Anodal transcutaneous DC stimulation enhances learning of dynamic balance control during walking in humans with spinal cord injury.

Deficits in locomotor function, including impairments in walking speed and balance, are major problems for many individuals with incomplete spinal cord injury (iSCI). However, it remains unclear which type of training paradigms are more effective in improving balance, particularly dynamic balance, in individuals with iSCI. The purpose of this study was to determine whether anodal transcutaneous spinal direct current stimulation (tsDCS) can facilitate learning of balance control during walking in individuals with iSCI. Fifteen individuals with iSCI participated in this study and were tested in two sessions (i.e., tsDCS and sham conditions). Each session consisted of 1 min of treadmill walking without stimulation or perturbation (baseline), 10 min of walking with either anodal tsDCS or sham stimulation, paired with bilateral pelvis perturbation (adaptation), and finally 2 min of walking without stimulation and perturbation (post-adaptation). The outcome measures were the dynamic balance, assessed using the minimal margin of stability (MoS), and electromyography of leg muscles. Participants demonstrated a smaller MoS during the late adaptation period for the anodal tsDCS condition compared to sham (p = 0.041), and this MoS intended to retain during the early post-adaptation period (p = 0.05). In addition, muscle activity of hip abductors was greater for the anodal tsDCS condition compared to sham during the late adaptation period and post-adaptation period (p < 0.05). Results from this study suggest that anodal tsDCS may modulate motor adaptation to pelvis perturbation and facilitate learning of dynamic balance control in individuals with iSCI.

Enhanced error facilitates motor learning in weight shift and increases use of the paretic leg during walking at chronic stage after stroke.

The purpose of this study was to determine whether the application of lateral pelvis pulling force toward the non-paretic side during the stance phase of the paretic leg would enhance forced use of the paretic leg and increase weight shift toward the paretic side in stroke survivors. Eleven chronic stroke survivors participated in two experimental sessions, which consisted of (1) treadmill walking with the application of "pelvis resistance" or "pelvis assistance" and (2) overground walking. During the treadmill walking, the laterally pulling force was applied during the stance phase of the paretic leg toward the non-paretic side for the "pelvis resistance" condition or toward the paretic side for the "pelvis assistance" condition during the stance phase of the paretic leg. After force release, the "pelvis resistance" condition exhibited greater enhancement in muscle activation of hip ABD, ADD, and SOL and greater improvement in lateral weight shift toward the paretic side, compared with the effect of the "pelvis assistance" condition (P < 0.03). This improved lateral weight shift was associated with the enhanced muscle activation of hip ABD and ADD (R2 = 0.67, P = 0.01). The pelvis resistance condition also improved overground walking speed and stance phase symmetry when measured 10 min after the treadmill walking (P = 0.004). In conclusion, applying pelvis resistance forces to increase error signals may facilitate motor learning of weight shift toward the paretic side and enhance use of the paretic leg in chronic stroke survivors. Results from this study may be utilized to develop an intervention approach to improve walking in stroke survivors.

Increased motor variability facilitates motor learning in weight shift toward the paretic side during walking in individuals post-stroke.

The purpose of this study was to determine whether applying "varied" versus constant pelvis assistance force mediolaterally toward the paretic side of stroke survivors during walking would result in short-term improvement in weight shift toward the paretic side. Twelve individuals post-stroke (60.4 ± 6.2 years; gait speed: 0.53 ± 0.19 m/s) were tested under two conditions (varied vs. constant). Each condition was conducted in a single separate session, which consisted of (a) treadmill walking with no assistance force for 1 min (baseline), pelvis assistance toward the paretic side for 9 min (adaptation), and then no force for additional 1 min (post-adaptation), and (b) overground walking. In the "varied" condition, the magnitude of force was randomly changed across steps between 30% and 100% of the predetermined amount. In the abrupt condition, the magnitude of force was kept constant at 100% of the predetermined amount. Participants exhibited greater improvements in weight shift toward the paretic side (p < 0.01) and in muscle activity of plantar flexors and hip adductors of the paretic leg (p = 0.02) from baseline to late post-adaptation period for the varied condition than for the constant condition. Motor variability of the peak pelvis displacement at baseline was correlated with improvement in weight shift toward the paretic side after training for the varied (R2  = 0.64, p = 0.01) and the constant condition (R2  = 0.39, p = 0.03). These findings suggest that increased motor variability, induced by applying the varied pelvis assistance, may facilitate motor learning in weight shift and gait symmetry during walking in individuals post-stroke.

