Single-leg Landing Research Articles

Positive influence of neuromuscular training on knee injury risk factors during cutting and landing tasks in elite youth female handball players

Anterior cruciate ligament (ACL) ruptures are frequent in the age group of 15–19 years, particularly for female athletes. Although injury-prevention programs effectively reduce severe knee injuries, little is known about the underlying mechanisms and changes of biomechanical risk factors. Thus, this study analyzes the effects of a neuromuscular injury-prevention program on biomechanical parameters associated with ACL injuries in elite youth female handball players. In a nonrandomized, controlled intervention study, 19 players allocated to control (n = 12) and intervention (n = 7) group were investigated for single- and double-leg landings as well as unanticipated side-cutting maneuvers before and after a 12-week study period. The lower-extremity motion of the athletes was captured using a three-dimensional motion capture system consisting of 12 infrared cameras. A lower-body marker set of 40 markers together with a rigid body model, including a forefoot, rearfoot, shank, thigh, and pelvis segment in combination with two force plates was used to determine knee joint angles, resultant external joint moments, and vertical ground reaction forces. The two groups did not differ significantly during pretesting. Only the intervention group showed significant improvements in the initial knee abduction angle during single leg landing (p = 0.038: d = 0.518), knee flexion moment during double-leg landings (p = 0.011; d = −1.086), knee abduction moment during single (p = 0.036; d = 0.585) and double-leg landing (p = 0.006; d = 0.944) and side-cutting (p = 0.015;d = 0.561) as well as vertical ground reaction force during double-leg landing (p = 0.004; d = 1.482). Control group demonstrated no significant changes in kinematics and kinetics. However, at postintervention both groups were not significantly different in any of the biomechanical outcomes except for the normalized knee flexion moment of the dominant leg during single-leg landing. This study provides first indications that the implementation of a training intervention with specific neuromuscular exercises has positive impacts on biomechanical risk factors associated with ACL injury risk and, therefore, may help prevent severe knee injuries in elite youth female handball players.

Persons with patellar tendinopathy exhibit anatomical features that alter knee extensor mechanics: A comparison of persons with and without symptoms

It has been postulated that anatomical features of the patellofemoral joint may alter knee extensor mechanics in a way that may contribute to excessive patellar tendon loading. The purpose of this study was to compare the knee extensor mechanics in persons with and without patellar tendinopathy. Twenty-eight individuals participated (14 with patellar tendinopathy and 14 pain-free controls). Sagittal magnetic resonance images of the knee were acquired at the knee flexion angle that corresponded to the knee flexion angle at the time of peak knee extensor moment during a single-leg landing task. Measurements of patellar tendon/quadriceps tendon force ratio, quadriceps moment arm, patellar tendon moment arm, and patellar height (Insall-Salvati ratio) were obtained. Independent t-tests were used to compare the variables of interest between groups. When compared to the control group, the patellar tendinopathy group exhibited significantly a greater patellar tendon/quadriceps tendon force ratio (Mean ± SD, 1.0 ± 0.1 vs 0.8 ± 0.1, p < 0.05), a larger quadriceps moment arm (Mean ± SD, 23.9 ± 2.0 mm vs 22.1 ± 2.9 mm, p < 0.05), a smaller patellar tendon moment arm (Mean ± SD, 24.2 ± 1.7 mm vs 26.3 ± 2.4 mm, p < 0.05) and a greater Insall-Salvati ratio (Mean ± SD, 1.2 ± 0.1 vs 1.1 ± 0.1, p < 0.05). These results suggest that persons with patellar tendinopathy may experience greater forces in the patellar tendon for a given level of quadriceps force.

