Leg Jump Research Articles

A simple 2D multibody model to better quantify the movement quality of anterior cruciate ligament patients during single leg hop.

Patients with anterior cruciate ligament reconstruction frequently present asymmetries in the sagittal plane dynamics when performing single leg jumps but their assessment is inaccessible to health-care professionals as it requires a complex and expensive system. With the development of deep learning methods for human pose detection, kinematics can be quantified based on a video and this study aimed to investigate whether a relatively simple 2D multibody model could predict relevant dynamic biomarkers based on the kinematics using inverse dynamics. Six participants performed ten vertical and forward single leg hops while the kinematics and the ground reaction force "GRF" were captured using an optoelectronic system coupled with a force platform. The participants are modelled by a seven rigid bodies system and the sagittal plane kinematics was used as model input. Model outputs were compared to values measured by the force platform using intraclass correlation coefficients for seven outcomes: the peak vertical and antero-posterior GRFs and the impulses during the propulsion and landing phases and the loading ratio. The model reliability is either good or excellent for all outcomes (0,845 ≤ ICC ≤ 0.987). The study results are promising for deploying the developed model following a kinematics analysis based on a video. This could enable clinicians to assess their patients' jumps more effectively using video recordings made with widely available smartphones, even outside the laboratory.

대학축구선수의 성별에 따른 기능적 움직임 검사, Y-균형능력검 사 및 근본적 역량검사 간 상관관계 분석

The purpose of this study was to analyze the relationship between the factors of the Functional Movement Screen(FMS), Y-Balance Test(YBT), and Fundamental Capacity Screen(FCS) according to gender in collegiate soccer players registered with the Korea Football Association. To achieve the purpose of the study, FMS, YBT, and FCS were measured. The data were derived through descriptive statistics and Pearson correlation analysis using SPSS 28.0 and the statistical significance level was set at 0.05. The results analyzed in this study are as follows. First, male soccer players had higher levels of stability and symmetry in the FCS Single Leg Jump than female in the FMS total score. And, the level of symmetry in Single Leg Jump of FCS was also higher in men. Second, FMS Total Score and Stability Part showed correlations in most factors of YBT and FCS. Third, all of the YBT values showed correlations in most factors of the FCS. This result means that gender should be considered when seeking strategies to improve the performance of soccer players. It is also expected that it will be used as valuable data to understand the transferability of exercise effects of step-by-step training programs.

Countermovement jump and vertical hop demonstrate braking/deceleration and performance alterations after ACL reconstruction with BMA, DBM, and suture tape augmentation

ObjectivesThis study evaluated countermovement jump and Single Leg Jump measures to identify landing measures that best distinguish a novel Anterior Cruciate Ligament reconstruction technique using bone marrow aspirate, demineralized bone matrix, and suture tape augmentation patients from controls. The secondary objective assessed performance differences between operated and non-operated limbs post-reconstruction. The hypothesis was that novel Anterior Cruciate Ligament reconstruction patients at return to sport would not differ from controls during landing and that the operated limb's performance would not differ from the unoperated limb. MethodsThe study included 31 patients with the novel reconstruction technique matched with controls in a 1:10 ratio based on age, sex, weight, and height. Both groups underwent screening and were compared during a Countermovement Jump. Using a Sparta Science Force Platform, each patient's unoperated and operated limbs were also compared for Single Leg Jump post-op (6.5 months). ResultsTest patients showed no difference in center of pressure during landing of both jumps compared to controls (P=0.27) and the uninvolved limb (P=0.26). Test patients exhibited increased braking impulse relative to the uninvolved limb during Single Leg Jump (P<0.001). Deceleration upon landing of Countermovement Jump was also increased compared to controls (P<0.001). Test patients demonstrated slower concentric time during a Countermovement Jump compared to controls (P=0.03) and significantly slower compared to the uninjured leg (P<0.001). Countermovement Jump height was decreased compared to controls (P<0.001). Single-leg jump height was decreased in the injured limb compared to the uninjured limb (P<0.001). ConclusionsTest patients did not show significant differences in landing motion compared to controls or the uninvolved leg. However, power and performance alterations were evident at Return to Sport after reconstruction. Although these results are quite promising, they may be too preliminary to draw definitive conclusions. Double and single-legged assessments should be considered in return-to-sport decision-making.

