Drop Landing Research Articles

The Effects Of Age On Drop Landing Tibial Accelerations In U.S. Army Trainees

The Effects Of Age On Drop Landing Tibial Accelerations In U.S. Army Trainees

Knee joint biomechanics and cartilage damage prediction during landing: A hybrid MD-FE-musculoskeletal modeling.

Understanding the mechanics behind knee joint injuries and providing appropriate treatment is crucial for improving physical function, quality of life, and employability. In this study, we used a hybrid molecular dynamics-finite element-musculoskeletal model to determine the level of loads the knee can withstand when landing from different heights (20, 40, 60 cm), including the height at which cartilage damage occurs. The model was driven by kinematics-kinetics data of asymptomatic subjects at the peak loading instance of drop landing. Our analysis revealed that as landing height increased, the forces on the knee joint also increased, particularly in the vastus muscles and medial gastrocnemius. The patellar tendon experienced more stress than other ligaments, and the medial plateau supported most of the tibial cartilage contact forces and stresses. The load was mostly transmitted through cartilage-cartilage interaction and increased with landing height. The critical height of 126 cm, at which cartilage damage was initiated, was determined by extrapolating the collected data using an iterative approach. Damage initiation and propagation were mainly located in the superficial layers of the tibiofemoral and patellofemoral cartilage. Finally, this study provides valuable insights into the mechanisms of landing-associated cartilage damage and could help limit joint injuries and improve training programs.

Subsequent Jumping Increases the Knee and Hip Abduction Moment, Trunk Lateral Tilt, and Trunk Rotation Motion During Single-Leg Landing in Female Individuals.

Single-leg landings with or without subsequent jumping are frequently used to evaluate landing biomechanics. The purpose of this study was to investigate the effects of subsequent jumping on the external knee abduction moment and trunk and hip biomechanics during single-leg landing. Thirty young adult female participants performed a single-leg drop vertical jumping (SDVJ; landing with subsequent jumping) and single-leg drop landing (SDL; landing without subsequent jumping). Trunk, hip, and knee biomechanics were evaluated using a 3-dimensional motion analysis system. The peak knee abduction moment was significantly larger during SDVJ than during SDL (SDVJ 0.08 [0.10]N·m·kg-1·m-1, SDL 0.05 [0.10]N·m·kg-1·m-1, P = .002). The trunk lateral tilt and rotation angles toward the support-leg side and external hip abduction moment were significantly larger during SDVJ than during SDL (P < .05). The difference in the peak hip abduction moment between SDVJ and SDL predicted the difference in the peak knee abduction moment (P = .003, R2 = .252). Landing tasks with subsequent jumping would have advantages for evaluating trunk and hip control as well as knee abduction moment. In particular, evaluating hip abduction moment may be important because of its association with the knee abduction moment.

The Effects of FIFA 11+ Kids Prevention Program on Kinematic Risk Factors for ACL Injury in Preadolescent Female Soccer Players: A Randomized Controlled Trial.

This study aimed to investigate the effects of the 8-week FIFA 11+ Kids program on kinematic risk factors for ACL injury in preadolescent female soccer players during single-leg drop landing. For this, 36 preadolescent female soccer players (10-12 years old) were randomly allocated to the FIFA 11+ Kids program and control groups (18 players per group). The intervention group performed the FIFA 11+ Kids warm-up program twice per week for 8 weeks, while the control group continued with regular warm-up. Trunk, hip, and knee peak angles (from initial ground contact to peak knee flexion) were collected during the single-leg drop landing using a 3D motion capture system. A repeated measure ANOVA was used to analyze groups over time. Significant group × time interactions were found for the peak knee flexion, with a medium effect size (p = 0.05; effect size = 0.11), and peak hip internal rotation angles, with a large effect size (p < 0.01; effect size = 0.28). We found that the FIFA 11+ Kids program was effective in improving knee flexion and hip internal rotation, likely resulting in reducing ACL stress during single-leg drop landing in young soccer players.

