Drop Landing Research Articles

Biomechanical Risk Factors of Injury-Related Single-Leg Movements in Male Elite Youth Soccer Players

Altered movement patterns during single-leg movements in soccer increase the risk of lower-extremity non-contact injuries. The identification of biomechanical parameters associated with lower-extremity injuries can enrich knowledge of injury risks and facilitate injury prevention. Fifty-six elite youth soccer players performed a single-leg drop landing task and an unanticipated side-step cutting task. Three-dimensional ankle, knee and hip kinematic and kinetic data were obtained, and non-contact lower-extremity injuries were documented throughout the season. Risk profiling was assessed using a multivariate approach utilising a decision tree model (classification and regression tree method). The decision tree model indicated peak knee frontal plane angle, peak vertical ground reaction force, ankle frontal plane moment and knee transverse plane angle at initial contact (in this hierarchical order) for the single-leg landing task as important biomechanical parameters to discriminate between injured and non-injured players. Hip sagittal plane angle at initial contact, peak ankle transverse plane angle and hip sagittal plane moment (in this hierarchical order) were indicated as risk factors for the unanticipated cutting task. Ankle, knee and hip kinematics, as well as ankle and hip kinetics, during single-leg high-risk movements can provide a good indication of injury risk in elite youth soccer players.

Effects of Patellofemoral Pain Syndrome on Changes in Dynamic Postural Stability during Landing in Adult Women.

Background This study investigated the effects of lower limb movements on dynamic postural stability (DPS) during drop landing in adult women with patellofemoral pain syndrome (PFPS). Methods Thirty-eight adult women were recruited and divided into two groups, the PFPS group and the control group. The study participants performed a single-leg drop landing from a 30 cm box, and their lower limb movements and DPS were measured. Differences between groups were examined using independent sample t-tests. In addition, stepwise multiple linear regression was used to examine the kinematic parameters that contribute to the DPS. Results The PFPS group had significantly lower hip flexion, internal rotation, knee flexion, ankle external rotation, pelvic oblique, tilt, rotation, and higher hip abduction, knee valgus, and ankle plantarflexion. In terms of DPS, the PFPS group had a significantly higher anteroposterior and a lower mediolateral than that of the control group. In the control group, regression analysis revealed a controlled anteroposterior using knee flexion, while the PFPS group controlled mediolateral through ankle plantarflexion. Conclusions Patients with PFPS experienced more shock on their knee joint during landing than patients in the control group with greater anteroposterior instability and lower mediolateral instability.

Effects of limited previously acquired information about falling height on lower limb biomechanics when individuals are landing with limited visual input

BackgroundInhibitions in the acquisition of accurate information about the environment can affect control of the lower extremities and lead to anterior cruciate ligament injury. This study aimed to clarify the effects of limited prior knowledge of the height of the fall, as well as limited visual input, on lower limb and trunk motion and ground reaction force during landing. MethodsTwenty healthy university students were recruited. Drop landings from a 30-cm platform were measured under three conditions: (1) unknown, without prior knowledge of the height of the fall and without visual input; (2) known, with prior knowledge of the height of the fall and without visual input; and (3) control, with prior knowledge of the height of the fall and visual input. FindingsIn the unknown condition, the peak ground reaction force for the vertical and posterior directions was significantly higher than that in the known and control conditions; leg and knee stiffness, ankle joint work, and joint flexion motion of the knee, ankle, and trunk after landing were decreased as well. In the known condition, there were no significant differences in leg and knee stiffness and vertical ground reaction force compared to the control condition. InterpretationThe results of this study indicate that the risk of anterior cruciate ligament injury during landing increases when individuals have limited visual input and prior knowledge of the height of the fall. This finding suggests that an accurate perception of the surrounding environment may help prevent anterior cruciate ligament injuries.

Effects of lead leg selection on bilateral landing force-time characteristics: Return to sport testing implications.

