The effects of a prophylactic knee brace and two neoprene knee sleeves on the performance of healthy athletes: a crossover randomized controlled trial

Performance effects of functional knee brace removal and prolonged use in healthy male athlete: Lower extremity power, acceleration, speed, and agility

OBJECTIVES

Knee braces were introduced to sports 30 years ago. However, knee brace use for non-contact anterior cruciate ligament injury prevention intervention remains contentious due to concerns about performance hindrances. Since knee brace use is a potential modifiable risk factor, we aimed to investigate the effect of discounting and continued functional knee brace (FKB) on lower extremity power-vertical jump (VJ), acceleration, speed, and agility performance.

DESIGN

Prospective cohort crossover study.

METHODS

Twenty-seven healthy male athletes performed seven tests, over six days of 12 test sessions (S), during three test conditions (non-braced, braced, and removed brace or continued brace use). This study focuses on VJ, acceleration, speed, and agility performance during S12 when athletes were randomly selected to remove the FKB after 17.5 h or continue using the FKB for 21.0 h.

RESULTS

After brace removal, nonsignificant performance levels improved in the VJ (2.7 %; 95 % CI 52.5-62.8; Cohen's effect size (ES) = trivial), acceleration (1.8 %; 95 % CI 0.500-0.562; ES = small), and agility (0.5 %; 95 % CI 9.25-10.13; ES = trivial), while a nonsignificant slower speed was recorded (0.5 %; 95 % CI 1.81-1.95; ES = trivial). Continued brace use led to a nonsignificant performance improvement in all tests; VJ (3.1 %; 95 % CI 53.5-60.2; ES = small), acceleration (1.5 %; 95 % CI 0.511-0.561; ES = trivial), speed (1.0 %; 95 % CI 1.83-1.95; ES = trivial), and agility (1.8 %; 95 % CI 9.26-10.04; ES = trivial).

CONCLUSIONS

Removal of FKB led to improved performance in three performance tests, while continued brace use improved performance in all four tests.

Functions and Effectiveness of Unloader, Patellofemoral, and Knee Sleeve Orthoses: A Review

Background

Knee orthoses have been extensively used as a nonsurgical approach to improving knee deficiencies. Currently, arthritic knee conditions remain the leading cause of disability, and this number is expected to increase. As the use of knee orthoses varies widely, so has their effectiveness which is still largely debatable. Here, we present the functions and effectiveness of the three most prominent knee orthotic models dedicated to supporting knee osteoarthritis-unloader, patellofemoral, and knee sleeves.

Purpose/Research Question

Considering the depth and diversity of the many clinical studies and documented laboratory reports published to date, this literature review was created to educate the clinician, patient, and researcher on common knee orthoses used for the management of arthritic knee conditions. In doing so, we discuss their design, biomechanical effects, and clinical efficacy, as well as broader outcomes, limitations, and recommendations for use.

Results/Synthesis

The knee orthoses discussed within the scope of this paper are dedicated to protecting the knee against strenuous compressive loads that may affect the patellofemoral and tibiofemoral joints of the knee. Since the knee has multiple axes of motion and articulating surfaces that experience different loads during functional activities, it can be implied that, to a large extent, knee brace designs can differ drastically. Unloader knee orthoses are designed to decrease tibiofemoral and patellofemoral joint pressures. Patellofemoral knee orthoses are designed to decrease strain on the patellofemoral and quadriceps tendons while stabilizing the patella. Knee sleeves are designed to stabilize movements, reduce pain in joints, and improve proprioception across the knee joint.

Conclusion

Although patients often report benefits from wearing braces, these benefits have not been confirmed by clinicians and scientific investigators. Results from these three orthosis types show that clinical efficacy is still elusive due to the different methodologies used by researchers.

