Lecture 16 ORTHOTICS Bracing the Lower Extremity

A long leg brace allows patients to walk despite weakness. When prescribing a brace, the physician should consider its six components—trunk attachment, thigh piece, knee joint, calf piece, ankle joint and foot piece. Short leg braces and foot braces pose different problems, but, like the long leg brace, they should be comfortable, durable and accomplish their purpose.     

Electromyographic and cinematographic analysis of movement from a kneeling to a standing position in healthy 5- to 7-year-old children

Physical therapists often use transitional postures such as half-kneeling to help children with movement dysfunction attain an upright posture. Little is known, however, about how healthy children activate lower extremity muscles to move the hip, knee, and ankle joints as they move from kneeling through half-kneeling to stand up against gravity. The purpose of this study was to describe movement from kneeling to standing in 10 healthy 5- to 7-year-old children. Electromyography was used to record the activity of four lower extremity muscles. Cinematography was used to record joint motion of the hip, knee, and ankle of the leg initiating movement, in addition to trajectories of specific anatomical landmarks as the children rose from a kneeling to a standing position. Greater active range of motion of the hip, knee, and ankle was necessary to move from a kneeling to a standing position using the half-kneel transitional posture than is required during normal gait. The activation patterns of the gastrocnemius, tibialis anterior, rectus femoris, and biceps femoris muscles of the leg initiating movement exhibited variability among subjects during the kneel-to-stand movement. Maximum joint range of motion and position of the hip, knee, and ankle joints at specific points in the movement exhibited less variability than patterns of muscle activation. The results showed that movement from a kneeling to a standing position in healthy children is quantifiable and can be used to help determine what normal components of movement are necessary to successfully master this movement against gravity that is antecedent to ambulation. Further studies are needed to investigate antigravity movement in younger children and in children with movement dysfunction to more fully understand normal and abnormal movement in children.     

The effect of functional knee brace design and hinge misalignment on lower limb joint mechanics

BACKGROUND: Knee bracing has been shown to alter lower limb joint mechanics, which may protect the anterior cruciate ligament. The effect of brace alignment and brace type, however, remains largely unknown. This study was conducted to determine whether the use of a functional knee brace, the type of brace used or its alignment relative to the knee causes biomechanical alterations to gait. METHODS: Ten healthy participants took part in two walking conditions (aligned brace and misaligned brace) for two different types of brace (sleeve brace with bilateral hinges and hinge-post-shell). A non-braced condition was included as a baseline measure. Three-dimensional kinematics and force platform data were used to calculate the joint intersegmental forces and net joint moments of the ankle, knee and hip. FINDINGS: In comparison to non-braced walking, the shell brace in its aligned position significantly reduced the peak ankle plantarflexor moment. There was a decreased peak knee flexion angle with both the aligned shell and sleeve braces. The shell brace in its aligned position significantly increased peak knee adduction and reduced peak knee internal rotation. INTERPRETATION: In this sample of healthy participants, functional knee bracing failed to alter lower limb mechanics in such a way that would reduce the force transmitted to the anterior cruciate ligament. In addition, although there were brace induced changes in lower limb kinematics with 2cm of distal hinge misalignment, it is unlikely that hinge misalignment of this magnitude is detrimental to an uninjured knee joint during walking.     

NOT ALL SINGLE LEG SQUATS ARE EQUAL: A BIOMECHANICAL COMPARISON OF THREE VARIATIONS

Background

The single leg squat (SLS) is a functional task used by practitioners to evaluate and treat multiple pathologies of the lower extremity. Variations of the SLS may have different neuromuscular and biomechanical demands. The effect of altering the non-stance leg position during the SLS on trunk, pelvic, and lower extremity mechanics has not been reported.

Purpose

The purpose of this study was to compare trunk, pelvic, hip, knee, and ankle kinematics and hip, knee, and ankle kinetics of three variations of the SLS using different non-stance leg positions: SLS-Front, SLS-Middle, and SLS-Back.

Methods

Sixteen healthy women performed the three SLS tasks while data were collected using a motion capture system and force plates. Joint mechanics in the sagittal, frontal, and transverse planes were compared for the SLS tasks using a separate repeated-measures analysis of variance (ANOVA) for each variable at two analysis points: peak knee flexion (PKF) and 60 ° of knee flexion (60KF).

