Unilateral Jumps Research Articles

Microdosing Plyometric Training Enhances Jumping Performance, Reactive Strength Index, and Acceleration among Youth Soccer Players: A Randomized Controlled Study Design.

Microdosing can facilitate better accommodation to the training stimulus while aligning with the scheduling needs of teams. In this study, the effectiveness of microdosing exposure was investigated by comparing the effects of microdosing plyometric jump training (microPJT) with those of regular plyometric jump training (regPJT) and a control group not exposed to plyometric training. The comparison focused on the effects on jumping performance, reactive strength index (RSI), and acceleration over a 10-meter distance. Fifty-two male youth soccer players (16.3 ± 0.6 years old) from under-17 teams participated in a randomized controlled study, with interventions lasting 8 weeks. Assessments were conducted twice, before and after the intervention, measuring squat jump (SJ), countermovement jump (CMJ), RSI during drop jumps, and acceleration in a 10-meter sprint test. The regPJT group completed 34 bilateral jumps and 48 unilateral jumps per week over two weekly sessions, totaling 82 jumps. Conversely, the microPJT group performed 17 bilateral jumps and 24 unilateral jumps weekly over 4 sessions week, totaling 41 jumps. Significant interactions between groups and time were observed concerning SJ (p < 0.001; η2= 0.282), CMJ (p < 0.001; η2= 0.368), RSI (p < 0.001; η2= 0.400) and 10-m sprint time (p < 0.001; η2 = 0.317). Between-group analysis indicated that both the microPJT (p < 0.001) and regPJT (p < 0.001) groups exhibited significant better results compared to the control group in post-intervention evaluation of SJ, CMJ, RSI and 10-m sprint time, while no significant differences were found between experimental groups (p > 0.050). In conclusion, this study has revealed that both microPJT and regPJT are equally effective in enhancing jumping performance and acceleration time in soccer players. This suggests that a smaller training volume, distributed more frequently across the week, can effectively induce improvements in soccer players.

The Inclusion of Preplanned and Random and Unanticipated/Unexpected Events During Strength Training Improves the Ability to Repeat High-Intensity Efforts Under Uncertainty.

To compare the effects of unilateral flywheel training (FT), using a rotational conical pulley, including multidirectional movements with either preplanned or random unanticipated/unexpected executions on functional performance in football players. A total of 32 young male football players were randomly assigned to an FT program including preplanned unilateral multidirectional movements (PTG, n = 11), an FT executing the same unilateral movements through random (ie,right or left leg) unanticipated (ie,verbal or visual cue) or unexpected (ie,moment where the cue was provided) situations (UTG, n = 11), or a control group (n = 10) that followed their football training routine. FT consisted of 1 set × 5-12 repetitions of 4 exercises performed once a week for 10weeks. Intermittent endurance performance, repeated unilateral and bilateral jumping ability, change-of-direction (COD) ability, linear sprint velocity, preplanned repeated-sprint ability (RSA), and uncertainty RSA (RSA-RANDOM) were assessed preintervention and postintervention. Significant improvements were found in RSA-RANDOM performance (P < .05, effect size [ES] range: UTG [1.83-2.16], PTG [0.69-0.73]) and COD (P < .05, ES: UTG = 1.34, PTG = 0.98]) in both training groups. Furthermore, significant improvements were also found in intermittent endurance performance (P = .016, ES = 0.37) and sprinting (P = .006, ES = 0.45) in UTG. No changes in any variable were found in the control group. No significant between-groups differences (P > .05) were reported between UTG and PTG, while differences were observed to the control group in unilateral jumping ability, COD, and RSA-RANDOM for UTG, and in RSA-RANDOM for PTG. A 10-week unilateral FT improved RSA-RANDOM and COD ability in youth football players, so both preplanned and unexpected situations should be included on strength training.

