Unbraced Conditions Research Articles

Influence of Prophylactic Ankle Bracing on Knee Joint Moments and Ground Reaction Forces during Side-step Cutting Tasks

OBJECTIVES Prophylactic ankle bracing is widely used to prevent ankle sprains, but its effects on knee joint mechanics, particularly regarding ACL injury risk, are less understood. This study aimed to investigate the influence of ankle bracing on knee joint kinetics and ground reaction forces (GRFs) during a 90° side-step cutting task.METHODS Thirty physically active participants (15 males, 15 females) performed cutting trials under braced and unbraced conditions. Knee flexion, abduction, and internal rotation moments, along with mediolateral, anteroposterior, and vertical GRFs, were measured using a motion analysis system and a force plate. Paired t tests were conducted to compare the knee joint moments and GRFs between the two conditions.RESULTS The results showed that while ankle bracing did not significantly affect GRFs, it significantly increased knee internal rotation moment (<i>p</i> = 0.003). No significant differences were observed in knee flexion or abduction moments.CONCLUSIONS Ankle bracing, though beneficial for ankle stability, may elevate the risk of ACL injuries during dynamic activities like cutting by increasing knee internal rotation moments. Clinicians and coaches should weigh the benefits of ankle bracing against potential risks to knee health and consider alternative injury prevention strategies focused on neuromuscular control and strength training.

Immediate Effects of Walking With a Knee Brace After Anterior Cruciate Ligament Reconstruction: A Biomechanical, Biochemical, and Structural Approach.

Individuals who undergo anterior cruciate ligament reconstruction (ACLR) are at higher risk of posttraumatic osteoarthritis. Altered joint tissue loading caused by aberrant gait biomechanics leads to deleterious changes in joint health linked to the onset of posttraumatic osteoarthritis. Knee braces have been used to modify joint tissue loading in individuals with joint injury, yet the effects of walking with a brace after ACLR on biomechanical, biochemical, and structural cartilage outcomes are unknown. To compare biomechanical, biochemical, and structural outcomes between braced and nonbraced walking in individuals with ACLR. Crossover study. Research laboratory. A total of 34 individuals with unilateral ACLR (18 females, 16 males; time since ACLR = 50.1 ± 36.8 months). Gait biomechanics were assessed during braced and unbraced conditions on separate days. Vertical ground reaction force, knee-flexion angle, and internal knee-extension moment waveforms were evaluated throughout the stance phase and compared between conditions. Percentage changes in serum cartilage oligomeric matrix protein (%ΔCOMP) and femoral cartilage cross-sectional area (%ΔCSA) measured via ultrasound were calculated after a 3000-step walking protocol. Braced walking increased the knee-flexion angle (largest difference = 3.56°; Cohen d effect size = 1.72) and knee-extension moment (largest difference = -0.48% body weight × height; Cohen d effect size = -1.14) compared with nonbraced walking but did not influence vertical ground reaction force. Whereas no difference (P = .20) in %ΔCOMP existed between the braced and nonbraced conditions in the entire cohort (n = 30 with complete blood data), a larger increase (P = .04) in %ΔCOMP was seen during nonbraced than braced walking in individuals who demonstrated increased COMP during nonbraced walking. No difference (P = .86) in %ΔCSA was present between the braced and nonbraced conditions. Braced walking may improve sagittal-plane gait biomechanics and %ΔCOMP in a subset of individuals who demonstrate a typical increased COMP response to load (ie, increase in COMP) after nonbraced walking.

