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

Background

Research has demonstrated that performing a secondary task during a drop vertical jump (DVJ) may affect landing kinetics and kinematics.

Purpose

To examine the differences in the trunk and lower extremity biomechanics associated with anterior cruciate ligament (ACL) injury risk factors between a standard DVJ and a DVJ while heading a soccer ball (header DVJ).

Study Design

Descriptive laboratory study.

Methods

Participants comprised 24 college-level soccer players (18 female and 6 male; mean ± SD age, 20.04 ± 1.12 years; height, 165.75 ± 7.25 cm; weight, 60.95 ± 8.47 kg). Each participant completed a standard DVJ and a header DVJ, and biomechanics were recorded using an electromagnetic tracking system and force plate. The difference (Δ) in 3-dimensional trunk, hip, knee, and ankle biomechanics between the tasks was analyzed. In addition, for each biomechanical variable, the correlation between the data from the 2 tasks was calculated.

Results

Compared to the standard DVJ, performing the header DVJ led to significantly reduced peak knee flexion angle (Δ = 5.35°; P = .002), knee flexion displacement (Δ = 3.89°; P = .015), hip flexion angle at initial contact (Δ = -2.84°; P = .001), peak trunk flexion angle (Δ = 13.11°; P = .006), and center of mass vertical displacement (Δ = -0.02m; P = .010), and increased peak anterior tibial shear force (Δ = -0.72 N/kg; P = .020), trunk lateral flexion angle at initial contact (Δ = 1.55°; P < .0001), peak trunk lateral flexion angle (Δ = 1.34°; P = .003), knee joint stiffness (Δ = 0.002 N*m/kg/deg; P = .017), and leg stiffness (Δ = 8.46 N/kg/m; P = .046) compared to those in standard DVJs. In addition, individuals' data for these variables were highly and positively correlated between conditions (r = 0.632-0.908; P < .001).

Conclusion

The header DVJ task showed kinetic and kinematic parameters that suggested increased risk of ACL injury as compared with the standard DVJ task.

Clinical Relevance

Athletes may benefit from acquiring the ability to safely perform header DVJs to prevent ACL injury. To simulate real-time competition situations, coaches and athletic trainers should incorporate such dual tasks in ACL injury prevention programs.

Presence of an Overhead Goal Does Not Improve the Effectiveness of Jump Training

ABSTRACT

Akbaş, A, Marszałek, W, and Król, H. Presence of an overhead goal does not improve the effectiveness of jump training. J Strength Cond Res 37(4): e280-e288, 2023-This study investigated the effectiveness of jump training with and without an overhead goal (OG) on a modified countermovement jump (CMJ) tested in a similar manner, with and without OG. Fifty-two men divided into 3 groups-trained with OG, trained without OG, and untrained-were examined: before the commencement of training; after 2, 4, and 6 weeks of training; and 2 weeks after the discontinuation of training. Each session consisted of 50 modified CMJ and was performed 3 times per week. Countermovement jump height, mean power, peak power, countermovement depth, and take-off phase time were quantified, and the statistical level was set at p < 0.05. Although the results showed the beneficial effect of OG on jump height ( p < 0.01), the training with OG did not bring significantly better results than training without OG. In addition, the group trained without OG improved after 2 weeks in both testing conditions (with and without OG), whereas the group trained with OG improved after 2 weeks when tested with OG and only after 6 weeks when tested without OG. We believe the use of OG in jump training may be detrimental when the OG is withdrawn from the testing procedure because of its strong motivational and feedback features. Consequently, athletes in disciplines which require them to jump toward an object located over their head during a game, e.g., a ball or crossbar, should be tested with the presence of OG. Despite this, OG is still an important factor in maximizing jump performance.

Effect of incline versus block heel-raise exercise on foot muscle strength and vertical jump performance - an 11-week randomized resistance training study

Strengthening the toe flexors and ankle plantar flexors may improve vertical jump performance. One exercise that may be effective for concurrently strengthening these muscles is heel-raises performed on an incline. The purpose of this study was to investigate the effects of incline versus conventional (block) heel-raise exercise on hallux and II-V digit flexor strength, vertical jump performance, and ankle plantar flexor strength. Thirty-three female volleyball players were randomly allocated to perform incline (n = 17) or block (n = 16) heel-raise exercise for 11-weeks. Participants' toe flexor strength, countermovement jump, approach jump, and ankle plantar flexor strength were assessed before, after 7 weeks, and after 11 weeks of exercise. There were no significant time-by-group interactions for any variable (p > 0.05). However, both groups improved their hallux flexor strength (Δ0.27 ± 0.50 N·kg-1; p < 0.05), and vertical countermovement (Δ1.2 ± 2.3 cm; p < 0.05) and approach (Δ1.9 ± 2.6 cm; p < 0.05) jump height from pre- to post-test. No changes were observed in the ankle plantar flexor or II-V digit flexor strength (n > 0.05). Both incline and conventional heel-raises improve toe flexor strength. Practitioners seeking to improve individuals' foot function may consider incorporating incline or block heel-raises.

