A single set of biomechanical variables cannot predict jump performance across various jumping tasks

Jump Height and Hip Power Decrease During Cognitive Loading Regardless of Sex: Implications for Sport Performance Metrics

ABSTRACT

Shumski, EJ, Lempke, LB, Johnson, RS, Oh, J, Schmidt, JD, and Lynall, RC. Jump height and hip power decrease during cognitive loading regardless of sex: implications for sport performance metrics. J Strength Cond Res 37(4): 793-798, 2023-Sex and cognitive loading separately influence jumping performance. However, it is unknown how cognitive loading influences jump performance and how sex and cognitive loading interact. The purpose of our study was to determine if an interaction existed between sex and cognitive loading for the dependent variables jump height, ground contact time, reactive strength index, vertical stiffness, impulse, and lower extremity joint power during a double limb drop vertical jump. Twenty-one male (23.2 ± 2.5 years, 180.8 ± 8.4 cm, 80.4 ± 10.2 kg) and 20 female (21.7 ± 1.0 years, 163.7 ± 8.2 cm, 61.2 ± 9.4 kg) physically active individuals participated. Subjects jumped from a 30 cm box placed 50% of their height away from 2 force plates under single-task and dual-task (serial 6s or 7s) conditions. Separate 2 × 2 analyses of variance were used for all dependent variables (α = 0.05) with Bonferroni post hoc mean differences and 95% confidence intervals (CIs). There were no significant interactions for any outcomes ( p ≥ 0.190). Condition main effects demonstrated subjects jumped significantly higher (1.84 cm, 95% CI = 0.68-3.01, d = 0.26, p = 0.003) and with greater hip power (0.29 Watts·BW -1 ·HT -1 , 95% CI = 0.04-0.54, d = 0.21, p = 0.025) during single task compared with dual task. Sex main effects revealed males jumped higher (9.88 cm, 95% CI = 7.00-12.77, d = 2.17, p < 0.001), with greater reactive strength index (0.29, 95% CI = 0.17-0.41, d = 1.52, p < 0.001), greater ankle power (3.70 Watts·BW -1 ·HT -1 , 95% CI = 2.26-5.13, d = 1.64, p < 0.001), and greater knee power (5.00 Watts·BW -1 ·HT -1 , 95% CI = 3.25-6.75, d = 1.82, p < 0.001) compared with females. Jump performance is influenced by sex and dual-task conditions but not their interaction. To optimize jumping performance, testing should be completed without distractions (single task) to decrease cognitive loading.

Kinetic time-curves can classify individuals in distinct levels of drop jump performance

This study examined whether analysing kinetic features of drop jumps (DJ) as one-dimensional biomechanical curves can reveal specific patterns that are consistent and can cluster DJ performance. Hierarchical clustering analysis on DJ from 40 cm data performed by 128 physically active male participants (23.0 ± 4.5 yrs, 1.84 ± 0.07 m, 79.1 ± 10.8 kg) was performed on the derived time-normalised force, power and vertical stiffness curves to unmask the underlying patterns and to explore the dissimilarities identified from the subgroup (cluster) analysis. Results revealed poor, average and top DJ performers. Top performers exhibited larger peak force, power and vertical stiffness compared to the other two groups, and the poor performers had lower values compared to the average performers (p < .05). The time curves of force, power and vertical stiffness exhibited between cluster dissimilarities from ~25% to ~70%, and ~20% to 40% plus ~55% to 70% from the beginning of the ground contact, respectively. The force and power time-curves distinguished DJ ability similarly since they shared 69% of the cases in the top performers' cluster. The content of cases (membership) for vertical stiffness was different from the membership for the force and power time-curve clusters. In conclusion, stiffness should be considered during plyometric training, but does not distinctly define DJ performance.

Deaf and non-deaf basketball and volleyball players' multi-faceted difference on repeated counter movement jump performances: Height, force and acceleration

The aim of this study was to compare the performances of Repetitive Counter Movement Jumping (basketball/volleyball) of deaf/non-deaf athletes. Athletes playing in the Turkish Deaf Basketball and Volleyball national teams and in Basketball and Volleyball First Leagues participated in the study. The study group consisted of 51 male athletes, including deaf basketball (n = 11; age: 26.18 ± 4.79 years), deaf volleyball (n = 12, age: 26.33 ± 4.27 years), non-deaf basketball (n = 14, age: 26.93 ± 4.87 years), and non-deaf volleyball (n = 14, age: 24.93 ± 5.10 years) players. As a result of the test, Jump Height from Take Off Velocity, Jump Height from Take Off Velocity, Jump Height from Flight Time, Counter Movement Acceleration, Push Off Acceleration, Average Velocity, Average Power, and Average Force were analyzed. Differences in the jump performances among the groups (deaf basketball and volleyball, non-deaf basketball, and volleyball) were tested by one-way analyses of variance (ANOVA) with Tukey's post-hoc follow-up testing when necessary for jump test. As a result, this is the first study to investigate the number of jumps and jump height, the force produced, acceleration at the time of jump, and jump velocity during 30 s in deaf and non-deaf basketball and volleyball players within the scope of individual Repeated Counter Movement Jump test. Based on the biomechanical changes according to our results, our findings show a greater decrease in the number of jumps and jump heights, the force produced, the acceleration at the moment of the jump and the jump velocity in all athletes, especially those that affect the deaf.

Shoe Bending Stiffness Influence on Lower Extremity Energetics in Consecutive Jump Take-Off

Objective

This study examined the influence of shoe bending stiffness on lower extremity energetics in the take-off phase of consecutive jump.