Detecting side-to-side differences of lower limb biomechanics during single-legged forward landing after anterior cruciate ligament reconstruction

BackgroundMotion analysis can be used to evaluate functional recovery after anterior cruciate ligament (ACL) reconstruction; however, the biomechanics parameters of the lower limb that are specifically altered in ACL-reconstructed knees compared to the contralateral side are not well understood. This retrospective study aimed to compare side-to-side differences in lower limb biomechanics during the first 100 milliseconds (ms) after initial contact in a single-leg forward landing task. MethodsUsing three-dimensional motion analysis, lower joint kinematic and kinetic variables were measured 8–10 months postoperatively in 22 patients who had undergone ACL reconstruction. We determined side-to-side differences in lower limb biomechanics over the 100-ms timeframe after landing, and receiver operating characteristic (ROC) curve analyses were performed to calculate the area under the curve (AUC) for parameters showing significant side-to-side differences. ResultsDuring the 100-ms timeframe after landing, 58 kinematic and kinetic items showed significant side-to-side differences. Side-to-side differences in lower limb biomechanics over the 40-ms timeframe after landing existed. The ROC curve analysis identified 11 items with AUC values ≥ 0.70, including hip flexion, abduction moment, and knee joint power, and their AUC values were not significantly different. ConclusionHip flexion/abduction moment and knee power after GRF max could be used as outcomes for assessing functional recovery in patients who have undergone ACL reconstruction.

The Effect of Arm Dominance on Knee Joint Biomechanics During Basketball Block Shot Single-Leg Landing.

Single arm blocking is a key component of successful basketball defence. The player uses either their dominant or non-dominant arm to block the ball landing on a common leg. Understanding how the bio-physical loads of the landing leg change as a function of the blocking arm will provide insights into potential injury risk of the lower limb. The aim of this study was to investigate the effects of arm dominance on the biomechanical variables of injury risk of the lower limb, specifically the knee joint during the single-leg landing in female basketball players. Kinematic and kinetic data were collected from fourteen female basketball athletes (20.85 ± 1.35 years, 1.69 ± 0.06 m, 60.37 ± 7.75 kg), each performing three trials of a dominant arm and non-dominant block jump landing on the dominant leg. The results showed significantly higher anterior and medial ground reaction force, knee joint flexion and abduction and lateral knee force during the dominant arm landing (p < 0.05). These findings highlight potential injury risk and the need for the player to be more proficient at dominant arm block-shot landing. The player should aim to develop a larger landscape of technique to meet the demands of the game and facilitate a more effective and safer landing strategy.

Fatigue modifies hip and knee kinematics during single- and double-leg dynamic tasks: An investigation with female handball players

ABSTRACT This study investigated the effect of a handball-specific fatigue protocol on hip and knee kinematics. Twenty female handball athletesperformed three trials of the single-leg landing (SLL), sidestep cutting manoeuvre (SCM), and drop vertical jump (DVJ) before and after the fatigue protocol. Kneeand hip angle waveforms were compared using statistical parametric mapping (p< 0.05). During the SLL, the fatigue increased hip adduction (4–7% cycle)and knee abduction (4–9% and 25–27%). For the SCM, hip flexion was reducedunder fatigue during 14–29% and 44–68% of the cycle. Similarly, the kneeflexion decreased between 7–36% and 53–73%. Besides, during the fatigue state,the athletes reduced the hip abduction between 0–11% of the cycle and increasedthe knee abduction between 20–23%. During the DVJ task, when fatigued, the hipflexion decreased between 19–44% of the cycle and the knee flexion between1–16% and 18–77%. The fatigue protocol altered the lower limb kinematics,decreasing knee and hip flexions during the SCM and DVJ and increasing the kneevalgus during both single-leg landing tasks.

