Single-leg Drop Vertical Jump Research Articles

Is there a relationship between isometric hamstrings-to-quadriceps torque ratio and athletes' plyometric performance?

The application of the modified reactive strength index (RSImod) and isometric hamstrings to quadriceps (H:Q) torque ratio to monitoring the athletes' performance is well established, but their relationship to each other still remains unknown. Therefore, the purpose of this investigation was to clarify whether there is a relationship between RSImod and the isometric H:Q torque ratio. Twenty-one male recreational athletes (age, 24.89 ± 4.46 years; weight, 74.11 ± 8.66 kg; height, 179.78 ± 6.76 cm) volunteered to participate in this research. Their isometric H:Q torque ratio via hand-held dynamometer and jumping performance variables during the stop jump (STJ), double leg-drop vertical jump (DL-DVJ), and single leg-drop vertical jump (SL-DVJ) tasks were measured. Also, the RSImod was calculated by dividing the vertical jump height by the time to take-off. Pearson correlation coefficients were used to determine the relationship between the RSImod and jumping performance variables. The result showed a significant strong positive relationship between the H:Q torque ratio and STJ performance based on the RSImod (p = .027, r = .724). Although, there was a moderate positive relationship between the H:Q torque ratio and jumping height of the STJ task, but it wasn't statistically significant (p = .096, r = .588). Also, no significant relationship was found between the H:Q torque ratio and all jumping performance variables of the DL-DVJ and SL-DVJ tasks (p ≥ .05). The current study exhibited that the isometric H:Q torque ratio correlates to STJ performance based on RSImod but not to SL-DVJ and DL-DVJ. Notably, the difference in results between jumping tasks can be attributed to the complexity of the movement, which means that the RSImod is probably related to other factors. Therefore, the isometric H:Q torque ratio used to monitor the athletes' performance couldn't independently represent the jumping performance that is determined by RSImod.

Kinematic Differences Between the Dominant and Nondominant Legs During a Single-Leg Drop Vertical Jump in Female Soccer Players

Background: In soccer, the roles of the dominant (kicking) and nondominant (supporting) legs are different. The kinematic differences between the actions of the dominant and nondominant legs in female soccer players are not clear. Purpose: To clarify the kinematic differences between dominant and nondominant legs during a single-leg drop vertical jump (DVJ) in female soccer players. Study Design: Controlled laboratory study. Methods: A total of 64 female high school and college soccer players were included in this study. Participants performed a single-leg DVJ test utilizing video motion capture with artificial intelligence during the preseason period. This study assessed the knee flexion angles, knee valgus angles, hip flexion angles, and lower leg anterior inclination angle at 3 time points (initial contact, maximum flexion of the knee, and toe-off) and compared them between the dominant and nondominant legs. These angles were calculated from motion capture data and analyzed in 3 dimensions. A paired t test was used to analyze the differences between legs, and the significance level was set at P < .05. Results: The knee valgus angle at initial contact was greater in the nondominant leg (mean ± SD, 0.8°± 5.2°) than the dominant leg (−0.9°± 4.9°) (P < .01). There were no differences between legs for any other angles at any of the time points. Conclusion: The kinematics of the dominant and nondominant legs of female soccer players in a single-leg DVJ differ in knee valgus angle. Clinical Relevance: Leg dominance is associated with the risk of sports injuries. Kinematic differences between the dominant and nondominant legs may be a noteworthy factor in elucidating the mechanisms and risk of sports injury associated with leg dominance.