Real-time ground reaction force and knee extension moment estimation during drop landings via modular LSTM modeling and wearable IMUs.

This work investigates real-time estimation of vertical ground reaction force (vGRF) and external knee extension moment (KEM) during single- and double-leg drop landings via wearable inertial measurement units (IMUs) and machine learning. A real-time, modular LSTM-based model with four sub-deep neural networks was developed to estimate the vGRF and KEM from wearable IMUs. Sixteen subjects wore eight IMUs on the chest, waist, right and left thighs, shanks, and feet and performed drop landing trials. Ground embedded force plates and an optical motion capture system were used to capture lower extremity biomechanics for model training and evaluation. During single-leg drop landings, accuracy for the vGRF and KEM estimation was R2=0.88 ±0.12 and R2=0.84 ±0.14, respectively, and during double-leg drop landings, accuracy for the vGRF and KEM estimation was R2=0.85 ±0.11 and R2=0.84 ±0.12, respectively. The best vGRF and KEM estimations of the model with the optimal LSTM unit number (130) require eight IMUs placed on the eight selected locations during single-leg drop landings. During double-leg drop landings, the best estimation on a leg only needs five IMUs placed on the chest, waist, and the leg's shank, thigh, and foot. The proposed modular LSTM-based model with optimally-configurable wearable IMUs can accurately estimate vGRF and KEM in real-time with relatively low computational cost during single- and double-leg drop landing tasks. This investigation could potentially enable in-field, non-contact anterior cruciate ligament injury risk screening and intervention training programs.

The effects of the functional garment on the biomechanics during the single leg drop landing

IntroductionA functional biomechanics garment (FBG) may help to prevent injury by improved kinematics during motion such as single leg drop landing (SLDL). The purpose of this study was to investigate the effects of the FBG on the biomechanics of SLDL. MethodSeventeen female university basketball players participated. Characteristics of the FBG were designed based on biomechanics during weight-loaded performance of human movement. The average values of lower limb kinematics and kinetics in the sagittal and frontal planes from 3 SLDL with and without FBG were measured and compared. ResultsThe maximum varus angle of the knee showed a significant difference between the use of FBG (15.3 ± 15.1°) and without the use of FBG (5.9 ± 15.4°), the flexion angular displacement of the hip (with FBG, 21.5 ± 8.1°; without FBG, 24.0 ± 6.7°) between with and without FBG. The moment of the hip with FGB (1.1 ± 0.6 Nm) was significantly smaller than without FGB (1.4 ± 0.8 Nm). DiscussionRegarding function of the FBG, the rigid part of the hip could counter the excessive adduction and flexion of the hip, and the elastic part of the thigh could support the varus moment when the elastic part stretched. Therefore, the subjects with FBG could control the frontal motion of the knee, which has a risk of knee injury, such as the dynamic valgus of the knee during the SLDL. ConclusionUse of the FBG decreases dynamic knee valgus, which reduces risk of knee injury.

Position Statement: Exercise Guidelines for Osteoporosis Management and Fall Prevention in Osteoporosis Patients.

The effectiveness of exercise for improving osteoporosis and fall prevention in patients diagnosed with osteoporosis or osteopenia has not been fully summarized. The Korean Society for Bone and Mineral Research and the Korean Society of Exercise Physiology has developed exercise guidelines for patients with osteoporosis or osteopenia and provide evidence-based recommendations. A systematic review identified randomized controlled trials (RCT) assessing the effect of resistance, impact, balance, aerobic training, and physical activity in osteoporosis and osteopenia on bone quality, physical performance, quality of life, and fall prevention. PubMed, Embase, KoreaMed, and RISS were searched from January 2000 to August 2022. Ten key questions were established to review the evidence and formulate recommendations. The 50 RCTs reported that even with osteoporosis and osteopenia, resistance and impact training consistently maximized bone strength, improved body strength and balance, and eventually reduced fall incidences. Resistance exercise combining 3 to 10 types of free weight and mechanical exercise of major muscle groups performed with an intensity of 50% to 85% 1-repetition maximum, 5 to 12 repetitions/set, 2 to 3 days/week, for 3 to 12 months is recommended. Impact exercises such as jumping chin-ups with drop landings and jump rope performed 50 jumps/session for at least 6 months with 3 or more days/week are recommended. A multi-component exercise mainly comprised of resistance and impact exercise seems to be an effective strategy to attenuate the risk factors of osteoporosis and osteopenia. The integration of exercise guidelines and individualized exercise plans has significant potential to reduce the morbidity and mortality of osteoporosis.