Altered Muscle Activation Patterns During Unexpected Single-leg Landing In Chronic Ankle Instability Patients

Chronic ankle instability (CAI) patients display altered motor controls during inversion perturbation. Although these alterations may be vulnerable motor controls compared to controls, inversion perturbation under anticipatory conditions makes a less realistic simulation of lateral ankle sprains. PURPOSE: To examine differences in muscle activation during an unexpected inversion perturbation among CAI, coper, and control groups. METHODS: Twenty-two CAI patients (M = 11, F = 11; 22 ± 3 yr, 174 ± 8 cm, 71 ± 10 kg), 22 controls (M = 11, F = 11; 21 ± 2 yr, 173 ± 7 cm, 71 ± 10 kg), and 22 copers (M = 11, F = 11; 21 ± 2 yr, 174 ± 8 cm, 70 ± 13 kg) participated. Participants completed 5 trials of unexpected ankle inversion perturbation during single-leg landing onto a tilted force platform (25º) from a height of 30 cm. EMG data of tibialis anterior (TA), peroneus longus (PL), medial gastrocnemius (MG), and gluteus maximus (GX) were collected from 200 ms before and after initial contact (IC). Functional linear models were used to detect between-group differences. If 95% CIs did not cross zero, differences were significant. RESULTS: Figure 1 shows that CAI patients displayed greater TA and MG activation before IC relative to copers and/or controls. In addition, CAI patients showed greater TA and PL activation after IC relative to copers and/or controls. Copers and controls had similar muscle activation patterns. CONCLUSION: While copers and controls showed similar muscle activation during unexpected ankle perturbation, increased TA and MG activation prior to IC in CAI patients may indicate a neuromuscular effort to stabilize the ankle to prevent further sprains. Increased TA and PL activation after IC in CAI patients may also represent a protective motor control to prevent excessive displacement of the rear foot from the inversion perturbation. However, similar patterns in copers and controls seem to elicit coping mechanisms in an attempt to prevent further injuries after their initial injuries.

Effects Of Chronic Ankle Instability On Landing Kinematics During Unanticipated Single-leg Drop Landing

Effects Of Chronic Ankle Instability On Landing Kinematics During Unanticipated Single-leg Drop Landing

The effect of fatigue on lower extremity energy dissipation strategies during unanticipated single-leg landing in athletes with CLBP

The effect of fatigue on lower extremity energy dissipation strategies during unanticipated single-leg landing in athletes with CLBP

Anterior Cruciate Ligament Reconstruction And Alterations In Biomechanical Landing-stability And Decision-making Quality During Unanticipated Jump-landings

In team sports such as football, athletes are often required to adapt their motor plans in response to unpredictable/unanticipated visual information on the playing field under time pressure. These unanticipated movements lead to high-risk knee mechanics (landing safety decrements) which elevates injury/re-injury risk compared to pre-planned tasks. PURPOSE: To compare the magnititude of landing safety decrements (‘unanticipated-landing costs’) in athletes with and without a history of anterior cruciate ligament (ACL) reconstruction. METHODS: Matched-paired cross-sectional data from 14 ACL-reconstructed (females: n = 6, mean age: 23 ± 5 SD, BMI: 23 ± 4 Kg/m2, Tegner activity score (TAS): 8 ± 1; time since surgery: <2 years) and 14 healthy individuals (females: n = 6, mean age: 26 ± 3, BMI: 22 ± 2 Kg/m2, TAS: 8 ± 2) were analyzed. Participants performed countermovement-jumps with pre-planned or unanticipated single-leg landings on force plates. Landing kinetics (peak vertical ground reaction forces; pGRF), postural landing stability (center of pressure, time to stabilization), and decision-making quality (number of landings on wrong foot) were assessed. RESULTS: In both groups, the unanticipated condition resulted in significantly higher pGRF (ACL: 52 ± 4 vs. 56 ± 5 N/Kg, p = 0.004; Controls: 55 ± 7 vs. 59 ± 5 N/Kg, p = 0.021) and decision errors (ACL: 0 ± 0 vs. 3.2 ± 2, p = 0.001; Controls: 0 ± 0 vs. 2.1 ± 1.7, p = 0.003) compared to the pre-planned condition. The magnitude of unanticipated-landing costs did not differ significantly between groups (p > 0.05) for all the outcomes assessed. CONCLUSION: Unanticipated-landing costs occurred in both groups, but their magnitude was not significantly higher in the ACL-reconstructed group. To further elucidate the ACL-injury/re-injury risk associated with unanticipated movements, future biomechanical studies measuring joint kinetics and kinematics are warranted.