Finite Element Analysis of a Novel Approach for Knee and Ankle Protection during Landing

There is a high risk of serious injury to the lower extremities during a human drop landing. Prophylactic knee and ankle braces are commonly used to reduce injury by restraining the motion of joints. However, braces that restrain joint range of motion (ROM) may have detrimental effects on the user’s kinematical performance and joint function. The present study aimed to propose a novel set of double-joint braces and to evaluate its protective performance in terms of the ankle and knee. Accordingly, the finite element method was performed to investigate the biomechanical responses of the ankle and knee in braced and unbraced conditions. The results showed that the semi-rigid support at the ankle joint can share the high impact force that would otherwise be inflicted on one’s lower extremity, thereby reducing the peak stress on the inferior articular surface of the tibia, menisci, and articular cartilages, as well as the horizontal force on the talus. Moreover, with knee bending, the elongated spring component at the knee joint can convert the impact kinetic energy into elastic potential energy of the spring; meanwhile, the retractive force generated by the spring also provides a more balanced interaction between the menisci and articular cartilages. This biomechanical analysis can accordingly provide inspiration for new approaches to place human lower extremities at lower risk during landings.

Effect of Prophylactic Knee Bracing on Anterior Cruciate Ligament Agonist and Antagonist Muscle Forces During Perturbed Walking.

Background:Anterior cruciate ligament (ACL) injuries most commonly occur after a perturbation. Prophylactic knee braces (PKBs) are off-the-shelf braces designed to prevent and reduce the severity of knee injuries during sports, yet their effectiveness has been debated.Purpose:To identify differences in ACL agonist and antagonist muscle forces, during braced and unbraced conditions, while walking with the application of unexpected perturbations.Study Design:Controlled laboratory study.Methods:A total of 20 recreational athletes were perturbed during walking at a speed of 1.1 m/s, and motion analysis data were used to create patient-specific musculoskeletal models. Static optimization was performed to calculate the lower-limb muscle forces. Statistical parametric mapping was used to compare muscle forces between the braced and unbraced conditions during the stance phase of the perturbed cycle.Results:The brace reduced muscle forces in the quadriceps (QUADS), gastrocnemius (GAS), and soleus (SOL) but not in the hamstrings. The peak QUADS muscle force was significantly lower with the brace versus without at 49% to 60% of the stance phase (28.9 ± 12.98 vs 14.8 ± 5.06 N/kg, respectively; P < .001) and again at 99% of the stance phase (1.7 ± 0.4 vs 3.6 ± 0.13 N/kg, respectively; P = .049). The SOL muscle force peak was significantly lower with the brace versus without at 25% of the stance phase (1.9 ± 1.7 vs 4.6 ± 3.4 N/kg, respectively; P = .031) and at 39% of the stance phase (1.9 ± 1.4 vs 5.3 ± 5.6 N/kg, respectively; P = .007). In the GAS, there were no significant differences between conditions throughout the whole stance phase except between 97% and 100%, where the braced condition portrayed a smaller peak force (0.23 ± 0.13 vs 1.4 ± 1.1 N/kg for unbraced condition; P = .024).Conclusion:These findings suggested that PKBs that restrict knee hyperextension and knee valgus/varus motion can alter neuromuscular patterns, which result in a reduction of QUADS force.Clinical Relevance:Understanding the way PKBs alter muscle function and knee mechanics can provide invaluable information that will help in making decisions about their use. Further studies should investigate different types of braces and perturbations to evaluate the effectiveness of PKBs.

The effects of ankle barcing to the volleyball players performance

Volleyball is characterized by short and quick movements. The repetitive jumping and side-to-side movements required in volleyball increase the risk of injuries to the foot and ankle. Ankle injuries, particularly sprains, are the most common injuries sustained in volleyball. Ankle bracing used extensively to enhance ankle joint stability, prevent injury occurrence, and mitigate severity. Ankle braces are not mandatory in volleyball but it commonly used during the rehabilitation period after ankle sprains by the players for a long time. There are some adverse effects of bracing. Pressure to the muscles surrounding the joint can result additional damage such as muscle weakness. Muscle weakness can impair athletic performance can decrease jumping height. We measured and compared vertical jump height on braced and unbraced conditions. The results showed that, the tallest jump, less time for jumping and maximal force impulse were accounted for the unbraced condition.

