Lower extremity kinematic asymmetry in male and female athletes performing jump-landing tasks

What is normal? Female lower limb kinematic profiles during athletic tasks used to examine anterior cruciate ligament injury risk: a systematic review

BACKGROUND

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.

OBJECTIVE

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.

DATA SOURCES

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.

STUDY SELECTION

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.

STUDY APPRAISAL AND SYNTHESIS METHODS

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.

RESULTS

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.

LIMITATIONS

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.

CONCLUSIONS

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.

Do exercises used in injury prevention programmes modify cutting task biomechanics? A systematic review with meta-analysis

OBJECTIVE

Some injury prevention programmes aim to reduce the risk of ACL rupture. Although the most common athletic task leading to ACL rupture is cutting, there is currently no consensus on how injury prevention programmes influence cutting task biomechanics. To systematically review and synthesise the scientific literature regarding the influence of injury prevention programme exercises on cutting task biomechanics.

DESIGN

The three largest databases (Medline, EMBASE and CINAHL) were searched for studies that investigated the effect of injury prevention programmes on cutting task biomechanics. When possible meta-analyses were performed.

RESULTS

Seven studies met the inclusion criteria. Across all studies, a total of 100 participants received exercises that are part of ACL injury prevention programmes and 76 participants served in control groups. Most studies evaluated variables associated with the quadriceps dominance theory. The meta-analysis revealed decreased lateral hamstrings electromyography activity (p ≤ 0.05) while single studies revealed decreased quadriceps and increased medial hamstrings activity and decreased peak knee flexion moment. Findings from single studies reported that ACL injury prevention exercises reduce neuromuscular deficits (knee valgus moment, lateral trunk leaning) associated with the ligament and trunk dominance theories, respectively. The programmes we analysed appear most effective when they emphasise individualised biomechanical technique correction and target postpubertal women.

CONCLUSIONS

The exercises used in injury prevention programmes have the potential to improve cutting task biomechanics by ameliorating neuromuscular deficits linked to ACL rupture, especially when they emphasise individualised biomechanical technique correction and target postpubertal female athletes.

Motor control strategies during double leg squat following anterior cruciate ligament rupture and reconstruction: an observational study

BACKGROUND

Anterior cruciate ligament (ACL) injured individuals often show asymmetries between the injured and non-injured leg. A better understanding of the underlying motor control could help to improve rehabilitation. Double leg squat exercises allow for compensation strategies. This study therefore investigated motor control strategies during a double leg squat with the aim to investigate if individuals with ACL rupture (ACLD), ACL reconstruction (ACLR) and healthy control subjects (CONT) used different strategies.

METHODS

20 ACLD and 21 ACLR were compared to 21 CONT subjects. Participants performed eight continuous double leg squats to their maximum depth, while kinematic and kinetic data were collected. Outcome measures were calculated to quantify the behavior of the injured and non-injured legs and the asymmetry between these legs.

RESULTS

Squat depth was significantly reduced in ACLR and ACLD compared to CONT (p < 0.05; 106 ± 17°; 105 ± 21°; 113 ± 21°). Peak knee extensor moments (Mkn(mx)) were significantly reduced in ACLR and ACLD compared to CONT in the injured leg only (p < 0.05; 0.045 ± 0.015; 0.046 ± 0.016; 0.059 ± 0.022 body weight.height respectively). There was no significant correlation between symmetry of the support moment (SYM(Msup)) and of the % support moment by the knee (SYM%supkn) in CONT (R(2) = -0.07). Data distribution average indicated good symmetry. ACLR showed a significant correlation between SYM(Msup) and SYM%sup(kn) (R(2) = 0.561) when two participants who did not recover as well were excluded. ACLR controlled knee moment magnitude using two strategies; 1) transfer of support moment to non-injured leg; 2) transfer of support moment from knee to ankle and/or hip of injured leg. These were combined in different proportions, but with the same effect on the knee moment. ACLD showed no significant correlation between SYM(Msup) and SYM%sup(kn) (R(2) = 0.015). Data distribution average indicated reduced symmetry. ACLD therefore used an avoidance strategy: reducing squat depth and subsequently the support moment in the injured leg and the knee contribution.

CONCLUSIONS

ACLD and ACLR individuals used different squatting strategies compared to controls, with ACLR using controlled and ACLD using avoidance behavior regarding knee loading. This has major implications for rehabilitation as these kinetic strategies cannot be observed, but result in the injured leg not being exercised as intended.

Jump-landing biomechanics and knee-laxity change across the menstrual cycle in women with anterior cruciate ligament reconstruction

CONTEXT

Of the individuals able to return to sport participation after an anterior cruciate ligament(ACL) injury, up to 25% will experience a second ACL injury. This population may be more sensitive to hormonal fluctuations, which may explain this high rate of second injury.

OBJECTIVE

To examine changes in 3-dimensional hip and knee kinematics and kinetics during a jump landing and to examine knee laxity across the menstrual cycle in women with histories of unilateral noncontact ACL injury.