Effect of an overhead goal on landing error scoring system and jump height measures

OBJECTIVES

Compare overall Landing Error Scoring System (LESS) scores, risk categorisation, specific LESS errors, and double-leg jump-landing jump heights between overhead goal and no goal conditions.

DESIGN

Randomised cross-over.

SETTING

Laboratory.

PARTICIPANTS

76 (51% male).

MAIN OUTCOME MEASURES

Participants landed from a 30-cm box to 50% of their body height and immediately jumped vertically for maximum height. Participants completed three trials under two random-ordered conditions: with and without overhead goal. Group-level mean LESS scores, risk categorisation (5-error threshold), specific landing errors, and jump heights were compared between conditions.

RESULTS

Mean LESS scores were greater (0.3 errors, p < 0.001) with the overhead goal, but this small difference was not clinically meaningful. Similarly, although the number of high-risk participants was greater with the overhead goal (p = 0.039), the 9.2% difference was trivial. Participants jumped 2.7 cm higher with the overhead goal (p < 0.001) without affecting the occurrence of any specific LESS errors.

DISCUSSION

Performing the LESS with an overhead goal enhances sport specificity and elicits greater vertical jump performances with minimal change in landing errors and injury-risk categorisation. Adding an overhead goal to LESS might enhance its suitability for injury risk screening, although the predictive value of LESS with an overhead goal needs confirmation.

Ankle dorsiflexion range of motion and landing postures during a soccer-specific task

INTRODUCTION

Ankle dorsiflexion range of motion (DF-ROM) has been shown to be associated with poor landing posture. However, previously used tasks have been controlled, and it is unclear whether clinical measurements of the ankle DF-ROM, are associated with landing positions during sport-specific task. This study sought to determine the relationship between ankle DF-ROM and landing positions.

METHODS

Thirty male soccer players participated in this study. The ankle DF-ROM was measured by the weight bearing lunge test in degrees using a cell phone app (TiltMeter). Landing patterns were assessed during a soccer-specific task using landing error scoring system items using Kinovea software. Simple correlations were used to evaluate the relationships between ankle DF-ROM and landing error scores.

RESULTS

Significant correlations were found between ankle DF-ROM and landing errors (r = -0.450, P = 0.006). A decreased ankle DF-ROM was associated with greater landing errors in a soccer specific situation.

CONCLUSION

These results suggest that ankle DF-ROM may serve a useful clinical measure for identifying poor landing posture in the real-world environment. Therefore, assessment of ankle DF-ROM could be included in the screening process, which could help identify the cause of the faulty motion.

Age-Related Changes in Landing Mechanics in Elite Male Youth Soccer Players: A Longitudinal Study

The aim of this longitudinal observational study was to examine the age differences in jump landing kinematics in 13–17-year-old male soccer players. Landing technique was evaluated in three consecutive seasons in U14 (n = 15) and the U16 (n = 10) competition age groups using the Landing Error Scoring System (LESS). For the LESS, ANOVA revealed no significant interaction effect (p = 0.81, η2 = 0.009) or main effect for groups (p = 0.15, η2 = 0.086), but a significant year effect was observed (p < 0.001, η2 = 0.265). The LESS score in the U14 group decreased significantly in the second year (5.7 ± 1.9, p = 0.006, d = 0.84) and in the third year (5.9 ± 2.0, p = 0.020, d = 0.70) compared to the first year (7.1 ± 1.7). The LESS score in the U16 group decreased significantly in the second year (5.1 ± 0.9 points, p = 0.034, d = 0.77) and in the third year (4.9 ± 1.4, p = 0.013, d = 0.92) compared to the first year (6.4 ± 1.2). This trend was supported by the results of the separate assessment of the sagittal plane joint displacement. These findings support previous limited findings from cross-sectional studies, which point to improved landing mechanics during maturation. However, the LESS scores in both groups indicate that players who were around and/or post-peak height velocity during the observed periods may be considered “at-risk”, and suggest that preventive training programs should be introduced at earlier stages of players’ development.

