Jumping Tasks Research Articles

Effects of different pre-exercise strategies on jumping performance in female volleyball players.

The present study aimed to compare different pre-exercise strategies on jumping performance in female volleyball players. Fifteen healthy female volleyball players (age=18±0.6 years; training experience = 7.3±1.4 years; height = 164.8±5.4 cm; body mass = 57.2±8.1 kg) volunteered to participate in the study. Three different pre-exercise conditions (5 repetition maximum knee extension, electromyostimulation [EMS] and ischemic preconditioning [IPC]) were applied to the subjects and compared to a control condition performing a standardized warmup. Subjects performed the squat jump and 15 sec repeated countermovement jumps following a rest period. Measures associated with jumping performance were collected and compared between conditions. Rating of perceived exertion was also collected after each performance test. No pre-exercise condition outperformed a standardized warm-up on inducing improvements in jumping performance and in fact, EMS and IPC conditions resulted in performance decrements compared to control (P<0.05). We conclude that a standardized warm-up is enough to induce improvements in jumping performance in female volleyball players. Future research should examine alternative strategies alongside standardized warm-up to determine how best to prepare for jumping and related sport-specific tasks in female volleyball players.

Hamstring Muscle Stiffness in Athletes with and without Anterior Cruciate Ligament Reconstruction History: A Retrospective Study.

Introduction: Sports requiring sprinting, jumping, and kicking tasks frequently lead to hamstring strain injuries (HSI). One of the structural risk factors of HSI is the increased passive stiffness of the hamstrings. Anterior cruciate ligament (ACL) injury history is associated with a 70% increase in the incidence of HSI, according to a recent meta-analysis. The same report recommended that future research should concentrate on the relationships between the HSI risk factors. Hence, the present study aimed to retrospectively compare changes in the passive stiffness of the hamstrings in athletes with and without ACL reconstruction history. Methods: Using ultrasound-based shear-wave elastography, the mid-belly passive muscle stiffness values of the biceps femoris long head, semimembranosus, and semitendinosus muscles were assessed and compared amongst athletes with and without a history of ACL reconstruction. Results: There were no significant differences in the biceps femoris long head (injured leg (IL): 26.19 ± 5.28 KPa, uninjured contralateral (UL): 26.16 ± 7.41 KPa, control legs (CL): 27.64 ± 5.58 KPa; IL vs. UL: p = 1; IL vs. CL: p = 1; UL vs. CL: p = 1), semimembranosus (IL: 24.35 ± 5.58 KPa, UL: 24.65 ± 8.35 KPa, CL: 22.83 ± 5.67 KPa; IL vs. UL: p = 1; IL vs. CL: p = 1; UL vs. CL, p = 1), or semitendinosus (IL: 22.45 ± 7 KPa, UL: 25.52 ± 7 KPa, CL: 22.54 ± 4.4 KPa; IL vs. UL: p = 0.487; IL vs. CL: p = 1; UL vs. CL, p = 0.291) muscle stiffness values between groups. Conclusions: The passive mid-muscle belly stiffness values of the biceps femoris long head, semitendinosus, and semimembranosus muscles did not significantly differ between previously injured and uninjured athletes; therefore, further assessment for other muscle regions of hamstrings may be necessary. To collect more comprehensive data related to the structural changes that may occur following ACL reconstructions in athletes, a future study should examine the passive stiffness of wider muscle regions from origin to insertion.

Differences in Lower-Extremity Joint Coordination During Two Landing Phases of a Drop Jump Task.

