Is There a Pathological Gait Associated With Common Soft Tissue Running Injuries?

BACKGROUND

Previous research has demonstrated clear associations between specific running injuries and patterns of lower limb kinematics. However, there has been minimal research investigating whether the same kinematic patterns could underlie multiple different soft tissue running injuries. If they do, such kinematic patterns could be considered global contributors to running injuries.

HYPOTHESIS

Injured runners will demonstrate differences in running kinematics when compared with injury-free controls. These kinematic patterns will be consistent among injured subgroups.

STUDY DESIGN

Controlled laboratory study.

METHODS

The authors studied 72 injured runners and 36 healthy controls. The injured group contained 4 subgroups of runners with either patellofemoral pain, iliotibial band syndrome, medial tibial stress syndrome, or Achilles tendinopathy (n = 18 each). Three-dimensional running kinematics were compared between injured and healthy runners and then between the 4 injured subgroups. A logistic regression model was used to determine which parameters could be used to identify injured runners.

RESULTS

The injured runners demonstrated greater contralateral pelvic drop (CPD) and forward trunk lean at midstance and a more extended knee and dorsiflexed ankle at initial contact. The subgroup analysis of variance found that these kinematic patterns were consistent across each of the 4 injured subgroups. CPD was found to be the most important variable predicting the classification of participants as healthy or injured. Importantly, for every 1° increase in pelvic drop, there was an 80% increase in the odds of being classified as injured.

CONCLUSION

This study identified a number of global kinematic contributors to common running injuries. In particular, we found injured runners to run with greater peak CPD and trunk forward lean as well as an extended knee and dorsiflexed ankle at initial contact. CPD appears to be the variable most strongly associated with common running-related injuries.

CLINICAL RELEVANCE

The identified kinematic patterns may prove beneficial for clinicians when assessing for biomechanical contributors to running injuries.

The short-term effect of swimming training load on shoulder rotational range of motion, shoulder joint position sense and pectoralis minor length

BACKGROUND

Shoulder pain or injury is the most common issue facing elite competitive swimmers and the most frequent reason for missed or modified training. Literature suggests that highly repetitive upper limb loading leads to inappropriate adaptations within the shoulder complex. The most likely maladaptations to occur are variations in shoulder rotational range of motion, reduction in joint position sense and shortened pectoralis minor length. This has yet to have been confirmed in experimental studies. The aim of this study was to investigate the short-term effects of swimming training load upon internal and external rotation range of motion, joint position sense and pectoralis minor length.

METHOD

Sixteen elite swimmers training in the British Swimming World Class programme participated. Measures of internal and external range of motion, joint position sense error score and pectoralis minor length were taken before and after a typical 2 h swimming session.

RESULTS

Following swimming training shoulder external rotation range of motion and pectoralis minor length reduced significantly (-3.4°, p = <0.001 and -0.7 cm, p = <0.001, respectively), joint position sense error increased significantly (+2.0° error angle, p = <0.001). Internal rotation range of motion demonstrated no significant change (-0.6, p = 0.53).

DISCUSSION

This study determined that elite level swimming training results in short-term maladaptive changes in shoulder performance that could potentially predispose them to injury.

Testing Shoulder Pain Mapping

Objective

A previous study on shoulder pain mapping showed specific pain patterns for common shoulder disorders. This study aimed to test those patterns for accuracy, modify shoulder pain mapping as needed, and observe their reliability and validity.

Methods

This prospective study used a two-step process and was undertaken to determine its potential utility in daily practice. New shoulder pain patients marked their pain, its character and severity, on a custom-made mapping form. Then a researcher blinded to the diagnoses gave their estimations on the basis of previously established maps, and they were correlated with final diagnoses. Subsequently, a guide table was developed on how to read the maps, and intertester reliability was performed with three independent testers.

Results

The study included 194 patients, and the overall accuracy for estimations was between 45.4% and 49.5%. The sensitivity was high, especially for instability, followed by calcific tendinitis, acromio-calvicular joint pathology, and impingement. The intertester reliability showed clinically significant agreement between testers for both disease groups (κ = 0.70) and individual disorders (κ = 0.52).

Conclusions

This was a unique and extensive study on shoulder pain mapping. The study concluded that pain mapping could be a useful adjunct to the clinical assessment of patients with shoulder pain and can be used in the primary care setting as well as secondary care and for research.