We quantified the effect of lead leg selection on landing force-time characteristics during a vertical drop landing (VDL) initiated with a step-off. Plyometric-trained subjects (male: n=8; female: n=5; age =23±3.3years; body mass =74.4±11.2kg) performed 6step-off-initiated VDLs from a 45-cm box (n=3/lead leg). Pooled and lead leg stratified between-limb comparisons of limb-specific initial ground contact timing, peak vertical ground reaction force (Fzpeak ), and early landing-phase impulse (Impulse100ms ) were assessed by a two-factor, within-subject ANOVA, and limb symmetry indexes were calculated (α=0.05). Pooled data showed that the lead leg made contact prior to the trail leg and contributed a greater fraction to Fzpeak compared with the trail leg. Stratifying trials by lead leg selection led to significant between-limb differences in Fzpeak (p<0.05) and Impulse100ms (p<0.01) with the right leg leading but not with the left leg leading. Lead leg selection in step-off-initiated VDLs influenced landing performance and limb symmetry indexes of variables associated with lower limb injury risk, suggesting the need to control for lead leg selection in these tasks. A step-off may not be a suitable technique to initiate landing tasks when assessing limb symmetry.

Female Athletes Exhibit Greater Trial-to-Trial Coordination Variability When Provided with Instructions Promoting an External Focus

The purpose of this study was to examine how instructions promoting different attentional foci influence joint coordination patterns and trial-to-trial coordination variability during landing. Sixteen females performed drop landings with their typical technique (baseline) and after receiving instructions promoting an internal focus and an external focus. The coordination patterns, and trial-to-trial coordination variability, of the sagittal plane hip-knee, hip-ankle, and knee-ankle angle pairings were compared across conditions. While there was no difference in the joint coordination patterns among the conditions, subjects exhibited greater hip-ankle and knee-ankle trial-to-trial coordination variability for the external focus condition, vs. the baseline and internal focus conditions, which may help to explain the improved motor learning outcomes for athletes who train with an external focus.

The impact of sampling frequency on ground reaction force variables

New portable and low-cost technologies for assessing limb loading may be useful in non-laboratory environments, but have relatively low sampling frequencies. The lowest recommended sampling frequency for impact kinetics has not been investigated. The purpose of this study was to determine the effect of sampling frequency on metrics of impact kinetics during landing, walking, and running. This was a retrospective analysis of bilateral drop vertical jumps, unilateral drop landings, treadmill running, and flat, inclined, and declined treadmill walking. Landing data were collected at 1920 Hz while walking and running data were collected at 1440 Hz. Impact kinetics were computed at the highest possible sampling frequency, and then data were continuously down-sampled to determine the impact on the following computed metrics: peak impact force, average LR, and impulse. The minimum sampling frequency to compute each outcome with 90%, 95%, and 99.5% accuracy when compared to the original sampling frequency were determined. To achieve 90% of the true value of impact force, a sampling frequency of 180 Hz was needed for running, 62 Hz for bilateral landing, and 48 Hz for remaining tasks. For average LR, a sampling frequency of 1440 Hz was need for running, 63 Hz for inclined walking, 192 Hz for bilateral landing, and 48 Hz for the remaining tasks. For impulse, 48 Hz was required for all tasks. The results of this study provide future researchers with a guide for selecting the sampling frequency required to accurately assess impact kinetics during walking, landing, or running.

농구동호인의 만성발목관절불안정성 유무에 따른 낙하수직점프 시 하지의 운동학적 비교

This study aimed to compare and to analyze lower extremity kinematics during drop vertical jump depending on chronic ankle instability(CAI) among basketball club members. For 34 basketball club members who are currently affiliated with the B Metropolitan City Sports Association, 18 CAI groups and 16 CON groups were classified according to the CAI standards provided by the International Ankle Consortium. Drop vertical jump is performed to measure the one-leg drop landing pattern, and joint movement at the initial contact (IC), and the point of peak knee flexion. In addition, the one-leg drop landing pattern was tested with the muscular activity of tibialis anterior, peroneus longus, medial gastrocnemius and gluteus medius at landing phase. The results of this study showed that knee flexion angle at the point of peak knee flexion was confirmed to be larger in the CAI group(129.79±5.26°) than in the CON group(124.71±3.84°). In both groups, larger ankle dorsiflexion displacement during drop vertical jump was associated with larger knee flexion displacement(respectively r=.568, p=.014; r=.738, p=.001) and at the initial contact larger ankle dorsiflexion angle (r=.747, p=.001; r=.872, p=.001) and knee-flexion angle (respectively r=.497, p=.036; r=.818, p=.001). These results are thought to be a risk factor for re-injury of ankle joints and non-contact injury of knee and hip joints due to changes in the kinetic chain of the lower extremities due to CAI, and changes in the lower extremities should also be considered for rehabilitation or prevention of CAI.

