Semi-rigid Brace Research Articles

Effect of soft and semi-rigid ankle braces on kinematic and kinetic changes of the knee and ankle joints after forward and lateral drop landing in healthy young women

Effect of soft and semi-rigid ankle braces on kinematic and kinetic changes of the knee and ankle joints after forward and lateral drop landing in healthy young women

Effects of Ankle Bracing on Postural Sway

Ankle bracing can alter postural control strategies during static and dynamic tasks, theoretically through mechanical constraint of the ankle joint and/or sensorimotor reorganization. While a majority of studies have focused on center of pressure (COP) characteristics or clinical tests of balance to explore this theory, fewer studies have investigated sway characteristics of the center of mass (COM). Additionally, the effects of various styles of ankle braces on postural sway remains inconclusive. Assessing the effects of ankle bracing on postural sway could provide additional insight into potential systemic motor adaptations that occur in response to ankle constraint. PURPOSE: Examine effects of lace-up and semi-rigid bracing on postural sway characteristics during a quiet-standing task. METHODS: Thirty-five adults between the ages of 18-30yrs (height: 1.72 ± 0.1m; mass: 75.49 ± 18kg) participated in the study. Participants performed a single one-minute trial of quiet-standing during each of the following conditions: No brace (NB), lace-up brace (LB), and semi-rigid brace (SRB). A ten-camera motion capture system was utilized to capture lower extremity positon. To assess postural sway, mediolateral (ML) and anteroposterior (AP) lower extremity COM trajectories were extracted, and root-mean-square deviation (RMSx, RMSy) and velocity (RMSvx, RMSvy) of the COM were calculated. Repeated-measures ANOVAs were employed to assess differences in postural sway measures across all conditions. RESULTS: Analysis revealed a significant main effect for RMSy (F = 7.061; p < .01). Pairwise comparisons indicated that RMSy was significantly lower in the SRB condition (1.770±1.698mm) compared to C (2.182 ±1.515mm) (p < .01). CONCLUSION: Results from study indicate that subjects exhibited an altered AP postural sway pattern when a semi-rigid brace is applied. These findings align with previous research reporting reduced AP COP excursions with ankle bracing during quiet-standing. Altered sway patterns with ankle bracing appears to support the presence of sensorimotor reorganization, possibly due to altered proprioceptive and/or haptic feedback stemming from greater mechanical constraint of the ankle joint.

Effect of a Semirigid Ankle Brace on the In Vivo Kinematics of Patients with Functional Ankle Instability during the Stance Phase of Walking.

An ankle brace is commonly used by patients after they suffer from initial ankle sprains, reducing the incidents of recurrent sprain or limiting laxity in joints with functional ankle instability (FAI). However, whether the application of a semirigid ankle brace can improve the abnormal ankle gait kinematics of patients with FAI remains unknown. This study aimed to determine the effect of a semirigid ankle brace on the gait kinematics of ankle joints through 3D-2D fluoroscopy image registration. A total of 8 subjects with FAI (3 males and 5 females, 10 feet) as FAI group and 10 subjects without FAI (6 males and 4 females, 10 feet) as control group were enrolled in this study. Three-dimensional bone models created from computed tomography images were matched to fluoroscopic images to compute the 6 degrees of freedom (DOF) talocrural, subtalar, and ankle joints complex kinematics for control and FAI group with or without brace during the stance phase of walking. FAI patients had significantly less ROMs in inversion/eversion rotation of the talocrural and subtalar joint after wearing semirigid ankle brace. Laxity was observed in most of the displacements of the talocrural and subtalar joints in FAI group. The brace partly altered the ankle joints movement in opposite directions, especially joint rotation, and restricted the talocrural and subtalar joints in the dorsiflexion position during the touch down phase of walking.