Effect of Ankle-Foot-Orthosis on Loading of the Uninvolved Extremity in Children With Hemiplegic Cerebral Palsy

Bone deformities, the result of abnormal loading, are common in children with spastic hemiplegic cerebral palsy (SHCP). Although the purpose of ankle-foot-orthosis (AFO) is to account for loading abnormalities, little is known about the loading patterns of the uninvolved lower extremity (LE). The purpose, therefore, of this study was to investigate the loading patterns of the uninvolved hip in children with SHCP by comparing braced and un-braced conditions.

Effects of a knee valgus unloader brace on medial femoral articular cartilage deformation following walking in varus-aligned individuals

BackgroundKnee varus alignment may increase loading in the medial tibiofemoral compartment, which can increase strain on the articular cartilage. Knee valgus unloader braces seek to reduce loading through the medial femoral compartment, but their effects on cartilage characteristics during dynamic tasks have not been evaluated. ObjectiveTo determine the effects of a knee valgus unloader brace on medial femoral articular cartilage deformation following a single 5000-step walking protocol in individuals with varus-knee alignment. MethodsTwenty-four healthy individuals (63% female, BMI = 22 ± 3 kg/m2, age = 21 ± 3 years) completed two testing sessions (braced and unbraced) separated by one week. During both sessions, femoral cartilage ultrasound images were acquired prior to and following a 5000-step treadmill walking protocol at self-selected speed. Percent change scores in medial cartilage cross-sectional area (MCCA) were calculated and used as the primary outcome, and compared between the braced and unbraced conditions. ResultsThere was no difference in percent change of MCCA between conditions (braced = −2.77%, unbraced = −3.15%, p = 0.699). Individuals whose cartilage deformed more than a previously established minimal detectable change (MDC ≥ 1.58 mm2) deformed less during the braced condition (braced = −2.94%, unbraced = −6.34%, p = 0.028), compared to individuals who did not deform greater than the MDC (n = 15, braced = −2.67%, unbraced = −1.23%, p = 0.210). ConclusionsThere was no significant difference in MCCA percent change between the braced and unbraced conditions across the entire cohort; yet a valgus unloader braces may serve as a potential intervention strategy for reducing articular cartilage deformation in certain varus-aligned individuals who normally undergo measurable deformation during walking.

The effects of wearing an Ankle Stabilizing Orthosis (ASO) Ankle Brace on ankle joints kinetics and kinematics during a basketball rebounding task

Following an ankle injury, athletes sometimes brace the injured ankle in hopes of minimizing the likelihood of suffering a recurring injury. This study aims to evaluate the effects of wearing an Ankle Stabilizing Orthosis (ASO) ankle brace unilaterally on the dominant side on bilateral ankle joint kinetics and kinematics and peroneus longus EMG activity. Since a significant proportion of ankle injuries in basketball occur during rebounding, data was collected during a simulated rebounding task. Rebounding is defined as the act of retrieving a missed shot attempt. Subjects oftentimes jump vertically to acquire the basketball as it rebounds from the backboard or rim.Sixteen subjects participated in the study (11 males, 5 females; mean age = 26.94 years, SD = 5.32; mean height 1.72 m, SD = 0.08; mean weight 73.95 kg, SD = 13.68).Participants completed the rebounding task in braced (ASO) and unbraced (UB) conditions. Ankle and foot inversion angles, ankle inversion moments and peroneus longus EMG activity were recorded and analysed to determine the effects of wearing an ankle brace unilaterally.In the dominant limb, when compared to UB, ASO reduced ankle and foot inversion, and increased ankle inversion moments. No significant differences were observed in peroneus longus EMG activity. In the non-dominant limb, no significant differences were observed for any of the parameters.These results suggest that wearing an ASO ankle brace on the dominant ankle reduces maximum ankle and foot inversion angles without posing an increased risk to the unbraced leg. However, the increased ankle inversion moments in the braced ankle suggest that there are adjustments regarding force distribution, perhaps due to the restricted range of motion.