The aim of the present study was to compare the differences in joint coordination patterns and variability in the lower extremity between the first and second landing phases of the drop jump. Eighteen resistance-trained men (age: 22.8 ± 1.8years) performed drop jumps from a height of 0.40m. An eight-camera motion capture system was utilized to record kinematic trajectories. Modified vector coding technique and circular statistics were used to determine the coordination pattern and variability of the following joint couples during the first and second landings: hip frontal-knee frontal (HfKf), hip sagittal-knee frontal (HsKf), hip sagittal-knee sagittal (HsKs), knee frontal-ankle frontal (KfAf), knee sagittal-ankle frontal (KsAf), and knee sagittal-ankle sagittal (KsAs). Statistical differences in the distribution frequencies of coupling angles and variability between the dominant and nondominant limbs across the two landing phases were compared using two-way repeated analysis of variance and Wilcoxon rank-sum tests. During the second landing phase, the proportion of HsKs, KfAf, and KsAs showing in-phase coordination was reduced but the proportion of KfAf and KsAs showing proximal joint (knee) coordination was increased (p < .05). Significant differences in bilateral asymmetry were observed only for the HfKf and KfAf patients (p < .05). HsKs, KfAf, and KsAf varied considerably during the second landing phase (p < .05). Joint coordination patterns during the second landing phase of the drop jump differed considerably from those during the first landing phase, thereby increasing the risk of knee and ankle injuries.

Reliability of Spatiotemporal Characteristics During Single-Legged Hop and Bilateral Drop Jump Tasks Using an Instrumented Pressure Walkway.

Single-legged hop tests have been widely used to assess performance-based outcomes after anterior cruciate ligament (ACL) reconstruction. Traditional single, triple, or 6-meter (6m) timed hop tests only measure distance or time as the principal variables, neglecting other variables, such as individual hop distances within a series of hops, flight time, and stance time. The development of portable instrumented pressure walkways has made it possible to collect parameters such as hop velocity, flight time, stance time, distance, and pressure outside of a laboratory setting. However, the reliability of instrumented pressure walkways in measuring spatial and temporal variables during single-legged hop tests is unknown. This study aimed to determine if the Zeno walkway can reliably measure spatiotemporal (ST) characteristics of hop tests. Cross-Sectional Study. Individuals (n=38) in this cross-sectional study performed single, triple, and 6m hop tests on a pressure-sensitive Zeno walkway. Twenty-one participants completed follow-up testing between one and 14 days later. Intraclass correlation coefficients (ICC(3,k)) were used to assess test-retest reliability of ST variables. The accuracy of vertical jump height and 6m hop timing were also measured. All ST variables demonstrated excellent test-retest reliability (ICC > 0.86) with small minimal detectable change (MDC) values during single-legged hop tests. Six-meter hop time and jump height during a bilateral drop jump were also accurately measured by the walkway. An instrumented pressure walkway is a novel tool to reliably assess non-traditional parameters of clinically relevant hop and jump tests such as flight time, stance time, and jump height after lower extremity injury, surgery, and rehabilitation. 3b.

Fatigue Affects Body Acceleration During Vertical Jumping and Agility Tasks in Elite Young Badminton Players.

Badminton is a sport demanding both high aerobic and anaerobic fitness levels, and fatigue can significantly impact game performance. However, relevant studies are limited, and none have employed a wearable inertial measurement unit (IMU) to investigate the effects of fatigue on athletic performance in the field. Overall performance and body acceleration in both time and frequency domains during the fundamental badminton skills of vertical jumping and changes of direction will be affected by fatigue. Cross-sectional study. Level 3. A total of 38 young badminton players competing at the Division I level participated. Body accelerations while performing vertical jump and agility-T tests before and immediately after undergoing a fatigue protocol were measured by an IMU, positioned at the L4 to L5 level. Jumping height decreased significantly by 4 cm (P < 0.01) after fatigue with greater downward acceleration (1.03 m/s2, P < 0.05) during the squatting subphase. Finishing time increased significantly by 50 ms only during the 10-m side-shuffling of the agility-T test (P = 0.02) after fatigue with greater peak and mean accelerations (3.83 m/s2, P = 0.04; 0.43 m/s2, P < 0.01), and higher median and mean frequency (0.38 Hz, P = 0.04, 0.11 Hz, P = 0.01). This study using a wearable IMU demonstrates the effects of fatigue on body acceleration in badminton players. The frequency-domain analysis further indicated that fatigue might lead to loss of voluntary control of active muscles and increased impacts on the passive elastic elements. The findings imply that fatigue can lead to diminished athletic performance and highlight the potential for an increased risk of sports injuries. Consequently, maintaining precision in monitoring fatigue is crucial for elite young badminton players.