Layman Summary

Knee orthoses also referred to as knee brace are commonly used for support and stability of the knee. Unloader knee braces are designed to relieve and support those suffering from knee osteoarthritis by improving physical impairment and reducing pain. Patellofemoral knee braces aim to help patients manage patellofemoral pain syndrome. Rehabilitative compression sleeves, also known as knee sleeves, are often used to assist patients suffering from knee pain and laxity. Important findings on the three knee braces discussed show discrepancies in results. Their effectiveness and validity are yet to be understood.

Prophylactic Knee Bracing in Offensive Linemen of the National Football League: A Retrospective Analysis of Usage Trends, Player Performance, and Major Knee Injury

Background

Offensive linemen in American football are prone to high-energy valgus forces to the knee, leading to associated injuries. Some offensive linemen in the National Football League (NFL) wear prophylactic knee braces (PKB) to prevent ligamentous injury.

Purpose/Hypothesis

This purpose of the study was to compare injury rates and performance between NFL offensive linemen who wear PKB and those who do not. It was hypothesized that brace wear would be associated with fewer major knee injuries and no difference in gameplay performance.

Study Design

Cohort study; Level of evidence, 3.

Methods

For the 2014 through 2020 NFL seasons, offensive linemen with at least 200 game snaps per regular season were identified. Players were grouped by PKB status (bracers vs nonbracers) based on visualization of bilateral, dual-hinged metal knee braces as part of gameday uniforms on publicly available imaging databases and/or game videos. Major knee injuries, defined as those requiring the missing of games, were identified using publicly available data. Performance was assessed with Pro Football Focus grades for each season. Rates of major knee injury were compared between groups with the 2-sample Z test for proportions, and performance grades were compared with the unpaired t test.

Results

For the cumulative study period, bracers demonstrated a significantly lower rate of major knee injuries than nonbracers (0.013 vs 0.049 injuries per player, respectively; P = .04). Isolated MCL injury was the most common injury for nonbracers. There was no group difference in performance for the cumulative study period or during most individual seasons. Yearly prevalence of PKB usage declined steadily from 16.3% in 2014 to 5.6% in 2020. A subgroup analysis of rookie players demonstrated an overall downtrend in usage during the study period as well.

Conclusion

Results indicated that knee brace prophylaxis by NFL offensive linemen was associated with a reduced risk of major knee injury without a significant difference in performance when compared with nonbracers. Despite this, the prevalence of PKB declined over the study period.

Biomechanical Effects of Prophylactic Knee Bracing on Anterior Cruciate Ligament Injury Risk: A Systematic Review

OBJECTIVE

Prophylactic knee braces (PKBs) are widely used by athletes in pivoting and landing sports and have the potential to influence knee movement and alignment, thus modulating anterior cruciate ligament (ACL) injury risk. This systematic review analyses current evidence on the biomechanical effects that PKBs have in the prevention of ACL injuries.

DATA SOURCES

The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Searches were conducted on PubMed, Web of Science, Scopus, Ovid MEDLINE, EMBASE, Cochrane, and CINAHL for studies published from inception until May 31, 2021. Included studies assessed the effects of PKBs on biomechanical variables associated with ACL injuries in landing or pivoting tasks, comparing between braced and unbraced conditions.

MAIN RESULTS

A total of 234 articles were identified; from which, 14 controlled, laboratory, biomechanical studies were included in this review. The effects of PKBs on knee biomechanics could be divided into kinematic variables in the coronal, sagittal, and transverse planes; and common kinetic variables, such as ground reaction force (GRF) and ACL load/strain. Also, PKBs were found to have protective effects in coronal and transverse plane kinematics, but results in the sagittal plane were inconclusive. Assessing knee kinetics, PKBs were advantageous in decreasing ACL load/strain but had no significant effect on GRF.

CONCLUSIONS

Prophylactic knee braces may serve to reduce ACL injury risk by modulating knee coronal and transverse plane movements and ACL load/strain during high-risk maneuvres. Precise recommendations are limited by study heterogeneity. More prospective studies are needed to assess ACL injury risk during high-risk sports using specific PKBs.