The Effect of Ankle Bracing on Kinematics in Simulated Sprain and Drop Landings: A Double-Blind, Placebo-Controlled Study

Background: The efficacy of external ankle braces to protect against sudden inversion sprain has yet to be determined while taking into account the possible placebo effect of brace application. Purpose: To assess the protective effect of an external ankle brace on ankle kinematics during simulated inversion sprain and single-legged drop landings among individuals with a history of unilateral lateral ankle sprain. Hypothesis: The primary hypothesis was that active and placebo external braces would reduce inversion angle during simulated inversion sprain. Study Design: Controlled laboratory study. Methods: Sixteen participants with ankle instability and previous sprain performed single-legged drop landings and sudden inversion tilt perturbations. Kinematics of the affected limb were assessed in 3 conditions (active bracing, passive placebo bracing, and unbraced) across 2 measurement days. Participators and investigators were blinded to the brace type tested. The effect of bracing on kinematics was assessed with repeated measures analysis of variance with statistical parametric mapping, with post hoc tests performed for significant interactions. Results: Only active bracing reduced inversion angles during a sudden ankle inversion when compared with the unbraced condition. This reduction was apparent between 65 and 140 milliseconds after the initial fall. No significant differences in inversion angle were found between the passive placebo brace and unbraced conditions during sudden ankle inversion. Furthermore, no significant differences were found among all tested conditions in the sagittal plane kinematics at the knee and ankle. Conclusion: During an inversion sprain, only the actively protecting ankle brace limited inversion angles among participants. These results do not indicate a placebo effect of external bracing for patients with ankle instability and a history of unilateral ankle sprain. Furthermore, sagittal plane knee kinematics appear to remain unaffected by bracing during single-legged landing, owing to the limited effects of bracing on sagittal ankle kinematics. These results highlight the role of brace design on biomechanical function during sports-related and injury-prone movements. Clinical Relevance: Athletes prone to reinjury after lateral ankle sprain may benefit from brace designs that allow for full sagittal range of motion but restrict only frontal plane motion.

Do Prophylactic Knee Braces Protect the Knee Against Impacts or Tibial Moments? An In Vitro Multisensory Study.

Background:Knee braces are prescribed by physicians to protect the knee from various loading conditions during sports or after surgery, even though the effect of bracing for various loading scenarios remains unclear.Purpose:To extensively investigate whether bracing protects the knee against impacts from the lateral, medial, anterior, or posterior directions at different heights as well as against tibial moments.Study Design:Controlled laboratory study.Methods:Eight limb specimens were exposed to (1) subcritical impacts from the medial, lateral, anterior, and posterior directions at 3 heights (center of the joint line and 100 mm inferior and superior) and (2) internal/external torques. Using a prophylactic brace, both scenarios were conducted under braced and unbraced conditions with moderate muscle loads and intact soft tissue. The change in anterior cruciate ligament (ACL) strain, joint acceleration in the tibial and femoral bones (for impacts only), and joint kinematics were recorded and analyzed.Results:Bracing reduced joint acceleration for medial and lateral center impacts. The ACL strain change was decreased for medial superior impacts and increased for anterior inferior impacts. Impacts from the posterior direction had substantially less effect on the ACL strain change and joint acceleration than anterior impacts. Bracing had no effect on the ACL strain change or kinematics under internal or external moments.Conclusion:Our results indicate that the effect of bracing during impacts depends on the direction and height of the impact and is partly positive, negative, or neutral and that soft tissue absorbs impact energy. An effect during internal or external torque was not detected.Clinical Relevance:Bracing in contact sports with many lateral or medial impacts might be beneficial, whereas athletes who play sports with rotational moments on the knee or anterior impacts may be safer without a brace.