Methods

Fifteen basketball and volleyball players wearing control shoes and stiff shoes performed consecutive jumps. Joint angle, angular velocity, moments, power, jump height, take-off velocity, take-off time, and peak vertical ground reaction force data were simultaneously captured by motion capture system and force platform. Paired t-tests were performed on data for the two shoe conditions that fit the normal distribution assumptions, otherwise Wilcoxon signed-rank tests.

Results

There are significant differences (P < 0.05) in take-off velocity and take-off time between stiff and control shoe conditions; the stiff shoes had faster take-off velocity and shorter take-off time than control shoes. There was no significant difference between two conditions in jump height (P = 0.512) and peak vertical ground reaction force (P = 0.589). The stiff shoes had significantly lower MTP dorsiflexion angle and greater joint work than the control shoes (P < 0.05). The MTP range of motion and maximum angular velocity in stiff shoe condition were significantly lower than those in control shoe condition (P < 0.01). However, there are no significant differences between two conditions in kinetics and kinematics of the ankle, knee, and hip joint.

Conclusions

The findings suggest that wearing stiff shoes can reduce the effect of participation of the MTP joint at work and optimize the energy structure of lower-limb movement during consecutive jumps.

Influence of metatarsophalangeal joint stiffness on take-off performances and lower-limb biomechanics in jump manoeuvres

Forefoot and toes are prominent regions for locomotion and individual metatarsophalangeal joint (MTPJ) stiffness may be linked to jump take-off mechanics and performances. However, little is known about the relationships between MTPJ stiffness and take-off related variables. This study examined the relationship between individual MTPJ stiffness and biomechanical variables under various vertical countermovement jumps (CMJ) conditions. We measured MTPJ stiffness on 21 male university basketball players and then asked them to perform jumps under single, consecutive and running CMJ conditions. Pearson's correlation coefficient was employed to examine the relationships between MTP passive stiffness and each jumping performance, ground reaction force (GRF) and joint kinematic and kinetic variables. The results indicated that MTPJ stiffness significantly correlated with maximum jump height (r = 0.49, moderate), peak take-off velocity (r = 0.47, moderate), peak take-off ankle plantarflexion moment (r = 0.68, strong), peak dorsiflexion moment (r = 0.60, strong) and peak take-off ankle power (r = 0.44, moderate) in consecutive CMJ. Only a moderate correlation between MTPJ stiffness and peak MTPJ extension take-off velocity (r = -0.46, moderate) was determined in a single CMJ. There were no significant correlations found in running CMJ conditions. These findings imply that higher MTPJ stiffness of participants was related to improved jump performances in consecutive jumps.

The single-leg vertical hop provides unique asymmetry information in individuals after anterior cruciate ligament reconstruction

BACKGROUND

Traditional testing to identify asymmetries after anterior cruciate ligament reconstruction include four similar horizontal hopping tests. The purpose of this study was to determine whether a single-leg vertical hopping test can identify performance and biomechanical asymmetries, and whether performance asymmetries provide unique information compared to traditional tests.

METHODS

Twelve women with history of anterior cruciate ligament reconstruction [age: 21.1 years (SD 3.2), height: 165.8 cm (SD 6.0), mass: 68.3 kg (SD 8.8)] completed traditional horizontal hop testing. Participants also performed a single-leg vertical hop for maximal height while instrumented for three-dimensional motion analysis. Paired t-tests were performed to identify side-to-side differences in performance variables and Spearman's rank correlations were performed of limb symmetry indices to identify whether the single-leg vertical hop test provides unique information. Repeated measures MANOVAs were performed to identify single-leg vertical hop biomechanical asymmetries.

FINDINGS

Participants exhibited significant side-to-side performance differences during the single-leg vertical hop [mean difference = 0.02 m (SD 0.03), P = .04]. Only weak to moderate relationships were identified between limb symmetry indices of the single-leg vertical hop and other horizontal hopping tests. The vertical hop elicited significant asymmetries of joint kinematics (P = .04) and angular impulse (P = .04). Specifically, the involved limb showed lower peak ankle dorsiflexion (P = .004) and knee abduction (P = .02) angles, lower sagittal plane impulse at the knee (P = .02) and greater sagittal plane impulse at the hip (P = .03).

INTERPRETATION

The single-leg vertical hop can identify performance and biomechanical asymmetries in individuals after anterior cruciate ligament reconstruction, potentially providing complementary information to standard horizontal hopping tests.

Effect of consecutive jumping trials on metatarsophalangeal, ankle, and knee biomechanics during take-off and landing

This study examined the differences in single and consecutive jumps on ground reaction forces (GRF) as well as metatarsophalangeal (MTP), ankle and knee kinematics and kinetics during jumping take-off and landing. Eighteen basketball players performed countermovement jumps in both single and consecutive movement sessions. Synchronised force platform and motion capture systems were used to measure biomechanical variables during take-off and landing. Paired t-tests (or Wilcoxon signed-rank tests) were performed to examine any significant differences regarding mean and coefficient of variation in each of the variables tested. A Holm-Bonferroni correction was applied to P-values to control the false discovery rate of 5%. The findings indicated that consecutive jumps had lower jump height, take-off velocity and landing impact. During take-off, consecutive jumps demonstrated larger peak MTP and ankle extension velocities, knee extension moments as well as larger values for ankle and knee power generation; During landing, the consecutive jumps had larger peak MTP flexion angle, joint velocities (MTP, ankle and knee), and peak knee flexion moments and power absorption. Additionally, consecutive jumps had higher within-trial reliability (i.e. smaller CV) for peak MTP flexion angle at landing (P < 0.05), but lower reliability (i.e. higher CV) for peak knee flexion velocity and power absorption at landing. These results suggest that the consecutive jump trials led to distinct movement kinematics and higher loading responses in jump take-off and landing.