Effect of different ankle braces on lower extremity kinematics and kinetics following special-induced fatigue for volleyball players with functional ankle instability

BackgroundThe aim of this study is to examine the effects of different ankle braces on functional ankle instability (FAI) participants following special-induced fatigue, which will provide advice for preventing ankle sprains in volleyball game. MethodsA total of 18 male collegiate volleyball players with FAI were recruited. The kinematics and kinetics data were acquired from the participants during single-leg drop landing using the infrared motion capture system (Mars2H, Nokov, China) and the force platform (Bertec, USA). A 2 × 2 within subjects design ANOVA was adopted to analyze the data. ResultsWhether fatigue or not, soft and semi-rigid brace reduced the ankle inversion (P = 0.025). Moreover, soft brace reduced the sagittal range of motion (ROM) of the ankle joint before fatigue (P = 0.05). In addition, the semi-rigid brace shortened the time to stability in the medial and lateral directions (P = 0.039) as well as the vertical directions (P < 0.001). The semi-rigid brace reduced the ground reaction force post-fatigue (P = 0.001). ConclusionSoft ankle brace reduced the sagittal range of motion pre-fatigue. Since volleyball requires athletes to jumping and landing repeatedly, and the ankle sagittal ROM was an important cushion during landings. Thus, soft ankle brace might result in overuse injury for lower extremity. However, the semi-rigid ankle brace increased the dynamic stability in the medial and vertical directions, and reduced the ankle inversion angle and forward ground reaction force post-fatigue. This ensured that the volleyball player's ankle was in a neutral position during landing, reducing the risk of excessive inversion caused by contact with the opposing player during spike and block.

Mental Fatigue Uniquely Influences Drop Landing Biomechanics for Individuals With a Concussion History.

Induced mental fatigue negatively impacts sport performance and neurocognition. However, it is unclear how induced mental fatigue influences landing biomechanics. The purpose of this study was to examine the influence of mental fatigue on drop landing biomechanics in individuals with and without a concussion history. Crossover design. Forty-eight (24 per group) recreationally active individuals were matched on age (±3y), sex, and body mass index (±1kg/m2). All participants completed an experimental (30-min Stroop task) and control (30-min reading magazines) intervention on separate days separated by a minimum of 24 hours. Drop landings were performed before and after both interventions. Outcomes included peak vertical ground reaction force (vGRF), vertical loading rate (VLR), knee flexion angle, knee abduction angle, external knee flexion moment, external knee abduction moment, and initial ground contact knee flexion and knee abduction angles. Separate 2 (group) × 2 (intervention) between-within analyses of covariance compared drop landing outcomes. Each group's average pre-Stroop and premagazine outcomes were covariates. There was a significant interaction for vGRF (P = .033, ηp2=.097) and VLR (P = .0497, ηp2=.083). The vGRF simple effects were not statistically significantly (P range = .052-.325). However, individuals with a concussion history displayed a medium effect size for greater vGRF post-Stroop compared with their own postmagazine vGRF (mean difference (95% confidence interval [95% CI] = 0.163 (-0.002 to 0.327) bodyweight (BW), p = .052, ηp2=.081. In contrast, the control group displayed a small effect size (mean difference [95% CI] = 0.095 [-0.069 to 0.259] BW, p = .251, ηp2=.029). Individuals with a concussion history displayed greater VLR post-Stroop compared with controls (mean difference [95% CI], 26.29 [6.19 to 46.40] BW/s, P = .012, ηp2=.134) and their own postmagazine values (mean difference [95% CI] = 32.61 [7.80 to 57.42] BW/s, p = .011, ηp2=.135). Mental fatigue leads to greater VLR for individuals with a concussion history. Athletic competition and activities of daily living can increase mental fatigue. Training programs may seek to teach mental fatigue reducing strategies to athletes with a concussion history.