Mechanism for High-Precision Control of Movement at Maximum Output in the Vertical Jump Task.

Human movements are governed by a tradeoff between speed and accuracy. Previous studies that have investigated the tradeoff relationship in sports movements involving whole-body movements have been limited to examining the relationship from the perspective of competition-specific movements, and the findings on whether the relationship is valid have not been unified. Therefore, this study incorporated a vertical jump task with the introduction of a condition in which landing position control was added to evaluate the essence of a sports movement that requires both speed and accuracy. Accuracy was examined using a method that quantifies the coordinates of the landing and takeoff positions using entropy. The mechanism of that tradeoff was then examined by confirming the phenomenon and analyzing the 3D vector trajectories. An increase in accuracy and a decrease in speed were observed when the landing position was the control target, even in the vertical jumping task normally performed at maximum effort, and the 3D velocity vector was characterized by the following: a reduced scalar and a more vertical direction. While the entropy from the takeoff to the landing position seemed to decrease when the accuracy of the landing position improved, the following noteworthy results were obtained given the characteristics of the vertical jump. Unlike traditional feedback control in the entropy reduction in hand movements, the trajectory is predetermined in a feedforward-like manner by controlling the initial velocity vector at takeoff, which allows the landing point to be adjusted.

Jumping Motor Skills in Typically Developing Preschool Children Assessed Using a Battery of Tests.

The preschool period is characterised by the improvement in motor skills. One of the developmental tasks in children is the ability to jump. Jumping plays an important role in the development of leg strength and balance. It is the gateway to more complex movements. In the physiotherapy clinic, we see a lot of difficulties in jumping performance in 5-7-year-old children. The aim of this study is to present the jumping ability, assessed by the Motor Proficiency Test (MOT) and the G-sensor examination of the vertical countermovement jump (CMJ) and countermovement jump with arms thrust (CMJAT) parameters. A total of 47 children (14 boys and 33 girls) were randomly recruited. The mean age was 5.5 years. The mean height was 113 cm and the mean weight was 19.7 kg. The children were divided into two groups according to their results. Children with low basic motor skills have the greatest difficulty with jumping tasks. In the CMJ jump, the take-off force was lower than in the CMJAT (p = 0.04). Most CMJAT parameters correlate with age, weight, and height. Height correlates most with children's jumping performance. This study may be useful for sport educators and developmental researchers. The topic should be further explored and the CMJ and CMJAT parameters may be established as a basis.

Maximum Strength and Power as Determinants of Match Skating Performance in Elite Youth Ice Hockey Players.

Keiner, M, Kierot, M, Stendahl, M, Brauner, T, and Suchomel, TJ. Maximum strength and power as determinants of match skating performance in elite youth ice hockey players. J Strength Cond Res 38(6): 1090-1094, 2024-Maximum strength has a strong influence on speed-strength performances such as sprints and jumps. Important for sports practice is whether these findings are also reflected in game performance. Therefore, the aim of this study was to explore the influence of maximum strength and power performance on linear on-ice skating performance in testing and during game play. A cross-sectional study was conducted, and 24 highly trained male youth ice hockey players participated. Jump performances (countermovement jump [CMJ], drop jumps), maximum strength (1 repetition maximum [1RM] squat and isometric trap bar pull [ITBP]), and on-ice linear sprints (15 m [LS15], 30 m [LS30], flying 15 m [FLY15]) were measured. Match performances (among others: peak skating speed) were collected of 4 regular league games using a local positioning system. Correlation coefficient and explained variance were calculated ( ρ ≤ 0.05). Correlations between maximum strength and jump with on-ice linear sprint performance showed 1-35% explained variance. Correlations between "off ice" test (CMJ, relative 1RM) and game data (peak skating speed) showed 22-30% explained variance, respectively, while ITBP and DJ missed significant level. Between linear sprint and game performance showed 15-59% explained variance. In this study, a clear influence of 1RM in squatting and CMJ performance on on-ice linear sprint as well as in-game peak skating speed was observed. These findings show that strength and jumping performance can be valuable tests within a comprehensive test battery and indicate the relevance of strength and jumping tasks within the regular exercise program to improve in-game skating performance.