Reliability And Construct Validity Of The Single-leg Landing Error Scoring System (sl-less) In Physically Active Females

Reliability And Construct Validity Of The Single-leg Landing Error Scoring System (sl-less) In Physically Active Females

Lower limb kinematics during single leg landing in three directions in individuals with chronic ankle instability

ObjectivesTo compare the lower limb kinematics of participants with chronic ankle instability (CAI) and healthy participants during forward, lateral, and medial landings. DesignCross-sectional study. SettingLaboratory. ParticipantsEighteen athletes with CAI and 18 control athletes. Main outcome measuresHip, knee, and ankle joint kinematics during forward, lateral, and medial single-leg landings were compared between the groups using two-way ANOVA for discrete values and statistical parametric mapping two-sample t-tests for time-series data. ResultsThe CAI group had significantly greater ankle dorsiflexion than the control group (P ≤ 0.013), which was observed from the pre-initial contact (IC) for lateral and medial landings and post-IC for forward landing. The CAI group showed greater knee flexion than the control group from the IC for lateral landing and post-IC for forward landing (P ≤ 0.014). No significant differences in ankle inversion kinematics were found between the CAI and control groups. Lateral landing had a greater peak inversion angle and velocity than forward and medial landings (P < 0.001). Medial landing had a greater inversion velocity than forward landing (P < 0.001). ConclusionsThis study suggests that individuals with CAI show feedforward protective adaptations in the pre-landing phase for lateral and medial landings.

Does core stability training improve hopping performance and kinetic asymmetries during single-leg landing in anterior cruciate ligament reconstructed patients?

ABSTRACT Safe return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR) surgery is important. Core stabilization is common within rehabilitation, but its influence on hopping performance and single-leg landing kinetics among athletes post-ACLR is unclear. Twenty-four male professional athletes who had ACL reconstruction surgery (time since surgery = 11.47 ± 1.55 months) were recruited and randomly assigned to exercise (n = 12) and control (n = 12) groups. Exercise group received an 8-week core stability exercise program. Limb symmetry index (LSI) for single-leg hop for distance (SLH) and triple hop (TRH) tests, and single-leg landing kinetics (multidirectional ground reaction forces) were measured pre- and post-intervention. In post-test, the participants in exercise group were more symmetrical in SLH (P = .04, CI = 0.01–7.68) and TRH (P = .01, CI = 0.28–11.1) distances. They also improved their LSI values for vertical ground reaction force (vGRF), though not significantly (P < .05). LSI for anteroposterior (a-p) and mediolateral (m-l) GRFs remained unchanged for participants of both groups. Our findings indicate the positive effect of core exercise on decreasing between-limb asymmetries during SLH and TRH tests. Our results demonstrate that despite lack of change in kinetics, functional performance is more symmetrical following core stability training.

Muscle function during single leg landing

Landing manoeuvres are an integral task for humans, especially in the context of sporting activities. Such tasks often involve landing on one leg which requires the coordination of multiple muscles in order to effectively dissipate kinetic energy. However, no prior studies have provided a detailed description of the strategy used by the major lower limb muscles to perform single-leg landing. The purpose of the present study was to understand how humans coordinate their lower limb muscles during a single-leg landing task. Marker trajectories, ground reaction forces (GRFs), and surface electromyography (EMG) data were collected from healthy male participants performing a single-leg landing from a height of 0.31 m. An EMG-informed neuromusculoskeletal modelling approach was used to generate neuromechanical simulations of the single-leg landing task. The muscular strategy was determined by computing the magnitude and temporal characteristics of musculotendon forces and energetics. Muscle function was determined by computing muscle contributions to lower limb net joint moments, GRFs and lower limb joint contact forces. It was found that the vasti, soleus, gluteus maximus and gluteus medius produced the greatest muscle forces and negative (eccentric) mechanical work. Downward momentum of the centre-of-mass was resisted primarily by the soleus, vasti, gastrocnemius, rectus femoris, and gluteus maximus, whilst forward momentum was primarily resisted by the quadriceps (vasti and rectus femoris). Flexion of the lower limb joints was primarily resisted by the uni-articular gluteus maximus (hip), vasti (knee) and soleus (ankle). Overall, our findings provide a unique insight into the muscular strategy used by humans during a landing manoeuvre and have implications for the design of athletic training programs.