DESIGN

Controlled laboratory study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 20 women (age = 19.6 ± 1.3 years, height = 168.6 ± 5.3 cm, mass = 66.2 ± 9.1 kg) with unilateral, noncontact ACL injuries.

INTERVENTION(S)

Participants completed a jump-landing task and knee-laxity assessment 3 to 5 days after the onset of menses and within 3 days of a positive ovulation test.

MAIN OUTCOME MEASURE(S)

Kinematics in the uninjured limb at initial contact with the ground during a jump landing, peak kinematics and kinetics during the loading phase of landing, anterior knee laxity via the KT-1000, peak vertical ground reaction force, and blood hormone concentrations (estradiol-β-17, progesterone, free testosterone).

RESULTS

At ovulation, estradiol-β-17 (t = -2.9, P = .009), progesterone (t = -3.4, P = .003), and anterior knee laxity (t = -2.3, P = .03) increased, and participants presented with greater knee-valgus moment (Z = -2.6, P = .01) and femoral internal rotation (t = -2.1, P = .047). However, during the menses test session, participants landed harder (greater peak vertical ground reaction force; t = 2.2, P = .04), with the tibia internally rotated at initial contact (t = 2.8, P = .01) and greater hip internal-rotation moment (Z = -2.4, P = .02). No other changes were observed across the menstrual cycle.

CONCLUSIONS

Knee and hip mechanics in both phases of the menstrual cycle represented a greater potential risk of ACL loading. Observed changes in landing mechanics may explain why the risk of second ACL injury is elevated in this population.

Assessment of Kinematic Asymmetry for Reduction of Hamstring Injury Risk

Context:

Kinematic asymmetry is believed to be associated with elevated risk for muscle injury, but little is known about the links between hamstring injuries and asymmetry of sprinting mechanics.

Objective:

To evaluate the value of kinematic analysis of sprinting for the detection of injury-related asymmetry in athletes with a history of hamstring strain.

Participants:

Six sub-elite male sprinters, including two who sustained a hamstring strain injury.

Outcome Measures:

Absolute differences between left and right symmetry indices and symmetry angles were both calculated for ground contact time and selected angular displacements. Measurements were acquired at foot strike, during the stance phase, and at toe-off.

Results:

At toe-off, injured athletes exhibited greater knee flexion and less hip extension for the injured extremity compared to the uninjured extremity. Symmetry indices for these variables markedly exceeded an established 15% threshold for clinically relevant asymmetry. Each of the uninjured athletes exhibited a high degree of symmetry for all parameters, with mean values for symmetry indices significantly lower than the 15% threshold (P < 0.05).

Conclusions:

Kinematic analysis of sprinting asymmetry appears to be valuable for identification of elevated risk for hamstring injury.

Normative values for the foot posture index between right and left foot: a descriptive study

BACKGROUND

The foot posture index (FPI) is a commonly used method to quantify standing foot posture. No normative data have, however, been presented to establish the range of a normal difference and asymmetrical differences between FPI score in the right foot and in the left foot.

PURPOSE

The purpose of the present study was to establish normative values for the difference between the FPI scores across the two feet.

METHODS

Among 930 healthy adults, FPI score was quantified in both feet. Difference between the two feet was calculated as FPI score on the right foot minus the FPI score on the left foot. Based on a normal distribution of the differences, asymmetry was defined as values below or above one standard deviation (SD) from the mean. Severe asymmetry was below and above ±2SD from the mean. Normal difference was defined as the range between ±1SD.

RESULTS

A reference range for normal difference in FPI score between left foot and right foot was -2 to +2. Asymmetry scores ranged from -2 to -4 and +2 to +4, while severe asymmetry was <-4 and >4.

CONCLUSION

Normative values for the difference between FPI scores in right foot and left foot have been presented from a large sample of healthy adults. These normative values can be used to identify a normal difference or an asymmetrical difference in foot posture across feet in one individual.

Lessons learned from the last 20 years of ACL-related in vivo-biomechanics research of the knee joint

PURPOSE

Technological advances in recent years have allowed the easy and accurate assessment of knee motion during athletic activities. Subsequently, thousands of studies have been published that greatly improved our understanding of the aetiology, surgical reconstruction techniques and prevention of anterior cruciate ligament (ACL) injuries. The purpose of this review is to summarize the evidence from biomechanical studies on ACL-related research.

METHODS

High-impact articles that enhanced understanding of ACL injury aetiology, rehabilitation, prevention and adaptations after reconstruction were selected.

RESULTS

The importance of restoring internal tibial rotation after ACL reconstruction has emerged in several studies. Criteria-based, individualized rehabilitation protocols have replaced the traditional time-based protocols. Excessive knee valgus, poor trunk control, excessive quadriceps forces and leg asymmetries have been identified as potential high risk biomechanical factors for ACL tear. Injury prevention programmes have emerged as low cost and effective means of preventing ACL injuries, particularly in female athletes.

