Applications of EMG in Clinical and Sports Medicine

This second of two volumes on EMG (Electromyography) covers a wide range of clinical applications, as a complement to the methods discussed in volume 1. Topics range from gait and vibration analysis, through posture and falls prevention, to biofeedback in the treatment of neurologic swallowing impairment. The volume includes sections on back care, sports and performance medicine, gynecology/urology and orofacial function. Authors describe the procedures for their experimental studies with detailed and clear illustrations and references to the literature. The limitations of SEMG measures and methods for careful analysis are discussed. This broad compilation of articles discussing the use of EMG in both clinical and research applications demonstrates the utility of the method as a tool in a wide variety of disciplines and clinical fields

Stretching with whole body vibration versus traditional static stretches to increase acute hamstring range of motion

PURPOSE The purpose of this study was to determine if performing static active knee extension hamstring stretching using the Pneumex Pro-Vibe vibrating platform increased acute hamstring range of motion (ROM) greater than traditional static active knee extension hamstring stretching. METHODS: A within subject design was utilized with subjects undergoing static stretching with vibration and without vibration (conditions counterbalanced). Pre- and post-test active and passive ROM was measured for the right leg, with subjects first undergoing a 5-minute warm-up on a stationary bicycle. Supine active knee extension was performed on the Pro-Vibe platform with and without vibration. The stretch was held 3 times each for 30 seconds, with a 20-second rest period between each stretch. Vibration was set at 30 Hz at the “high” amplitude setting. Active hamstring ROM was measured via active knee extension using a goniometer with the leg in 90° of hip flexion. Passive ROM was measured via clinician-assisted knee extension with the leg in 90° of hip flexion. RESULTS: A 2-way repeated measures ANOVA was performed for passive ROM, and revealed a significant main effect for condition, F (1, 23) = 0.5875, p \u3c 0.05, and time, F (1, 23) = 5.029, p \u3c 0.05. Another repeated measures ANOVA was performed for active ROM with the same factors, and revealed a significant time by condition interaction, F (1, 23) = 4.730, p \u3c 0.05, and a significant main effect for time, F (1, 23) = 18.612, p \u3c 0.001. Post-hoc paired samples t-tests determined the difference between the pre-test and post-test measurements for each condition. Active ROM showed a significant difference pre-test to post-test for the vibration condition, t (23) = -5.41, p \u3c 0.001. The vibration condition also resulted in significantly different pre-test vs. post-test measurements on passive ROM, t (23) = -2.55, p \u3c 0.05. In both cases the average ROM was higher for the post-test. DISCUSSION: Three 30-second active knee extension hamstring stretches using a vibrating platform are sufficient to cause significant acute increases in hamstring ROM. These findings suggest this device may be useful when desiring increased hamstring ROM