Ankle bracing's effects on lower extremity iEMG activity, force production, and jump height during a Vertical Jump Test: An exploratory study

ObjectiveTo determine if softshell (AE) and semi-rigid (T1) ankle braces affect lower extremity iEMG activity, force, and jump height during a Vertical Jump Test. DesignRepeated measures, crossover. SettingLaboratory. Participants42 healthy, active individuals. Outcome measuresVertical jump height, iEMG activity, peak vGRF. ResultsThere was significant change across conditions in lateral gastrocnemius (LG) iEMG activity, F(2,70) = 5.31, p = .007, ηp2 = 0.132, with T1 LG iEMG being significantly less (−2.08(99% CI, −3.98 to 0.18) %MVIC, p = .004) than no brace. Significant changes were seen in rectus femoris (RF) iEMG activity, F(2,68) = 6.36, p = .003, ηp2 = 0.158, with T1 RF iEMG activity being significantly less than AE RF iEMG activity (−2.78(99% CI, −5.36 to −0.19) %MVIC, p = .005). There was a significant change in vertical jump height across conditions, F(2,78) = 22.13, p < .0005, ηp2 = 0.362, with a significant decrease in the AE (−2.41(99% CI, −3.66 to −1.17) cm, p < .0005) and T1 conditions (−2.89(99% CI,−4.56 to −1.23) cm, p < .0005), compared to no brace. ConclusionVertical jump height is significantly reduced when wearing ankle braces. Effects on lower extremity iEMG activity are dependent upon brace type.

Effect of simulated joint instability and bracing on ankle and subtalar joint flexibility

It is clinically challenging to distinguish between ankle and subtalar joints instability in vivo. Understanding the changes in load-displacement at the ankle and subtalar joints after ligament injuries may detect specific changes in joint characteristics that cannot be detected by investigating changes in range of motion alone. The effect of restricting joints end range of motion with ankle braces was already established, but little is known about the effect of an ankle brace on the flexibility of the injured ankle and subtalar joints. Therefore, the purposes of this study were to (1) understand how flexibility is affected at the ankle and subtalar joints after sectioning lateral and intrinsic ligaments during combined sagittal foot position and inversion and during internal rotation and (2) investigate the effect of a semi-rigid ankle brace on the ankle and subtalar joint flexibility. Kinematics and kinetics were collected from nine cadaver feet during inversion through the range of ankle flexion and during internal rotation. Motion was applied with and without a brace on an intact foot and after sequentially sectioning the calcaneofibular ligament (CFL) and the intrinsic ligaments. Segmental flexibility was defined as the slope of the angle-moment curve for each 1 Nm interval. Early flexibility significantly increased at the ankle and subtalar joint after CFL sectioning during inversion. The semi-rigid ankle brace significantly decreased early flexibility at the subtalar joint during inversion and internal rotation for all ligament conditions and at the ankle joint after all ligaments were cut.

Restrictions in the Ankle Sagittal- and Frontal-Plane Range of Movement during Simulated Walking with Different Types of Orthoses

Different types of orthoses are available to clinicians for non-surgical treatment of acute ankle sprains. The goal of this study was to scientifically compare the movement restrictions in the sagittal and frontal plane during simulated walking between one adaptable semi-rigid brace (OrthoTri-PhaseTM), four non-adaptable semi-rigid braces (OrthoStandardTM, MalleoLocTM, MalleoSprintTM, VACOankleTM), and one rigid cast. Predefined time sequences of rotational moments and axial loading during gait were applied via an ankle joint simulator, with the pneumatic pressure inside the orthoses kept constant to ensure the same condition for different trials and orthoses. The peak ranges of motion (RoMs) in the frontal and sagittal plane during gait were analyzed for statistically significant differences using single-factorial ANOVA with post-hoc Bonferroni analysis. Significant differences in peak plantar-/dorsiflexion and in-/eversion RoM during gait were found between different types of orthoses. In the sagittal plane, the rigid cast most significantly restricted overall RoM followed by the Ortho Tri-PhaseTM in Phase 1 and the Ortho StandardTM. The peak restriction in-/eversion RoM of the VACOankleTM came closest to the rigid cast, with a shift towards inversion. The VACOankleTM allowed for significantly larger dorsiflexion movement compared to all other orthoses. The present results may help clinicians in the decision-making process of finding the optimal orthosis for individual patients.