Results

Different non-stance leg positions during the SLS resulted in distinct movement patterns and moments at the trunk, pelvis, and lower extremity. At PKF, SLS-Back exhibited the greatest kinematic differences (p < 0.05) from SLS-Front and SLS-Middle with greater ipsilateral trunk flexion, pelvic anterior tilt and drop, hip flexion and adduction, and external rotation as well as less knee flexion and abduction. SLS-Back also showed the greatest kinetic differences (p < 0.05) from SLS-Front and SLS-Middle with greater hip external rotator moment and knee extensor moment as well as less hip extensor moment and knee adductor moment at PKF. At 60KF, the findings were similar except at the knee.

Conclusion

The mechanics of the trunk, pelvis, and lower extremity during the SLS were affected by the position of the non-stance leg in healthy females. Practitioners can use these findings to distinguish between SLS variations and to select the appropriate SLS for assessment and rehabilitation.

Level of Evidence

3     

Braces and splints for musculoskeletal conditions

Braces and splints can be useful for acute injuries, chronic conditions, and the prevention of injury. There is good evidence to support the use of some braces and splints; others are used because of subjective reports from patients, relatively low cost, and few adverse effects, despite limited data on their effectiveness. The unloader (valgus) knee brace is recommended for pain reduction in patients with osteoarthritis of the medial compartment of the knee. Use of the patellar brace for patellofemoral pain syndrome is neither recommended nor discouraged because good evidence for its effectiveness is lacking. A knee immobilizer may be used for a limited number of acute traumatic knee injuries. Functional ankle braces are recommended rather than immobilization for the treatment of acute ankle sprains, and semirigid ankle braces decrease the risk of future ankle sprains in patients with a history of ankle sprain. A neutral wrist splint worn full-time improves symptoms of carpal tunnel syndrome. Close follow-up after bracing or splinting is essential to ensure proper fit and use.     

Evaluation of physiological properties of ankle braces based on a review of the literature]

INTRODUCTION: The objective of this work was to proceed to a review of the literature to assess the physiological basis of the ankle brace use. METHOD: An analysis of the international literature relating to the years 1980-2002 was carried out by questioning the Medline data bank. RESULTS: Three hundred and twenty-two articles were collected and 25 physiological studies were retained. Various changes can occur during brace use, first of all stability parameters and proprioceptive sense. Main changes affect position sense, stiffness, mobility and stability of ankle when standing. DISCUSSION: This review of the literature allows to specify the mechanisms involved by brace use in ankle stability. Some studies allow to compare the principal devices used to stabilize the ankle (taping, semi rigid braces) but, no physiological study was able to discriminate between different orthosis models. CONCLUSION: Many studies have been conducted in the field of the physiological evaluation of ankle orthosis. When these devices are widely used in current medical practice, physiological studies do not allow to characterize a better device with a specific test. These data point out the methodological difficulties in ankle brace evaluation.     

Whole body kinematics and knee moments that occur during an overhead catch and landing task in sport

BACKGROUND: Athletes suffering an anterior cruciate ligament injury tend to exhibit similar body postures that in sidestep cutting are associated with increased knee moments. This relationship, however, has not been investigated in landing. Catching a ball in different overhead positions may affect landing postures and knee joint moments. This study investigated these possible relationships. It was anticipated that some joint postures would be associated increased knee loads during the landing task. METHODS: Twenty-five healthy male team sports athletes performed four variations of a landing task. Full body kinematics were identified at initial contact. Peak flexion, valgus and internal rotation moments at the knee, measured during early landing, were normalized to mass and height and statistically compared. Intra-participant correlations were performed between all kinematics and each moment. Mean slopes for each correlation were used to identify the existence of relationships between full body kinematics and knee joint moments. Findings Landing after an overhead catch when the ball moved towards a player's support leg resulted in increased peak valgus moments. These increased valgus moments were correlated with increased knee flexion, hip flexion, and torso lean, as well as torso rotation towards the support leg, and foot and knee external rotation. Increased internal rotation moments were correlated with reduced hip abduction and external rotation, increased ankle inversion, knee external rotation and torso lean away from the support leg. Interpretation Learning to land with techniques that do not reflect postures associated with high knee moments may reduce an athlete's risk of non-contact anterior cruciate ligament injury.     

Effect of an anterior-sloped brace joint on anterior tibial translation and axial tibial rotation: A motion analysis study

Background

Anterior tibial translation and axial tibial rotation are major biomechanical factors involved in anterior cruciate ligament injuries. This study sought to evaluate a brace prototype designed with an anterior-sloped joint, in terms of its efficacy in attenuating anterior tibial translation and axial tibial rotation during landing, using a motion analysis approach.