The Effects of Increasing Cognitive Load on Support Limb Kicking Mechanics in Male Futsal Players

Our objective was to examine the effects of cognitive load on support limb mechanics during a futsal kicking task. Twenty-one male futsal players completed kicks of a stationary ball without a secondary task (baseline), as well as kicks where cognitive load was increased by including a secondary cognitive task (dual-task) and requiring tracking of ball movement before the kick (pass). The athletes demonstrated less hip and knee flexion, higher loading rates, greater frontal and sagittal plane knee loading, and greater knee abduction for the dual-task condition, vs. baseline. They also demonstrated less knee flexion, higher loading rates, greater sagittal plane knee loading, and greater knee abduction for the pass condition, vs. baseline. It appears that cognitive load influences kicking mechanics.

Detection of knee wobbling as a screen to identify athletes who may be at high risk for ACL injury

This study developed a method to detect knee wobbling (KW) at low knee flexion. KW consists of quick uncontrollable medio-lateral knee movements without knee flexion, which may indicate a risk of ACL injury. Ten female athletes were recorded while performing slow, single-leg squats. Using motion capture data, the ratio of the frontal angular velocity to sagittal angular velocity (F/S) was calculated. An ‘F/S spike’ was defined when the F/S ratio exceeded 100%. The number of F/S spikes was counted before and after low-pass filtering at different cut-off frequencies. Intraclass correlation coefficients for KW and filtered F/S spike were analysed. KWs per squat cycle showed a median (range) of 3 (2–8) times. F/S spikes before and after low-pass filtering at 3-, 6-, 10-, and 15-Hz were 51 (12–108), 2 (0–6), 3 (1–12), 5 (2–21), and 9 (3–33) times, respectively. KWs and F/S spikes on motion capture with 6-Hz, low-pass filtering were well correlated (r = 0 .76). Median percentages of valgus and varus F/S spikes were 71% and 29%, respectively. After 6Hz, low-pass filtering, the number of F/S spikes was strongly correlated with observed KWs. An F/S spike assessment may be used to objectively detect KW, including flexion and varus/valgus angular velocity.

Evaluating the Spectrum of Cognitive-Motor Relationships During Dual-Task Jump Landing

Cognitive function plays a role in understanding noncontact anterior cruciate ligament injuries, but the research into how cognitive function influences sport-specific movements is underdeveloped. The purpose of this study was to determine how various cognitive tasks influenced dual-task jump-landing performance along with how individuals' baseline cognitive ability mediated these relationships. Forty female recreational soccer and basketball players completed baseline cognitive function assessments and dual-task jump landings. The baseline cognitive assessments quantified individual processing speed, multitasking, attentional control, and primary memory ability. Dual-task conditions for the jump landing included unanticipated and anticipated jump performance, with and without concurrent working memory and captured visual attention tasks. Knee kinematics and kinetics were acquired through motion capture and ground reaction force data. Jumping conditions that directed visual attention away from the landing, whether anticipated or unanticipated, were associated with decreased peak knee flexion angle (P < .001). No interactions between cognitive function measures and jump-landing conditions were observed for any of the biomechanical variables, suggesting that injury-relevant cognitive-motor relationships may be specific to secondary task demands and movement requirements. This work provides insight into group- and subject-specific effects of established anticipatory and novel working memory dual-task paradigms on the neuromuscular control of a sport-specific movement.

Kiss goodbye to the 'kissing knees': no association between frontal plane inward knee motion and risk of future non-contact ACL injury in elite female athletes

The aim of this study was to investigate if frontal plane knee and hip control in single-leg squats or vertical drop jumps with an overhead target were associated with future non-contact anterior cruciate ligament (ACL) injury in elite female athletes. Of the 429 handball and 451 football athletes (age 21.5 ± 4.0 years, height 169.6 ± 6.4 cm, body weight 67.1 ± 8.0 kg), 722 non-injured and 56 non-contact ACL injured participants were eligible for analysis. We calculated lateral pelvic tilt, frontal plane knee projection angle, medial knee position, and side-to-side asymmetry in these from 2D videos recorded at baseline, and recorded any new ACL injuries prospectively. None of the aforementioned variables in either screening task were different or could discriminate between injured and non-injured athletes (all p values >.05 and Cohen's d values < .27). Two-dimensional video assessment of frontal plane knee and hip control during both a single-leg squat and vertical drop jump was unable to identify individuals at increased risk of non-contact ACL injury, thus should not be used for screening.