The Effects of Drop Vertical Jump Task Variation on Landing Mechanics: Implications for Evaluating Limb Asymmetry

Limb asymmetry is an important consideration when evaluating rehabilitation progress or re-injury risk. The drop vertical jump (DVJ) task is commonly used to assess landing mechanics; however, the extent to which task setup influences limb asymmetry is unknown. Our purpose was to examine limb asymmetries across DVJ variations. We hypothesized that more demanding variations involving greater jump distance and target use would elicit greater landing asymmetries. Participants performed six DVJ variations while lower extremity joint kinematics and kinetics were collected. Joint angles and internal moments of the hip, knee and ankle were computed at initial contact and over the decent phase of the initial landing. The horizontal jump distance and the verbal instructions provided on how to jump off the box influenced limb asymmetries. The DVJ variation without a horizontal jump distance resulted in significant differences at the hip and knee; specifically, greater hip and knee flexion asymmetry (7.0° and 15.2° differences, respectively) were observed between limbs at initial contact. Instructions restricting take-off and landing strategies reduced asymmetry; this indicates that verbal instructions are critical to avoid altering natural landing mechanics. To best utilize DVJ as a tool, study protocols should be standardized to allow for more generalizable research and clinical findings.

Development of a simple algorithm to detect big air jumps and jumps during skiing.

Jumping is an important task in skiing, snowboarding, ski jumping, figure skating, volleyball and many other sports. In these examples, jumping tasks are a performance criterion, and therefore detailed insight into them is important for athletes and coaches. Therefore, this paper aims to introduce a simple and easy-to-implement jump detection algorithm for skiing using acceleration data from inertial measurement units attached to ski boots. The algorithm uses the average of the absolute vertical accelerations of the two boots. We provide results for different parameter settings of the algorithm and two types of jumps: Big Air jumps and jumps during skiing. The latter are divided into small (time of flight < 500 ms) and medium (time of flight ≥ 500 ms) jumps. The algorithm detects 100% of Big Air, 94% of medium and 44% of small jumps. In addition, the settings with the highest detection rates also have the highest number of overdetected jumps. To resolve this conflict, a penalty-adjusted score that considers the number of overdetected jumps in the final performance analysis is proposed.

The effects of joint hypermobility on pain and functional biomechanics in adolescents with juvenile fibromyalgia: secondary baseline analysis from a pilot randomized controlled trial

BackgroundJoint hypermobility is a common clinical finding amongst hereditary connective tissue disorders that is observed in pediatric rheumatological settings, and often associated with chronic pain. Joint hypermobility may also contribute to deficits in physical functioning and physical activity, but previous findings have been inconsistent. It is possible that physical activity impairment in joint hypermobility may be due to chronic aberrant movement patterns subsequent to increased joint laxity.MethodAs part of a larger randomized pilot trial of juvenile onset fibromyalgia (JFM), a secondary analysis was conducted to explore whether adolescents with JFM and joint hypermobility differed from non-joint hypermobility peers in terms of pain, daily functioning, and biomechanics (i.e., kinetics and kinematics) during a moderately vigorous functional task.ResultsFrom the larger sample of adolescents with JFM (N = 36), 13 adolescents (36.1%) met criteria for joint hypermobility and 23 did not have joint hypermobility. Those with joint hypermobility exhibited poorer overall functioning (Md = 20, Q1,Q3 [5.8, 7.6] vs. Md = 29, Q1,Q3 [5.1, 7.6]) but there were no differences in pain (Md = 6.9, Q1,Q3 [22, 33], vs. Md = 6.45, Q1,Q3 [15, 29.5]). Inspection of time-series plots suggests those with joint hypermobility exhibited decreased hip flexion and frontal plane hip moment (e.g., resistance to dynamic valgus) during the landing phase (early stance) and greater hip and knee transverse plane moments during the propulsion phase (late stance) of the drop vertical jump task (DVJ). No other differences in lower extremity biomechanics were observed between study groups.ConclusionsIn this exploratory study, there were small but notable differences in biomechanics between patients with JFM who also had joint hypermobility versus those without joint hypermobility during a landing and jumping task (e.g., DVJ). These differences may indicate decreased joint stiffness during landing, associated with increased joint laxity and decreased joint stability, which may put them at greater risk for injury. Further study with a larger sample size is warranted to examine whether these biomechanical differences in patients with JFM and joint hypermobility affect their response to typical physical therapy or exercise recommendations.

