increased to 21.2 +/- 5.1 mL x kg x min (P < .05), walking distance increased to 454.9 +/- 54.5M (P < .005), quadriceps strength increased to 404.9 +/- 108.6N (P < .005), whereas we did not observe a significant effect on body mass index (P > .05). CONCLUSIONS EMS can be used in sedentary adults with stable chronic heart failure to improve physical fitness and functional capacity. It may provide a viable alternative for patients unable to undertake more conventional forms of exercise.

Design and Evaluation of a Wearable Optical Sensor for Monitoring Seated Spinal Posture

This work describes the development and evaluation of a wearable plastic optical fiber (POF) sensor for monitoring seated spinal posture. A garment-integrated POF sensor was developed and tested on nine healthy subjects, and its performance compared to data taken simultaneously from a marker-based motion capture system. Sensor performance correlated strongly with motion-capture data with an average r of 0.913. Results show that the wearable sensor provides enough accuracy of measurement to reliably monitor seated spinal posture.

SHIMMER: A new tool for temporal gait analysis

Development of a flexible wireless sensor platform for measurement of biomechanical and physiological variables related to functional movement would be a vital step towards effective ambulatory monitoring and early detection of risk factors in the ageing population. The small form factor, wirelessly enabled SHIMMER platform has been developed towards this end. This study is focused assessing the utility of the SHIMMER for use in ambulatory human gait analysis. Temporal gait parameters derived from a tri-axial gyroscope contained in the SHIMMER are compared against those acquired simultaneously using the CODA motion analysis system. Results from a healthy adult male subject show excellent agreement (ICC(2, k) > 0.85) in stride, swing and stance time for 10 walking trials and 4 run trials. The mean differences using the Bland and Altman method for stance, stride and swing times were 0.0087, 0.0044 and -0.0061 seconds respectively. These results suggest that the SHIMMER is a versatile cost effective tool for use in temporal gait analysis.

Examining Neuromuscular Control During Landings on a Supinating Platform in Persons With and Without Ankle Instability

Background: Ankle instability is a costly public health concern because of the associated recurrent sprains. It is evident there are neuromuscular control deficits predisposing these individuals to their ankle “giving way.” Individuals with a history of lateral ankle sprain, who did not develop instability, may hold the key to understanding proper neuromuscular control after injury. Hypotheses: On the basis of previous research, the authors hypothesized that individuals with ankle instability would demonstrate reduced peroneal activation, causing a more inverted position of the ankle, before and after landing. Study Design: Controlled laboratory study. Methods: This study aimed to evaluate preparatory and reactive neuromuscular control when landing on a custom-designed ankle supinating device in individuals with ankle instability (AI), individuals with a history of lateral ankle sprains without instability (LAS), and uninjured controls (CON). Forty-five participants (15 per group) were asked to land on a device built to simulate the mechanism of a lateral ankle sprain (supination) while kinematics and muscle activity of the lower extremity were monitored. Results: Contrary to our hypotheses, the AI group displayed significantly increased preparatory (P = .01) and reactive (P = .02) peroneal activation, while the LAS group demonstrated a trend toward increased preparatory tibialis anterior muscle activation (P = .07), leading to a decreased plantar flexion of the ankle at landing. Conclusion: The AI group was likely acting in a protective fashion to a potentially injurious situation, indicating these individuals can activate the peroneals if needed. The LAS group’s strategy may be a safer strategy in that a less plantar-flexed position of the ankle is more close-packed and stable. Further, it appears the long-latency response of the peroneals may be enhanced in these individuals, which indicates motor learning at the supraspinal level to promote dynamic restraint. Clinical Relevance: Individuals with AI can increase peroneal activation when necessary to dynamically stabilize the ankle, indicating the potential for training/rehabilitation. Further, the LAS group may deploy a different control strategy after injury to protect the ankle from subsequent sprains, which deserves investigation during activities of daily living. A greater understanding of these strategies will lead to the development of more appropriate treatment paradigms after injury to minimize the incidence of instability.