Gradual adaptation to pelvis perturbation during walking reinforces motor learning of weight shift toward the paretic side in individuals post-stroke.

The purpose of this study was to determine whether the gradual versus abrupt adaptation to lateral pelvis assistance force improves weight shift toward the paretic side and enhance forced use of the paretic leg during walking. Sixteen individuals who had sustained a hemispheric stroke participated in two experimental sessions, which consisted of (1) treadmill walking with the application of lateral pelvis assistance force (gradual vs. abrupt condition) and (2) overground walking. In the "gradual" condition, during treadmill walking, the assistance force was gradually increased from 0 to 100% of the predetermined force step by step. In the abrupt condition, the force was applied at 100% of the predetermined force throughout treadmill walking. Participants exhibited significant improvements in hip abductor and adductor, ankle dorsiflexor, and knee extensor muscle activities, weight shift toward the paretic side, and overground walking speed in the gradual condition (P < 0.05), but showed no significant changes in the abrupt condition (P > 0.20). Changes in weight shift toward the paretic side were statistically different between conditions (P < 0.001), although changes in muscle activities were not (P > 0.11). In the gradual condition, the error amplitude was proportional to the improvement in weight shift during the late post-adaptation (R2 = 0.32, P = 0.03), but not in the abrupt condition (R2 = 0.001, P = 0.93). In conclusion, the "gradual adaptation" inducing "small errors" during constraint-induced walking may improve weight shift and enhance forced use of the paretic leg in individuals post-stroke. Applying gradual pelvis assistance force during walking may be used as an intervention strategy to improve walking in individuals post-stroke.

FEAR-AVOIDANCE AND SELF-EFFICACY PSYCHOSOCIAL FACTORS ARE ALTERED AFTER PARTIAL MENISCECTOMY AND ASSOCIATED WITH REHABILITATION OUTCOMES.

BACKGROUND: Little research has examined how psychosocial factors change over time and influence rehabilitation outcomes following meniscectomy. This information can inform the need to assess and address psychosocial factors in meniscectomy rehabilitation. HYPOTHESIS/PURPOSE: The purpose of this study was to examine changes in fear-avoidance and self-efficacy psychosocial factors from pre-surgery to one year after meniscectomy and their associations with rehabilitation outcomes. The hypothesis was that psychosocial factors would improve following meniscectomy, and less improvement in psychosocial factors would be associated with less improvement in rehabilitation outcomes. STUDY DESIGN: Prospective cohort. METHODS: Twenty-five patients with partial meniscectomy participated. Testing time points were pre-surgery, after post-surgical rehabilitation, and one-year post-surgery. Fear avoidance (pain catastrophizing and kinesiophobia) and self-efficacy (knee-related activity) psychosocial factors were assessed with the Pain Catastrophizing Scale (PCS), the Tampa Scale for Kinesiophobia (TSK-11), and Knee Activity Self-efficacy (KASE) questionnaires; respectively. Rehabilitation outcomes were quadriceps strength, evaluated with isokinetic testing at 60 °/sec; knee pain, measured with the Numeric Pain Rating Scale (NPRS); and self-reported knee function, measured with the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF). RESULTS: PCS scores improved from pre-surgery to after post-surgical rehabilitation, while TSK-11 and KASE scores improved from pre-surgery to after post-surgical rehabilitation and from after post-surgical rehabilitation to 1-year post-surgery. Pre-surgery PCS and KASE scores were associated with 1-year post-surgery NPRS score (r = 0.50) and quadriceps peak torque (r = 0.48), respectively. From pre-surgery to 1-year post-surgery, change in TSK-11 score was associated with change in NPRS score (r = 0.65), and change in KASE score was associated with change in IKDC-SKF score (r = 0.44). From pre-surgery to after post-surgical rehabilitation, changes in TSK-11 and KASE scores were associated with changes in NPRS (TSK-11, r = 0.47; KASE, r = -0.50) and IKDC-SKF scores (TSK-11, r = -0.39; KASE, r = 0.71). From after post-surgical rehabilitation to 1-year post-surgery, changes in KASE score was associated with changes in IKDC-SKF score (r = 0.59). CONCLUSIONS: Assessment of pain catastrophizing and knee activity self-efficacy pre-surgery might help to identify patients at risk for sustained knee pain and quadriceps muscle weakness. Decreasing kinesiophobia and increasing knee activity self-efficacy were associated with improved knee pain and function. LEVEL OF EVIDENCE: 2b.