The effects of manipulated somatosensory input on simulated falls during walking

Previous research has demonstrated that there is a distinct relationship between aging and instability. The somatosensory system plays a significant role in balance control in conjunction with vision and the vestibular system (Qiu et al., 2012). Evidence has shown that manipulation of the mechanoreceptors on the plantar surface of the foot has a direct effect on balance control. By manipulating these receptors with hypothermic anesthesia and vibration, researchers are capable of simulating the effect of sensory modification on healthy individuals, in order to understand the role that plantar-surface sensation has in adapting to perturbation during gait (Perry et al., 2001; Priplata et al., 2006). This study included 14 healthy young adults (mean age 23.07 (±2.43)). Within this study, participants were asked to walk the length of an 8-meter platform at a comfortable speed. Participants were required to walk with reduced, enhanced and normal levels of somatosensory information of the plantar foot surface. During walking trials the participants travelled along a raised platform that had 4 sections in which removable foam squares were placed to provide either a stable or unstable situation when stepped upon. Located underneath three of these squares were three force plates (OR-6-2000 (AMTI, Waterdown, MA)). In order to prevent learning bias the location of the foam, as well as the direction of the perturbation was randomized. Participants were perturbed in either the anterior or lateral direction based upon the direction in which the removable foam squares within the platform were placed. Moreover, participants experienced three separate conditions (control, vibration, and cooled) on the plantar surface of the foot to manipulate the sensory information received. Electromyography (AMT-8 (Bortec, Calgary, Alberta)) was used to analyze magnitude and onset changes in muscle activity within the Gastrocnemius and Tibialis Anterior of the right lower limb, and the Rectus Femoris, and Biceps Femoris muscles of the left lower limb. Three-dimensional motion analysis was also used to capture observable changes in gait (Optotrak, NDI, Waterloo, Ontario). A main effect of condition was found for the third burst of muscle activity recorded within the Tibialis Anterior (F(2,17)=2.75, p\u3c0.01), with post-hoc analysis between the cooled and vibration conditions. A significant positive correlation was found between Rectus Femoris EMG amplitude and rate of loading (r=0.94,p=0.05). Within the anterior perturbations, a main effect for condition was observed for maximum COM velocity ((F(2,35)=3.71, p=0.05), minimum COP velocity (F(2,35)=4.62, p=0.03), and for the maximum distance between COM and COP (F(2,35)=4.37, p=0.04). A trend was also observed for the maximum distance the COM travelled within the lateral direction in the BOS (F(9,35)=2.61, p=0.06). Within the lateral perturbations, a trending effect for condition was also observed for maximum COM velocity (F(2,55)=3.07, p=0.06), the maximum distance between the COM and COP (F(2,55)=2.98, p=0.06), and a main effect was observed for condition for the rate of loading (F(2,55)=3.86, p=0.03). This study provides evidence of a relationship between the plantar cutaneous mechanoreceptors and gait parameters regarding to balance control as observed by the significant effects on commonly used measurements of balance control (i.e. COP and COM velocity). A relationship between mechanoreceptors and EMG amplitude, as well as foot contact forces and EMG amplitude is also evident. These relationships may be used to further knowledge for balance control during adaptive gait, as well as provide further development of footwear and insoles to improve balance control

Gait Variability and Kinematic Alterations in People with Diabetes Mellitus and Peripheral Neuropathy

Background: People with diabetes and peripheral neuropathy have been reported to show alterations in lower limb joint function compared to healthy non-diabetic people. Specifically the maximum angular movement available at certain joints can be reduced during static, non-weight bearing tasks. Limited joint range of motion has the potential to compromise balance and stability thereby increasing the risk of falling. It is unclear whether a reduction in the extent of movement available at the joints is reflected by a reduction in the amount of angular movement actually utilised during a functional task such as stair negotiation. The aim of this study was to determine if people with diabetes show reduced dynamic range of motion at the ankle, knee and hip joints during stair ascent and descent in comparison to controls. Falls risk during stair negotiation was calculated by measuring the degree of variability in dynamic joint range of motion. Methods: Data were generated from three groups: subjects with diabetes and peripheral neuropathy (DPN), diabetes without peripheral neuropathy (DM), and healthy controls (Ctl). The study was conducted in a gait laboratory using motion capture and related 3D software for analysis. Joint range of motion for the ankle, knee, and hip were captured during level walking, stair ascent, and descent. A seven step, bespoke staircase was fabricated for this purpose. Analysis of Variance (ANOVA) and Newman-Keuls tests were used to analyse the data. Results: Significantly reduced ankle range of motion, in the sagittal plane, was observed in the DPN group during stair ascent when compared to the controls. For stair descent, the DPN group demonstrated a significant increase in knee and hip ROM in the frontal plane, and also hip ROM in the transverse plane. No significant differences between the groups were identified for joint variability. Conclusions: People with DPN demonstrate alterations in dynamic range of motion at the lower limb joints during stair ascent and descent. The degree of angular movement utilised for both stair tasks was decreased at the ankle joint and this has the potential to undermine balance and stability. In contrast, angular movement at the knee and hip joints was increased in the frontal and transverse planes. This may compensate for impaired balance and stability by increasing the base of support to maintain balance and assist in foot clearance and placement. The specific combination of increased angular movement at the knee and hip may represent a compensatory stair gait strategy in response to reduced angular movement at the ankle joint

A review of the effectiveness of lower limb orthoses used in cerebral palsy

To produce this review, a systematic literature search was conducted for relevant articles published in the period between the date of the previous ISPO consensus conference report on cerebral palsy (1994) and April 2008. The search terms were 'cerebral and pals* (palsy, palsies), 'hemiplegia', 'diplegia', 'orthos*' (orthoses, orthosis) orthot* (orthotic, orthotics), brace or AFO