Immediate and six-week effects of wearing a knee sleeve following anterior cruciate ligament reconstruction on knee kinematics and kinetics: a cross-over laboratory and randomised clinical trial

BACKGROUND

Elastic knee sleeves are often worn following anterior cruciate ligament reconstruction (ACLR) but their effects on movement patterns are unclear.

AIM

To determine the immediate and six-week effects of wearing a knee sleeve on biomechanics of the knee during a step-down hop task.

METHODS

Using a cross-over design, we estimated sagittal plane knee kinematics and kinetics and stance duration during a step-down hop for 31 participants (age 26.0 [SD 6.6] years, 15 women) after ACLR (median 16 months post-surgery) with and without wearing a knee sleeve. In a subsequent randomised clinical trial, participants in the 'Sleeve Group' (n = 9) then wore the sleeve for 6 weeks at least 1 h daily, while a 'Control Group' (n = 9) did not wear the sleeve. We used statistical parametric mapping to compare (1) knee flexion/extension angle and external flexion/extension moment trajectories between three conditions at baseline (uninjured side, unsleeved injured side and sleeved injured side); (2) within-participant changes for knee flexion angles and external flexion/extension moment trajectories from baseline to follow-up between groups. We compared discrete flexion angles and moments, and stance duration between conditions and between groups.

RESULTS

Without sleeves, knee flexion was lower for the injured than the uninjured sides during mid-stance phase. When wearing the sleeve on the injured side, knee flexion increased during the loading phase of the stance phase. Discrete initial and peak knee flexion angles increased by (mean difference, 95% CIs) 2.7° (1.3, 4.1) and 3.0° (1.2, 4.9), respectively, when wearing the knee sleeve. Knee external flexion moments for the unsleeved injured sides were lower than the uninjured sides for 80% of stance phase, with no change when sleeved. The groups differenced for within-group changes in knee flexion trajectories at follow-up. Knee flexion angles increased for the Control group only. Stance duration decreased by 22% for the Sleeve group from baseline to follow-up (-89 ms; -153, -24) but not for the Controls.

CONCLUSIONS

Application of knee sleeves following ACLR is associated with improved knee flexion angles during hop landing training. Longer term (daily) knee sleeve application may help improve hop stance duration, potentially indicating improved hop performance.

TRIAL REGISTRATION

The trial was prospectively registered with the Australia New Zealand Clinical Trials Registry No: ACTRN12618001083280, 28/06/2018. ANZCTR.

Alternatives to Knee Braces

Knee braces continue to be a widely utilized piece of medical equipment, ranging from simple over the counter sleeves to more complex functional braces, with the ability to provide electrical stimulation to muscle groups. Despite their popularity, alternatives to knee braces exist for patients who find braces to be ineffective, uncomfortable, cumbersome, or overly expensive. While high-quality studies are lacking for modalities such as neoprene sleeves, compression stockings, and kinesiotaping, there is promising evidence that these interventions can confer an element of stability and pain relief for a variety of knee pathologies both with regard to acute and chronic injuries as well as in the postoperative rehabilitation period. While no "holy grail" exists for the ideal brace, or bracing alternative, it is important for providers to be aware of the options available to patients as well as the current evidence for these various modalities, so that the provider can best guide musculoskeletal care.