Targeted Pelvic Constraint Force Induces Enhanced Use of the Paretic Leg During Walking in Persons Post-Stroke.

The purpose of this study was to determine whether activation of muscles in the paretic leg, particularly contributing to propulsion, and gait symmetry can be improved by applying a targeted resistance force to the pelvis in the backward direction during stance phase while walking in individuals post-stroke. Thirteen individuals post-stroke participated in two experimental sessions, which consisted of treadmill walking, with either targeted or constant resistances, together with overground walking. For the targeted condition, a resistance force was applied to the pelvis during the stance phase of the paretic leg. For the constant condition, the resistance force was applied throughout the whole gait cycle. Participants showed greater increase in medial hamstring muscle activity in the paretic leg and improved step length symmetry after the removal of targeted resistance force, compared to effects of a constant resistance force (P < 0.03). In addition, treadmill walking with the targeted resistance induced more symmetrical step length during overground walking 10 min after the treadmill walking, compared to the result of the constant resistance force (P = 0.01). Applying a targeted resistance force to the pelvis during the stance phase of the paretic leg may induce an enhanced use of the paretic leg and an improvement in gait symmetry in individuals post-stroke. These results provide evidence showing that applying a targeted resistance to the pelvis may induce a forced use of the paretic leg during walking.

Varied movement errors drive learning of dynamic balance control during walking in people with incomplete spinal cord injury: a pilot study.

The purpose of this study was to determine whether the application of a varied pelvis perturbation force would improve dynamic balance control and gait stability of people with incomplete spinal cord injury (iSCI). Fourteen participants with iSCI completed the test in two conditions, i.e., walking paired with pelvis perturbation force and treadmill walking only, with 1-week interval in between. The order of the testing condition was randomized across participants. For the pelvis pertubation condition, subjects walked on a treadmill with no force for 1 min, with a varied pelvis perturbation force that was bilaterally applied in the medial-lateral direction for 10 min, without force for 1 min, and then with the perturbation for another 10 min after a sitting break. For the treadmill only condition, a protocol that was similar to the perturbation condition was used but no force was applied. Margin of stability (MoS), weight shifting, and other spatiotemporal gait parameters were calculated. Compared to treadmill training only, participants showed significant smaller MoS and double-leg support time after treadmill walking with pelvis perturbation. In addition, participants showed significantly greater improvements in overground walking speed after treadmill walking with pelvis perturbation than treadmill only (p = 0.021). Results from this study suggest that applying a varied pelvis perturbation force during treadmill walking could improve dynamic balance control in people with iSCI, which could be transferred to overground walking. These findings may be used to develop a new intervention to improve balance and walking function in people with iSCI.

Use of Pelvic Corrective Force With Visual Feedback Improves Paretic Leg Muscle Activities and Gait Performance After Stroke.