A Narrative Review of Limb Dominance: Task Specificity and the Importance of Fitness Testing

ABSTRACT

Virgile, A and Bishop, C. A narrative review of limb dominance: Task specificity and the importance of fitness testing. J Strength Cond Res 35(3): 846-858, 2021-Preferential limb function must be sustained through repetitious asymmetrical activities for continuous athletic development and, ultimately, optimal athletic performance. As such, the prevalence of limb dominance and between-limb differences is common in athletes. Severe between-limb differences have been associated with reductions in athletic performance and increased injury risk in athletes. However, in the current literature, the terms limb preference and limb dominance have been used interchangeably. Together, these terms include a limb that is subjectively preferred and one that is objectively dominant in 1 or more performance measures from a variety of athletic tasks. In this review, we (a) discuss reported correspondence between task-specific limb preference and limb dominance outcomes in athletes, (b) provide greater context and distinction between the terms limb preference and limb dominance, and (c) offer pragmatic strategies for practitioners to assess context-specific limb dominance. A limb that is subjectively preferred is not necessarily objectively dominant in 1 or more athletic qualities or sport-specific tasks. Further to this, a limb that is objectively superior in 1 task may not exhibit such superiority in a separate task. Thus, limb preference and limb dominance are both task-specific. As such, we propose that practitioners intentionally select tasks for limb dominance assessment which resemble the most relevant demands of sport. Because limb dominance profiles are inconsistent, we suggest that practitioners increase assessment frequency by integrating limb dominance testing into standard training activities. This will allow practitioners to better understand when changes reflect sport-specific adaptation vs. potential performance or injury ramifications.

The influence of decision making and divided attention on lower limb biomechanics associated with anterior cruciate ligament injury: a narrative review

Cognitive loads have been shown to influence anterior cruciate ligament (ACL) injury risk. Two main sources of cognitive loads that athletes experience are decision making and dividing attention between multiple tasks. The aim of this paper was to review previous studies examining the effects of decision making and divided attention on lower limb biomechanics during landing and cutting. Previous research has shown decision making to significantly influence a number of biomechanical variables associated with increased risk of ACL injury, such as reduced knee flexion at initial contact, increased knee valgus angles, increased knee extension moment and increased knee valgus moment in decision-making tasks compared to pre-planned tasks. Furthermore, dividing attention between multiple tasks has been shown to result in reduced knee flexion at initial contact, increased vertical ground reaction force, and reduced stability during landing/cutting. The changes in lower limb biomechanics observed as a result of both decision making and dividing attention are likely due to a reduced ability to anticipate ground contact and implement protective movement patterns associated with reduced ACL loading. Collectively, these findings emphasise the need for tasks that incorporate decision making and divided attention when investigating ACL injury mechanisms and developing ACL injury risk screening assessments.

Forefoot and heel take-off strategies result in different distribution of lower extremity work during landings

Previous research suggests that landing mechanics may be affected by the mechanics of the preceding jump take-off. The purpose of the present study was to investigate whether jump take-off mechanics influence the subsequent landing mechanics. Female volleyball (n = 17) and ice hockey (n = 19) players performed maximal vertical jumps with forefoot and heel take-off strategies. During forefoot and heel jumps, participants were instructed to shift their weight to their forefoot or heel, respectively, and push through this portion of the foot throughout the jump. Jump mechanics were examined using 3D motion analysis, where lower extremity net joint moment (NJM) work, NJM, and segment angles were compared between forefoot and heel jumps using multivariate ANOVA. During jump take-off, participants performed more positive ankle plantar flexor and knee extensor NJM work in forefoot compared to heel jumps (P < 0.05). From initial foot contact to foot flat, participants performed more negative ankle plantar flexor and hip extensor NJM work during heel compared to forefoot jumps (P < 0.05). The present results demonstrate that using a heel take-off strategy results in a different distribution of lower extremity NJM work and NJM during landing compared to landings following forefoot jumps.

Visual-Spatial Memory Deficits Are Related to Increased Knee Valgus Angle During a Sport-Specific Sidestep Cut

BACKGROUND

Identifying athletes at an increased risk of injury is a promising approach to improve the effect of injury prevention interventions; however, it requires first identifying the potential athlete-specific risk factors. Cognitive ability was recently shown to correlate with noncontact anterior cruciate ligament injury rates and lower extremity mechanics, marking an underexplored area. A better understanding of how individuals' cognitive ability is associated with neuromuscular control during sport-specific tasks may improve injury prevention.