Analysis of the relationship between muscular strength and joint stiffness in children with Down syndrome during drop landing.

BACKGROUND: Children with Down syndrome (DS) have critical biomechanical impairments such as increased ligamentous laxity, muscle hypotonia, and dysfunctional motor coordination, which makes performing everyday tasks challenging.OBJECTIVE: The purpose of the study was to explore the differences in the vertical joint stiffness, plantar force, and range of motion during drop landing for DS and age-matched typically developing children.METHODS: Six young male children with DS and age-matched seven healthy typically developing children (TD) assessed joint strength using an isokinetic dynamometer and performed five trials of single-leg drop jump using force platform and motion capture system.RESULTS: The peak vertical ground reaction force (VGRF), Range of motion (ROM), joint stiffness, and joint strength of lower limb were calculated and compared across DS and TD groups. The results revealed a significantly larger peak VGRF [2.857, 0.001] values for the DS group compared to the TD groups. The results of Spearman’s correlation analysis showed a negative correlation between hip joint stiffness and knee joint ROM [0.886, 0.05] and ankle joint stiffness and knee joint ROM [0.829, 0.05] for DS.CONCLUSIONS: The abnormal movements observed among DS was not due to the difference in stiffness of the lower extremity but due to the utilization of different landing mechanisms with changes in ROM.

Analysis of landing performance and ankle injury in elite British artistic gymnastics using a modified drop land task: A longitudinal observational study

ObjectivesTo determine whether differences in landing force and asymmetry of landing force exist between gymnasts at the time of data collection versus those that subsequently experienced an ankle injury 12-months later. Study designProspective longitudinal observational design with baseline measures and 12 month follow up. SettingBritish Gymnastics National Training Centre. ParticipantsThirty-two asymptomatic elite level gymnasts from three artistic gymnastic squads (n = 15 senior female, n = 10 junior female and n = 7 senior male). Main outcome measuresA modified drop land task was used to quantify measures of landing performance. Peak Vertical Ground Reaction Force (PVGRF) was used to measure landing force. The level of inter-limb asymmetry of landing force was calculated using the Limb Symmetry index (LSI). Other measures included injury incidence and percentage coefficient of variation (% CV). ResultsThere was no statistical difference for landing force (p = 0.481) and asymmetry of landing force (p = 0.698) when comparing injured and non-injured gymnasts. Most participants (69%) demonstrated inter-limb asymmetry of landing forces. ConclusionsOur findings observed inter-limb asymmetry of landing force in injured gymnasts, although uninjured gymnasts also exhibited asymmetry of landing force. Both magnitude of landing force and inter-limb asymmetries of landing force failed to identify the risk of ankle injury.