The purpose of this study was to examine the effects of combined pelvic corrective force and visual feedback during treadmill walking on paretic leg muscle activity and gait characteristics in individuals with post-stroke hemiparesis. Fifteen chronic stroke participants completed visual feedback only and combined pelvic corrective force and visual feedback conditions during treadmill walking. Each condition included: 1-minute baseline, 7-minute training with visual feedback only or additional pelvic corrective force, 1-minute post training, 1-minute standing break, and another 5-minute training. EMGs from the paretic leg muscles and step length were measured. Overground walking was evaluated before treadmill walking, immediately and 10 minutes after treadmill walking. Greater increases in integrated EMG of all muscles, except vastus medialis and tibialis anterior, were observed with the application of additional pelvic corrective force compared to visual feedback only during treadmill walking. Overground walking speed significantly increased after treadmill training with combined pelvic correction force and visual feedback, but was not significant for the visual feedback only condition. Voluntary weight shifting with additional pelvic corrective force enhanced paretic leg muscle activities and improved gait characteristics during walking. Individuals with post-stroke hemiparesis could adapt feedforward control and generalize the adaptation to overground walking.

Forced use of paretic leg induced by constraining the non-paretic leg leads to motor learning in individuals post-stroke.

The purpose of this study was to determine whether applying repetitive constraint forces to the non-paretic leg during walking would induce motor learning of enhanced use of the paretic leg in individuals post-stroke. Sixteen individuals post chronic (> 6 months) stroke were recruited in this study. Each subject was tested in two conditions, i.e., applying a constraint force to the non-paretic leg during treadmill walking and treadmill walking only. For the constraint condition, subjects walked on a treadmill with no force for 1 min (baseline), with force for 7 min (adaptation), and then without force for 1 min (post-adaptation). For the treadmill only condition, a similar protocol was used but no force was applied. EMGs from muscles of the paretic leg and ankle kinematic data were recorded. Spatial-temporal gait parameters during overground walking pre and post treadmill walking were also collected. Integrated EMGs of ankle plantarflexors and hip extensors during stance phase significantly increased during the early adaptation period, and partially retained (15-21% increase) during the post-adaptation period for the constraint force condition, which were significantly greater than that for the treadmill only (3-5%) condition. The symmetry of step length during overground walking significantly improved (p = 0.04) after treadmill walking with the constraint condition, but had no significant change after treadmill walking only. Repetitively applying constraint force to the non-paretic leg during treadmill walking may lead to a motor learning of enhanced use of the paretic leg in individuals post-stroke, which may transfer to overground walking.

Error variability affects the after effects following motor learning of lateral balance control during walking in people with spinal cord injury.

People with incomplete spinal cord injury (iSCI) usually show impairments in lateral balance control during walking. Effective interventions for improving balance control are still lacking, probably due to limited understanding of motor learning mechanisms. The objective of this study was to determine how error size and error variability impact the motor learning of lateral balance control during walking in people with iSCI. Fifteen people with iSCI were recruited. A controlled assistance force was applied to the pelvis in the medial-lateral direction using a customized cable-driven robotic system. Participants were tested using 3 conditions, including abrupt, gradual, and varied forces. In each condition, participants walked on a treadmill with no force for 1 min (baseline), with force for 9 min (adaptation), and then with no force for additional 2 min (post-adaptation). The margin of stability at heel contact (MoS_HC) and minimum value moment (MoS_Min) were calculated to compare the learning effect across different conditions. Electromyogram signals from the weaker leg were also collected. Participants showed an increase in MoS_Min (after effect) following force release during the post-adaptation period for all three conditions. Participants showed a faster adaptation and a shorter lasting of after effect in MoS_Min for the varied condition in comparison with the gradual and abrupt force conditions. Increased error variability may facilitate motor learning in lateral balance control during walking in people with iSCI, although a faster learning may induce a shorter lasting of after effect. Error size did not show an impact on the lasting of after effect.