CONCLUSION

As a result of biomechanical research, clinicians have a better understanding of ACL injury aetiology, prevention and rehabilitation. Athletes exhibiting neuromuscular deficits predisposing them to ACL injury can be identified and enrolled into prevention programmes. Clinicians should assess ACL-reconstructed patients for excessive internal tibial rotation that may lead to poor outcomes.

Kinetic and kinematic differences between first and second landings of a drop vertical jump task: implications for injury risk assessments

BACKGROUND

Though the first landing of drop vertical jump task is commonly used to assess biomechanical performance measures that are associated with anterior cruciate ligament injury risk in athletes, the implications of the second landing in this task have largely been ignored. We examined the first and second landings of a drop vertical jump for differences in kinetic and kinematic behaviors at the hip and knee.

METHODS

A cohort of 239 adolescent female basketball athletes (age=13.6 (1.6) years) completed drop vertical jump tasks from an initial height of 31 cm. A three dimensional motion capture system recorded positional data while dual force platforms recorded ground reaction forces for each trial.

FINDINGS

The first landing demonstrated greater hip adduction angle, knee abduction angle, and knee abduction moment than the second landing (P-values<0.028). The second landing demonstrated smaller flexion angles and moments at the hip and knee than the first landing (P-values<0.035). The second landing also demonstrated greater side-to-side asymmetry in hip and knee kinematics and kinetics for both the frontal and sagittal planes (P-values<0.044).

INTERPRETATION

The results have important implications for the future use of the drop vertical jump as an assessment tool for anterior cruciate ligament injury risk behaviors in adolescent female athletes. The second landing may be a more rigorous task and provides a superior tool to evaluate sagittal plane risk factors than the first landing, which may be better suited to evaluate frontal plane risk factors.

Impact differences in ground reaction force and center of mass between the first and second landing phases of a drop vertical jump and their implications for injury risk assessment

The drop vertical jump (DVJ) task is commonly used to assess biomechanical performance measures that are associated with ACL injury risk in athletes. Previous investigations have solely assessed the first landing phase. We examined the first and second landings of a DVJ for differences in the magnitude of vertical ground reaction force (vGRF) and position of center of mass (CoM). A cohort of 239 adolescent female basketball athletes completed a series of DVJ tasks from an initial box height of 31 cm. Dual force platforms and a three dimensional motion capture system recorded force and positional data for each trial. There was no difference in peak vGRF between landings (p=0.445), but side-to-side differences increased from the first to second landing (p=0.007). Participants demonstrated a lower minimum CoM during stance in the first landing than the second landing (p<0.001). The results have important implications for the future assessment of ACL injury risk behaviors in adolescent female athletes. Greater side-to-side asymmetry in vGRF and higher CoM during impact indicate the second landing of a DVJ may exhibit greater perturbation and better represent in-game mechanics associated with ACL injury risk.

Normal inter-limb differences during the straight leg raise neurodynamic test: a cross sectional study

Background

The straight leg raise (SLR) neurodynamic test is commonly used to examine the sensitivity of the lower quarter nervous system to movement. Range of motion during the SLR varies considerably, due to factors such as age, sex and activity level. Knowing intra-individual, inter-limb differences may provide a normative measure that is not influenced by such demographic characteristics. This study aimed to determine normal asymmetries between limbs in healthy, asymptomatic individuals during SLR testing and the relationship of various demographic characteristics.

Methods

The limb elevation angle was measured using an inclinometer during SLR neurodynamic testing that involved pre-positioning the ankle in plantar flexion (PF/SLR) and neutral dorsiflexion (DF/SLR). Phase 1 of the study included 20 participants where the ankle was positioned using an ankle brace replicating research testing conditions. Phase 2 included 20 additional participants where the ankle was manually positioned to replicate clinical testing conditions.

Results

The group average range of motion during PF/SLR was 57.1 degrees (SD: 16.8 degrees) on the left and 56.7 degrees (SD: 17.2 degrees) on the right while during DF/SLR the group average was 48.5 degrees (SD: 16.1 degrees) on the left and 48.9 degrees (SD: 16.4 degrees) on the right. The range of motion during SLR was moderately correlated to weight (−0.40 to −0.52), body mass index (−0.41 to −0.52), sex (0.40 to 0.42) and self-reported activity level (0.50 to 0.57). Intra-individual differences between limbs for range of motion during PF/SLR averaged 5.0 degrees (SD: 3.5 degrees) (95% CI: 3.8 degrees, 6.1 degrees) and during DF/SLR averaged 4.1 degrees (SD: 3.2 degrees) (95% CI: 3.1 degrees, 5.1 degrees) but were not correlated with any demographic characteristic. There were no significant differences between Phase 1 and Phase 2.

Conclusions

Overall range of motion during SLR was related to sex, weight, BMI and activity level, which is likely reflected in the high variability documented. We can be 95% confident that inter-limb differences during SLR neurodynamic testing fall below 11 degrees in 90% of the general population of healthy individuals. In addition, inter-limb differences were not affected by demographic factors and thus may be a more valuable comparison for test interpretation.