Effects of a hip brace on biomechanics and pain in people with femoroacetabular impingement

ObjectivesThis study evaluates whether hip bracing in patients with femoroacetabular impingement (FAI) (a) immediately reduces range of hip internal rotation, flexion, adduction, and pain during functional tasks; and (b) improves patient-reported outcomes when worn daily over 4 weeks. DesignWithin-participant design followed by a case series. MethodsTwenty-five adults with symptomatic FAI underwent 3D kinematic assessment with and without a hip brace during single-leg squat, double-leg squat, stair ascent, and stair descent. A subset of this population (n=17) continued to wear the brace daily for 4-weeks. A linear mixed statistical model was used to assess pain and kinematic differences between the braced and unbraced conditions at baseline testing. Patient-reported outcomes (NRS pain, iHot-33 and HAGOS questionnaires) at 4-weeks were compared to baseline using paired t-tests. ResultsBracing resulted in significant but small reductions in peak hip flexion ranging between 5.3° (95% CI 0.8°–9.7°) and 5.6° (95% CI 1.1°–10.0°), internal rotation ranging between 2.5° (95% CI 0.6°–4.4°) and 6.4° (95% CI 4.5°–8.2°), and adduction ranging between 2.2° (95% CI 0.5°–3.8°) and 3.3° (95% CI 1.6°–5.0°) during all tasks, except flexion during single-leg squat, compared with the unbraced condition; pain was not significantly improved with the brace. Bracing over four weeks did not significantly change patient-reported outcomes. ConclusionsBracing subtly limited impinging hip movements during functional tasks, but did not immediately reduce pain or improve patient-reported clinical outcomes after 4 weeks in a young adult cohort with long-standing FAI.

The effect of ankle bracing on landing biomechanics in female netballers

ObjectivesInvestigate the impact of lace-up ankle braces on landing biomechanics. DesignWithin-subject repeated measures. Participants completed a drop jump, drop land, and netball-specific task in braced and unbraced conditions. SettingBiomechanical research laboratory. ParticipantsTwenty female high school netballers. Main outcome measuresLeg, knee, and ankle stiffness, knee/ankle stiffness ratio, knee and ankle sagittal excursion, peak vertical ground reaction force, time-to-peak vertical ground reaction force, and loading rate. ResultsIn the brace condition leg stiffness increased bilaterally during the drop land (ES = 0.21, 0.22), ankle stiffness increased bilaterally during the drop jump (ES = 0.37, 0.29) and drop land (ES = 0.40, 0.60), and knee/ankle stiffness ratio decreased in all three tasks (ES = −0.22 to −0.45). Ankle sagittal excursion decreased bilaterally during the drop jump (ES = −0.35, −0.53) and drop land (ES = −0.23, −0.46), and decreased in the lead limb during the netball jump (ES = −0.36). Knee excursion decreased bilaterally during the drop jump (ES = −0.36, −0.40) and in the lead limb during netball task (ES = −0.59). Lead limb TTP was greater during the netball jump (ES = 0.41). ConclusionsLace-up ankle braces may increase leg and joint stiffness and reduce joint excursion during landing but do not appear to affect landing forces. The observed effect on landing biomechanics may predispose young netballers to injury.

Electromyographic analysis of anterior cruciate deficient knees with and without functional bracing during lunge exercise.

The use of functional knee braces for returning to sports or during demanding activities following anterior cruciate ligament rupture is common; yet despite being commonly prescribed, its mechanism of action remains unknown. To examine the effect of functional knee braces on mean muscle activity when performing lunge exercises. Pre-/post-test (within-subject research design). A total of 10 male participants with unilateral isolated anterior cruciate ligament deficiency participated. Electromyographic activities of six muscles around the knee were recorded during lunge exercises, with and without wearing a custom functional knee brace. The lunge cycle movement was subdivided into three phases: eccentric, isometric, and concentric. The quadriceps and hamstrings were no different in the braced and unbraced conditions. When braced, the mean amplitude of the medial gastrocnemius was significantly lower throughout the whole movement (p = 0.01) and during the concentric (p = 0.006) and eccentric (p = 0.028) phases, but not within the isometric phase. The lateral gastrocnemius was found to have lower mean amplitude in the isometric phase (p = 0.044). With its origin on the medial femoral condyle, perhaps reduced medial gastrocnemius activity may better guide knee rotation and assist the joint achieving a healthier kinematic pattern. Lower medial gastrocnemius activity may facilitate lower medial compartment contact pressure, for which greater loading is known to increase the risk of osteoarthritis in anterior cruciate ligament-deficient (ACLD) knees. However, further research is needed.