Dynamic Postural Stability Is Decreased During the Single-Leg Drop Landing Task in Male Collegiate Soccer Players With Chronic Ankle Instability.

Background:Chronic ankle instability (CAI) is commonly encountered in soccer players. The feelings of instability and anxiety caused by CAI can lead to poor performance, such as difficulty in sharp change of direction during soccer play. The single-leg drop landing (SLDL) task is often used to evaluate dynamic postural stability.Purpose/Hypothesis:The purpose of this study was to clarify whether dynamic stability measured during SLDL is altered in male collegiate soccer players with CAI. The hypothesis was that athletes with CAI would show poor dynamic postural stability.Study Design:Controlled laboratory study.Methods:A total of 103 male collegiate soccer players were recruited, and their limbs were classified based on the new international CAI criteria. All players performed three 5-second SLDL trials on a force plate. The main outcome measures included time to stabilization of the horizontal ground-reaction force (GRF); peak GRF in the vertical, horizontal, and sagittal directions; and trajectory length of the center of pressure during SLDL.Results:Data from 59 CAI limbs and 147 non-CAI limbs were collected in this study. Time to stabilization of horizontal GRF was significantly longer in the CAI limbs (P < .001), and the peak GRFs in all directions were significantly lower in the CAI limbs (vertical, P < .001; horizontal, P < .001; sagittal, P = .001). Additionally, the trajectory length of the center of pressure was significantly greater in the CAI limbs (P = .004).Conclusion:Soccer players with CAI had decreased dynamic postural stability that led them to land softly when performing the SLDL task. Measurement of dynamic postural stability may be useful in the evaluation of CAI.Clinical Relevance:Our findings may be useful for strategies of daily training or as an evaluation tool.

Relationship Between Posterior Tibial Slope and Lower Extremity Biomechanics During a Single-Leg Drop Landing Combined With a Cognitive Task in Athletes After ACL Reconstruction.

Background:A steeper posterior tibial slope (PTS) is an important risk factor for anterior cruciate ligament (ACL) reinjury. The PTS may affect lower extremity biomechanics under competition-like conditions for athletes with a reconstructed ACL.Hypothesis:It was hypothesized that the PTS would be associated with lower extremity biomechanics, which may increase ACL strain.Study Design:Descriptive laboratory study.Methods:Included were 10 athletes (mean age, 20.9 ± 1.8 years) who had undergone ACL reconstruction. The authors recorded the 3-dimensional lower extremity biomechanics while participants performed a single-leg drop jump with the Stroop task (dual task). Kinematic and kinetic data were analyzed and compared between the involved and contralateral limbs. The medial and lateral PTSs were measured using magnetic resonance imaging scans of the involved knee. The correlation between the biomechanical data and the PTS in each knee was evaluated.Results:The lateral PTS was significantly correlated with the maximum hip adduction moment (r = 0.64; P < .05) and maximum internal tibial rotation angle (r = 0.71; P < .05) in the involved limb. There were no differences in kinematic and kinetic data between the involved and contralateral limbs.Conclusion:In athletes after ACL reconstruction, the lateral PTS was directly associated with the maximum internal tibial rotation angle during single-leg drop landing with a cognitive task.Clinical Relevance:The findings in this study indicate that a steeper lateral PTS may cause internal rotation of the tibia during landing, which may be associated with reinjury in athletes with a reconstructed ACL.