Knee Pads Do Not Affect Physical Performance in Young Female Volleyball Players

Knee pads have become increasingly popular among volleyball players. Given the fact high-intensity activities that are crucial to successfully playing this sport lead to an increased risk of a knee injury, the primary use of knee pads is to prevent potential injury. However, no research has been carried out to explain the effects of knee pads on the most important physical abilities in volleyball players, thus directly affecting performance. This study was undertaken to determine the effects of knee pads on the explosive power of the lower extremities, linear speed, and agility in young female volleyball players. In two separated sessions, 84 female volleyball players (age: 14.83 ± 0.72 years; height: 163.19 ± 8.38 cm; body mass: 53.64 ± 10.42 kg; VE: 5.30 ± 3.39 years) completed squat jumps (SJ), countermovement jumps (CMJ) with and without arm swing, linear sprints at 5-m and 10-m, modified t-test, and 5-10-5 shuttle test. Data analyses included descriptive statistics, paired sample T-tests and use of effect size (ES). There was no statistical difference between the two conditions for SJ (p = 0.156; ES = 0.18), CMJ (p = 0.817; ES = 0.03), CMJ with arm swing (p = 0.194; ES = 0.14), linear sprint at 5 m (p = 0.789; ES = 0.03) and 10 m (p = 0.907; ES = −0.01), modified t-test (p = 0.284; ES = 0.13), and 5-10-5 shuttle test (p = 0.144; ES = 0.19). Wearing knee pads has neither an inhibitory nor positive effects on explosive power of the lower extremities, linear speed, and agility in young female volleyball players.

Development of a modified cross-over hop test to reduce measurement errors in return-to-competition testing

CONTEXT

 Hop tests play an important role in the rehabilitation process after injuries. A comparison of the jumping distances of both extremities allows for an evaluation of the injured limb. In the conventional cross-over hop test for distance, the jump width (medial vs. lateral) that the athlete has to cross during the jump is not standardised and therefore highly variable. This affects the absolute jump length in each jump series.

HYPOTHESIS

 Modifying the test may reduce the jump length variance between test series of an athlete as well as the test-dependent variations in the cross-over hop for distance.

METHODS

 N = 47 athletes from the German and French national Judo youth teams were included in the study (age: 15.3 years ± 13-17). A modified version of the cross-over hop for distance was developed with a cross-over width of 50 cm and a fixed landing zone of 10 cm. The jump lengths of the conventional test and the modified test were documented. The change in jump length variations of the two sexes were compared.

RESULTS

 The mean value of the coefficient of variation decreased significantly from 4.09 % to 2.83 % (p < 0.01) due to the test modification. This resulted in an absolute improvement in accuracy of 1.26 % and a relative improvement of 30.8 %. A comparison of the limb symmetry index between the conventional and the modified cross-over hop for distance revealed no significant differences.

CONCLUSION

 The modified cross-over hop for distance showed a significantly lower variation in jump lengths compared with the conventional cross-over hop for distance. As a result, more accurate statements can be made regarding the patient's return-to-competition progress.

Neoprene Knee Sleeves of Varying Tightness Augment Barbell Squat One Repetition Maximum Performance Without Improving Other Indices of Muscular Strength, Power, or Endurance

ABSTRACT

Machek, SB, Cardaci, TD, Wilburn, DT, Cholewinski, MC, Latt, SL, Harris, DR, and Willoughby, DS. Neoprene knee sleeves of varying tightness augment barbell squat one repetition maximum performance without improving other indices of muscular strength, power, or endurance. J Strength Cond Res 35(2S): S6-S15, 2021-Neoprene knee sleeves are commonly used by powerlifters and recreational users but are heavily under-researched. Furthermore, no data exist on whether knee sleeves of varying compressive tightness impact muscular performance similar to commonly used knee wraps, which are both generally effective and more so when increasingly constrictive. Fifteen resistance trained, knee sleeve naive, recreational weight lifting men (22.1 ± 4.1 years; 177.5 ± 5.9 cm; 87.8 ± 7.8 kg) visited the laboratory on 3 separate occasions one week apart, assigned in a randomized, crossover, and counterbalanced fashion to either a minimally supportive control sleeve (CS) condition, a manufacturer-recommended sizing neoprene knee sleeve ("normal" sleeve; NS), or a one size smaller (than NS) neoprene knee sleeve (tighter sleeve [TS]). On each visit, subjects sequentially completed vertical jump (countermovement and squat jumps for both peak and mean power), one repetition maximum (1RM) barbell squat, and GymAware assessments (peak power, peak velocity, and dip) at 90% (reported) and 100% (tested) 1RM as well as one-leg extension (1RM, repetitions to failure, and total volume load at 75% 1RM) tests. All data were analyzed using one-way repeated measures analysis of variance at p < 0.05. Analysis revealed a significant condition effect on barbell squat 1RM (p = 0.003; η2 = 0.339), whereby both NS (p = 0.044; 166 ± 24 kg) and TS (p = 0.019; 166 ± 21 kg) outperformed CS (161 ± 22 kg), with no difference between neoprene sleeves. Conversely, no other tested parameters differed between knee sleeve conditions (p ≥ 0.05). The present results demonstrate that neoprene knee sleeves may function independent of tightness, relative to recommended sizing and ultimately unlike knee wraps. Furthermore, the singular benefits observed on barbell squat maximal strength potentially suggests an exercise-specific benefit yet to be fully elucidated.