Limiting the Use of Electromyography and Ground Reaction Force Data Changes the Magnitude and Ranking of Modelled Anterior Cruciate Ligament Forces

Neuromusculoskeletal models often require three-dimensional (3D) body motions, ground reaction forces (GRF), and electromyography (EMG) as input data. Acquiring these data in real-world settings is challenging, with barriers such as the cost of instruments, setup time, and operator skills to correctly acquire and interpret data. This study investigated the consequences of limiting EMG and GRF data on modelled anterior cruciate ligament (ACL) forces during a drop-land-jump task in late-/post-pubertal females. We compared ACL forces generated by a reference model (i.e., EMG-informed neural mode combined with 3D GRF) to those generated by an EMG-informed with only vertical GRF, static optimisation with 3D GRF, and static optimisation with only vertical GRF. Results indicated ACL force magnitude during landing (when ACL injury typically occurs) was significantly overestimated if only vertical GRF were used for either EMG-informed or static optimisation neural modes. If 3D GRF were used in combination with static optimisation, ACL force was marginally overestimated compared to the reference model. None of the alternative models maintained rank order of ACL loading magnitudes generated by the reference model. Finally, we observed substantial variability across the study sample in response to limiting EMG and GRF data, indicating need for methods incorporating subject-specific measures of muscle activation patterns and external loading when modelling ACL loading during dynamic motor tasks.

Single-leg medial drop landing with trunk lean includes improper body mechanics related to anterior cruciate ligament injury risk: A comparison of body mechanics between successful trials and failed trials in the drop landing test among female basketball athletes

Improper body mechanics during landing is a typical risk factor of anterior cruciate ligament injury. Drop landing test is used to evaluate landing mechanics by observing not only successful trials but also failed trials. Leaning of the trunk, which is frequently observed during failed trials, may lead to improper body mechanics related to anterior cruciate ligament injury. This study aimed to elucidate the mechanisms of landing with trunk lean that may underlie the risks of anterior cruciate ligament injury by comparing body mechanics between failed and successful trials. Participants were 72 female basketball athletes. The athletic task was single-leg medial drop landing, and the body mechanics was recorded by a motion capture system and force plate. Participants fixed the landing pose for ≥3s in successful trials but failed to do so in failed trials. Failed trials included the large lean of trunk. There were significant changes in thoracic and pelvic leans at initial contact in failed trials with medial trunk lean (p<0.05). Kinematics and kinetics during the landing phase in failed trials were associated with the risks of anterior cruciate ligament injury. These findings suggest that landing mechanics with trunk lean involves many biomechanical factors related to anterior cruciate ligament injury and demonstrates the inappropriate pose of trunk from the dropping phase. Exercise programs aimed at the landing manoeuver without trunk lean may contribute to reduce the risks of anterior cruciate ligament injury in female basketball athletes.