The Relationship Between Various Jump Tests and Baseball Pitching Performance: A Brief Review

ABSTRACT Multidirectional ground reaction forces (GRFs) and jump tests within baseball pitchers provide insight into athletic ability and coordination to produce lower-body force and power. Lower-body power is a biomechanical feature that denotes physiological capacity through dynamic and passive tissue stretch-shortening in transferring energy from the ground through the kinetic chain. Optimized lower-body power may lessen the magnitude of forces on the upper extremity. Insufficient lower-body power may create a greater risk of upper-body injury. Lower-body power and its relationship to ball velocity have been minimally investigated, yet some research points to a correlation between jumping ability and fastball velocity. Because pitching is unilateral, practitioners should consider unilateral jumps to determine the extent of bilateral asymmetry or stride to drive leg differences that can guide training to remediate deficiencies. The purposes of this brief review are to (a) examine factors that influence vertical jump performance among baseball players, (b) examine research on pitching multidirectional GRFs, and (c) examine literature concerning jump performances to baseball pitching performance. Collectively, this review can assist coaches and practitioners in lower-body power testing and training for baseball pitchers.

Unilateral dynamic balance assessment: The test-retest reliability of the OptoJump next drift protocol

BackgroundThe OptoJump Next Drift Protocol is a test designed to assess unilateral dynamic balance. Participants are required to perform a series of unilateral jumps from which left/right and forward/back displacement (Drift) is calculated. ObjectivesThis investigation set out to establish the test-retest reliability of the OptoJump Next Drift Protocol. MethodTwenty-six participants performed the OptoJump Next Drift Protocol on two separate occasions. Drift Area and Drift Area as a percentage of total available jump area were calculated for each leg. ResultsInterclass Correlation Coefficients (ICC) indicated poor reliability for Drift Area and Drift Area as a percentage of total available jump area (right leg r = .44; left leg r = −0.20). However, 95% Limits of Agreement (LoA) suggested a stronger relationship. For Drift Area, between trial Mean Difference for the right leg was 50.87 cm2 (95% LoA = −227.57 – 328.87) and for the left leg it was 54.08 cm2 (95% LoA = −333.62 – 441.79). For Drift Area as a percentage of total available jump area, Mean Difference for the right leg was 0.56% (95% LoA = −2.44 – 3.65) and for left 0.60% (95% LoA = - 3.76–4.89). ConclusionsBased on the 95% LoA data, the authors suggest that the OptoJump Next Drift Protocol does offer an acceptable level of reliability.

Effects of tendon elastic energy and electromyographic activity pattern on jumping height and pre-stretch augmentation during jumps with different pre-stretch intensity

ABSTRACT The present study aimed to investigate the effects of tendon elastic energy and electromyographic activity patterns (ratio of pre-landing to concentric: mEMG PLA/CON; ratio of eccentric to concentric; mEMG ECC/CON) on jump performance. Twenty-nine males performed five kinds of unilateral jumps using only ankle joint (no-countermovement jump: noCMJ; countermovement jump: CMJ; drop jumps at 10, 20 and 30 cm drop height: DJ10, DJ20 and DJ30). Jumping height, pre-stretch augmentation and electromyographic activity of the plantar flexor muscles were measured. The elastic energy of the Achilles tendon was measured during isometric contractions. Relative tendon elastic energy (to body mass) was highly correlated with jumping heights of CMJ, DJ10 and DJ20 but not with noCMJ and DJ30, whereas that was significantly correlated with pre-stretch augmentation in CMJ, but not with three DJs. The mEMG PLA/CON was significantly correlated with the pre-stretch augmentation of DJ20 and DJ30, but not with DJ10, whereas the mEMG ECC/CON was significantly correlated with the pre-stretch augmentation of DJ20 and DJ30, but not with CMJ and DJ10. These results suggested that jumping exercises with low pre-stretch intensity benefited from tendon elastic energy, but those with high pre-stretch intensity benefited from electromyographic activity patterns.

Exploratory Investigation Into the Impact of Bilateral and Unilateral Jump Characteristics on Ground Reaction Force Applications in Baseball Pitching.