Effect of a spinal brace on postural control in different sensory conditions in adolescent idiopathic scoliosis: A preliminary analysis

BackgroundDespite the positive effects of spinal braces on postural stability, they may constrain movement, resulting in poor balance control in patients with adolescent idiopathic scoliosis (AIS). Therefore, assessment of postural dynamics may aid in designing new less-constraining braces. ObjectivesThe effects of a spinal brace on postural stability and Cobb angle were investigated in this study. MethodsThirteen pediatric patients (10 females, three males) with AIS were recruited to participate in the study. Cobb angle was assessed by X-ray analyses, and postural stability was tested by computerized dynamic posturography in braced and unbraced conditions. A polyethylene underarm corrective spinal brace was fabricated for the subjects. ResultsThoracic and lumbar curvature decreased to 18.88±11.73° and 17.70±10.58°, respectively, after bracing (p<0.05). Lower equilibrium scores were observed in the “eyes closed” condition and higher scores in the “eyes closed with a swaying support” condition; higher composite equilibrium scores were also observed for the sensory organization test (p<0.05) in the braced condition. Lower scores were observed for the “toes-up adaptation test” in the braced condition (p<0.05). In the braced condition, the reaction time was slower in the right-backward direction and movement velocity was higher in the right-front direction on the limits of stability test (p<0.05). Furthermore, lower on-axis velocity during forward/backward dynamic balance control was observed in the braced condition (p<0.05). ConclusionsWearing a spinal brace improved postural stability in terms of increased proprioception, equilibrium performance, and rhythmic movement ability in patients with AIS.

Kinematic Evaluation of 4 Pediatric Collars and Distribution of Cervical Movement Between Primary and Coupled Angles

Primary and coupled angle restrictions, when neck collars are used, have been investigated mainly in adults and not yet in children. To evaluate the efficiency of 4 pediatric collars in reducing cervical range of motion (ROM) in primary and coupled planes. Thirty asymptomatic children (16 boys and 14 girls) aged 6 to 12 years participated in the study. A motion analysis system was used to evaluate the ROM of the cervical spine during flexion/extension, left and right lateral bending, and left and right axial rotation. Primary and coupled ROM were evaluated in unbraced and braced conditions. Four cervical collars were tested: Philadelphia, Miami Jr, Necloc, and the conventional Hard Collar. Thirteen subjects were tested 2 times to evaluate the repeatability of the parameters. The ROM in each plane was normalized to the sum of the ROM in the 3 planes, for each movement, to estimate the percentage of the movement in each plane (normalized ROM), in braced and unbraced conditions. The analysis of variance and post hoc Benferroni tests were applied on raw and normalized ROM. ROM collected in collars showed a significant difference compared with the unbraced condition. ROM obtained in Necloc and Miami Jr showed a significant difference compared with Philadelphia and conventional Hard Collar. The primary plane is activated at 80% during flexion-extension and left-right axial rotation; however, 55% of the total movement was completed in the frontal plane during left-right lateral bending in unbraced condition. Statistical differences in the normalized ROM were found between the braced and unbraced conditions and among collars. Necloc and Miami Jr presented the highest limitation of movement in the primary and secondary planes. The distribution strategy of a movement, between primary and coupled angles, is different between the braced and unbraced conditions.