무릎 신전근 피로 수준이 외발 드롭 착지 시 무릎 관절 안정성에 미치는 영향

This study was to investigate the effect of experimentally induced knee extensor muscle fatigue on biomechanical variables related to knee stability during landing after a drop jump. Methods: A total of 14 young men participated voluntarily. As for the fatigue induction method, isokinetic equipment (Biodex System 4, Biodex Medical Systems, Inc. USA) was used, Kinematic data of the lower limbs were collected using a 3D Motion Analysis Eagle system (EVART 4.6, Santa Rosa, CA, USA) connected to 12 cameras at a sampling rate of 200 Hz, and ground reaction forces were obtained using an AMTI OR6-5 force platform (Watertown, MA, USA) was used to collect at a sampling rate of 1200 Hz. Results: The maximum knee flexion angle during one-leg drop landing was significantly increased after fatigue induction than before fatigue induction, but there was no significant difference among the fatigue induction conditions in knee valgus and varus, lateral rotation and medial rotation during one-leg drop landing. The shear stress in the tibia showed a tendency to increase according to the level of fatigue, but no significant difference was found. On the other hand, in the sagittal plane, the maximum knee joint moment was significantly decreased after fatigue induction, and the maximum ground reaction force was also found to be significantly decreased in the condition after fatigue induction compared to the condition before fatigue induction. Conclusion: Fatigue of the knee joint extensors following the fatigue protocol did not lead to significant changes in biomechanical variables related to knee stability. However, there was a significant decrease in maximum knee joint moment and maximum ground reaction force, and a significant increase in maximum knee joint angle during one-leg drop landing after fatigue induction. Therefore, the results of the study demonstrated that local fatigue (knee extensor fatigue exercise) according to the fatigue protocol did not affect biomechanical variables related to knee stability, but did affect biomechanical variables related to task performance.

Predictive modeling of lower extremity injury risk in male elite youth soccer players using least absolute shrinkage and selection operator regression.

To (1) identify neuromuscular and biomechanical injury risk factors in elite youth soccer players and (2) assess the predictive ability of a machine learning approach. Fifty-six elite male youth soccer players (age: 17.2 ± 1.1 years; height: 179 ± 8cm; mass: 70.4 ± 9.2kg) performed a 3D motion analysis, postural control testing, and strength testing. Non-contact lower extremities injuries were documented throughout 10months. A least absolute shrinkage and selection operator (LASSO) regression model was used to identify the most important injury predictors. Predictive performance of the LASSO model was determined in a leave-one-out (LOO) prediction competition. Twenty-three non-contact injuries were registered. The LASSO model identified concentric knee extensor peak torque, hip transversal plane moment in the single-leg drop landing task and center of pressure sway in the single-leg stance test as the three most important predictors for injury in that order. The LASSO model was able to predict injury outcomes with a likelihood of 58% and an area under the ROC curve of 0.63 (sensitivity=35%; specificity=79%). The three most important variables for predicting the injury outcome suggest the importance of neuromuscular and biomechanical performance measures in elite youth soccer. These preliminary results may have practical implications for future directions in injury risk screening and planning, as well as for the development of customized training programs to counteract intrinsic injury risk factors. However, the poor predictive performance of the final model confirms the challenge of predicting sports injuries, and the model must therefore be evaluated in larger samples.

드롭 랜딩 시 팔의 위치에 따른 발레 무용수들의 하지분절 충격흡수 전략 차이

Purpose: The purpose of this study is to investigate the difference rthough analysis of kinematic and kinetics variables to determine how ballet dancers absorb the impact on the human body during drop landing to minimize injury.BR Method: Twelve female ballerinas in their twenties (age: 21.83±1.85 years, height: 161.82±4.86㎝, weight: 51.47±6.55㎏, experience: 9.67±2.77 years old) who were familiar with jumping and landing movements were studied. To analyze the motion of the lower extremity for the drop landing motion, a 3D motion analysis was performed using 18 infrared cameras (Qualasiys7+, SWE), and the ground reaction force was obtained using a ground reaction force measuring device (Kistler 9287BA).BR Results: The results of this study are as follows. 1) There was a stisatically significant difference in the maximum and minimum angles of the hip joint during single-leg rdop landing according to the position of the arm (p＜.05). 2) There was a statistically significant difference in the range of motion of the hip joint during single-leg drop landing according to the position of th earm (p＜.05). 3) There was a statistically significant difference in ankle angular velocity during single-leg drop landing according to the position of the arm (p＜.05). 4) There was no statistically significant difference in the amount of change in the moment of the lower extremity joint during single-leg drop landing according to the position of the arm (p＞.05). 5) There was no statistically significant difference in the maximum ground reaction force value during singleleg drop landing according to the position of the arm (p＞.05).BR Conclusion: Therefore, as a result of this study, there was no differenc ein both feet during one drop landing depending on the position of the arm, and it seems that the ballet dancer makes a stable landing by increasing the flexion movement of the hip joint.