Motor Adaptation to Weight Shifting Assistance Transfers to Overground Walking in People with Spinal Cord Injury.

BACKGROUND: Locomotor training has been used to improve walking function in people with incomplete spinal cord injury (iSCI), but functional gains are relatively small for some patients, which may be due to the lack of weight shifting training. OBJECTIVE: To determine whether applying a pelvis assistance force in the coronal plane during walking would improve weight shifting and stepping in people with iSCI. DESIGN: Repeated measures study. SETTING: Rehabilitation hospital. PARTICIPANTS: Seventeen people with iSCI. INTERVENTIONS: A controlled assistance force was bilaterally applied to the pelvis in the medial-lateral direction to facilitate weight shifting, which gradually increased during the course of treadmill walking. MAIN OUTCOME MEASURES: Weight shifting, step length, margin of stability, and muscle activities of the weaker leg were used to quantify gait performance. The spatial-temporal gait parameters during overground walking were collected pre, post, and 10 minutes after treadmill training. RESULTS: During treadmill walking, participants significantly improved weight shifting (ie, center of mass [CoM] lateral distance reduced from 0.16 ± 0.06 m to 0.12 ± 0.07 m, P = .012), and increased step length (from 0.35 ± 0.08 m to 0.37 ± 0.09 m, P = .037) on the stronger side when the force was applied, which were partially retained (ie, CoM distance was 0.14 ± 0.06, P = .019, and step length was 0.37 ± 0.09 m, P = .005) during the late postadaptation period when the force was removed. In addition, weight shifting and step length on the weaker side during overground walking also improved (support base reduced from 0.13 ± 0.06 m to 0.12 ± 0.06 m, P = .042, and step length increased from 0.48 ± 0.12 m to 0.51 ± 0.09 m, P = .045) after treadmill training. CONCLUSIONS: Applying pelvis assistance during treadmill walking may facilitate weight shifting and improve step length in people with SCI, which may partially transfer to overground walking. LEVEL OF EVIDENCE: III.

Combined Visual Feedback with Pelvic Assistance Force Improves Step Length during treadmill walking in Individuals with Post-Stroke Hemiparesis.

Altered spatiotemporal gait characteristics are common impairments after stroke. Visual feedback has been used to improve spatiotemporal gait characteristics. In addition, pelvic assistance force applied in the mediolateral direction to the paretic side can improve walking pattern. Potentially, combined visual feedback and pelvic assistance force can have better rehabilitation outcomes on walking patterns. The purpose of this study was compare the effects of combined visual feedback with pelvic assistance force and visual feedback only during treadmill walking in individuals with post-stroke hemiparesis. Fifteen subjects with hemiparesis due to chronic (>6 months) stroke participated. A computer monitor placed in front of the treadmill was used to provide visual feedback on subjects' weight bearing on the paretic leg. A customized cabledriven robotic system was used to apply pelvic assistance force. The magnitude of pelvic assistance force was 9% of body weight. The session consisted of 5 sections: 1-min baseline, 7-min treadmill training (visual feedback only or combined visual feedback and pelvic assistance force), 1-min post-training (no visual feedback or pelvic assistance force), 1-min standing break, and 5-min treadmill training. The order of the visual feedback only and combined visual feedback and pelvic assistance force sessions was randomized across subjects. Spatiotemporal gait variables within the session, including stance time, single leg support time and step length, were computed. Combined visual feedback with pelvic assistance force resulted in a better improvement in step length of the paretic leg when compared to visual feedback only (p=0.03). Walking patterns after stroke could potentially be improved by applying visual feedback regrading paretic leg weight bearing and pelvic assistance force. Future study is needed to confirm the effectiveness of visual feedback for treadmill training after stroke.

Forced Use of the Paretic Leg Induced by a Constraint Force Applied to the Nonparetic Leg in Individuals Poststroke During Walking.