The Effect of Knee Braces on Tibial Rotation in Anterior Cruciate Ligament – Deficient Knees During High Demand Athletic Activities

OBJECTIVE To examine if bracing can restrict tibial rotation in anterior cruciate ligament (ACL)-deficient patients during high loading activities. DESIGN Repeated measures. Kinematic data were collected with an 8-camera Vicon system while each patient performed 2 tasks that are known to cause increased rotational and translational loads on the knee: (1) descending from a stair and subsequent pivoting, and (2) landing from a platform and subsequent pivoting. The tasks were repeated under 3 brace conditions for the ACL-deficient knee: (1) wearing a prophylactic brace (braced condition), (2) wearing a patellofemoral brace (sleeved condition), and (3) without brace (unbraced condition). SETTING Biomechanical laboratory study. PATIENTS Twenty-one male subjects with a confirmed unilateral ACL rupture were assessed in vivo. MAIN OUTCOME MEASURES Tibial internal rotation. Two repeated measures ANOVAs tested for differences in tibial internal rotation among the 3 conditions of the ACL-deficient knee and the unbraced condition of the intact knee. RESULTS In both tasks, tibial rotation was significantly lower in the intact knee compared with all 3 conditions of the ACL-deficient knee (P ≤ 0.031). Bracing the ACL-deficient knee resulted in lower rotation than the unbraced (P ≤ 0.001) and sleeved (P ≤ 0.033) conditions. The sleeved condition resulted in lower tibial rotation in the drop landing and pivoting task compared with the unbraced condition (P = 0.019) but not in the stair descending and pivoting task (P = 0.256). CONCLUSIONS Bracing decreased the excessive tibial rotation in ACL-deficient patients during high-demand activities but failed to fully restore normative values. If knee braces can enhance rotational knee stability in ACL-deficient patients, then they could possibly play an important role in preventing further knee pathology in such patients.

Brace Evaluation in Children with Diplegic Cerebral Palsy with a Jump Gait Pattern

Brace prescription for children with diplegic cerebral palsy challenges the clinician with a variety of options and little evidence for rational decisions. Previous studies have indicated that ankle-foot orthoses improve toe-walking, but it is unclear if any brace is better than another. The goal of the present study was to compare the effectiveness of hinged and dynamic ankle-foot orthoses in terms of improving gait and motor function in a homogeneous group of children with diplegic cerebral palsy exhibiting a jump gait pattern. Fifteen children (mean age, 7.5 years) with spastic diplegic cerebral palsy who were able to walk independently with a jump gait pattern and twenty children (mean age, 10.6 years) with normal gait participated in the study. Standardized Gross Motor Function Classification System scores, Pediatric Outcomes Data Collection Instrument scores, and gait data were collected, analyzed, and compared. The subjects were tested while barefoot and while wearing hinged and dynamic ankle-foot orthoses. Data were analyzed to detect differences among these conditions. Significant improvements in gait metrics were seen during brace wear. No significant differences were seen between the two different braces used. The barefoot and braced conditions differed most significantly in terms of ankle kinematics and kinetics. Among the patients with cerebral palsy, no significant differences in the standardized outcome measurements were found between the braced and unbraced conditions or between the two braced conditions. Our data suggest that gait improves with brace wear in children with cerebral palsy with a level-I Gross Motor Function Classification System score. The Pediatric Outcomes Data Collection Instrument and the Gross Motor Function Measure were not sensitive to brace treatment in the population studied. The hinged and dynamic braces were equally effective for improving ankle kinematics and kinetics in these relatively highly functioning children with cerebral palsy.

Ankle Bracing, Plantar-Flexion Angle, and Ankle Muscle Latencies During Inversion Stress in Healthy Participants

Ankle braces may enhance ankle joint proprioception, which in turn may affect reflexive ankle muscle activity during a perturbation. Despite the common occurrence of plantar-flexion inversion ankle injuries, authors of previous studies of ankle muscle latencies have focused on inversion stresses only. To examine the latency of the peroneus longus (PL), peroneus brevis (PB), and tibialis anterior (TA) muscles in response to various degrees of combined plantar-flexion and inversion stresses in braced and unbraced asymptomatic ankles. Repeated measures. University biomechanics laboratory. Twenty-eight healthy females and 12 healthy males (n = 40: mean age = 23.63 years, range = 19 to 30 years; height = 172.75 +/- 7.96 cm; mass = 65.53 +/- 12.0 kg). Participants were tested under 2 conditions: wearing and not wearing an Active Ankle T1 brace while dropping from a custom-made platform into 10 degrees , 20 degrees , and 30 degrees of plantar flexion and 30 degrees of inversion. The time between platform drop and the onset of PL, PB, and TA electromyographic activity was measured to determine latencies. We calculated a series of 2-way analyses of variance to determine if latencies were different between the conditions (braced and unbraced) and among the plantar-flexion angles (alpha = .05). No interaction was found between condition and plantar-flexion angle. No significant main effects were found for condition or plantar-flexion angle. Overall means for braced and unbraced conditions were not significantly different for each muscle tested. Overall means for angle for the PL, PB, and TA were not significantly different. Reflexive activity of the PL, PB, or TA was unaffected by the amount of plantar flexion or by wearing an Active Ankle T1 brace during an unanticipated plantar-flexion inversion perturbation.