The ability to produce a timely explosive force may affect loading rate at landing

BackgroundSports injuries are strongly associated with the impact loading at landing. The abilities to produce force and adjust timing are simultaneously required to absorb impact loading.AimsHence, we aimed to examine the hypothesis that the ability to produce an explosive force at the right timing is related to the ability to absorb the impact loading at landing.MethodsTwenty-nine healthy young men volunteered to participate in the study. We proposed a new test to measure the rate of force development (RFD) in accordance with the countdown signal. To evaluate the ability to produce explosive force at the right time, we measured the rate of change between the RFD at the standard start signal and the RFD at the countdown signal. Furthermore, to evaluate the ability to land from a jump, we measured the loading rate at single-leg drop landing (20 cm).ResultsWe divided the participants into two groups based on the timing effect: the positive group (participants with increased RFD at the countdown signal, n = 11) and the negative group (participants with decreased RFD at the countdown signal, n = 18). The loading rate was significantly greater (P < .01) in the negative group (47.4 ± 11.2 body weight (BW)/s) than in the positive group (34.7 ± 7.1 BW/s).ConclusionsParticipants with increased RFD at the countdown signal had a lower loading rate at landing. Our results suggest that the ability to produce a timely explosive force may be a determinant of safe landing ability.

Altering muscle activity in the lower extremities by bipedal landing with different drop tasks and shoes

BACKGROUND: The ability of the lower-extremity muscle activation directly affects the performance and in turn interacts with the loading conditions of the muscle itself. However, systematic information concerning the characteristics of lower-extremity muscle during landings is lacking. In particular, the landing height and shoes are also important factors based on the actual situation, which could further contribute to understanding the neuromuscular activity and how biochemical response of the body tissues to double-leg drop landings. OBJECTIVE: The study was to investigate the effects of landing tasks on the activation of lower-extremity muscles and explore the relationship among movement control, landing heights, shoe cushioning, and muscle activities. METHODS: Twelve male basketball players were recruited to perform drop jump (DJ) and passive landing (PL) from three heights (30, 45, and 60 cm) while wearing highly-cushioned basketball shoes (HC) and less-cushioned control shoes (LC). EMG electrodes were used to record the activities of the target muscles (rectus femoris, vastus lateralis, biceps femoris, tibialis anterior, and lateral gastrocnemius) during the landing tasks. RESULTS: Pre- and post-activation activity of the lower-extremity muscles significantly decreased during PL compared with those during DJ (p&lt; 0.05). No significant shoe effects on the characteristics of muscle activation and coactivation during DJ movements were observed. However, the participants wearing LC showed significantly higher muscle post-activation (p&lt; 0.05) at the three drop heights during PL compared with those wearing HC. Coactivation of the ankle muscles was higher in LC than in HC during 30-cm PL (p&lt; 0.05). CONCLUSIONS: The activation patterns of lower-extremity muscles can be significantly influenced by landing types. Highly-cushioned basketball shoes would help reduce the risk of injuries by appropriately tuning the muscles during the PL.

Effectiveness of Augmented Feedback on Drop Landing Using Baseline Vertical Ground Reaction in Female Athletes

Context: Targeted training using augmented feedback to influence landing mechanics may be beneficial to athletes. Purpose: Examine how augmented feedback may influence vertical ground reaction force (VGRF) and improve knee valgus in females that display greater VGRF during drop landings. Main Results: Two hundred and forty female athletes participated and were divided into quartiles based on VGRF. Reductions in VGRF and knee valgus were seen across all quartiles with augmented feedback. Greatest reductions were found in the quartile with the largest baseline VGRF. Interpretation: Augmented feedback may be more effective in reducing VGRF and improving knee to ankle ratio in female athletes that have greater baseline VGRF.