ENHANCING STRENGTH CAPACITY FOR TRIATHLON COMPETITORS

Triathlon is a sport that combines three different disciplines: swimming, cycling and running. Athletes have to cover varying distances in each discipline and move quickly from one to the next, making triathlon an extremely demanding sport. This research aims to develop and implement a training program with athletic means in order to optimize the strength capacity of triathletes. This paper sought to identify statistically significant differences between the results recorded by the participants, i.e. the performance of athletes at the beginning and end of the study, following an experimental intervention. The present research was carried out with the participation of 3 male athletes, aged between 20 and 36 years (m = 26), from the triathlon sports branch, with over 4 years of competitive experience, competitor in the National Championship. Strength evaluation was conducted using the Optojump system in the case of the participants who performed one test: Left and Right Leg Jumps (5 jumps). Statistical analysis using the Wilcoxon signed-rank test showed significant differences between the initial and final results for explosive strength, indicating that the improvements were not random but were due to the experimental intervention. The training program had a significantly positive impact on the participants' strength capacity and overall performance.

Test-Retest Reliability of Single Leg Jump Performance Using the Drift Protocol in Division I Baseball Pitchers

Test-Retest Reliability of Single Leg Jump Performance Using the Drift Protocol in Division I Baseball Pitchers

Hamstring activation deficits in different jumping directions in athletes with a history of hamstring strain injuries: a cross-sectional laboratory study

ABSTRACT This study aimed to investigate the hamstring onset time and recruitment level during jumping tasks in athletes with chronic hamstring strain injuries. Thirteen hamstring injured athletes and thirteen matched healthy athletes were recruited. Activation onset time and muscle recruitment (median frequency of the EMG) of the lateral hamstring (LH) and medial hamstring (MH) was measured during double leg jumps in vertical and horizontal directions on the force platforms. The peak vertical ground reaction force and loading rate were obtained for all jumps. The injured group showed a delayed onset time (p = 0.029) and a lower recruitment of the LH during the landing (p = 0.018) than the control group. Activation deficits in the injured group led to a higher landing force and loading rate. Additionally, the LH and MH were lesser recruited in the vertical direction than the horizontal directions in the landing. In conclusion, athletes with hamstring injuries show hamstring activation deficits of the injured leg during jumping leading to degrading jump-landing performance. Also, jumping in different directions play a role to modify the recruitment of the hamstrings in the injured athletes. Therefore, movement plane is suggested to be considered in clinical rehabilitation for the hamstring injury.

Horizontal jump asymmetries are associated with reduced range of motion and vertical jump performance in female soccer players

BackgroundPerformance in jumping and change of direction tests are good proxies to reflect the skill level during soccer-specific actions. Greater inter-leg asymmetries have been identified as a risk factor for developing acute and overuse injuries and jeopardizing soccer performance. The aim of this study was to assess the association between asymmetry in the unilateral vertical and horizontal jump tests, ankle range of motion, linear velocity, and change of direction in a sample of highly trained adult female soccer players.MethodsThirty-eight highly trained female soccer players underwent a testing protocol including ankle dorsiflexion, single leg jumps for height (CMJ), distance (HJ), 40 m sprint and 180° change of direction tests.ResultsWithin-session reliability was acceptable (CV ≤ 7.9%), and relative reliability showed good to excellent (ICC: 0.83 to 0.99). The one-way ANOVA reported higher inter-limb differences for change of direction deficit (10.9 ± 8.04%) and single leg CMJ (5.70 ± 5.22%). Pearson correlations highlighted significant relationships between horizontal jump asymmetries and ankle dorsiflexion (r = -0.41), CMJ (r = -0.36 to -0.49) and HJ (r = -0.28 to -0.56).ConclusionsAssessing inter-limb asymmetries through different methods can help scientists understand the specificity of their detrimental effects on soccer performance. Practitioners should be aware of these specificities as well as the magnitude and direction of the asymmetries when aiming to improve specific on-field skills.