Methods

Ten healthy male subjects performed single-leg landing tasks from a 0.6-m height with and without the brace prototype. Ground reaction force and kinematics data were obtained using a motion-capture system and force-plates. Anterior tibial translation and axial tibial rotation were determined based on tibial and femoral marker reference frames. Vertical and anterior–posterior ground reaction forces, hip, knee and ankle joint range-of-motions and angular velocities, anterior tibial translation and axial tibial rotation were compared between unbraced and braced conditions using Wilcoxon signed-rank test.

Findings

We found no significant difference in peak vertical and anterior–posterior ground reaction forces (p = 0.770 and p = 0.332 respectively) between unbraced and braced conditions. Knee joint range-of-motion and angular velocity were lower (p = 0.037 and p = 0.038 respectively) for braced condition than unbraced condition. Anterior tibial translation and axial tibial rotation were reduced (p = 0.027 and p = 0.006 respectively) in braced condition, compared to unbraced condition.

Interpretation

The anterior-sloped brace joint helps to attenuate anterior tibial translation and axial tibial rotation present in the knee joint during landing. It is necessary to test the brace prototype in a sporting population with realistic sports landing situations in order to assess its effectiveness in lowering anterior cruciate ligament injury risk.     

Comprehensive testing of 10 different ankle braces. Evaluation of passive and rapidly induced stability in subjects with chronic ankle instability

OBJECTIVE: The aim of the present investigation was to test the stability of 10 different ankle braces under passive and rapidly induced loading conditions in a population suffering from chronic ankle instability in order to provide objective information to choose or recommend an appropriate model for specific needs. In addition, the relationship between passive and rapidly induced testing of the stabilizing effect against inversion was evaluated to identify if passive support characteristics of braces are reflected under rapidly induced conditions. DESIGN: An experimental in vivo study with a repeated-measures design was used. BACKGROUND: Ankle braces are commonly used for treatment, rehabilitation, and prevention of ankle injuries. A variety of products exists but there is few information available to assist clinicians, physiotherapists and coaches as well as consumers in choosing a brace on a basis of objective information. Furthermore, there is a lack of studies that provide data for both passively and rapidly induced movement of the ankle joint when using different ankle braces. METHODS: Twenty-four subjects with chronic ankle instability participated in the project. Passive ankle range of motion measurements were performed in a custom-built fixture and simulated inversion sprains were elicited on a tilting platform. RESULTS: The tested braces restrict range of motion significantly compared to the no-brace condition for both the passively and rapidly induced inversion and marked differences between braces were revealed. A close relationship between passive and rapidly induced test results for inversion was found. CONCLUSIONS: Passive as well as rapidly induced stability tests provide a basis of objective information to describe the characteristics of different ankle braces. Combined results of passive and rapidly induced inversion as well as correlation between results demonstrate that passive support characteristics of braces are reflected under rapidly induced conditions but the amount of restriction is reduced. Therefore, caution should be taken when recommending braces for applications under dynamic circumstances only on the basis of passive support characteristics. RELEVANCE: A basis of information regarding the stability characteristics of different ankle braces under passive and rapidly induced conditions will help the clinician and consumer in choosing the most appropriate brace model for specific use. The results also provide more insights into factors that influence stability characteristics of ankle braces.     

Biomechanics of the Thorax: A Clinical Mode of in Vivo Function

Abstract

A clinical model of the in vivo biomechanics within the thorax is proposed. The relative motion of the thoracic vertebrae and the associated ribs both as moving bones (osteokinematics) and moving joints (arthrokinematics) is considered during sagittal, coronal and transverse motion of the trunk. Flexion and extension of the thorax induces anterior/posterior translation together with slight vertical translation of the vertebral elements. Simultaneously the ribs anteriorly/posteriorly rotate at the costotransverse joints. Sideflexion and rotation can occur both to the same side and to the opposite side in the midthorax and the lower thorax. The first pattern of motion occurs during axial rotation of the trunk while the latter occurs during lateral bending. The ribs rotate anteriorly on one side and posteriorly on the other during both lateral bending and axial rotation of the trunk. A clinical hypothesis of the mechanism which produces these coupling movement patterns is discussed.     