Effect of two different exercises on balance, pain and ankle motor function in male college students with chronic ankle instability

Strength and proprioceptive exercise are known to be representative exercise methods used in patients with chronic ankle instability (CAI) and they are effective in restoring ankle stability and body balance, which gets reduced by repetitive ankle sprains. But, there is a lack of data comparing the effects of strengthening or proprioceptive exercise rehabilitation program for CAI patients. The purpose of this study is to investigate the effect of a 4-week exercise program on ankle range of motion (ROM), static/dynamic balance, and drop landing in college students with CAI. The subjects of this study were 21 male college students who had the Cumberland ankle instability tool (CAIT) questionnaire scores of 24 or less, and they were divided into three groups; the non-treated group (NTG), the traditional strength exercise group (SEG) and the proprioceptive exercise group (PEG). The exercise rehabilitation program was applied 3 times a week for 4 weeks. To examine the difference between groups, CAIT, visual analogue scale (VAS), body composition, ankle ROM, one-leg standing with eyes closed and Y-balance test (YBT) as well as center of pressure (COP) 95% confidence ellipse area during drop landing were measured before and after the exercise intervention. CAIT scores and static balance were significantly increased in the PEG compared to the NTG and the SEG, and ankle dorsiflexion ROM and Y-balance were significantly increased in the SEG and the PEG compared to the NTG. In addition, pain, ankle inversion ROM, and COP 95% confidence ellipse area were significantly reduced in the SEG and the PEG compared to the NTG. The proprioceptive exercise program is thought to be effective therapeutic approach on improving the symptoms of CAI patients.

Effects of fatigue on balance and ankle proprioception during drop landing among individuals with and without chronic ankle instability

This study aimed to explore the effects of fatigue on the balance and ankle proprioception during drop landing of individuals with chronic ankle instability (CAI). A total of 35 participants with unilateral CAI and 35 healthy participants participated in this study. A static balance test, dynamic balance test, and ankle proprioception test were conducted before and after fatigue. Fatigue was induced with turn back runs and vertical jumps protocol. Sway distance of the center of pressure (COP), root mean square of the COP (RMS), total excursions (TOTEX), mean velocity (MVELO), 95% confidence ellipse area of the COP movements (95% AREA), Normalise Reach Distance in the anterior (ANT), posteromedial (PM), and posterolateral (PL) directions, and the area under the curve (AUC) were calculated and analyzed. There were significant group by fatigue interactions for static balance variables, normalise reach distance in the PM and PL directions, and AUC. Fatigue reduced balance and ankle proprioception in individuals with CAI. After fatigue, static and dynamic balance and ankle proprioception during drop landing were significantly worse in the CAI group than in the control group. Fatigue had a significant negative effect on balance and ankle proprioception in CAI patients. Therefore, fatigue may be an important factor causing repeated ankle sprain in CAI patients.

기능적 발목관절 불안정성 축구선수의 신경근 훈련이 발목관절 기능 및 운동 수행능력에 미치는 영향

This study attempted to investigate the functional ankle instability (FAI) of soccer players. In this study, twelve college soccer players were selected as subjects. Before the experiment, based on the ankle joint instability scale (AII, FAAM, idFAI), six subjects with FAI were divided into FAI experimental group, while the other six subjects without FAI were classified as control groups. Firstly, functional movement tests were performed on two groups of subjects, including dynamic balance ability, rear-foot angle and hopping. Then, the two groups of subjects performed neuromuscular training for up to six weeks. When the training was over, we performed the same functional movement tests on both groups. Finally, we analyzed and compared the indicators of the experimental group and the control group before and after the training. The detailed results are as follows: After six weeks of neuromuscular training, there was a tendency for the dorsiflexion of the ankle joint to increase as well as the varus of knee-joint during the drop landing. After six weeks of neuromuscular training, the dynamic stability forward extension of the CON group was increased and the ability of side hop and figure-of-8 hop was improved. After six weeks of neuromuscular training, it was confirmed that the forward extension and figure-of-8 hop in the dynamic stability of the CON group were significantly improved than the FAI group, although we did not point out the differences between the groups before training. These results will provide useful information about the design considered for rehabilitation or prevention of CAI for soccer players.