Concerns About Ankle Injury Prophylaxis and Acceptance of the Parachute Ankle Brace Among Jumpmaster Students.

Several studies have shown that the parachute ankle brace (PAB) is safe, cost-effective, and reduces the rates of ankle injuries during military parachuting. However, the acceptability and usability of the PAB has not been well established in units that regularly do airborne exercises. Many anecdotal concerns in the past may be limiting common use. The purpose of the study is to ascertain the attitudes toward the PAB among experienced paratroopers. One hundred experienced paratroopers training to be jumpmasters at the Advanced Airborne School (Fort Bragg, NC) voluntarily responded to a 13-item, paper questionnaire to assess attitudes toward the PAB, its use, and concerns about future ankle injuries. The survey was offered to all 100 students enrolled in an Advanced Airborne School course. Results were input into an online database using Qualtrics and qualitative responses were evaluated for thematic content and categorized appropriately. Analysis was performed using Qualtrics and SPSS for descriptive statistics, two-sample t-tests, and chi-square tests. The Wilcoxon signed-rank test was used to evaluate Likert-type responses. Of the 100 paratroopers who responded to the survey 32% had over 10 yr of military service, 58% had over 5 yr of service, and 32% had over 5 yr on active jump status. Results show that none of the respondents had ever used the PAB; 62% had never heard of the PAB, and 72% had never observed use of the PAB. A majority of respondents (87%) had never injured an ankle during a parachute landing fall (PLF), but 79% believed that an ankle injury could affect their career potential as a paratrooper. Almost one-half of the respondents (47%) had seen that ankle injuries affect another paratrooper's career. A third of the respondents (35%) said that they had concerns that would keep them from using the PAB, whereas 21% were uncertain, as they had never heard of it. Only 19% of the respondents were willing to use measures such as taping, lace-up bracing, semi-rigid brace inside a normal boot, specialized jump boot with stabilizing braces built in, or outside-the-boot braces to prevent ankle injury. However, 40% said that they were likely to use these measures on jumps after experiencing an ankle injury. Previous research clearly establishes the advantages of the PAB. None of the participants had ever used the PAB but expressed a fear about how an ankle injury might impact their future career potential. Yet half of the jumpmasters indicated a willingness to use prophylactic measures after an ankle injury. This survey assessed the attitude and knowledge related to the PAB among jumpmaster students. Results show that despite the benefits of the PAB, a negative attitude exists toward the PAB, and it is not currently being used. This survey clearly demonstrates the need either to educate paratroopers on the existence of the PAB or to explore other designs that may be more readily accepted in the airborne community.

Prophylactic Ankle Braces and the Kinematics and Kinetics of Half-Squat Parachute Landing.

The objective of the study was to investigate the effects of dropping heights and prophylactic ankle braces on ankle joint biomechanics during half-squat parachute landing from two different heights. There were 30 male elite paratroopers with formal parachute landing training and more than 2 yr of parachute jumping experience who were recruited for this study. The subjects tested three different ankle brace conditions (no-brace, elastic brace, semirigid brace). Each subject was instructed to jump off a platform from two different heights of 0.4 m and 0.8 m, and land on a force plate in a half-squat posture. The Vicon 3D motion capture system and force plate were used to record and calculate kinematic and kinetic data. Dropping height had a significant effect on peak vertical ground reaction force (vGRF), maximum ankle angular displacement, and time to vGRF. As compared with the no-brace group, use of an elastic ankle brace significantly reduced peak vGRF by 18.57% and both braces significantly reduced the maximal angular displacements of dorsiflexion. The semirigid brace provided greater restriction against maximal angular displacement of inversion. The elastic and semirigid ankle braces both effectively restricted motion stability of the ankle joint in the sagittal plane, and the semirigid ankle brace prevented excessive inversion, although the comfort of this device should be improved overall.Wu D, Zheng C, Wu J, Hu T, Huang R, Wang L, Fan Y. Prophylactic ankle braces and the kinematics and kinetics of half-squat parachute landing. Aerosp Med Hum Perform. 2018; 89(2):141-146.