The effect of tibial insert design on rising from a chair; motion analysis after total knee replacement

BACKGROUND: There are few previous studies of sit-to-stand movement following total knee arthroplasty. Aim of the study was to test the hypotheses that total knee replacement alters the maximum trunk, hip, knee and ankle flexion-extension movements during chair rising, and that the design of the tibial plateau has small influence on the kinematics. METHODS: A motion analysis system was used to evaluate kinematics of the trunk, hip, knee and ankle when rising from one chair and sitting down on another. Patients with 5 degrees varus/valgus alignment or less received either a flat or a concave tibial insert with retention of the posterior cruciate ligament. Patients who had more malalignment and /or extension defect of 10 degrees or more were randomized to receive the concave or a posterior-stabilized tibial component with resection of the posterior cruciate ligament. The two groups of patients operated with and without resection of the posterior cruciate ligament were analysed separately and compared with a control group. 28 patients (29 knees) and 16 controls were in the final analysis. FINDINGS: Decreased hip and knee extension compared to the controls was seen, but there were no statistically significant differences in kinematics between the designs. INTERPRETATION: Choice of implant design in total knee arthroplasty had no detectable effects on kinematics of hip and knee joints during sit-to-stand movement.     

Movement variability during single leg jump landings in individuals with and without chronic ankle instability

Background

Repeated episodes of giving way at the ankle may be related to alterations in movement variability.

Methods

Eighty-eight recreational athletes (39 males, 49 females) were placed in 4 groups: mechanically unstable, functionally unstable, copers, and controls based on ankle injury history, episodes of giving way, and joint laxity. Lower extremity kinematics and ground reaction forces were measured during single leg landings from a 50% maximum vertical jump in the anterior, lateral, and medial directions. Ensemble curves of 10 trials were averaged and coefficients of variation were identified for ankle, knee, hip, and trunk motion in 3 planes. A log_e (ln) transformation was performed on the data. Mixed model analyses of variance (ANOVAs) with Tukey post-hoc tests were utilized with Bonferroni corrections to α ≤ 0.008.

Findings

At the knee, controls were more variable than functionally unstable and copers for knee rotation before initial contact, and were more variable during stance than functionally unstable in knee rotation (P ≤ 0.008). Interactions during stance revealed controls were more variable than functionally unstable in lateral jumps for hip flexion, and than mechanically and functionally unstable in hip abduction in the anterior direction (P ≤ 0.008). Controls were more variable than all other groups in hip flexion and than mechanically unstable in hip abduction (P ≤ 0.008).

Interpretation

Individuals with ankle instability demonstrated less variability at the hip and knee compared to controls during single leg jump landings. Inability to effectively utilize proximal joints to perform landing strategies may influence episodes of instability.     

Comparison of the ankle,knee, hip,and trunk corrective action shown during single-leg stance on firm,foam, and multiaxial surfaces

OBJECTIVE: To compare the quantity of ankle, knee, hip, and trunk corrective actions shown during single-leg stance. DESIGN: Counter-balanced crossover design. Single-leg stance under the conditions of eyes open on firm, foam, and multiaxial surfaces and eyes closed on a firm surface were recorded for 12 seconds in 18 participants. SETTING: A university neuromuscular research laboratory. PARTICIPANTS: Eighteen healthy and recreationally active college students. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Average angular displacement magnitude between successive sampling instances for the ankle, knee, hip, and trunk. RESULTS: A significant condition by joint interaction was revealed. Post hoc comparisons revealed that the ankle dominated as the source of corrective action across each of the testing conditions. As the challenge became greater because of foam surface or eyes closed, more corrective action occurred at proximal joints (hip and/or knee). CONCLUSIONS: The ankle is of primary importance during single-leg stance on firm, foam, and multiaxial surfaces, with proximal joints having an increased role under more challenging conditions. These results provide a scientific basis for clinicians' and researchers' decisions about support surface and visual condition during single-leg postural control testing and training.     