Comparison Of Marker-based And Markerless Motion Capture During Single And Double Leg Jumping

Markerless motion capture (MMC) is a newer technology that utilizes advanced computer vision and machine learning algorithms to evaluate human movement. Traditional marker-based motion capture (MBC) systems can be time consuming for both participant and researcher and setup can often take more time than collection. Further, MMC allows athletes to perform in a more familiar environment without the potential error introduced by the laboratory environment. However, it is imperative to examine its accuracy in comparison to the gold-standard of conventional MBC. PURPOSE: To determine interrater reliability between a marker-based and markerless motion capture systems. METHODS: 15 collegiate basketball players (8 females, height: 180.8 ± 14.0 cm, mass: 80.8 ± 19.0 kg) participated in this study. 3 double leg drop vertical jumps (DVJ) and 3 maximum single leg vertical countermovement hops on each limb were performed. Limb dominance (Dom vs NDom) was self-reported through survey. Standard MBC techniques were utilized to track markers throughout the execution of each task. A MMC system collected data concurrently and used advanced computer vision and machine learning algorithms to estimate the pose of individuals during dynamic movements without the need of markers. Hip joint centers were estimated from each system and used to determine the lowest and highest vertical displacement during each trial. Intraclass correlation coefficient (ICC[3,1]) was used to determine the interrater reliability between systems. ICC and 95% confidence interval were used for interpretation. RESULTS: Interrater reliability between MMC and MBC was excellent for DOM side single leg jumps (MMC 47.8 ± 10.6 cm, MBC 47.1 ± 10.8 cm, ICC = 0.986 [95 CI 0.966, 0.994]), NDom side single leg jumps (MMC 48.4 ± 10.3 cm, MBC 47.2 ± 10.7 cm, ICC = 0.983 [95 CI 0.958, 0.993]), and double leg drop vertical jumps (MMC 67.7 ± 11.1 cm, MBC 66.9 ± 12.1 cm, ICC = 0.982 [95 CI 0.956, 0.993]). The root mean square error between systems was less than 2.3 cm (Dom: 1.8 cm, NDom: 2.2 cm, DVJ: 2.3 cm). CONCLUSIONS: Markerless motion capture techniques to calculate vertical jump displacement had excellent agreement to marker-based motion capture during both single leg and double leg tasks. Future studies should compare additional kinematic and kinetic variables between systems.

Relationship Between Lateral Single Leg Jump Kinetics And Pitcher Success Determined By Earned Run Average And Strikeouts Per Inning: A Pilot Study.

INTRODUCTION: Lower body force production is a fundamental component of the pitching motion and may be an important predictor of pitching success. An exercise that mimics lower body movement during pitching is the lateral single leg jump (LSLJ). Lateral force production and horizontal takeoff velocity calculated from the LSLJ may be associated with pitching success, however, the relationship between these parameters is currently unknown. Therefore, the purpose of this pilot study was to examine the correlation between horizontal takeoff velocity calculated from force production during the LSLJ with earned run average (ERA) and strikeouts per inning (SO/I). METHODS: Eight NCAA Division I baseball pitchers (age range = 18 to 22) who had pitched more than 8 innings during the 2019 - 2021 baseball seasons volunteered to participate. Subjects performed two LSLJ trials on a force platform as part of data collection for a larger study. The force plate signal was filtered, and acceleration was calculated according to Newton’s 2nd law. Acceleration was then integrated with respect to time to calculate horizontal takeoff velocity for each LSLJ. Pearson r correlation coefficients were calculated to determine the relationship between the average horizontal takeoff velocity from the two trials with ERA and SO/I. RESULTS: There were no significant (p < 0.05) correlations between the horizontal jump velocity and ERA (r = 0.235, p = 0.65) or SO/I (r = -0.353, p = 0.49). CONCLUSION: Horizontal takeoff velocity during the LSLJ does not appear to be related to pitching performance characterized by ERA and SO/I in this small sample size. Further research using larger samples of subjects are needed to gain a better understanding of the relationship between jump kinetics and pitching success.