Protective Knee Braces and the Biomechanics of the Half-Squat Parachute Landing.

Knee injuries are common among paratroopers and skydivers during landing maneuvers. The aim of this study was to investigate the effects of dropping height and the use of protective knee braces on parachute landing biomechanics. The study cohort consisted of 30 male elite paratroopers with formal parachute landing training and more than 2 yr of parachute jumping experience. Each participant was instructed to jump off a platform at two different heights (40 and 80 cm, respectively) and land on force plates in a half-squat posture. All participants tested three different knee brace conditions (no-brace, elastic brace, and semi-rigid brace) at each height. With an increase in dropping height, peak vertical ground reaction forces (GRF), peak flexion angle, peak flexion angular displacement, peak abduction angle, peak abduction angular displacement, peak extorsion angle, and peak extorsion angular displacement of the knee joint all increased. As compared without the use of a brace, use of an elastic or semi-rigid knee brace significantly reduced peak flexion angle, peak flexion angular displacement, peak abduction angular displacement, and peak extorsion angle, while there were no significant differences in peak vertical GRF or peak extorsion angular displacement. The semi-rigid brace provided the greatest restriction against peak abduction angle (3-6°). The elastic and semi-rigid knee braces both effectively restricted motion stability of the knee joint in the sagittal and coronal planes. The semi-rigid brace had a more marked effect, although the comfort of this device should be improved.Wu D, Zheng C, Wu J, Wang L, Wei X, Wang L. Protective knee braces and the biomechanics of the half-squat parachute landing. Aerosp Med Hum Perform. 2018; 89(1):26-31.

Effects of a semi-rigid ankle brace on ankle joint loading during landing on inclined surfaces

ABSTRACT Ankle bracing is commonly used to prevent ankle sprain occurrences. The present study investigated the effects of a semi-rigid ankle brace on the ankle joint complex during landing on inclined surfaces. Seventeen recreational athletes performed a single leg landing task onto three different surface alignments (everted, neutral, inverted), with and without the brace. Ground reaction forces (GRF), kinematics, and brace pressure were recorded. Six two-way repeated measures MANOVA tested for differences in GRF, talocrural and subtalar kinematics and kinetics. Participants landed with a significantly less plantar flexed (P < 0.001) and more everted (P = 0.001) foot during the braced condition. Although no differences were observed for the joint moments, an increased subtalar compression force (P = 0.009) was observed with the brace. Landing on the inverted surface resulted in significantly higher peak magnitudes of the vertical and the mediolateral GRF and the talocrural inversion moment compared to landing on the neutral surface. Ankle bracing altered ankle kinematics by restricting the ROM of the ankle joint complex. This study confirmed that landing on inverted surfaces may increase the risk for lateral ankle ligaments injuries. The significantly higher subtalar compression force during the brace condition might contribute to overuse injuries.

The effects of ankle braces and taping on lower extremity running kinematics and energy expenditure in healthy, non-injured adults

Ankle braces and taping are commonly used to prevent ankle sprains and allow return to play following injury, however, it is unclear how passive restriction of joint motion may effect running gait kinematics and energy expenditure during exercise. The purpose of this study was to determine the effect of different types of ankle supports on lower extremity kinematics and energy expenditure during continuous running. Thirteen healthy physically active adults ran at self-selected speed on the treadmill for 30min in four different ankle support conditions: semi-rigid hinged brace, lace-up brace, tape and control. Three-dimensional lower extremity kinematics and energy expenditure were recorded every five minutes. The semi-rigid hinged brace was most effective in restricting frontal plane ankle motion. The lace-up brace and tape restricted sagittal plane ankle motion, while semi-rigid hinged bracing allowed for normal sagittal plane ankle kinematics. Kinematic changes from all three ankle supports were generally persistent through 25–30min of exercise. Only tape influenced knee kinematics, limiting flexion velocity and flexion-extension excursion. Small but significant increased in energy expenditure was found in tape and semi-rigid hinged brace conditions; however, the increases were not to any practically significant level (<0.5kcal/min).