The non-sagittal knee moment vector identifies ‘at risk’ individuals that the knee abduction moment alone does not

ABSTRACT Multi-planar forces and moments are known to injure the anterior cruciate ligament (ACL). In ACL injury risk studies, however, the uni-planar frontal plane external knee abduction moment is frequently studied in isolation. This study aimed to determine if the frontal plane knee moment (KM-Y) could classify all individuals crossing a risk threshold compared to those classified by a multi-planar non-sagittal knee moment vector (KM-YZ). Recreationally active females completed three sports tasks—drop vertical jumps, single-leg drop vertical jumps and planned sidesteps. Peak knee abduction moments and peak non-sagittal resultant knee moments were obtained for each task, and a risk threshold of the sample mean plus 1.6 standard deviations was used for classification. A sensitivity analysis of the threshold from 1–2 standard deviations was also conducted. KM-Y did not identify all participants who crossed the risk threshold as the non-sagittal moment identified unique individuals. This result was consistent across tasks and threshold sensitivities. Analysing the peak uni-planar knee abduction moment alone is therefore likely overly reductionist, as this study demonstrates that a KM-YZ threshold identifies ‘at risk’ individuals that a KM-Y threshold does not. Multi-planar moment metrics such as KM-YZ may help facilitate the development of screening protocols across multiple tasks.

Relationship between lumbopelvic-hip complex stability, muscle activity, and 2-dimensional kinematics of the trunk and lower extremity

ObjectivesTo observe isolated lumbopelvic-hip complex (LPHC) stability and muscle activity using the Seated Trunk Control Test (STCT) and evaluate the relationship between LPHC stability and 2-dimensional kinematics during movements. DesignDescriptive Study. SettingLaboratory. Participants22 healthy participants (12F, 10M, 23.5 ± 3.1yrs, 173.0 ± 9.0 cm, 76.1 ± 10.7 kg). Main outcome measure(s)Time to first error and number of errors, and muscle activity of the abdominals, erector spinae, and gluteus medius were recorded during the STCT. Lateral trunk movement, hip and knee frontal plane projection angles, hip and knee flexion during single leg squats and single leg drop vertical jumps were measured. Pearson r correlations were calculated among STCT performance, muscle activity, and 2-dimensional kinematics. ResultsNumber of errors was moderately correlated to hip and knee flexion during single leg squatting (r = 0.456–0.649, p < 0.05). Number of errors and time to first error were moderately correlated to knee-frontal plane projection angle and hip flexion respectively during single leg drop vertical jumping (r = 0.463–0.515, p < 0.05). ConclusionsDecreased LPHC stability relates to decreased sagittal plane motion during single leg squatting and increased frontal plane motion during single leg drop vertical jumping. Pairing the STCT with 2-dimensional kinematic analysis can demonstrate influence of LPHC function.

Landing instructions focused on pelvic and trunk lateral tilt decrease the knee abduction moment during a single-leg drop vertical jump

ObjectivesTo investigate the effects of pelvic and trunk lateral tilt-focused landing instructions on the knee abduction moment during the single-leg drop vertical jump task. DesignDescriptive laboratory study. SettingMotion analysis laboratory. ParticipantsFifteen young, healthy female participants. Main outcome measuresThe participants performed 15 single-leg drop vertical jumps. Landing instructions with self-video recordings were provided so that the participants’ pelvis and trunk remained horizontal in the frontal plane. Pelvic, trunk and knee kinematics and kinetics were evaluated using a three-dimensional motion analysis system before and after the landing instructions. ResultsThe peak knee abduction moment significantly decreased postinstruction (preinstruction 22.6 ± 15.3 Nm, postinstruction 17.9 ± 15.4 Nm, P = 0.004), as did pelvic and trunk lateral tilt (P < 0.01). The knee abduction and internal rotation angles at initial contact significantly decreased postinstruction (P = 0.037, P = 0.007), with no significant change in the peak knee abduction and internal rotation angles from pre-to postinstruction. ConclusionsLanding instructions focused on pelvic and trunk lateral tilt are effective in decreasing the knee abduction moment during the single-leg drop vertical jump. Pelvic and trunk lateral tilt should be controlled to decrease the knee abduction moment during single-leg landing.