Effects of Upper-Body and Lower-Body Conditioning Activities on Postactivation Performance Enhancement During Sprinting and Jumping Tasks in Female Soccer Players.

Santos da Silva, V, Nakamura, FY, Gantois, P, Nogueira Gouveia, JN, Peña, J, Beato, M, and Abade, E. Effects of upper-body and lower-body conditioning activities on postactivation performance enhancement during sprinting and jumping tasks in female soccer players. J Strength Cond Res 38(2): 342-349, 2024-This study aimed to investigate the postactivation performance enhancement (PAPE) effects of "specific" (half-back squat) and "nonspecific" (bench press) conditioning activities on sprinting and jumping performances in female soccer players. Fourteen players (mean ± SD : age = 22.3 ± 4.0 years; body mass = 60.2 ± 7.8 kg; height = 164.1 ± 4.2 cm) competing at national level (first League) participated in this within-subject crossover study. The players performed a warm-up protocol including 3 sets of 3 repetitions of half-back-squat or bench press exercises at 90% 1RM or a warm-up protocol without lifting weights (i.e., control condition). Forty-meter shuttle sprints (20 + 20 m with change of direction [COD-180°]), countermovement jump (CMJ), and horizontal jump (HJ) performances were recorded 6 minutes after the conditioning activities protocols or the control condition. Nonsignificant large positive effects were found for the HJ after the half-back-squat (ES = 1.68; p > 0.05) and bench press (ES = 1.68; p > 0.05) protocols. Although nonsignificant, HJ changes ( Δ = 0.07 m) were greater than the smallest worthwhile change (0.02 m) and standard error of measurement (0.03 m) after both conditioning activities. Moreover, no significant changes were found for sprint and CMJ performance after neither half-back-squat nor bench press protocols ( p > 0.05). In conclusion, both specific and nonspecific conditioning activities using heavy loads (i.e., 90% 1RM) may be suitable to enhance individual HJ. Finally, both conditioning activities are potentially ineffective for increasing sprint and CMJ performance in the context of this study.

Wearable ultrasound system for assessing muscle function during physical activity

Conventional ultrasound transducers, which are meant for hand-held operation, are not ideally suited for MSK-US during dynamic physical activity. We have developed a custom wearable ultrasound system for Motion-mode (M-mode) MSK-US, which enables multi-site hands-free sensing of tissue movement during physical activity such as that encountered during rehabilitation exercises. Participants performed a jumping task on a force plate with a sensor attached to their right vastus lateralis (VL). Mean pixel value (MPV) and normalized pixel differences (NPDs) were acquired from the images during the jumping task. Signals were filtered and normalized to root-mean square baseline and percent change was calculated for peaks of jump take-off and landing. The correlation coefficient was calculated to determine a relationship between metrics. Concurrently acquired force-plate data showed that the percent change during take-off and landing was 0.28% ± 0.09 and 0.66% ± 0.17 relative to baseline for each peak, respectively. MPV values changed 0.42% ± 0.29 and 0.81% ± 0.17, and NPD changed 0.41% ± 0.32 and 0.84% ± 0.12 for corresponding peaks. Overall results indicated significant correlation between force data and MSK-US (p &amp;lt; 0.05). Our system can maintain acoustic coupling during complex movements providing real-time feedback and expanding the potential for wearable MSK-US sensors.