BACKGROUND: Individuals with stroke usually show reduced muscle activities of the paretic leg and asymmetrical gait pattern during walking. OBJECTIVE: To determine whether applying a resistance force to the nonparetic leg would enhance the muscle activities of the paretic leg and improve the symmetry of spatiotemporal gait parameters in individuals with poststroke hemiparesis. METHODS: Fifteen individuals with chronic poststroke hemiparesis participated in this study. A controlled resistance force was applied to the nonparetic leg using a customized cable-driven robotic system while subjects walked on a treadmill. Subjects completed 2 test sections with the resistance force applied at different phases of gait (ie, early and late swing phases) and different magnitudes (10%, 20%, and 30% of maximum voluntary contraction [MVC] of nonparetic leg hip flexors). Electromyographic (EMG) activity of the muscles of the paretic leg and spatiotemporal gait parameters were collected. RESULTS: Significant increases in integrated EMG of medial gastrocnemius, medial hamstrings, vastus medialis, and tibialis anterior of the paretic leg were observed when the resistance was applied during the early swing phase of the nonparetic leg, compared with baseline. Additionally, resistance with 30% of MVC induced the greatest level of muscle activity than that with 10% or 20% of MVC. The symmetry index of gait parameters also improved with resistance applied during the early swing phase. CONCLUSION: Applying a controlled resistance force to the nonparetic leg during early swing phase may induce forced use on the paretic leg and improve the spatiotemporal symmetry of gait in individuals with poststroke hemiparesis.

Applying a pelvic corrective force induces forced use of the paretic leg and improves paretic leg EMG activities of individuals post-stroke during treadmill walking.

OBJECTIVE: To determine whether applying a mediolateral corrective force to the pelvis during treadmill walking would enhance muscle activity of the paretic leg and improve gait symmetry in individuals with post-stroke hemiparesis. METHODS: Fifteen subjects with post-stroke hemiparesis participated in this study. A customized cable-driven robotic system based over a treadmill generated a mediolateral corrective force to the pelvis toward the paretic side during early stance phase. Three different amounts of corrective force were applied. Electromyographic (EMG) activity of the paretic leg, spatiotemporal gait parameters and pelvis lateral displacement were collected. RESULTS: Significant increases in integrated EMG of hip abductor, medial hamstrings, soleus, rectus femoris, vastus medialis and tibialis anterior were observed when pelvic corrective force was applied, with pelvic corrective force at 9% of body weight inducing greater muscle activity than 3% or 6% of body weight. Pelvis lateral displacement was more symmetric with pelvic corrective force at 9% of body weight. CONCLUSIONS: Applying a mediolateral pelvic corrective force toward the paretic side may enhance muscle activity of the paretic leg and improve pelvis displacement symmetry in individuals post-stroke. SIGNIFICANCE: Forceful weight shift to the paretic side could potentially force additional use of the paretic leg and improve the walking pattern.

Motor adaptation to lateral pelvis assistance force during treadmill walking in individuals post-stroke.

The goal of this study was to determine how individuals post-stroke response to the lateral assistance force applied to the pelvis during treadmill walking. Ten individuals post chronic (> 6 months) stroke were recruited to participate in this study. A controlled assistance force (∼10% of body weight) was applied to the pelvis in the lateral direction toward the paretic side during stance of the paretic leg. Kinematics of the pelvis and legs were recorded. Applying pelvis assistance force facilitated weight shifting toward the paretic side, resulting in a more symmetrical gait pattern but also inducing an enlarged range of motion of the pelvis during early adaptation period. The neural system of individuals post stroke adapted to the pelvis assistance force and showed an aftereffect consists of reduced range of motion of the pelvis following load release during post adaptation period.

Fear of Reinjury in Athletes.