Effects of an intermittent exercise protocol on ankle control during a single-legged landing

PurposeTo identify the effects of fatigue from an exercise protocol (similar to a soccer match) on ankle motion and forces during single-legged drop landing.MethodsSeventeen males aged (mean ± SD) 22.2 ± 2.0 years participated in this repeated measures study. A 90-min intermittent exercise protocol with a 15-min rest at halftime was performed. Before, at halftime and after the exercise, participants were tested via a single-legged drop landing task onto a force platform whilst wearing a three-dimensional inertial measurement system (Xsens). Ankle angles (plantarflexion/dorsiflexion and inversion/eversion) were analysed before landing and at peak ground reaction force after landing, and center of pressure was analysed at peak ground reaction force.ResultsNo significant differences were found for the outcomes between pre-, halftime and post-exercise (p > 0.05).ConclusionsFindings suggest that exercises simulating a soccer match (regarding exertion) do not necessarily lead to significant changes in ankle motion or forces around the ankle.

Concurrent Validity of Movement Screening Criteria Designed to Identify Injury Risk Factors in Adolescent Female Volleyball Players.

Anterior cruciate ligament (ACL) injuries in female adolescent athletes occur at disproportionately high levels compared to their male counterparts. However, limited prospective data exist on the validity of low-cost screening tools that can proactively identify ACL injury risk, specifically for female athletes. The purpose of this study was to assess the concurrent validity of a three-task injury risk factor assessment by comparing visually derived outcome scores from two-dimensional (2D) video data with dichotomized three-dimensional (3D) biomechanical variables collected using motion capture technology. A total of 41 female club volleyball athletes (14.7 ± 1.4 years) were tested and asked to perform three tasks: double-leg vertical jump (DLVJ), single-leg squat (SLS), and single-leg drop landing (SLDL). One rater was trained on the scoring criteria for the 2D data and independently scored one forward-facing and one side-facing video for each task. Risk factors identified included poor knee position, lateral trunk lean, and excessive trunk flexion/extension. In addition, 3D joint angles were calculated for the trunk and knee in the sagittal and frontal planes and converted to dichotomous variables based on biomechanical thresholds of injury risk. For comparison of 2D and 3D outcomes, percent agreement and Cohen's kappa were calculated for each risk factor individually. Overall, 2D scores were found to exhibit moderate to excellent percent agreement with 3D outcomes for trunk position (69.1–97.1%). Specifically, ipsilateral trunk lean during single-leg tasks exhibited the highest agreement (85.3–88.2%) with moderate reliability (κ = 0.452–0.465). In addition, moderate to substantial reliability was found for trunk flexion during double-leg tasks (κ = 0.521–0.653); however, an evaluation of single-leg tasks resulted in only fair reliability (κ = 0.354). Furthermore, 2D scores were not successful in identifying poor knee position as percent agreement fell below 50% for both the single-leg tasks and averaged 60% agreement across both the phases of the DLVJ. Kappa coefficients further emphasized these trends indicating no to slight concurrent validity (κ = −0.047–0.167) across tasks. Overall, these findings emphasize the potential for valid, low-cost screening tools that can identify high-risk movement patterns. Further study is needed to develop improved assessment guidelines that may be employed through visual assessment in sports environments.

Effects of badminton insole design on stress distribution, displacement and bone rotation of ankle joint during single-leg landing: a finite element analysis

ABSTRACT Previous research has reported that up to 92% of injuries amongst badminton players consist of lower limb, whereby 35% of foot fractures occurred at the metatarsal bone. In sports, insoles are widely used to increase athletes’ performance and prevent many injuries. However, there is still a lack of badminton insole analysis and improvements. Therefore, this study aimed to biomechanically analyse three different insole designs. A validated and converged three-dimensional (3D) finite element model of ankle–foot complex was developed, which consisted of the skin, talus, calcaneus, navicular, three cuneiform, cuboid, five metatarsals and five phalanges. Three existing insoles from the market, (1) Yonex Active Pro Truactive, (2) Victor VT-XD 8 and (3) Li-Ning L6200LA, were scanned using a 3D scanner. For the analysis, single-leg landing was simulated. On the superior surface of the skin, 2.57 times of the bodyweight was axially applied, and the inferior surface of the outsole was fixed. The results showed that Insole 3 was the most optimum design to reduce peak stress on the metatarsals (3.807 MPa). In conclusion, the optimum design of Insole 3, based on the finite element analysis, could be a justification of athletes’ choices to prevent injury and other complications.