The effects of virtual reality immersion on drop landing mechanics

ABSTRACT Virtual reality (VR) can be used to alter the environment and challenge sensory calibration which rehabilitation and return-to-sport testing lack. The purpose was to establish how VR manipulation of the environment changes knee landing biomechanics. Twenty-nine healthy active adults (22 males; 20.52 ± 1.21 years; 1.75 ± 0.09 m; 78.34 ± 14.33 kg) were recruited. Three drop landing trials (31 cm height box) were performed for three conditions: eyes-open (EO), eyes-closed (EC), and VR, consisting of a head-mounted display of a 360° photo of a steep man-made edge or drop. Knee kinematics and kinetics were evaluated using 3D motion capture. The VR condition significantly increased Landing Error Score System errors relative to EO (1.28 ± 0.20, p < 0.001) and EC (0.98 ± 0.22, p < 0.001) and increased vertical ground reaction force relative to EO (0.41 ± 0.09 N·bw−1, p < 0.001) and EC (0.34 ± 0.07 N·bw−1, p < 0.001). The VR condition had less knee flexion at initial contact compared to EO (4.39 ± 0.75°, p = 0.001) and EC (1.83 ± 0.63°, p = 0.021). The VR condition had more knee abduction at initial contact compared to EO (0.71 ± 0.24°, p = 0.002) and EC (0.69 ± 0.22°, p = 0.002) and increased knee abduction at maximum flexion compared to EO (2.01 ± 0.58°, p = 0.026). Landing in VR increased injury risk landing biomechanics, indicating that VR may option to incorporate into return-to-play or injury risk assessment.

Soleus H-reflex modulation during a double-legged drop landing task.

Muscle spindle afferent feedback is modulated during different phases of locomotor tasks in a way that facilitates task goals. However, only a few studies have studied H-reflex modulation during landing. This study aimed to characterize soleus (SOL) H-reflex modulation during the flight and early landing period of drop landings. Since landing presumably involves a massive increase in spindle afferent firing due to rapid SOL muscle stretching, we hypothesized H-reflex size would decrease near landing reflecting neural modulation to prevent excessive motoneuron excitation. The soleus H-reflex was recorded during drop landings from a 30cm height in nine healthy adults. Electromyography (SOL, tibialis anterior (TA), medial gastrocnemius, and vastus lateralis), ankle and knee joint motion and ground reaction force were recorded during landings. Tibial nerve stimulation was timed to elicit H-reflexes during the flight and early ground contact period (five 30ms Bins from 90ms before to 60ms after landing). The H-reflexes recorded after landing (0-30 and 30-60ms) were significantly smaller (21-36% less) than that recorded during the flight periods (90-0ms before ground contact; P ≤ 0.004). The decrease in H-reflex size not occurring until after ground contact indicates a time-critical modulation of reflex gain during the last 30ms of flight (i.e., time of tibial nerve stimulation). H-reflex size reduction after ground contact supports a probable neural strategy to prevent excessive reflex-mediated muscle activation and thereby facilitates appropriate musculotendon and joint stiffness.

Effects of IMU Sensor-to-Segment Misalignment and Orientation Error on 3-D Knee Joint Angle Estimation

Accurate joint angle estimation using magneto-inertial measurement units (IMU) is a significant challenge for human movement analysis outside of the lab. Sensor-to-segment misalignment and sensor orientation errors are key factors in joint angle estimation. However, the effects of these factors on 3-D knee joint angle estimation accuracy are not well understood. This paper presents a general model to investigate the effects of sensor-to-segment misalignment and IMU orientation error on 3-D knee joint angle estimation accuracy. An analytical model was built to quantify the effects of sensor-to-segment misalignment and IMU orientation errors for 3-D knee joint angle estimation. Precise outcomes were quantified via simulation analysis and experimental testing in which fourteen healthy subjects performed drop landing and cutting tasks while wearing IMUs and optical motion capture markers for ground truth estimation. Sensor-to-segment misalignment accounted for 52% of the total knee abduction angle error and 40% of the knee internal rotation angle error but did not significantly affect knee flexion angle error. Conversely, IMU orientation error accounted for 55% of the knee flexion angle error but did not significantly affect knee abduction or internal rotation angle errors. These results indicate that sensor-to-segment misalignment significantly affects knee abduction and internal rotation angle estimation while IMU orientation error significantly affects knee flexion angle estimation. This study could serve to inform the development of accurate IMU-based 3-D knee joint angle algorithms for human movement analysis.