Comparison of Measured and Observed Exercise Fidelity during a Neuromuscular Training Warm-Up

Neuromuscular training (NMT) warm-up programs effectively prevent injuries in youth, but monitoring exercise fidelity is challenging. The purpose of this study was to compare the exercise fidelity as measured via an inertial measurement unit (IMU) with direct observations of selected exercises. Youth basketball and soccer players performed single leg jumps, squat jumps, Nordic hamstring curls, and/or single leg balance exercises as part of an NMT warm-up. An IMU was placed on the lower back of each participant and the warm-up was video recorded. A physiotherapist evaluated the volume aspect of exercise fidelity (i.e., performing the prescribed number of repetitions) using the video recordings and a checklist. Algorithms were developed to count the number of repetitions from the IMU signal. The repetitions from the algorithms were compared with the physiotherapist’s evaluation, and accuracy, precision, and recall were calculated for each exercise. A total of 91 (39 female, 52 male) athletes performed at least one of the four warm-up exercises. There was an accuracy, precision, and recall of greater than 88% for all exercises. The single leg jump algorithm classified all sets correctly. IMUs may be used to quantify exercise volume for exercises that involve both impact during landing and changes in orientation during rotations.

Effects of weighing phase duration on vertical force-time analyses and repeatability

ABSTRACT Force plate analyses of various activities sometimes require the average (WPav) and standard deviation (WPsd) of force across the Weighing Phase (i.e., quiet period) to calculate kinetic, temporal and kinematic metrics. Yet, the influence of weighing phase duration on these analyses has been scarcely investigated. This study investigated the effects of weighing phase duration on the agreement between vertical force-time variables and the repeatability of WPav and WPsd. Durations of 0.5, 1.0 and 1.5 s were compared to 2.0 s. Limits of agreement (LOA) for system weight, onset threshold, onset time, net impulse, take-off velocity and take-off displacement were calculated for 137 counter-movement, squat and single leg jumps. Repeatability coefficients for WPav and WPsd estimated the consistency between repeated trials. Shorter weighing phase durations produced small differences in WPav (LOA < ±0.25%), which accumulated during integration, affecting net impulse, take-off velocity (LOA ±2%) and take-off displacement (LOA ±23%). Differences were substantial using 5xWPsd as the onset threshold (LOA approximately ±25% to ±72%), consequently influencing onset time (LOA approximately ±6% to ±18%). WPav repeatability was high but the within-trial differences could augment with integration, requiring weighing phases longer than 2 s. WPsd had poor repeatability and its use requires further investigation.

I Am Not All the Way Here

I Am Not All the Way Here

Effects of Single Leg Jumping and Squat Training in Various Directions on Balance Ability in Healthy Individuals

Effects of Single Leg Jumping and Squat Training in Various Directions on Balance Ability in Healthy Individuals

Fitness profiles of elite male Italian teams handball players.

The aim of this study was to examine the fitness profile of the Italian national male Team-Handball players of different competitive level. Forty-one male handball players from the senior (N.=21, height 1.90±0.06m, body mass 94.04±11.59kg, BMI 26.13±2.45) to the junior category (N.=20, height 1.86±0.06m, body weight 84.99±12.52kg, BMI: 24.56±3.35) Italian National Teams participated in this study. Players were tested for lower and upper limbs muscle strength, change of direction ability and specific endurance. Lower limbs explosive strength was assessed with squat (SJ) countermovement (CMJ), stiff leg (stiffness) jumps. Explosive strength was assessed by measuring kinematic aspects of squat and bench exercises. Change of direction ability was assessed with the 505 test. The Yo-Yo intermittent recovery test (YYIR1) was considered for specific endurance. Large and significant differences (d>1; partial η2>0.14; P<0.01) between senior and junior national team players were found in anthropometrics, jumping, power, sprint, agility, and aerobic fitness (junior body weight accounting for 10% less than the senior one, P=0.021; SJ and CMJ in juniors smaller than the seniors by 15% and 12%, P=0.000 and P=0.001, respectively). Similar differences were found among positional roles (goalkeepers, backs, centers, pivots, wings), suggesting practical implications for training. The differences between the competitive level and the playing role in relevant handball performance were reported in Italian national team players. The magnitude of the differences suggests the need of individual training approach when dealing with the young handball players.