Lis, R, Szymanski, DJ, Qiao, M, and Crotin, RL. An exploratory investigation into the impact of bilateral and unilateral jump characteristics on ground reaction force applications in baseball pitching. J Strength Cond Res XX(X): 000-000, 2022-Jump tests are effective, valid, and reliable in examining lower-body power that can influence ground reaction forces (GRFs) in baseball pitching. Relationships between drive and stride leg GRFs and fastball velocities while pitching from the wind-up and stretch were evaluated for performance influences across the following conditions: (a) lower-body GRFs from unilateral countermovement jumps (UCMJ) and bilateral countermovement jumps (BCMJ) and (b) BCMJ and drive and stride leg UCMJ height. Nineteen Division I collegiate baseball pitchers (age; 19.9 ± 1.5 years, height; 1.86 ± 0.06 m, body mass; 90.7 ± 13.8 kg) completed BCMJ and UCMJ tests and threw four-seam fastballs from a pitching mound with 2 embedded force plates. Three moderate associations (r ≥ 0.47) were statistically significant (p < 0.05) for BCMJ and UCMJ heights to pitching GRFs. Stride leg UCMJ height was significantly greater than drive leg UCMJ height, p < 0.01, η2 = 0.34. Wind-up and stretch GRFs were statistically similar. Fastball velocities showed a statistically significant association that was moderately high with wind-up and stretch stride leg anterior-posterior GRFs (r ≥ 0.65, p < 0.01). Collegiate pitchers jumped significantly higher with their stride leg, and the sum of vertical unilateral jump height of both legs was significantly greater (27%) than BCMJ height to indicate greater single-leg dominance in jumping. Although stride leg height was higher, improving stride leg jumping performance may be functionally more important in producing greater momentum into foot strike that has the potential to increase fastball velocity.

The Effect of Foot Position and Lean Mass on Jumping and Landing Mechanics in Collegiate Dancers

The purpose of this study was to investigate the effects of foot positioning and lean mass on jumping and landing mechanics in collegiate dancers. Thirteen dancers performed 3 unilateral and bilateral vertical jumps with feet in neutral and turnout positions. Dual-energy x-ray absorptiometry scans, jump height, vertical stiffness, and joint stiffness were assessed for relationships between foot positions. Jump heights were greater in right compared with left limb (P = .029) and neutral compared with turnout (P = .020) during unilateral jumping. In unilateral landing, knee stiffness was greater in turnout compared with neutral (P = .004) during the loading phase. Jump height (P < .001) was significantly increased, and vertical stiffness (P = .003) was significantly decreased during bilateral jumping in neutral compared with turnout. Significantly increased hip stiffness during the attenuation phase was observed in neutral compared with turnout (P = .006). Left-limb lean mass was significantly less than the right limb (P < .05). Adjustments for bilateral jumping were focused on hip stiffness, whereas there was a slight shift to knee strategy for unilateral jump.

RELAÇÃO ENTRE O DESEMPENHO DE SALTO E SPRINT EM VELOCISTAS ADOLESCENTES

ABSTRACT Objectives: This study aimed to examine the relationship between vertical jumping at forces of specific time phase and sprint performance in teenage sprinters. Methods: Fifteen male teenage sprinters (age: 14±2 years, height: 168±2 cm, weight: 61±1 kg) participated in the study. The subjects performed the following bilateral/unilateral jumps on a force platform: a) squat jump (SJ), b) unilateral SJ (USJ), c) 40cm drop jump (DJ), and d) 20cm unilateral DJ (UDJ). The 60m sprint test was administered on the second day. Brower split timers were positioned to record subjects’ 5m, 10m, 50m and 60m split times. The variables for inclusion were vertical jump height, maximum force, and force output at 120ms in all jumps and sprint time measures. Results: The results of the Pearson Product Moment Correlation analysis showed that SJ120ms was correlated to 5m and USJ120ms was correlated to 10m. UDJ120ms showed a stronger correlation with 50m than DJ120ms. Although significant correlations using maximum force and height were observed, there were inconsistent results between bilateral and unilateral jumps. Conclusion: Our results highlighted that jumps that have similar form with certain force outputs at specific event timing could more precisely predict sprint performance in teenage sprinters. USJ120ms and UDJ120ms could better predict the acceleration (10m) and high-speed phase (50m) in sprint performance, respectively. Moreover, coaches and practitioners should be cautious when using only jump height or maximum force to predict sprint performance, since the results could be inaccurate when specific movement variables are not thoughtfully considered. Level of evidence III.

Frontal Plane Neurokinematic Mechanisms Stabilizing the Knee and the Pelvis during Unilateral Countermovement Jump in Young Trained Males.