Surgical correction of leg alignment in unilateral knee osteoarthrosis reduces the load on the hip and knee joint bilaterally

Seventeen patients with strictly unilateral medial knee osteoarthrosis that justified surgical treatment constituted the study group. No patient had any symptoms from the hip or ankle joints or from the other knee. Eight patients were operated with high tibial osteotomy and nine were operated with unicompartmental prosthetic replacement (Brigham model). The forces and the external moment about the hip, knee, and ankle joints of the involved and uninvolved leg were calculated before and 1 year after corrective surgery and compared to the external moment in 10 normal controls. Clinical examinations was performed and the hip-knee-ankle angle in the involved leg was determined from whole-leg weightbearing radiographs before and 1 year after surgery. The external moments about the hip, knee, and ankle joints and the knee moment arms at mid-stance in the frontal plane during gait were determined with a Kistler force plate and a videorecording system. All patients improved clinically after surgery. The mean hip-knee-ankle angle changed from 11 degrees of varus to 0 degrees. In the uninvolved leg the mid-stance adduction moments about the hip and knee joints were significantly increased compared to normal subjects in the control group before surgery, but reduced to a normal level 1 year after surgery. This reduction was mainly due to a significant reduction of the medially directed force. The moments about the ankle joints were not found to be changed by the knee deformity or by the corrective surgery. RELEVANCE: This study demonstrates that a varus malalignment in the osteoarthrotic knee is accompanied by increased load about the uninvolved hip and knee joint. One might expect a more rapid progression of degenerative changes in joint cartilage as a consequence of such increased load. The reduced load after surgical correction of leg alignment might be beneficial to patients with osteoarthrosis of their hip and knee joints.     

The influence of an ankle foot orthosis on the percentage of weight loading during standing tasks in stroke patients

[Purpose] The aim of this study was to investigate the effects of an ankle foot orthosis on weight-bearing abilities of stroke patients by comparing weight loading during performance of tasks in various standing positions on the affected side. [Subjects and Methods] This study was performed with 16 stroke patients. To measure the weight loading value and percentage of weight loading in affected lower extremities, 5 standing tasks were performed with and without an ankle foot orthosis in random order. [Results] In the rising from a chair, maintaining a standing position, and forward weight shifting tasks, the affected lower extremities showed a significantly higher percentage of weight loading with an ankle foot orthosis. In the tasks requiring weight shifting to one leg, weight shifting to the lateral side showed the best weight-bearing ability with or without an ankle foot orthosis, followed by the forward and backward weight shifting, respectively. There were statistically significant correlations in all 5 tasks with or without an ankle foot orthosis. [Conclusion] An ankle foot orthosis improves the weight-bearing ability, especially when shifting weight forward, resulting in increased weight-bearing ability in activities of daily living tasks such as quiet standing and rising from a chair. The 5 tasks in this study would be a fine assessment tool under clinical conditions to investigate the postural stability of the affected side with or without application of an ankle foot orthosis.Key words: Ankle foot orthosis, Stroke, Weight-bearing ability     

Reliability of a Photographic Method for Assessing Standing Posture of Elementary School Students

ObjectiveA high prevalence of poor standing posture among elementary schoolchildren indicates the need for the introduction of school-based interventions for improvement of postural alignments. For assessing the effect of intervention programs, reliable quantitative measures of standing posture should be used. Therefore, the purpose of this study was to examine the reliability of a photographic method for assessment of standing posture among elementary schoolchildren.MethodsThe study was conducted on a convenience sample of 273 male students between 10 and 13 years old. Each subject was photographed in habitual standing posture, 3 times in a front view and 3 times in a side view. Deviations from ideal postural alignment were calculated with Posture Image Analyzer software and UTHSCSA ImageTool software. Interitem reliability was estimated using intraclass correlation coefficient.ResultsIntraclass correlation coefficients for posture deviations assessed with Posture Image Analyzer ranged from 0.81 for knee joints deviation and ankle joints deviation in the coronal plane to 0.92 for trunk deviation and knee joints deviation in the sagittal plane. Intraclass correlation coefficients for posture deviations assessed with UTHSCSA ImageTool ranged from 0.80 for knee joints deviation in the coronal plane to 0.91 for trunk deviation and knee joints deviation in the sagittal plane.ConclusionsThis study showed a satisfactory interitem reliability of a photographic method for the assessment of standing posture among elementary schoolchildren.     