Kinematic Analysis of a Series of Jumps In First Position In Professional Ballet Dancers

Purpose: Few ballet-specific studies in the literature examine kinematics during dance activities. Sports studies have identified injury risk in athletes by observing kinematics during specific activity, but this has not yet been explored for ballet. Evaluating kinematics in dancers has the potential to identify injury risk and influence treatment for prevention and rehabilitation. Therefore, the purpose of this study was to examine the landing kinematics of professional ballet dancers during a series of 16 ballet-specific jumps. Methods: This study was a multi-factor repeated measures design. Participants (3 males, 16 females aged 19-33 years; first or second company members) performed 16 consecutive sautés in first position to a metronome set at 120 beats per minute. Lower extremity kinematic data was captured using the Noraxon myoMOTIONTM system and was analyzed at peak knee flexion of landing on jumps 1, 8, and 15 for hip abduction (HA), hip flexion (HF), and hip external rotation (HER). Analyses included: right versus left side differences (RvL), differences between jumps 1, 8, and 15, and interaction between the specific jump and RvL. Results: Statistically significant differences (SD) were found in: RvL HA (p=0.000, 10.68 degrees; clinically relevant) and in HF between jumps 1 and 8 (p=0.000) and 1 and 15 (p=0.006). There was no interaction effect of HA between jump number and RvL (p=0.470) or of HER between jump number and RvL (p=0.599). There was no SD in: HF between jumps 8 and 15 (p=0.245), HA between jumps (p=0.062), RvL HF (p=0.190), RvL HF between jumps (p=0.972), HER between jumps (p=0.366), or RvL HER (p=0.562). Conclusions: The RvL difference in HA (p=0.000) suggests asymmetrical loading of hip joints. This difference did not change between jumps (p=0.062), suggesting repeated preferential frontal plane loading. The SD in HF between jumps 1 and 8 (p=0.000) and 1 and 15 (p=0.006) suggests that a small series of jumps that are standard in ballet class are not consistent motions for professional dancers. Limitations include small sample size and lack of controlled warm up. Future work should examine single leg jumps or sautés following a fatigue protocol to assess joint motion more accurately.

Complex training Methodology Increases Standard of Amateurs Boxing for Senior

The presented research reflects an aspect of the training process with the amateur boxing champion team of sports club "Tirana" of Albania, for 2019, in which prominent boxers have been prepared, who are worthily represented in national and international activities, winning medals national. Normalization and modeling of the training process in a complex way according to special preparation cycles, in order to qualitatively develop the training indicators, in accordance with the physical, physiological and psychological requirements set by amateur boxing for senior. Experimentation; an original complex training methodology based on macrocycles was experimented, which are divided in 4 phases (adapter, developer, reinforcer and perfection) with senior amateur sports club boxers . "Tirana", within a period of one year (January 6, 201 9 to December 31, 201 9 ) , Athletes are tested 3 times during the year at the beginning, between and the finish.Where they are tested indicatorsphysical movements, special functional and Leonardo platforms are tested. It is worth mentioning the developments in physical , technical and functional indicators,, where there was an average increase of 8.1 percent. N Special test with the first two exercises, marked a rise of 14.9 percent (8:44 percent in the amount of repetitions, 2:26 in the blinking percent in cargo and 4:20 in the blinking percent after one minute) . In Drop-jump test was a marked increase in h 7:55 percent. In te s tin Singel 2 Leg Jump (assisted), at 6.54 percent (FFI, at 5.96 percent, Jump Height, at 7.55 percent and Efficiency, at 6.12 percent). In the Singel leg Jump test (without assistance): 6.17 percent (where F.Mes, Rel, at 7.69 percent, F.Mes.Rel / weight, at 9.73 percent and A. C ontakt time, at 1.09 percent). Conclusion: N of the training process should take advantage character loads pronounced aqnaerobik physiological during which prevailing energy processes anaerobic against those aerobic (process anaerobic alaktik, at 10 percent, anaerbik process lactic glikolitik, 60 percent and aerobic process, to the extent 30 percent).