HYPOTHESIS

Athletes with lower cognitive performance on a standardized cognitive assessment would demonstrate greater increases in knee valgus angle and moment when performing a sidestep cut with soccer ball dribbling versus without. Visual-spatial memory was expected to demonstrate stronger relationships than reaction time or processing speed.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Fifteen male collegiate club soccer players participated (mean ± SD: 20.7 ± 2.0 years, 1.78 ± 0.07 m, 76.5 ± 8.9 kg). Participants performed anticipated 45° run-to-cut trials with and without a dual task of dribbling a soccer ball. Peak early-stance knee valgus angle and moment for the plant limb were calculated. Participants also completed a cognitive assessment to evaluate visual memory, verbal memory, reaction time, and processing speed. These composite scores were entered as candidate predictors for a stepwise regression analysis on the dual-task change scores in lower extremity biomechanical parameters (ie, ball handling - non-ball handling).

RESULTS

Visual memory composite score (a measure of visual-spatial memory) was the only cognitive outcome significantly associated with the change in biomechanical parameters. Each unit decrease in the visual memory composite score was associated with an increase of 0.21°± 0.05° in peak knee valgus angle during the ball-handling task as compared with the non-ball handling task ( R² = 52%, P = .003).

CONCLUSION

Visual-spatial memory was associated with neuromuscular control during a sidestep cutting task during soccer ball dribbling, with deficits in this cognitive domain being associated with increased peak knee valgus angle.

CLINICAL RELEVANCE

Assessing visual-spatial memory ability may provide useful information to better understand conditions associated with impaired neuromuscular control and to potentially identify athletes at an elevated risk for musculoskeletal injury.

Cognitive Demands Influence Lower Extremity Mechanics During a Drop Vertical Jump Task in Female Athletes

Study Design Cross-sectional study. Background The drop vertical jump task is commonly used to screen for anterior cruciate ligament injury risk; however, its predictive validity is limited. The limited predictive validity of the drop vertical jump task may be due to not imposing the cognitive demands that reflect sports participation. Objectives To investigate the influence of additional cognitive demands on lower extremity mechanics during execution of the drop vertical jump task. Methods Twenty uninjured women (age range, 18-25 years) were required to perform the standard drop vertical jump task, as well as drop vertical jumps that included additional cognitive demands. The additional cognitive demands were related to attending to an overhead goal (ball suspended overhead) and/or temporal constraints on movement selection (decision making). Three-dimensional ground reaction forces and lower extremity mechanics were compared between conditions. Results The inclusion of the overhead goal resulted in higher peak vertical ground reaction forces and lower peak knee flexion angles in comparison to the standard drop vertical jump task. In addition, participants demonstrated greater peak knee abduction angles when trials incorporated temporal constraints on decision making and/or required participants to attend to an overhead goal, in comparison to the standard drop vertical jump task. Conclusion Imposing additional cognitive demands during execution of the drop vertical jump task influenced lower extremity mechanics in a manner that suggested increased loading of the anterior cruciate ligament. Tasks utilized in anterior cruciate ligament injury risk screening may benefit from more closely reflecting the cognitive demands of the sports environment. J Orthop Sports Phys Ther 2018;48(5):381-387. Epub 10 Jan 2018. doi:10.2519/jospt.2018.7739.

The influence of single-leg landing direction on lower limbs biomechanics

BACKGROUND

The purpose of this study was to investigate whether different directions of single-leg landing tasks would influence lower limbs joints biomechanics.

METHODS

Using a controlled and experimental design, thirty physically active male subjects (age: 26.4±4.4 years; height: 180.5±3.7 cm; weight: 79.8:±4.4 kg), by dropping down from the top of a wooden box of 31 cm height, performed three one-leg landing tasks featured by different landing directions: frontward (FL), lateral (LL), and rotational (RL). The trunk and lower limbs` joints biomechanical responses were assessed through a laboratory setup consisting in a 6-camera motion capture system synchronized with force plates. A repeated measures one-way Analysis of Variance (ANOVA) was used to investigate the main effects of the landing directions on the lower limbs joints biomechanics during the main phases of interest of the landing tasks.

RESULTS

The results indicated two major findings: 1) FL resulted in an advantageous active whole-body configuration; 2) the lower limbs' joints adopted different and specific energy absorption strategies between the landing tasks.

CONCLUSIONS

This study indicates that the different landing tasks likely generate meaningful changes in in whole body biomechanics and specific lower limbs joints kinetic and kinematic responses. Such outcomes might be used by clinicians towards a practical approach in selecting either assessment modalities or exercise interventions.