Effect of Heading a Soccer Ball as an External Focus During a Drop Vertical Jump Task: Response.

Effect of Heading a Soccer Ball as an External Focus During a Drop Vertical Jump Task: Response.

Effect of Heading a Soccer Ball as an External Focus During a Drop Vertical Jump Task: Letter to the Editor

Effect of Heading a Soccer Ball as an External Focus During a Drop Vertical Jump Task: Letter to the Editor

Investigating Player Selection within UK Academy Soccer: The Application of Objective and Subjective Assessments in Detecting Talent

Talent selection and development in academy soccer is highly dependent on coach intuition. Given such reliance upon subjective inputs, a greater understanding towards the utility of coach intuition may prove invaluable. The present study investigated coach agreement, the associations between subjective and objective outcomes and prominent traits highlighted within player (de)selection. Academy players (n = 45, age = 14 ± 2yrs) and coaches (n = 10, age = 31 ± 5yrs) were recruited from a professional soccer academy. Objective assessments included tactical and psychological surveys, physical assessments (linear sprints, change of direction and jumping tasks) and performance analysis (performance assessment for team sports). Coach subjective player gradings were collected using a visual analogue scale aligned to the objective assessments. Lead and assistant coaches demonstrated poor-to-moderate agreements in perceived player skills (ICC = 0.48 to 0.76) and fair to almost perfect agreement in player (de)selection (ICC= 0.23-1.00, P &lt;.001 to .26). However, coach agreement reduced as players aged. Likewise, a maturation related bias was present whereby biologically older players were selected over their lesser mature players. Moreover, coach intuition demonstrated a strong predictive capability to select players, whilst the study was incapable of distinguishing exclusive traits related to selection outcome.

The Association Between Lower Extremity Kinematics And Impact Load During The Drop Vertical Jump Task

The Association Between Lower Extremity Kinematics And Impact Load During The Drop Vertical Jump Task

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.

Complexity of spatio-temporal plantar pressure patterns during everyday behaviours.

The human foot sole is the primary interface with the external world during balance and walking, and also provides important tactile information on the state of contact. However, prior studies on plantar pressure have focused mostly on summary metrics such as overall force or centre of pressure under limited conditions. Here, we recorded spatio-temporal plantar pressure patterns with high spatial resolution while participants completed a wide range of daily activities, including balancing, locomotion and jumping tasks. Contact area differed across task categories, but was only moderately correlated with the overall force experienced by the foot sole. The centre of pressure was often located outside the contact area or in locations experiencing relatively low pressure, and therefore a result of disparate contact regions spread widely across the foot. Non-negative matrix factorization revealed low-dimensional spatial complexity that increased during interaction with unstable surfaces. Additionally, pressure patterns at the heel and metatarsals decomposed into separately located and robustly identifiable components, jointly capturing most variance in the signal. These results suggest optimal sensor placements to capture task-relevant spatial information and provide insight into how pressure varies spatially on the foot sole during a wide variety of natural behaviours.

Identification Obstacles Biology Learning using Sharing and Jumping Task on Didactical Design Research

The purpose of this study is identify student learning barriers in other classes. This type of research is descriptive qualitative. This research method is Didactical Design Research (DDR), which consists of three stages, namely (1) prospective analysis, (2) metapedadidactical analysis, and (3) retrospective analysis. The results of this study are (1) Student learning obstacle are included in epistemological barriers, namely student knowledge with limited application contexts. Students have not been able to understand the concept thoroughly and have not been able to connect one concept to another and (2) Analysis of learning barriers aims to be used as a reference in the preparation of learning tools and to predict didactic responses and anticipations that occur during the learning process.