Do neoprene sleeves and prophylactic knee braces affect neuromuscular control and cutting agility?

OBJECTIVES

To evaluate the effects of neoprene sleeves (NSs) and prophylactic knee braces (PKBs) on neuromuscular control and cutting agility.

DESIGN

Markerless motion-capture technology tracked subjects (1) without a brace as a control (2) with NSs and (3) with PKBs during single-leg drop vertical jump (SLDVJ), single-leg squat (SLS), Y-excursion, and cutting movements. Movements were recorded five times per bracing condition in three different sessions.

SETTING

University laboratory.

PARTICIPANTS

Ten healthy, active subjects (5 male, 5 female; age range, 22-26 years).

MAIN OUTCOME MEASURES

Degrees of motion and time to completion.

RESULTS

Use of NSs and PKBs reduced subjects' hip internal rotation in the loading phase of SLDVJ (p = 0.026, 0.02) and SLS (p = 0.005, <0.001), reduced knee flexion in the loading phase of SLDVJ (p = 0.038, <0.001), and reduced knee frontal plane abduction (FPA) with SLS (p = 0.015, 0.024) and Y-excursion (p = 0.002, 0.005) compared to control. Use of PKBs decreased subjects' hip internal rotation in the Y-excursion (p = 0.024) and reduced knee FPA in the SLDVJ loading phase (p = 0.014) compared to control. There was no difference in cutting agility for either group (p = 0.145, 0.347).

CONCLUSION

Both NSs and PKBs positively impacted neuromuscular control without impacting cutting agility.

Effect of wearing a knee brace or sleeve on the knee joint and anterior cruciate ligament force during drop jumps: A clinical intervention study

BACKGROUND

Knee braces are considered to be extremely useful tools in reducing the shear force of knee joints for non-contact anterior cruciate ligament (ACL) injury prevention. However, the effectiveness of sports knee braces and sleeves remains to be identified. Therefore, the purpose of this study was to evaluate the effectiveness of wearing commercialized sports knee braces and sleeves on knee kinematics, kinetics, and ACL force during drop jumps using musculoskeletal modeling analysis.

METHODS

Musculoskeletal modeling analysis was conducted on 19 male alpine skiers who performed drop jump motions from a 40-cm box under three conditions: without a brace/sleeve, with a brace, and while wearing a neoprene sleeve.

RESULTS

The physical performance (i.e., the center of mass of the jumping height) was not affected by the type of brace or sleeve. However, wearing a brace or sleeve during drop jump tasks reduced the knee joint's maximum flexion, abduction angles, and adduction moment. The knee joint shear force when wearing the brace or sleeve exhibited no statistical differences. Further, the ACL load estimated in this study did not exhibit any statistical differences in relation to wearing a brace or sleeve.

CONCLUSIONS

The knee braces and sleeves reduced flexion and abduction movement, and adduction moment but did not reduce the knee joint shear force, internal rotation moment, or the ACL force. Therefore, if a sports knee brace that controls the knee joint's shear force and internal rotation moment is developed, it may aid in preventing ACL injuries.