Investigation the effect of Graston Technique on strength and postural stabilization in individuals with asymptomatic dynamic knee valgus

To observe isolated lumbopelvic-hip complex (LPHC) stability and muscle activity using the Seated Trunk Control Test (STCT) and evaluate the relationship between LPHC stability and 2-dimensional kinematics during movements.Descriptive Study.Laboratory.22 healthy participants (12F, 10M, 23.5 ± 3.1yrs, 173.0 ± 9.0 cm, 76.1 ± 10.7 kg).Time to first error and number of errors, and muscle activity of the abdominals, erector spinae, and gluteus medius were recorded during the STCT. Lateral trunk movement, hip and knee frontal plane projection angles, hip and knee flexion during single leg squats and single leg drop vertical jumps were measured. Pearson r correlations were calculated among STCT performance, muscle activity, and 2-dimensional kinematics.Number of errors was moderately correlated to hip and knee flexion during single leg squatting (r = 0.456–0.649, p < 0.05). Number of errors and time to first error were moderately correlated to knee-frontal plane projection angle and hip flexion respectively during single leg drop vertical jumping (r = 0.463–0.515, p < 0.05).Decreased LPHC stability relates to decreased sagittal plane motion during single leg squatting and increased frontal plane motion during single leg drop vertical jumping. Pairing the STCT with 2-dimensional kinematic analysis can demonstrate influence of LPHC function.

The effect of silicone ankle sleeves and lace-up ankle braces on neuromuscular control, joint torque, and cutting agility

ObjectiveTo evaluate the effects of silicone ankle sleeves (SASs) and lace-up ankle braces (LABs) on neuromuscular control, net joint torques, and cutting agility in healthy, active individuals. DesignMarkerless motion-capture technology tracked subjects fitted with SASs, LABs, or no brace while they performed the movements: Y-excursion, left cutting, right cutting, single-leg drop vertical jump (SLDVJ), 45-degree bound, and single-leg squat (SLS). SettingUniversity Laboratory. ParticipantsTen healthy, active individuals (5 males and 5 females, mean ± SD 23.60 ± 1.43 years of age). Main outcome measuresDegrees of joint range of motion (ROM), Newton-meters of joint torque, time to perform a cutting maneuver. ResultsSASs and LABs resulted in significantly different knee and ankle ROM and hip internal rotation in the SLDVJ, SLS, Y-excursion, cutting maneuver, and 45-degree bound when compared to control (p < .05). Both ankle and knee torque were significantly reduced in the 45-degree bound and cutting movements with both types of PABs (p < .05). There were minimal differences between the SASs and LABs for all conditions. There were no statistically significant differences in cutting times for any of the 3 conditions. ConclusionBoth SAS and LAB positively impacted neuromuscular control, reduced net joint torque, and neither impaired cutting agility when compared to control.

Do neoprene sleeves and prophylactic knee braces affect neuromuscular control and cutting agility?

ObjectivesTo evaluate the effects of neoprene sleeves (NSs) and prophylactic knee braces (PKBs) on neuromuscular control and cutting agility. DesignMarkerless motion-capture technology tracked subjects (1) without a brace as a control (2) with NSs and (3) with PKBs during single-leg drop vertical jump (SLDVJ), single-leg squat (SLS), Y-excursion, and cutting movements. Movements were recorded five times per bracing condition in three different sessions. SettingUniversity laboratory. ParticipantsTen healthy, active subjects (5 male, 5 female; age range, 22–26 years). Main outcome measuresDegrees of motion and time to completion. ResultsUse of NSs and PKBs reduced subjects' hip internal rotation in the loading phase of SLDVJ (p = 0.026, 0.02) and SLS (p = 0.005, <0.001), reduced knee flexion in the loading phase of SLDVJ (p = 0.038, <0.001), and reduced knee frontal plane abduction (FPA) with SLS (p = 0.015, 0.024) and Y-excursion (p = 0.002, 0.005) compared to control. Use of PKBs decreased subjects’ hip internal rotation in the Y-excursion (p = 0.024) and reduced knee FPA in the SLDVJ loading phase (p = 0.014) compared to control. There was no difference in cutting agility for either group (p = 0.145, 0.347). ConclusionBoth NSs and PKBs positively impacted neuromuscular control without impacting cutting agility.