CONTEXT: A sports injury has both physical and psychological consequences for the athlete. A common postinjury psychological response is elevated fear of reinjury. OBJECTIVE: To provide an overview of the implications of fear of reinjury on the rehabilitation of athletes, including clinical methods to measure fear of reinjury; the impact of fear of reinjury on rehabilitation outcomes, including physical impairments, function, and return to sports rate; and potential interventions to address fear of reinjury during rehabilitation. EVIDENCE ACQUISITION: PubMed was searched for articles published in the past 16 years (1990-2016) relating to fear of reinjury in athletes. The reference lists of the retrieved articles were searched for additionally relevant articles. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 3. RESULTS: Fear of reinjury after a sports injury can negatively affect the recovery of physical impairments, reduce self-report function, and prevent a successful return to sport. Athletes with high fear of reinjury might benefit from a psychologically informed practice approach to improve rehabilitation outcomes. The application of psychologically informed practice would be to measure fear of reinjury in the injured athletes and provide interventions to reduce fear of reinjury to optimize rehabilitation outcomes. CONCLUSION: Fear of reinjury after a sports injury can lead to poor rehabilitation outcomes. Incorporating principles of psychologically informed practice into sports injury rehabilitation could improve rehabilitation outcomes for athletes with high fear of reinjury.

Association of Quadriceps Strength and Psychosocial Factors With Single-Leg Hop Performance in Patients With Meniscectomy.

BACKGROUND: Clinicians use the single-leg hop test to assess readiness for return to sports after knee injury. Few studies have reported the results of single-leg hop testing after meniscectomy. Additionally, the contributions of impairments in quadriceps strength and psychosocial factors to single-leg hop performance are unknown. PURPOSE: To compare single-leg hop performance (distance and landing mechanics) between limbs and to examine the association of single-leg hop performance with quadriceps strength and psychosocial factors in patients with meniscectomy. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 22 subjects who underwent meniscectomy for traumatic meniscal tears received either standard rehabilitation alone or with additional quadriceps strengthening. Testing was conducted immediately postrehabilitation and at 1 year postsurgery. A single-leg hop test was performed bilaterally, and hop distance was used to create a hop symmetry index. Landing mechanics (peak knee flexion angle, knee extension moment, and peak vertical ground-reaction force) were analyzed with a motion-capture system and a force plate. An isokinetic dynamometer (60 deg/s) assessed knee extensor peak torque and rate of torque development (RTD0-200ms and RTD0-peak torque). Questionnaires assessed fear of reinjury (Tampa Scale for Kinesiophobia [TSK-11]) and self-efficacy (Knee Activity Self-Efficacy [KASE]). RESULTS: Rehabilitation groups did not significantly differ in single-leg hop performance; therefore, groups were combined for further analyses. The mean hop symmetry index was 88.6% and 98.9% at postrehabilitation and 1 year postsurgery, respectively. Compared with the nonsurgical limb, the surgical limb showed decreased peak knee flexion angle at postrehabilitation and decreased knee extension moment at 1 year postsurgery. The hop symmetry index was positively associated with peak torque, RTD0-200ms, and the KASE score at postrehabilitation. Moreover, at postrehabilitation, the peak knee flexion angle was positively associated with peak torque and RTD0-200ms, and the knee extension moment was positively associated with RTD0-200ms. At 1 year postsurgery, peak knee flexion angle and knee extension moment were both positively associated with peak torque, RTD0-200ms, and RTD0-peak torque. CONCLUSION: Although the hop symmetry index could be considered satisfactory for returning to sports, asymmetries in landing mechanics still exist in the first year postmeniscectomy. Greater quadriceps strength was associated with greater single-leg hop distance and better landing mechanics at both postrehabilitation and 1 year postsurgery. Knee activity self-efficacy was the only psychosocial factor associated with single-leg hop performance and isolated to a positive association with single-leg hop distance at postrehabilitation. CLINICAL RELEVANCE: Rate of development is not typically measured in the clinic but can be an additional quadriceps measure to monitor for single-leg hop performance. Quadriceps strength and psychosocial factors appear to have separate influence on single-leg hop performance after meniscectomy, which has implications for developing appropriate interventions for optimal single-leg hop performance.