Effects of knee sleeves on coordination of lower-limb segments in healthy adults during level walking and one-leg hopping

The evaluation of multisegment coordination is important in gaining a better understanding of the gait and physical activities in humans. Therefore, this study aims to verify whether the use of knee sleeves affects the coordination of lower-limb segments during level walking and one-leg hopping. Eleven healthy male adults participated in this study. They were asked to walk 10 m on a level ground and perform one-leg hops with and without a knee sleeve. The segment angles and the response velocities of the thigh, shank, and foot were measured and calculated by using a motion analysis system. The phases between the segment angle and the velocity were then calculated. Moreover, the continuous relative phase (CRP) was calculated as the phase of the distal segment subtracted from the phase of the proximal segment and denoted as CRPTS (thigh–shank), CRPSF (shank–foot), and CRPTF (thigh–foot). The root mean square (RMS) values were used to evaluate the in-phase or out-of-phase states, while the standard deviation (SD) values were utilized to evaluate the variability in the stance and swing phases during level walking and in the preflight, flight, and landing phases during one-leg hopping. The walking velocity and the flight time improved when the knee sleeve was worn (p < 0.05). The segment angles of the thigh and shank also changed when the knee sleeve was worn during level walking and one-leg hopping. The RMS values of CRPTS and CRPSF in the stance phase and the RMS values of CRPSF in the preflight and landing phases changed (p < 0.05 in all cases). Moreover, the SD values of CRPTS in the landing phase and the SD values of CRPSF in the preflight and landing phases increased (p < 0.05 in all cases). These results indicated that wearing a knee sleeve caused changes in segment kinematics and coordination.

Effects of prophylactic ankle and knee braces on leg stiffness during hopping

During human movement, the leg can be represented as a mechanical spring, with its stiffness potentially contributing to sports performance and injury prevention. Although many individuals perform athletic activities with joint stabilizers, little is known about the effects of prophylactic lower extremity braces on leg stiffness. The objective of this study was to investigate the effect of ankle and/or knee braces on leg stiffness measured during one-legged hopping at a range of frequencies. Thirteen male participants performed one-legged hopping with their dominant leg at frequencies of 2.2, 2.6, and 3.0 Hz. All participants were randomly tested under the following four brace conditions: 1) no brace (control), 2) prophylactic ankle brace, 3) prophylactic knee brace, and 4) prophylactic ankle and knee braces. Based on a spring-mass model, leg stiffness was calculated using data from an accelerometer. It was found that leg stiffness increased with increasing hopping frequency for each brace condition. However, there were no significant differences in leg stiffness among the four brace conditions at the three hopping frequencies. Since some level of leg stiffness is needed for optimal athletic performance and training, these results suggest that ankle and knee braces do not significantly interfere with dynamic hopping activities.

Biomechanical and functional efficacy of knee sleeves: A literature review

BACKGROUND

Knee sleeves are widely used for the symptomatic relief and subjective improvements of knee problems. To date, however, their biomechanical effects have not been well understood.

OBJECTIVE

To determine whether knee sleeves can significantly improve the biomechanical variables for knee problems.

METHOD

Systematic literature search was conducted on four online databases - PubMed, Web of Science, ScienceDirect and Springer Link - to find peer-reviewed and relevant scientific papers on knee sleeves published from January 2005 to January 2015. Study quality was assessed using the Structured Effectiveness Quality Evaluation Scale (SEQES).

RESULTS

Twenty studies on knee sleeves usage identified from the search were included in the review because of their heterogeneous scope of coverage. Twelve studies found significant improvement in gait parameters (3) and functional parameters (9), while eight studies did not find any significant effects of knee sleeves usage.