Lower-Extremity Energy Absorption During Side-Step Maneuvers in Females With Knee Valgus Alignment.

Excessive knee valgus on landing can cause anterior cruciate ligament injury. Therefore, knee valgus alignment may show characteristic energy absorption patterns during landings with lateral movement that impose greater impact forces on the knee joint compared with landings in other alignments. To investigate the energy absorption strategy in lower-extremities during side steps in females with knee valgus alignment. Controlled laboratory study. University research laboratory. A total of 34 female college students participated in this experiment. Participants performed single-leg drop vertical jump and side steps. All participants were divided into valgus (n = 13), neutral (n = 9), and varus (n = 12) groups according to knee position during landing in single-leg drop vertical jumps. Lower-extremity joint angles, moments, and negative works were calculated during landing in side steps, and 1-way analysis of variance and post hoc tests were used to determine between-group differences. Negative works of hip extensors, knee abductors, and ankle plantar flexors during landing in side steps were significantly smaller in the valgus than in the varus group; however, negative work of the knee extensors was significantly greater in the valgus group than in varus group. The findings of this study indicated that landing with knee valgus induced the characteristic energy absorption strategy in the lower-extremity. Knee extensors contributed more to energy absorption when landing in knee valgus than in knee varus alignment. Learning to land in knee varus alignment might reduce the impact on the knee joint by increasing the energy absorption capacities of hip extensors, knee abductors, and ankle plantar flexors.

Association of Hip and Trunk Strength With Three-Dimensional Trunk, Hip, and Knee Kinematics During a Single-Leg Drop Vertical Jump.

Martinez, AF, Lessi, GC, Carvalho, C, and Serrao, FV. Association of hip and trunk strength with three-dimensional trunk, hip, and knee kinematics during a single-leg drop vertical jump. J Strength Cond Res 32(7): 1902-1908, 2018-Kinematic changes have been correlated with different lower-limb injuries. Movement is influenced by multiple factors and strength is one of the contributors that can influence it. Thus, the aim of this study was to evaluate the correlation among trunk and hip isometric strength with trunk and lower-limb kinematics during a single-leg drop vertical jump. Twenty-three healthy recreational female athletes aged between 18 and 35 years underwent isometric evaluation of hip abductor, hip extensor, and lateral trunk muscle strength and 3-dimensional trunk and lower-limb kinematics during a single-leg drop vertical jump. Pearson's correlation coefficients (r) were calculated to establish the association among hip and trunk strength and trunk, hip, and knee kinematics. As result, no significant correlations were found between the peak and movement excursion values of kinematic and hip and trunk isometric strength data. The lack of correlation between isometric strength and kinematics in healthy female athletes indicates that intervention programs should not be focused solely on strength exercises to influence the movement pattern during single-landing activities.

Is There a Predictable Value of the Drop Vertical Jump Test for Running Gait Injury Risk?

PURPOSE: A three-dimensional (3D) motion analysis of running gait is often used to identify modifiable lower extremity biomechanical risk factors, but can be time consuming and costly. The Drop Vertical Jump (DVJ) test when combined with the Landing Error Scoring System (LESS) can easily be done in the field to assess lower extremity coordination and injury risk. The purpose of this study was to determine if correlations existed between biomechanical variables of the DVJ and a 3D gait analysis. Positive findings would indicate that the DVJ may serve as a simple surrogate for the running analysis to quickly screen for lower extremity injury risk. METHODS: 24 runners (26.1 ± 8.6 yrs; 27.7 ± 11.3 miles/wk; 16 Male, 8 Female) participated. During one testing session, a 3D motion analysis and an instrumented treadmill were used to capture and determine lower extremity kinematics, ground reaction forces (GRF) and knee moments during the gait cycle. Subjects completed five DVJs and a gait analysis at a self-selected running speed (6.7 ± 0.9 mph). Data were gathered on the dominant leg for both the DVJ and the gait analysis (1 left dominant). LESS scores were calculated through frontal and sagittal plane videos of the DVJ using a score from 22 items. Individual LESS items were selected based on similar measures that could be captured in the 3D gait analysis: asymmetric motion of feet and knees in the sagittal and frontal planes, foot contact patterns and overall impression. RESULTS: Significant associations existed between maximal knee flexion angle (sagittal plane 3D running) and overall LESS score (r=-.791; p<0001). There were no other significant associations between lower extremity kinematics, GRFs and knee moments and LESS items and overall score. There were also no significant associations between DVJ biomechanical variables and the 3D gait measures. CONCLUSION: Contrary to our expectation, associations between 3D gait, DVJ and LESS were minimal. A possible explanation could be that the dual-leg DVJ test may not be able to account for factors of balance and stability that are critical for the single-leg nature of running. A single-leg DVJ may be a more accurate field test when predicting running-related injuries.