착지동작에서 착지높이, 양발간격, 디딤형태가 하지분절에 미치는 영향

Purpose: The purpose of this study is to analyze the kinematics and kinematic changes of the lower extremity in the landing height, landing stand width, and foot contact patterns, and to reveal the relationship between these factors and lower extremity injuries.<BR> Method: The subjects of this study were nine male college students. The experimental task was to perform drop landing with both feet on the jump platform. The landing procedures were to land in accordance with the conditions of the landing height (30, 50cm), the landing stand width (narrow, wide), and foot contact patterns(flatfoot, forefoot). Three-dimensional cinematography was performed to analyze the ground reaction force, loading rate, angle, moment, and joint stiffness of the lower extremity.<BR> Results: The peak vertical ground reaction force increased when the landing height was increased, but the loading rate did not differ in all factors. As the landing height was increased, flexion and abduction of the hip joint increased, and the extension moment of the hip joint increased at the same time. As the landing stand width increased, abduction of the hip joint and inversion of the ankle joint increased. The change in foot contact pattern resulted in differences in all factors except hip flexion angle, and in particular, increased plantar flexion moment along with dorsiflexion of the ankle joint during forefoot contact. Finally, there was no difference in joint stiffness of the lower extremity in all conditions.<BR> Conclusion: The landing height affected the hip and knee joints, but the ankle joint was affected by the foot contact patterns. An increase in ankle plantar flexion moment during forefoot contact could be considered an effective feature to reduce lower extremity injuries. The landing stand width resulted in opposite anatomical characteristics in the hip and ankle joints, and further studies are likely to be needed to clarify the results related to this factor.

Differences in strength and landing biomechanics between female jumpers and swimmers

BACKGROUND: It remains unclear if plyometric training as a single component could improve landing mechanics that are potentially associated with lower risk of ACL injury in the long term OBJECTIVE: The purpose of this study was to investigate the influence of experience undertaking plyometrics on landing biomechanics in female athletes. METHODS: Non-jumpers with little experience in plyometric training (12 female college swimmers) and jumpers with five years of experience in plyometric training (12 female college long jumpers and high jumpers) were recruited to participate in two testing sessions: an isokinetic muscle force test for the dominant leg at 120∘/s and a 40-cm drop landing test. An independent t test was applied to detect any significant effects between cohorts for selected muscle force, kinematic, kinetic, and electromyography variables. RESULTS: While female jumpers exhibited greater quadriceps eccentric strength (P= 0.013) and hamstring concentric strength (P= 0.023) during isokinetic testing than female swimmers, no significant differences were observed in kinematics, kinetics, and muscle activities during both drop landing and drop jumping. CONCLUSIONS: The results suggest that the female jumpers did not present any training-induced modification in landing mechanics regarding reducing injury risks compared with the swimmers. The current study revealed that plyometric training as a single component may not guarantee the development of low-risk landing mechanics for young female athletes.

Improper Body Mechanics During Single-Leg Medial Drop Landing with Trunk Lean are Related to Anterior Cruciate Ligament Injury Risk: A Comparison of Body Mechanics between Successful Trials and Failed Trials in the Drop Landing Test

Improper Body Mechanics During Single-Leg Medial Drop Landing with Trunk Lean are Related to Anterior Cruciate Ligament Injury Risk: A Comparison of Body Mechanics between Successful Trials and Failed Trials in the Drop Landing Test

A cross-sectional study of single-leg drop landing test in junior male soccer players &mdash;focusing on the grade difference about center of pressure trajectory and shock absorbing technique&mdash;

A cross-sectional study of single-leg drop landing test in junior male soccer players &mdash;focusing on the grade difference about center of pressure trajectory and shock absorbing technique&mdash;

Sensitivity of a Subject-specific Ankle Sprain Simulation to Extrinsic Versus Intrinsic Biomechanical Factors.

Ankle sprains are the most common musculoskeletal injury in sport and military activity, despite existing prophylactic strategies. The purpose of this report was to develop a probabilistic simulation of lateral ankle sprains during single-limb drop landing, towards accelerating innovation in ankle sprain prevention. A deterministic, subject-specific musculoskeletal model was extended with automation and probabilistic distributions on sprain-related biomechanical factors. Probabilistic simulations were generated using traditional Monte Carlo techniques and the advanced mean value method, a more computationally-efficient approach. Predicted distributions of peak ankle joint rotations, velocities, and moments borne by supporting passive structures agreed favorably with the deterministic model and with reports of real sprain biomechanics. Parameter sensitivities identified that predictions were most strongly influenced by drop height, subtalar joint posture at contact, invertor/evertor co-activation, and passive ankle stiffness. The advanced mean value method predicted confidence bounds comparable to a 1000-trial Monte Carlo simulation, and required only 14 model evaluations and 4-min processing time. The extended probabilistic simulation may be useful to virtually test new prophylactic strategies for ankle sprains, and is made available for open-source use (https://simtk.org/projects/sprain-sim).