CONCLUSION

Most improvements were observed in: proprioception for healthy knees, gait and balance for osteoarthritic knees, and functional improvement of injured knees. This review suggests that knee sleeves can effect functional improvements to knee problems. However, further work is needed to confirm this hypothesis, due to the lack of homogeneity and rigor of existing studies.

Orthoses and exoprostheses for companion animals

Exoprostheses are devices that are secured to incomplete limbs to enable locomotion. By comparison, orthoses are devices externally applied to support or protect an injured body part. Orthoses also can be used to control, guide, protect, limit motion of, or immobilize an extremity, a joint, or a body segment. Exoprostheses and orthoses are a growing aspect of the physical rehabilitation of companion animals. They require precise design and fabrication. Patients and owners must be trained to use the devices. Exoprostheses and orthoses can have a profound beneficial impact on the mobility and the quality of life of companion animals.

Differences in proprioception, muscle force control and comfort between conventional and new-generation knee and ankle orthoses

The aim of this study was to compare muscle force control and proprioception between conventional and new-generation experimental orthoses. Sixteen healthy subjects participated in a single-blind controlled trial in which two different types of orthosis were applied to the dominant knee or ankle, while the following variables were evaluated: muscle force control (accuracy), joint position sense, kinesthesia, static balance as well as subjective outcomes. The use of experimental orthoses resulted in better force accuracy during isometric knee extensions compared to conventional orthoses (P=0.005). Moreover, the use of experimental orthoses resulted in better force accuracy during concentric (P=0.010) and eccentric (P=0.014) ankle plantar flexions and better knee joint kinesthesia in the flexed position (P=0.004) compared to conventional orthoses. Subjective comfort (P<0.001) and preference scores were higher with experimental orthoses compared to conventional ones. In conclusion, orthosis type affected static and dynamic muscle force control, kinesthesia, and perceived comfort in healthy subjects. New-generation experimental knee and ankle orthoses may thus be recommended for prophylactic joint bracing during physical activity and to improve the compliance for orthosis use, particularly in patients who require long-term bracing.

Influence of functional knee bracing on the isokinetic and functional tests of anterior cruciate ligament deficient patients

Use of functional knee braces has been suggested to provide protection and to improve kinetic performance of the knee in Anterior cruciate ligament(ACL)-injured patients. However, many athletes might refrain from wearing the braces because of the fear of performance hindrance in the playing field. The aim of this study was to examine the effect of three functional knee brace/sleeves upon the isokinetic and functional performance of ACL-deficient and healthy subjects. Six anterior cruciate ligament deficient (29.0±5.3 yrs., 175.2±5.4 cm, and 73.0±10.0 kg) and six healthy male subjects (27.2±3.7 yrs., 176.4±6.4 cm, and 70.3±6.9 kg) were selected. The effect of a custom-made functional knee brace, and two neoprene knee sleeves, one with four metal supports and one without support were examined via the use of isokinetic and functional tests in four sets (non-braced,wearing functional knee brace,and wearing the sleeves). Cross-over hop and single leg vertical jump test were performed and jump height, and hop distance were recorded. Peak torque to body weight ratio and average power in two isokinetic velocities(60°.s⁻¹,180°.s⁻¹) were recorded and the brace/sleeves effect was calculated as the changes in peak torque measured in the brace/sleeves conditions, expressed as a percentage of peak torque measured in non-braced condition. Frequency content of the isokinetic torque-time curves was also analyzed. Wilcoxon signed rank test was used to compare the measured values in four test conditions within each control and ACL-deficient group,and Mann-Whitney U test was used for the comparison between the two groups. No significant differences in peak torque, average power, torque-time curve frequency content, vertical-jump and hop measurements were found within the experimental and the non-braced conditions (p>0.05). Although the examined functional knee brace/sleeves had no significant effect on the knee muscle performance, there have been some enhancement regarding the extension peak torques and power generating capacity of the ACL-deficient subjects that could be helpful in reducing the bilateral asymmetry in these patients.