WHAT SEPARATES AN INDIVIDUAL AT RISK OF ACL INJURY? A FIRST STEP TOWARDS AN ACL-RISK MOVEMENT PASSPORT

BackgroundSeveral prospective studies have suggested biomechanical risk factors for non-contact anterior cruciate ligament (ACL) injury. Ideally an individual at risk should be ranked at risk across a variety of dynamic...

Fatigue influences lower extremity angular velocities during a single-leg drop vertical jump.

[Purpose] Fatigue alters lower extremity landing strategies and decreases the ability to attenuate impact during landing. The purpose of this study was to reveal the influence of fatigue on dynamic alignment and joint angular velocities in the lower extremities during a single leg landing. [Subjects and Methods] The 34 female college students were randomly assigned to either the fatigue or control group. The fatigue group performed single-leg drop vertical jumps before, and after, the fatigue protocol, which was performed using a bike ergometer. Lower extremity kinematic data were acquired using a three-dimensional motion analysis system. The ratio of each variable (%), for the pre-fatigue to post-fatigue protocols, were calculated to compare differences between each group. [Results] Peak hip and knee flexion angular velocities increased significantly in the fatigue group compared with the control group. Furthermore, hip flexion angular velocity increased significantly between each group at 40 milliseconds after initial ground contact. [Conclusion] Fatigue reduced the ability to attenuate impact by increasing angular velocities in the direction of hip and knee flexion during landings. These findings indicate a requirement to evaluate movement quality over time by measuring hip and knee flexion angular velocities in landings during fatigue conditions.

Can two-dimensional video analysis during single-leg drop vertical jumps help identify non-contact knee injury risk? A one-year prospective study

BackgroundPrevious studies showed that the amount of hip flexion and the combination of knee valgus and lateral trunk motion, measured with two-dimensional video analysis, were related to three-dimensional measured knee joint moments during single-leg drop vertical jumps, but it remains unclear whether these measurements can be used to identify non-contact knee injury risk. MethodsFifty injury-free female athletes participated in the study. Two-dimensional video analysis was used to measure hip flexion, knee valgus and lateral trunk motion angles during single-leg drop vertical jumps. Time loss non-contact knee injuries were registered during a one-year follow-up. Independent t-tests and receiver operating characteristic analysis were used to analyze the predictive ability of the two-dimensional angles. FindingsSeven participants sustained a time loss non-contact knee injury. Hip flexion was not significantly different between groups (P>.05). The combination of knee valgus and lateral trunk motion was significantly smaller in the injured (P=.036) and non-injured legs (P=.009) of the future injured group compared with the respective matched leg of the non-injured group. The receiver operating characteristic analysis showed a significant discriminative accuracy between groups for the combination of knee valgus and lateral trunk motion of the uninjured leg of the future injured group with the matched leg of the non-injured group (area under curve=0.803; P=.012). InterpretationThe measurement of a combination of increased knee valgus and ipsilateral trunk motion during the single-leg drop vertical jump with two-dimensional video analysis can be used to help identify female athletes with increased non-contact knee injury risk.