The effects of gluteus medius and tibialis anterior kinesio taping on postural control, knee kinematics, and knee proprioception in female athletes with dynamic knee valgus

ObjectivesThis study aimed to investigate the effects of Kinesio taping on postural control, kinematics, and knee proprioception in female athletes with dynamic knee valgus (DKV).Design: a single-blind randomized clinical trial. Participants40 female athletes between the age of 18 and 28 years with DKV in single-leg drop landing (>13°) participated in this study. They were randomly classified into the Kinesio taping (KT) and placebo control (PC) groups. Main outcome measuresAll the evaluations and measurements were performed on each subject in the pre-test and post-test stages (with an interval of 72 h). The dynamic balance (Y balance test), proprioception (Knee position sense error), and knee kinematics (flexion and DKV angles) of the subjects were measured, prior and post gluteus medius and tibialis anterior KT. ResultsThe results of study demonstrate that the DKV angle and knee position sense error significantly decreased and YBT increased in the KT group from pre-test to post-test (p < 0.05). Nevertheless, there was no significant difference in knee flexion angle (p > 0.05). ConclusionThe results of the present study indicated that KT improves dynamic balance and proprioception and reduces the DKV angle. Therefore, KT is recommended for female athletes with DKV.

FIFA 11+ Kids program effects on jump kinetics in soccer players – A randomized controlled clinical trial

ABSTRACT This study aimed to analyse the effects of the FIFA 11+ Kids programme on jump kinetics in soccer players. Twenty-four athletes (aged 9–11 years) were randomly allocated to the following groups: 1) the FIFA 11+ Kids programme (FT, n = 12), and 2) control training (CT, n = 12). Kinetic assessments of vertical jump (VJ), drop landing (DL), and anterior jump + maximum vertical jump (AJ) were performed on a force platform before and after eight weeks of training. Post-intervention impulse peak force and maximum impulse force (VJ) were significantly greater than the baseline values in the FT group (P < 0.001). Post-intervention landing peak force values for the first and second landings (DL) were significantly greater than the baseline values in the FT group (P = 0.01 and P = 0.05, respectively). Post-intervention landing peak force in the first landing (AJ) was significantly greater than the baseline values in the FT group (P = 0.005). The FT was effective in improving the impulsion performance during VJ. However, it increased the landing forces during DL and VJ.

Regression model for predicting knee flexion angles using ankle plantar flexion angles, body mass index and generalised joint laxity

ABSTRACT Increased knee flexion angles are associated with reduced non-contact anterior cruciate ligament (ACL) injury risks. Ankle plantar flexion angles and internal risk factors could influence knee flexion angles, but their correlations are unknown. This study aimed to establish and validate a regression model to predict knee flexion angles using ankle plantar flexion angles, body mass index (BMI) and generalised joint laxity (GJL) at initial contact of single-leg drop landings. Thirty-two participants performed single-leg drop landings from a 30-cm-high platform. Kinematics and vertical ground reaction forces were measured using a motion capture system and force plate. A multiple regression was performed, and it was validated using a separate data set. The prediction model explained 38% (adjusted R2) of the change in knee flexion angles at initial contact (p = 0.001, large effect size). However, only the ankle plantar flexion angle (p < 0.001) was found to be a significant predictor of knee flexion angles. External validation further showed that the model explained 26% of knee flexion angles (large effect size). The inverse relationship between ankle plantar flexion and knee flexion angles suggests that foot landing strategies could be used to increase knee flexion angles, thereby reducing non-contact ACL injury risks.