(1) The unilateral countermovement jump is commonly used to examine frontal plane kinetics during unilateral loading and to identify athletes with an increased risk of lower limb injuries. In the present study, we examined the biomechanical mechanisms of knee and pelvis stabilization during unilateral vertical jumps. (2) Healthy males performed jumps on a force plate with the dominant leg. Activity of the dominant-side gluteus medius and the contralateral-side quadratus lumborum and erector spinae muscles was recorded with surface EMG. The EMG data were normalized to the EMG activity recorded during maximal voluntary isometric hip abduction and lateral trunk flexion contractions. During jumps, the propulsive impulse was measured, and the pelvis and thigh segmental orientation angles in the frontal plane were recorded and synchronized with the EMG data. (3) The magnitude of knee valgus during the jump did not correlate with hip abduction force, but negatively correlated with gluteus medius activity. This correlation became stronger when gluteus medius activity was normalized to hip abduction force. Propulsive impulse did not correlate with any neuromechanical measurement. (4) We conclude that hip abduction force itself does not regulate the magnitude of knee valgus during unilateral jumps; rather, the gluteus medius should be highly activated to increase frontal-plane knee joint stability.

Foot tracking can be an alternative to determine foot strike and take-off during vertical jumps

ABSTRACT Determining foot strike and take-off during vertical jumps is essential to calculate a range of performance measures, which normally requires the use of expensive equipment such as force platforms. This study evaluated whether tracking the foot centre of mass(CoM) and hallux could be suitable alternatives to determine foot strike and take-off during jumps. Thirteen recreational runners performed six unilateral jumps. Foot strike and take-off instants were observed using three algorithms from foot CoM, pelvis CoM and the hallux marker and results were compared with data determined by the force platform. Bland-Altman method and Cohen effect sizes were used to assess the differences between methods. For foot strike, the difference between the foot CoM and the force platform (12 ms, d < 0.01) was smaller than using the pelvis CoM (46 ms, d < 0.01) and similar to the hallux (16 ms, d < 0.01). For the take-off, the foot CoM produced the smallest difference (i.e., 4 ms, d < 0.01; pelvis = 22 ms, d < 0.01 and hallux = 18 ms, d < 0.01). The foot CoM seems to yield the closest agreement with the force platform when determining foot strike and take-off during vertical jumps. However, the hallux marker can be used as an alternative to the foot CoM once corrected for mean bias.

Relationship between Performance and Inter-Limb Asymmetries Using Flywheel Resistance Device in Elite Youth Female Basketball Players.

Simple SummaryInter-limb asymmetry is defined as the difference in performance or function between limbs. Inter-limb asymmetries have become the focus of recent research, with many studies describing differences in performance on the right and left sides. Most of these studies have reported asymmetry values during unilateral jumps or COD tests, but few have used flywheel resistance (iso-inertial) devices. Our study quantified inter-limb asymmetries using a variety of methods and compared asymmetry with physical performance in a sample of elite youth female basketball players. The results of this set of tests indicated that mean asymmetry magnitudes greatly varied among all metrics and showed different directionality, thus highlighting the lack of consistency across the tests and the task-specific nature of inter-limb asymmetry. Existing recommendations note that a battery of tests is needed to gain a holistic picture of inter-limb asymmetries (such as jumps, changes of direction, or power-specific skills). Identifying inter-limb asymmetries could help practitioners determine the workload ratios for each limb during individual training sessions. Moreover, the use of flywheel resistance devices could be included in the battery of tests for the detection of inter-limb asymmetries.The purposes of this study were to quantify inter-limb asymmetries from unilateral jumps, change of direction (COD) speed, and flywheel resistance skill tests and to examine their relationship with physical performance in a sample of elite youth female basketball players. Eleven female basketball players (age = 17.56 ± 0.60 year; body mass = 75.13 ± 12.37 kg; height = 1.83 ± 0.08 m; BMI = 22.42 ± 2.28; sports experience = 6.31 ± 1.73 year; years post-peak height velocity = 4.79 ± 0.68 year) performed a battery of fitness tests in the post-season consisting of the Single Leg Countermovement Jump in vertical (SLCJ-V), horizontal (SLCJ-H), and lateral (SLCJ-L) directions, 135° and 90° COD tests, and four skills (acceleration step, deceleration step, sidestep, and crossover step) with an flywheel resistance device. The results showed significant differences between the higher performing and lower performing limbs across all tasks (p < 0.05). The mean asymmetry index values ranged from 1.26% (COD 135°) to 11.75% (SLC-V). Inter-limb asymmetries were greatest during the flywheel resistance skills. Spearman’s correlations (ρ) for all tests were only significant for inter-limb asymmetries during the sidestep test and reduced performance in SLCJ-L (ρ = −0.61; p = 0.046) and all COD deficits (ρ range = −0.72 to −0.81). The findings of the present study showed that inter-limb asymmetries are task-specific in female youth basketball players and suggest that the use of flywheel devices can be included in the battery of tests to detect inter-limb asymmetry.