The Effect of Hopping Exercises on the Feedforward and Feedback Activity and Start Time of Selected Lower Limb Muscles in Athletes with Functional Ankle Instability in Single Leg Jump Task

Introduction : The aim of this study was to investigate the effect of hopping exercises on the feedback and feedforward activity of selected lower limb muscles in single leg jump landing task in athletes with functional ankle instability. Materials and Methods: 24 male athletes (12 in the control group and 12 in the training group) with functional ankle instability participated in this randomized clinical trial. Hopping exercises were given for six weeks, three times a week to the experimental group. The control group continued their routine exercise three sessions per week. The electric activity of Peroneus Longus, Tibialis Anterior, Medial Gastrocnemius, gluteus medius, and gluteus maximus muscles in the jump landing, before and after the hopping exercises were collected. Results: The results of this study showed that after six weeks of hopping exercises, there was a significant effect on the onset of activity of the Peroneus Longus and gluteus medius muscles (P ≤ 0.001). There was a significant increase in the activity of Peroneus Longus (P ≤ 0.003), Medial Gastrocnemius (P ≤ 0.005), and gluteus medius (P ≤ 0.001) muscles in 100 milliseconds before the first contact of the foot on the ground. In addition, Peroneus Longus (P ≤ 0.001) and gluteus medius (P ≤ 0.001) activity increased significantly between 100-200 milliseconds after the first contact of the foot on the ground. However, no significant difference was observed in muscle activity of the untreated control group (P > 0.050). No significant change was recorded in the activity of the Tibialis Anterior, Medial Gastrocnemius, and gluteus maximus muscles (P > 0. 050). Conclusion : Six weeks of hopping exercises seem to reduce the time interval before the onset of activity and increase the activity amplitude for aforementioned muscles in single leg jump landing in athletes with functional ankle sprain. Therefore, while planning therapeutic exercise programs for athletes with functional ankle instability, it may be beneficial to have a look at hoping exercises.

Comparison Of Novel Hop Testing Method To Identify Decreased Performance And Asymmetries

Hop testing is used to evaluate athletes that are returning to sport. Evaluating alternative tools that use less repetitive impact could put these vulnerable populations at lower risk for injury during testing. Limited research examines various plyometric tests and traditional hop testing at identifying decreased performance and asymmetries. PURPOSE: To examine the association between alternative and traditional hop tests in physically active adults. METHODS: Participants performed a series of seven hop tests in a randomized order including both single and double leg takeoffs for a single, double, and triple jump, and 2-1-2 bound. Three successful trials were performed for each jump. Left and right limbs were combined for all analyses. Spearman’s Rho correlations were performed to investigate the relationship between jump tests. RESULTS: Twenty physically active individuals (age 18 - 32; 11 female, 9 male) participated. There were large associations between single leg single, double, and triple jumps (r = 0.854-0.960, p<0.001).There were large association between double leg single, double, and triple jumps (r = 0.908-0.923, p<0.001). There were large associations between single leg single jump and double leg single jump (r = 0.939, p<0.0001), single leg double jump and double leg double jump (r = 0.886, p<0.0001), and single leg triple jump and double leg triple jump (r = 0.851, p<0.001). There were large associations between single leg single jump and 2-1-2 jump (r = 0.853, p<0.001), single leg double jump and 2-1-2 jump (r = 0.900, p<0.0001) and single leg triple jump and 2-1-2 jump (r = 0.904, p<0.001). There were large associations between double leg single jump and 2-1-2 jump (r= 0.929, p<0.001), double leg double jump and 2-1-2 jump (r = 0.905, p<0.0001), and double leg triple jump and 2-1-2 jump (r = 0.832, p<0.001). CONCLUSION: There was a high positive correlation between all single leg jumps tested and the 2-1-2 jump as well as all double leg jumps and the 2-1-2 jump. These results indicate that utilization of double leg 2-1-2 jump may be a safer precursor to examining performance before initiating single leg jumps. These results demonstrate that the 2-1-2 jump and double leg jumps may be utilized without the increased load of repetitive landing impact on a unilateral limb as seen in traditional hop testing.