User Survey of 3 Ankle Braces in Soccer, Volleyball, and Running: Which Brace Fits Best?

Recurrence rates for ankle sprains are high. Therefore, preventive measures such as ankle bracing during sports are recommended. To systematically evaluate the perceived ease of use, quality, comfort, stability, and hindrance of and the overall satisfaction with 3 contemporary brace types in 3 types of sports. Randomized comparative user survey. Recreational sports: soccer, volleyball, and running. Young adult recreational athletes (29 soccer players, 26 volleyball players, and 31 runners). Compression brace (CB), lace-up brace (LB), and semirigid brace (SB). Rating of perceived ease of use, quality, comfort, stability, and hindrance of and overall satisfaction with the brace types during sports on a 5-point Likert scale. The secondary outcome measure was participants' willingness to buy the tested brace. Overall, the 3 brace types received high mean scores for ease of use and quality. Soccer players preferred the CB over both alternatives, considering the higher scores for comfort (CB = 4.0, LB = 3.5, SB = 2.8), hindrance (CB = 3.7, LB = 2.9, SB = 2.8), overall satisfaction (CB = 3.6, LB = 3.0, SB = 2.5), and greatest willingness to buy this brace. Volleyball players preferred the LB over both alternatives, considering the higher scores for stability (LB = 4.2, CB = 3.2, SB = 3.3), overall satisfaction (LB = 3.8, CB = 3.0, SB = 3.0), and greatest willingness to buy this brace. Runners preferred the CB over both alternatives considering the better score for hindrance (CB = 3.6, LB = 2.8, SB = 2.9) and greatest willingness to buy this brace. All 3 ankle-brace types scored high on perceived ease of use and quality. Regarding the brace types, soccer players, volleyball players, and runners differed in their assessments of subjective evaluation of comfort, stability, hindrance, overall satisfaction, and willingness to buy the brace. Soccer players and runners preferred the CB, whereas volleyball players preferred the LB.

Stiffness and proprioceptive contributions of ankle braces and the influence of localized muscle fatigue

Ankle braces are a common treatment to reduce ankle sprain recurrence among individuals with chronic ankle instability (CAI). Bracing provides supplemental external joint stiffness and/or improved proprioceptive acuity. The goals of this study were to assess the effects of two ankle braces on joint position sense (JPS) and ankle stiffness, and determine whether bracing effects are reduced with localized muscle fatigue. Measures of JPS and ankle stiffness were obtained from participants with CAI (n=12) for three conditions (no brace, a neoprene wrap brace, and a semi-rigid brace), before and after inducing localized muscle fatigue at the ankle. Pre-fatigue JPS measures did not differ between brace conditions, but pre-fatigue stiffness was ∼0.8 and 2.5Nm/rad (∼5 and 14%) greater for the semi-rigid brace than the neoprene and no brace conditions, respectively. Fatigue increased absolute JPS errors by 0.3° (∼6 to 12%) across all conditions. Stiffness was unaffected by fatigue among females. Among males, fatigue increased stiffness by 0.75Nm/rad (∼3.3%) with the semi-rigid brace and decreased stiffness by 0.32Nm/rad (1.5%) with no brace. The semi-rigid brace may better protect males from sprains while either brace may be effective for females.

Prophylactic Ankle Bracing in Military Settings: A Review of the Literature.