Association between Concentric and Eccentric Isokinetic Torque and Unilateral Countermovement Jump Variables in Professional Soccer Players.

Isokinetic tests have been highly valuable to athletic analysis, but their cost and technical operation turn them inaccessible. The purpose of this study was to verify the correlation between unilateral countermovement jump variables and isokinetic data. Thirty-two male professional soccer players were subjected to the isokinetic testing of both knee extensors and flexors in concentric and eccentric muscle contractions. They also executed unilateral countermovement vertical jumps (UCMJ) to compare maximum height, ground reaction force, and impulse power with isokinetic peak torque. Data analysis was conducted through Pearson correlation and linear regression. A high correlation was found between dominant unilateral extensor concentric peak torque and the UCMJ maximum height of the dominant leg. The non-dominant leg jump showed a moderate correlation. No other variable showed statistical significance. Linear regression allowed the generation of two formulae to estimate the peak torque from UCMJ for dominant and non-dominant legs. Although few studies were found to compare our results, leading to more studies being needed, a better understanding of the unilateral countermovement jump may be used in the future as a substitute to the expensive and technically demanding isokinetic testing when it is unavailable, allowing the assessment of lower limb physical asymmetries in athletic or rehabilitation environments.

The effect of a core training program on jump performance in female handball players

Objectives: To evaluate changes on bilateral and unilateral jump performance and frontal knee projection angle after an implementation of a core strength program in female handball players.&#x0D; Equipment and methods: This is a randomized controlled trial study. A total of 20 participants [age = 17.2 (1.9) years, height = 1.7 (0.1) m, weight = 62.8 (7) kg ] were recruited and split in: a core training group and a control group. The core training group participated in 8 weeks in-season of a core strength program (2 times/week). Pre- and post-intervention jump height, contact time and reactive strength index were collected during bilateral and unilateral drop vertical jumps. Frontal knee projection angle was measured only at unilateral drop jumps.&#x0D; Results: Core training group increased the bilateral jump height by 18.8% and showed a statistically significant difference in reactive strength index from pre-intervention [0.07 (0.03)] to post-intervention [0.10 (0.04)]. The core training group also improved the unilateral jump height by 20%, but only at the non-dominant leg. This improvement was accompanied by a statistically significant decreased in the frontal knee projection angle from pre-intervention [13.8 (7.38) degrees] to post-intervention [9.3 (6.09) degrees]. Statistical significant difference was set at p ˂0.05.&#x0D; Conclusion: A core strength training increased jump performance and it could play a role in ACL injury prevention programs in female team players.&#x0D; &#x0D;

Influence of Physical and Technical Aspects on Change of Direction Performance of Rugby Players: An Exploratory Study.

We examined the relationships between change of direction (COD) speed and deficit, and a series of speed- and power-related measurements in national team rugby union players and analyzed the influence of movement patterns on COD ability. Eleven male athletes completed the following physical assessments on different days: day 1—anthropometric measurements, and lower-body kinematic parameters (assessed with eight inertial sensors) and completion time in COD tests (pro-agility, 45° cutting maneuver (CUT), and “L” (L-Drill)); day 2—bilateral and unilateral squat and countermovement jumps, 40 m linear sprint, and bar-power output in the jump squat and half-squat exercises. Pearson’s product–moment correlations were performed to determine the relationships between COD velocities, COD deficits, and the speed–power variables. Differences between players with higher and lower COD deficits were examined using magnitude-based inferences. Results showed that (1) greater sprint momentum was associated with higher COD deficits, particularly in drills with sharper angles and multiple directional changes (L-drill and pro-agility); (2) higher unilateral jump heights were associated with greater COD deficits in the pro-agility and L-drill but not in the CUT; (3) faster athletes were less efficient at changing direction and presented greater trunk and knee flexion angles during COD maneuvers, probably as a consequence of higher inertia.