Association between Selected Screening Tests and Knee Alignment in Single-Leg Tasks among Young Football Players.

This study aimed to examine the relationship between knee valgus in the frontal plane projection angle (FPPA) during single-leg squat (SLS), single-leg landing (SLL), and other selected clinical tests in young athletes. Forty-three young healthy elite football players (age: 13.2 (1.7) years) that were regularly training in a local sports club participated in the study. The FPPA was assessed using 2D video analysis. The screening tests included the passive single-leg raise (PSLR), hip external and internal rotation (hip ER and IR), sit and reach test, weight-bearing lunge test (WBLT), modified star excursion balance test (mSEBT), countermovement jump (CMJ), single-leg hop for distance (SLHD), and age peak height velocity (APHV). There was a significant positive relationship between the knee valgus angles in the SLS test and the sit and reach test (r = 0.34) and a negative relationship with the hip ER ROM (r = −0.34) (p < 0.05). The knee valgus angles in the SLL were negatively associated with the hip IR (r = −0.32) and ER ROM (r = −0.34) and positive associated with the WBLT (r = 0.35) and sit and reach test (r = 0.33) (p < 0.05). Linear regression analysis showed that the results of the hip ER ROM and sit and reach tests were independent predictors of the FPPA in the SLS test (r2 = 0.11, p = 0.03 and r2 = 0.12, p = 0.02, respectively). The conducted study showed that individuals with more hip range of motion, more spine flexion extensibility, and less ankle dorsiflexion ROM may be more likely to experience high degrees of knee valgus in FPPA.

Reliability of three-dimensional motion analysis during single-leg side drop landing test after anterior cruciate ligament reconstruction: An in vivo motion analysis study.

Background:Anterior cruciate ligament (ACL) injury is a common sport injury and investigation of landing biomechanics is helpful in injury prevention and rehabilitation. Recent study found a lateral single-leg drop landing test resulted in the highest peak knee valgus angle (PKVA), but its reliability on patients who received ACL reconstruction (ACLR) is unknown.Objective:This study aimed to investigate the reliability in both within and between days on the normalized vertical ground reaction force (NVGRF) and kinematics of lower limbs after receiving ACLR. The findings can form the cornerstone for further study related to lateral jumping-and-landing biomechanics in patients with ACLR.Methods:This was a test-retest reliability study. Twelve patients (four females and eight males) who received ACLR with mean age of 29.4 (SD 1.66) were recruited. The subjects were instructed to jump laterally from 30 cm height and landed with single-leg for five times. The procedure was conducted on both legs for comparison. The NVGRF and local maxima of the hip, knee and ankle angles during the first 100 ms in all three planes were analyzed. The measurement was conducted by the same assessor to evaluate the within-session reliability, and the whole procedure was repeated one week later for the evaluation of the between-session reliability. Intra-class correlation coefficient (ICC) test was used to assess the within- and between-session reliability by ICC (3, 1) and ICC (3, K) respectively.Results:The within-session reliability of NVGRF [ICC (3, 1)] was 0.899–0.936, and its between-session reliability [ICC (3, K)] was 0.947–0.923. Overall reliability for kinematics within-session [ICC (3, 1)] was 0.948–0.988, and the between-session reliability [ICC (3, K)] was 0.618–0.982, respectively. Good to excellent reliability for the lateral single-leg drop landing test was observed in most of the outcome measures for within- and between-session. The ICC value of NVGRF of ACLR leg was lower than that of the good leg in the within-session which may associate with lower neuromuscular control in ACLR leg than that of the good leg.Conclusion:The results of this study support the use of a lateral single-leg drop landing test to evaluate lower limb biomechanics for ACLR.