Within athletics and the military, ankle sprains are one of the most common injuries with the potential for long-term functional deficits. Incidence rates for ankle sprains within the military are one of the leading causes of limited duty days, especially during basic combat training, parachute training exercises, and in cadet populations. In 2008, the Department of Defense U.S. Army Center for Health Promotion and Preventative Medicine report recommended that military personnel should wear semirigid ankle braces during parachuting, basketball, soccer, and other similar high-risk activities to reduce ankle sprain injuries. This recommendation was developed using a majority of athletic references with limited data stemming from military works. Of these included military studies, none presented data on ankle braces and their effects on performance, especially in military-specific environments. The purpose of this review was to provide an up-to-date account on the use of ankle braces in military populations and effects on performance measures. A comprehensive online systematic review of the literature was conducted to delineate the current use of ankle braces in the military and how they specifically affect functional performance measures. The scope of this study eliminated military studies that were not prospective in nature or did not incorporate subjects wearing military equipment (i.e., combat boots). It was determined that little progress has been made in validating the use of semirigid ankle braces in military populations other than in instances such as parachuting and only in reducing the number ankle injuries. To date, only one study has looked specifically at the use of ankle braces and its effects on performance measures in a military sample. With the high incidence rate and increased risk for subsequent reinjury, ankle sprains are an economic and force readiness burden to the U.S. Armed Forces. This study was conducted to determine whether additional literature was available for the use of ankle braces on performance measures in the military. It was determined that there is a scarcity of information currently available on the use of ankle braces in military populations, outside of parachuting activities. The Department of Defense recommendation of using semirigid ankle braces may ultimately be beneficial to a multitude of high-risk military activities, but further research must be conducted to determine possible detrimental performance effects.

A Study to Find out the Effectiveness of Taping Versus Semi rigid Bracing in Ankle Sprain

A Study to Find out the Effectiveness of Taping Versus Semi rigid Bracing in Ankle Sprain

EARLY ORTHOTICS IN COMPLEX TREATMENT OF CHILDREN WITH VERTEBRAL COMPRESSION FRACTURES OF THE THORACIC AND LUMBAR SPINE

Objective. To compare the results of treatment of compression fractures of the thoracic and lumbar vertebrae in children by classical functional extension and by early orthotics with hyperextension braces. Material and Methods . The study included 175 children aged 3 to 18 years with vertebral compression fractures of the thoracic and lumbar spine. In the study group (32 patients), early orthotics with a rigid hyperextension brace was used, in the control group (143 patients) - a standard Gorinevskaya - Dreving’s technique followed by wearing a semi-rigid brace. Results . In the study group, the average vertebral compression ratio was 63 %, WI - 0.6-0.8, and vertebral body height restoration was observed in 90.5 % of cases. In the control group, the average compression ratio was 75 %, WI - 0.75-0.9, and abnormal wedging of vertebral bodies after the treatment was observed in 48.0 % of patients. In the study group, the length of hospital stay was reduced, the mode of physical activity in the early stages was increased with better and faster restoration of vertebral bodies in comparison with the control group. Conclusion . Application of hyperextension braces shortens hospital stay, contributes to the complete restoration of the height and shape of the damaged vertebral body, and allows for more early returning the children to the familiar social environment.

The cost-effectiveness of semi-rigid ankle brace to facilitate return to work following first-time acute ankle sprains.

To examine the cost-effectiveness of semi-rigid ankle brace to facilitate return to work following first-time acute ankle sprains. Economic evaluation based on cost-utility analysis. Ankle sprains are a source of morbidity and absenteeism from work, accounting for 15-20% of all sports injuries. Semi-rigid ankle brace and taping are functional treatment interventions used by Musculoskeletal Physiotherapists and Nurses to facilitate return to work following acute ankle sprains. A decision model analysis, based on cost-utility analysis from the perspective of National Health Service was used. The primary outcomes measure was incremental cost-effectiveness ratio, based on quality-adjusted life years. Costs and quality of life data were derived from published literature, while model clinical probabilities were sourced from Musculoskeletal Physiotherapists. The cost and quality adjusted life years gained using semi-rigid ankle brace was £184 and 0.72 respectively. However, the cost and quality adjusted life years gained following taping was £155 and 0.61 respectively. The incremental cost-effectiveness ratio for the semi-rigid brace was £263 per quality adjusted life year. Probabilistic sensitivity analysis showed that ankle brace provided the highest net-benefit, hence the preferred option. Taping is a cheaper intervention compared with ankle brace to facilitate return to work following first-time ankle sprains. However, the incremental cost-effectiveness ratio observed for ankle brace was less than the National Institute for Health and Care Excellence threshold and the intervention had a higher net-benefit, suggesting that it is a cost-effective intervention. Decision-makers may be willing to pay £263 for an additional gain in quality adjusted life year. The findings of this economic evaluation provide justification for the use of semi-rigid ankle brace by Musculoskeletal Physiotherapists and Nurses to facilitate return to work in individuals with first-time ankle sprains.