Relationship between Asymmetries Measured on Different Levels in Elite Basketball Players

In this study, we investigated the association of magnitude and agreement in direction between asymmetries measured on single-joint (hip and trunk), complex movement (jumping), and skill (change of direction (CoD)) levels. The study sample comprised 43 junior- and senior-level (age = 20.5 ± 6.0 years; height = 194.5 ± 7.2 cm; body mass = 86.8 ± 10.1 kg) elite male basketball players. Both limbs/sides were tested in hip and trunk isometric strength; passive range of motion (RoM); unilateral, horizontal, and vertical jumping; and CoD tests, from which asymmetry indexes were calculated. The associations between asymmetry magnitudes were calculated with Spearman’s ρ correlation coefficient. The agreement between the direction of asymmetries on different levels was calculated with Cohen’’s Kappa (κ) coefficient. The average magnitude of asymmetry varied substantially (2.9–40.3%). Most associations between asymmetry magnitudes measured on different levels were small and statistically non-significant, with a few exceptions of moderate and large associations. Asymmetry in single-leg countermovement jump parameters was strongly associated with hip abduction maximal strength (ρ = 0.58 and 0.50, p &lt; 0.01). Agreement between asymmetry directions was slight to fair, with a few moderate exceptions. Results indicate that multiple tests are needed to obtain a comprehensive picture of athletes’ asymmetries and that universal thresholds and golden standard tests for return to play should be reconsidered and reinvestigated.

Determining the Prognostic Validity of the Unilateral Horizontal Cyclic Jumps Test in Sprint Performance

In sports practice, motor tests are commonly used to predict success in specific segments of sprint running, as well as post-injury tests in rehabilitation. The purpose of this analytical cross-sectional study was to determine the prognostic validity of the unilateral horizontal cyclic jumps for a 20 m (UHCJ20m) test on sprint running success. A sample of 118 kinesiology students aged 20.5 ± 1.2 years with an average height of 179.7 ± 6.4 cm and a body mass of 75.6 ± 7.3 kg was used to determine the correlation between the results of the UHCJ20m test and the results of the 20 m sprint start run (MRLS20m), the 20 m sprint flying start run (MRFS20m), and the 100 m run (M100m). The results showed a moderate correlation in all tests (MRLS20m (R = 0.49), MRFS20m (R = 0.53), and M100m (R = 0.38)) with UHCJ20m. In addition to the final result, the multiple regression analysis showed a significant moderate correlation between the kinematic parameters of the UHCJ20m test and the results in the MRLS20m (R = 0.38), MRFS20m (R = 0.49), and M100m (R = 0.37) tests. The stride length (SL) and the contact time (CT) of the UHCJ20m test were statistically significant predictors for the 100 m sprint, the number of steps for MRLS20m, and the SL and the CT for MRFS20m sprint success. Unilateral horizontal cyclic jumps are a significant predictor of success in sprint running, especially for the maximal speed running segment.

Assessing the Magnitude and Direction of Asymmetry in Unilateral Jump and Change of Direction Speed Tasks in Youth Female Team-Sport Athletes.

The direction of inter-limb asymmetries and the change of direction (COD) deficit are two aspects that have increased in recent years. The main objective of the present study was to assess the magnitude of neuromuscular asymmetries in an elite youth female team-sports sample and determine its directionality. Secondary objectives were to evaluate the relationship between COD deficit, linear speed and COD time performance. Elite female youth basketball and handball players (n = 33, age = 16 ± 1.17 y) performed the Single Leg Countermovement Jump in vertical (SLCJ-V), horizontal (SLCJ-H), and lateral (SLCJ-L) directions, the COD and the 10-m sprint. Results showed statistical differences between limbs in all the neuromuscular tests (p < 0.001). The Kappa coefficient showed poor to fair levels of agreement between tasks (K range = -0.087 to 0.233), indicating that asymmetries rarely favoured the same limb between skills. Additionally, small and non-significant correlations were found between the linear sprint capacity and the COD ability. The findings of the present study highlight the independent directionality of asymmetries across tests. The COD deficit does not appear to be much more advantageous than COD total time to measure asymmetry. Practitioners are encouraged to use a fitness testing battery to detect existing side differences and each ability should be specifically trained with functional tasks.