Assessment of functional knee bracing: an in vivo three-dimensional kinematic analysis of the anterior cruciate deficient knee

OBJECTIVE: To describe three-dimensional tibial and femoral movements in vivo and examine the effect of a brace on knee kinematics during moderate to intense activity. DESIGN: Skeletal kinematics of anterior cruciate ligament deficient knees was measured with and without braces during moderate to intense activity. BACKGROUND: Invasive markers implanted into the tibia and femur are the most accurate means to directly measure skeletal motion and may provide a more sensitive measure of the differences between brace conditions. METHODS: Steinmann traction pins were implanted into the femur and tibia of four subjects having a partial or complete anterior cruciate ligament rupture. Non-braced and braced conditions were randomly assigned and subjects jumped for maximal horizontal distance to sufficiently stress the anterior cruciate ligament. RESULTS: Intra-subject peak vertical force and posterior shear force were generally consistent between conditions. Intra-subject kinematics was repeatable but linear displacements between brace conditions were small. Differences in angular and linear skeletal motion were observed across subjects. Bracing the anterior cruciate ligament deficient knee resulted in only minor kinematic changes in tibiofemoral joint motion. CONCLUSION: In this study, no consistent reductions in anterior tibial translations were observed as a function of the knee brace tested. Relevance. Investigations have reported that knee braces fail when high loads are encountered or when load is applied in an unpredictable manner. Questions remain regarding tibiofemoral joint motion, in particular linear displacements. The pin technique is a means for direct skeletal measurement and may provide a more sensitive measure of the differences between brace conditions.     

Changes in the range of angular variation of the ankle,knee, hip and neck joints related to the awareness of an impending perturbation

ObjectivesChallenging quiet standing tasks for the ankle, knee, hip, and neck joints were used to test the effect of pre-cueing on the reaction time of articular stabilization strategies.MethodWe assessed balance recovery in 15 subjects who were exposed to backward translations on a movable platform during two conditions: alerted, where participants gazed at a countdown light that pre-cued the onset of the platform translation; and unalerted, without onset time pre-cue.ResultsWe compared the angular variation of the ankle, knee, hip, and neck joints between the two conditions over four window epochs (0–50 ms; 50–100 ms; 100–150 ms; 150–200 ms). When comparing the window epochs of the ankle and hip joints between conditions, a significant effect was observed in the first and second windows. In the second and third windows, a significant effect was only observed in the alerted group, thereby indicating a faster stability for alerted condition. No significant effect was observed for the knee joint, while a significant effect was observed in the neck joint during the third and fourth windows of the alerted condition.ConclusionsPre-cueing can modify the synergies of the automatic reactive postural responses, prioritizing the stabilization of main joints such as the ankle and hip over that of the neck and knee. It was suggested that joint stabilization in the hip occurred due to the involuntary anticipation preprogrammed in the cortex by the visual pre-cue.     

Gonarthroses sévères et orthèses de décharge compartimentaire

Unloading of an arthritic tibiofemoral compartment of the knee joint may be effected by a knee brace extended by a heel cup, or by a long leg brace terminating beyond the ankle joint. Several conditions must be satisfied to ensure effectiveness of the appliance. These include a certain degree of anterior mobility, moulding of the brace with the joint under stress, rigidity of the brace in the anterior aspect and well-placed and comfortable supports.     

Fatigue-related changes in stance leg mechanics during sidestep cutting maneuvers

BACKGROUND: The increased number of women participating in sports has been paralleled by a greater knee injury rate in women compared to men. Among these injuries, those occurring to the anterior cruciate ligament are commonly observed during sidestep cutting maneuvers. In addition, general fatigue appears to correlate with injuries to the passive structures during a game. The purpose of the study was to examine the fatigue-related changes in lower limb mechanics during a cutting maneuver in female athletes. METHODS: Twelve college female soccer players were recruited. Sidestep cutting maneuvers were performed prior to, and after a fatiguing exercise (60-min shuttle run). Fatigue state was evaluated by calculating power output from countermovement jumps performed before and after the shuttle run. Three-dimensional stance leg hip, knee and ankle kinematics and kinetics during the cutting task were calculated and reported as initial ground contact angle, ranges of motion and peak moments of the stance phase. Cutting maneuver stance leg mechanics were analyzed through repeated measures two-way ANOVAs (P<0.05). FINDINGS: Jumping power output decrements suggested fatigue was induced. Sagittal and frontal planes kinematics and kinetics of the cutting task did not change after fatigue. In the transverse plane, the hip, knee and ankle joints were more externally rotated at touchdown, and during stance the knee underwent greater internal rotation. INTERPRETATION: Increased knee internal rotation has potentially important implication for increased injury risk when combined with unexpected perturbation faced in a game. Also, the fact that the sub-maximal level of fatigue did not lead to greater dynamic changes suggests a possible threshold of fatigue before function is dramatically affected.