Ankle bracing effects on knee and hip mechanics during landing on inclined surfaces

Knee and hip alignment and knee moments during landing are considered risk factors for knee injuries while ankle bracing has been demonstrated to alter landing kinematics and kinetics at these joints. The aim of this study was to investigate whether a semi-rigid ankle brace has an effect on knee and hip kinematics and kinetics during landing on uneven surfaces. Seventeen recreational athletes performed a landing task on a randomly inclined platform with and without an ankle brace. Three different surface alignments were generated: everted, neutral, and inverted. Ground reaction forces (GRF), kinematics, and brace reaction forces were measured. Two independent variables were tested: the brace factor (braced and non-braced) and the inclination factor (everted, neutral, and inverted). Seven separate 2 × 3 repeated measures MANOVAs were employed to compare GRF, knee, and hip initial angles and range of motion (ROM), knee, and hip forces and moments. Participants landed with a more flexed knee and hip during the brace condition, followed by a knee ROM reduction. No differences were observed for the kinetic variables. Landing on the inverted surface resulted in increased peak magnitudes of the vertical and the mediolateral GRF compared to landing on the neutral surface. Landing on the everted surface caused higher knee and hip abduction moments during early contact. Results confirm that ankle bracing may affect the kinematics of the whole lower extremity with no effect on knee or hip loading. Landing on uneven surfaces may increase injury risk, but no adverse effects were shown for wearing the brace.

Effects of 2 Resistive Exercises on Electrophysiological Measures of Submandibular Muscle Activity

ObjectiveTo compare the electrophysiological activity in submandibular hyolaryngeal muscles during performance of 2 exercises that incorporate resistance against muscular contraction. DesignWithin-subject repeated-measures design. SettingAcademic research laboratory. ParticipantsHealthy, young adult women (N=26; mean age, 24.1y) without a history of dysphagia, cervical spine conditions, neurologic disease, or head/neck cancer. InterventionsParticipants performed 2 isometric exercises requiring contraction against resistance to the submandibular hyolaryngeal muscles: one requiring jaw opening against a semirigid brace (chin-to-chest [CtC] exercise) and one requiring a chin tuck against an air-inflated rubber ball (chin tuck against resistance [CTAR] exercise). Measures of electrophysiology using surface electromyography (sEMG) were obtained during exercise performance. Main Outcome MeasuresMicrovolts as measured from sEMG electrode sensors placed on the skin surface above the hyolaryngeal muscles (surface of skin above geniohyoid, mylohyoid, and anterior digastric). Dependent variables included peak contraction amplitude (in μV) and mean contraction amplitude (in μV) across 10 seconds of sustained contraction. ResultsSignificant effects of exercise on peak and mean contraction amplitudes were present when both exercises were compared with baseline sEMG activity. (P<.001 for both). Normalized values of peak contraction amplitude and mean contraction amplitude during performance of CtC were not significantly different compared with CTAR. ConclusionsThis study provides supporting evidence for the influence of 2 published exercises on motor unit recruitment in the submandibular hyolaryngeal muscles, both of which have been previously proposed as rehabilitative modalities. Theoretical and clinical implications are discussed.

Semi-rigid ankle braces and force transfer in the ankle joint when landing on inclined surfaces

Ankle bracing is a commonly used and successful intervention to reduce the incidence of ankle sprain injuries in sports games (e.g. Sitler et al., 1994). It has been pointed out that the exact mech...