What is Normal? Female Lower Limb Kinematic Profiles During Athletic Tasks Used to Examine Anterior Cruciate Ligament Injury Risk: A Systematic Review

It has been proposed that the performance of athletic tasks where normal motion is exceeded has the potential to damage the anterior cruciate ligament (ACL). Determining the expected or 'normal' kinematic profile of athletic tasks commonly used to assess ACL injury risk can provide an evidence base for the identification of abnormal or anomalous task performances in a laboratory setting. The objective was to conduct a systematic review of studies examining lower limb kinematics of females during drop landing, drop vertical jump, and side-step cutting tasks, to determine 'normal' ranges for hip and knee joint kinematic variables. An electronic database search was conducted on the SPORTDiscus(TM), MEDLINE, AMED and CINAHL (January 1980-August 2013) databases using a combination of relevant keywords. Studies identified as potentially relevant were independently examined by two reviewers for inclusion. Where consensus could not be reached, a third reviewer was consulted. Original research articles that examined three-dimensional hip and knee kinematics of female subjects during the athletic tasks of interest were included for review. Articles were excluded if subjects had a history of lower back or lower limb joint injury or isolated data from the female cohort could not be extracted. Two reviewers independently assessed the quality of included studies. Data on subject characteristics, the athletic task performed, and kinematic data were extracted from included studies. Studies were categorised according to the athletic task being examined and each study allocated a weight within categories based on the number of subjects assessed. Extracted data were used to calculate the weighted means and standard deviations for hip and knee kinematics (initial contact and peak values). 'Normal' motion was classified as the weighted mean plus/minus one standard deviation. Of 2,920 citations, a total of 159 articles were identified as potentially relevant, with 29 meeting all inclusion/exclusion criteria. Due to the limited number of studies available examining double-leg drop landings and single-leg drop vertical jumps, insufficient data was available to include these tasks in the review. Therefore, a total of 25 articles were included. From the included studies, 'normal' ranges were calculated for the kinematic variables of interest across the athletic tasks examined. Joint forces and other additional elements play a role in ACL injuries, therefore, focusing solely on lower limb kinematics in classifying injury risk may not encapsulate all relevant factors. Insufficient data resulted in no normal ranges being calculated for double-leg drop land and single-leg drop vertical jump tasks. No included study examined hip internal/external rotation during single-leg drop landings, therefore ranges for this kinematic variable could not be determined. Variation in data between studies resulted in wide normal ranges being observed across certain kinematic variables. The ranges calculated in this review provide evidence-based values that can be used to identify abnormal or anomalous athletic task performances on a multi-planar scale. This may be useful in identifying neuromuscular factors or specific muscular recruitment strategies that contribute to ACL injury risk.

The reliability and validity of the measurement of lateral trunk motion in two-dimensional video analysis during unipodal functional screening tests in elite female athletes

ObjectiveTo investigate the reliability and validity of the measurement of lateral trunk motion (LTM) in two-dimensional (2D) video analysis of unipodal functional screening tests. DesignObservational study. SettingResearch laboratory. ParticipantsForty-three injury-free female athletes. Main outcome measuresKnee valgus (KV) and lateral trunk motion (LTM) angles were measured with a standard digital camera during the single leg squat and the single leg drop vertical jump (SLDVJ). Three-dimensional motion analysis was used during the SLDVJ to measure peak external knee abduction moment (pKAM). Intraclass correlation coefficients were calculated to assess the intra- and intertester reliability of the LTM angle. Correlations between 2D angles and pKAM were calculated for the SLDVJ. ResultsExcellent intraclass correlation coefficients for the LTM angle were found within (0.99–1.00) and between testers (0.98–0.99). The sum of KV and LTM was significantly correlated with the pKAM during the SLDVJ for the dominant (r = −0.36; p = 0.017) and non-dominant leg (r = −0.32; p = 0.034), while either angle alone was not. ConclusionsLTM can be measured with excellent intra- and intertester reliability. The combination of KV and LTM was moderately associated with pKAM and thus including LTM may aid assessment of movement quality and injury risk.