Study on three-dimensional kinematics and electromyography of ACL deficient knee participants wearing a functional knee brace during running

This investigation examined the muscular activity and 3D knee joint kinematic changes of anterior cruciate ligament-deficient (ACLD) participants in the involved leg under bracing condition during running. Different adaptation strategies have been found between patients who can cope with the injury and patients who cannot. One of the expected changes can be the muscle activation characteristic of the injured knee during strenuous activity with and without a functional knee brace. Three-dimensional kinematic and electromyographical (EMG) data were collected from 11 participants for 10 consecutive gait cycles during running on a treadmill under both braced and unbraced conditions. Participants were administered the "Knee Outcome Survey Activities of Daily Living Scale" to distinguish functional and non-functional candidates. No significant differences on 3D kinematics and EMG data were noted between functional and non-functional participants, thus data analysis focused on comparisons of bracing conditions for one combined group. Bracing significantly reduced total range of motion in the frontal and transverse planes (P<0.05). Muscle activity at heel-strike showed a consistent trend to increase for the hamstrings and decrease for the quadriceps under the braced condition when compared to the unbraced condition. Our findings indicate that bracing the ACLD knee alters the kinematics of the injured leg while running. Tendencies toward reductions in quadriceps and increases in hamstrings activity at heel-strike indicate that bracing might have resulted in added stability of the injured knee. The adaptations to bracing found in this preliminary study further support the potential mechanical and proprioceptive contributions of the functional knee brace to protect the ACLD knee.

The Effect of Custom-Made Braces for the Ankle and Hindfoot on Ankle and Foot Kinematics and Ground Reaction Forces

Kitaoka HB, Crevoisier XM, Harbst K, Hansen D, Kotajarvi B, Kaufman K. The effect of custom-made braces for the ankle and hindfoot on ankle and foot kinematics and ground reaction forces. Objective To assess the effects on gait of custom-made polypropylene orthoses: ankle-foot orthosis (AFO), rigid hindfoot orthosis (HFO-R), and articulated hindfoot orthosis (HFO-A). Design Experimental assessment. Setting Institutional practice, motion analysis laboratory. Participants Twenty asymptomatic normative subjects. Interventions Not applicable. Main Outcome Measures Three-dimensional kinematics, ground reaction force, and time-related factors in 4 conditions: shoe only, and shod with the AFO, HFO-R, and HFO-A. Results The AFO and HFO-R limited sagittal and coronal plane ankle-hindfoot motion. The HFO-A limited hindfoot coronal motion while allowing normal sagittal motion. At the midfoot, the AFO and HFO-A limited transverse motion, but the HFO-A also limited sagittal and coronal motion. Use of the HFO-R resulted in exaggerated midfoot sagittal and coronal motion. Braces that limited motion to a greater degree were associated with more atypical kinetic variables, indicative of less dynamic gait. The HFO-A resulted in ground reaction forces most similar to unbraced conditions. Conclusions Alteration in gait was affected by orthosis design. Orthoses with a rigid component crossing a joint restricted motion at that joint, but potentially compromised typical gait kinetic factors. For immobilizing the hindfoot, the HFO-A may be more comfortable and still provide more stability than the HFO-R or AFO.