Differences Between Pointe Shoe And Barefoot Jumping In A Professional Ballet Dancer: A Case Study

Ballet is an art form that requires highly trained athletes to perform specialized movements specific to their field. Some of the most unique aspects of ballet training that sets it apart from other athletics are the use of pointe shoes, the emphasis on bilateral training, and the full body aesthetic requirements of every movement. PURPOSE: To determine how wearing pointe shoes alters full body kinematics during ballet temps levé jumps on both the preferred stance leg and the non-preferred stance leg, to compare the left and right side to determine the effectiveness of bilateral ballet training, and to observe the contribution of upper extremity movement to jump execution. METHODS: One professional female ballet dancer (23 yrs) with 17 years of ballet training performed various jumps in two footwear conditions. She was instrumented with 39 reflective markers, and a 10-camera motion capture system was used to collect three dimensional marker position data at 250 Hz. Sagittal plane upper and lower extremity angles were calculated and compared between conditions as well as between left and right sides. RESULTS: During single leg jumps, ankle range of motion (ROM) was slightly larger en pointe (79.1° ± 1.31°) than barefoot (56.4° ± 0.68°) due to an increase in plantarflexion, regardless of preferred takeoff leg. Conversely, knee ROM was slightly smaller due to a decrease in knee flexion en pointe (45.8° ± 2.43°) than barefoot (56.1° ± 6.33°) for single leg jumps, regardless of preferred takeoff leg. A bilateral jump revealed no distinct differences between left and right sides. Upper extremity angles did not show clear trends between left and right sides or between footwear conditions, however, the ipsilateral shoulder (114.7° ± 6.69°) had slightly greater ROM than the contralateral shoulder (103.4° ± 8.49°) during single leg jumps. CONCLUSIONS: Wearing pointe shoes causes alterations to lower limb angles during single leg jumps, altering the demand on the dancer’s body during these movements. The increase in ipsilateral shoulder ROM implies ballet dancers utilize the upper extremity to accurately execute single leg jumps. The lack of obvious differences between left and right side joint angles indicates that bilateral ballet training is effective at the professional level.

Biomechanical Characteristics of Single Leg Jump in Collegiate Basketball Players Based on Approach Technique

Our study investigated the characteristics of the biomechanics of lower extremities during running single leg jump (RSJ) in collegiate basketball players. Twelve division III male basketball players voluntarily participated in this study. They performed three trials of the running single leg jump with two approach speeds (fast and preferred) randomly. The kinematic data were collected by motion analysis system (200 Hz), and kinetic data were collected using the AMTI force platform (1000 Hz), and electromyography (EMG) data were recorded by the Delsys surface Electromyography (EMG) system (2000 Hz). Kinematic, kinetic and EMG signal were synchronized using EvaRT 4.6. Peak Ground reaction force, eccentric loading rate (ELR), gastrocnemius (GA) of pre-activation phase, and tibialis anterior (TA) of push-off phase were found significantly larger in the fast approach speed (p &lt; 0.05). RSJ improves muscle activation level and stretch reflex. Higher activation of TA and GA during RSJ may have the benefit of decreasing risk of injury and jump training. Thus, it is helpful in muscle stretch adaptation.