Measurements of Lower-limb Isometric Single-joint Maximal Voluntary Torque and Rate of Torque Development Capacity Offer Limited Insight into Vertical Jumping Performance

ABSTRACT We examined the relationships between heights of different vertical jumps and isometric single-joint strength characteristics of ankle, knee, hip, and trunk joints in young male soccer players (n = 117). The highest peak torque and rate of torque development (RTD) outcomes were in low to moderate correlation with jump heights (r = 0.25–0.50). The correlations were generally higher for bilateral than unilateral jumps. Linear regression models accounted for 33–35% and 24.5 of the variance in bilateral and unilateral jump height, respectively. Hip extension peak torque, ankle RTD and trunk lateral flexion peak torque were most consistently included in the regression models. Our results suggest the that single-joint isometric testing does not seem to be useful to detect weaknesses related to vertical jump performance. The relative importance of individual lower limb joints for vertical jumping seems comparable. Trunk strength should not be neglected as the determinant of jumping performance.

Caffeine Doses of 3 mg/kg Increase Unilateral and Bilateral Vertical Jump Outcomes in Elite Traditional Jiu-Jitsu Athletes.

Caffeine increases vertical jump, although its effects on kinetics and kinematics during different phases of bilateral and unilateral jumps remain unclear. The aim of this study was to identify the effects of 3 mg/kg on kinetic, kinematic and temporal variables in the concentric and eccentric phases of bilateral and unilateral countermovement jumps. A total of 16 Spanish national team traditional Jiu-Jitsu athletes took part in two experimental trials (3 mg/kg caffeine or placebo) in a randomized, double-blind crossover study. Sixty minutes after ingestion, bilateral and unilateral jumps were performed on a force platform. Compared to the placebo, caffeine increased bilateral jump height (p = 0.008; Δ% = 4.40), flight time (p = 0.008; Δ% = 2.20), flight time:contraction time (p = 0.029; Δ% = 8.90), concentric impulse (p = 0.018; Δ% = 1.80), peak power (p = 0.049; Δ% = 2.50), RSI-modified (p = 0.011; Δ% = 11.50) and eccentric mean braking force (p = 0.045; Δ% = 4.00). Additionally, caffeine increased unilateral RSI-mod in both legs (Left: p = 0.034; Δ% = 7.65; Right: p = 0.004; Δ% = 11.83), left leg flight time (p = 0.044; Δ% = 1.91), left leg jump height (p = 0.039; Δ% = 3.75) and right leg FT:CT (p = 0.040; Δ% = 9.72). Caffeine in a dose of 3 mg/kg BM in elite Jiu-Jitsu athletes is a recommended ergogenic aid as it increased performance of bilateral and unilateral vertical jumps. These increases were also accompanied by modified jump execution during the different phases of the countermovement prior to take-off.

DETERMINING ASYMMETRY USING SPECIFIC UNILATERAL TESTS IN YOUNG BASKETBALL PLAYERS

Defining the differences between the dominant (D) and non-dominant (ND) leg is one of the ways to determine the asymmetry between the extremities and thus the risk of injury. The aim of this research is to determine the differences in specific unilateral tests in young male and female basketball players. The sample consisted of 17 female basketball players (average height 177.96 ± 6.38 cm; average weight 69.53 ± 8.00 kg and age 15.50 ± 0.96 yr.) and 34 male basketball players (average height 194.29 ± 7.52 cm; average weight 83.66 ± 9.66 kg and age 15.40 ± 1.28 yr.) of the cadet and junior national teams. Tests were used to assess the explosive power of the lower extremities: high jump with D and ND leg take-off with arm swing (S_vis_jedn_L; S_vis_jedn_D), basketball two-step with D and ND leg take-off (Dvokorak_L, Dvokorak_D) and Drift protocol consisting of 5 consecutive unilateral jumps in place (Drift_L, Drift_D). The tests S_vis_jedn (p = 0.02) and Dvokorak (p = 0.03) showed statistically significant differences with an error of p˂0.05 in the group of male basketball players. Significant differences were found in female basketball players in the test S_vis_jedn (p = 0.03). In other tests, there are no significant differences between jumps with D and ND leg take-off. The presented results indicate differences between the extremities and represent the basis for the correction of the training plan and program. The methodology in this paper is simple to implement and analyse and is