Patellofemoral Joint Loads During Running at the Time of Return to Sport in Elite Athletes With ACL Reconstruction

BACKGROUND

Patellofemoral joint pain and degeneration are common in patients who undergo anterior cruciate ligament reconstruction (ACLR). The presence of patellofemoral joint pain significantly affects the patient's ability to continue sport participation and may even affect participation in activities of daily living. The mechanisms behind patellofemoral joint pain and degeneration are unclear, but previous research has identified altered patellofemoral joint loading in individuals with patellofemoral joint pain when running. It is unclear whether this process occurs after ACLR.

PURPOSE

To assess the patellofemoral joint stresses during running in ACLR knees and compare the findings to the noninjured knee and matched control knees.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-four elite sports practitioners who had undergone ACLR and 34 age- and sex-matched controls participated in the study. The participants' running gait was assessed via 3D motion capture, and knee loads and forces were calculated by use of inverse dynamics.

RESULTS

A significance difference was found in knee extensor moment, knee flexion angles, patellofemoral contact force (about 23% greater), and patellofemoral contact pressure (about 27% greater) between the ACLR and the noninjured limb ( P ≤ .04) and between the ACLR and the control limb ( P ≤ .04); no significant differences were found between the noninjured and control limbs ( P ≥ .44).

CONCLUSION

Significantly greater levels of patellofemoral joint stress and load were found in the ACLR knee compared with the noninjured and control knees.

CLINICAL RELEVANCE

Altered levels of patellofemoral stress in the ACLR knee during running may predispose individuals to patellofemoral joint pain.

Does the Powers™ strap influence the lower limb biomechanics during running?

Previous research has reported a prevalence of running related injuries in 25.9% to 72% of all runners. A greater hip internal rotation and adduction during the stance phase in running has been associated with many running related injuries, such as patellofemoral pain. Researchers in the USA designed a treatment device 'the Powers™ strap' to facilitate an external rotation of the femur and to thereby control abnormal hip and knee motion during leisure and sport activities. However, to date no literature exists to demonstrate whether the Powers™ strap is able to reduce hip internal rotation during running. 22 healthy participants, 11 males and 11 females (age: 27.45±4.43 years, height: 1.73±0.06m, mass: 66.77±9.24kg) were asked to run on a 22m track under two conditions: without and with the Powers™ strap. Three-dimensional motion analysis was conducted using ten Qualisys OQUS 7 cameras (Qualisys AB, Sweden) and force data was captured with three AMTI force plates (BP600900, Advanced Mechanical Technology, Inc.USA). Paired sample t-tests were performed at the 95% confidence interval on all lower limb kinematic and kinetic data. The Powers™ strap significantly reduced hip and knee internal rotation throughout the stance phase of running. These results showed that the Powers™ strap has the potential to influence hip motion during running related activities, in doing so this might be beneficial for patients with lower limb injuries. Future research should investigate the influence of the Powers™ strap in subjects who suffer from running related injuries, such as patellofemoral pain.

THE EFFECT OF CONSERVATIVELY TREATED ACL INJURY ON KNEE JOINT POSITION Sense

BACKGROUND

Proprioception is critical for effective movement patterns. However, methods of proprioceptive measurement in previous research have been inconsistent and lacking in reliability statistics making it applications to clinical practice difficult. Researchers have suggested that damage to the anterior cruciate ligament (ACL) can alter proprioceptive ability due to a loss of functioning mechanoreceptors. The majority of patients opt for reconstructive surgery following this injury. However, some patients chose conservative rehabilitation options rather than surgical intervention.

PURPOSE

The purpose of this study was to determine the effect of ACL deficiency on knee joint position sense following conservative, non-operative treatment and return to physical activity. A secondary purpose was to report the reliability and measurement error of the technique used to measure joint position sense, (JPS) and comment on the clinical utility of this measurement.

STUDY DESIGN

Observational study design using a cross-section of ACL deficient patients and matched uninjured controls.

METHODS

Twenty active conservatively treated ACL deficient patients who had returned to physical activity and twenty active matched controls were included in the study. Knee joint position sense was measured using a seated passive-active reproductive angle technique. The average absolute angle of error score, between 10 °-30 ° of knee flexion was determined. This error score was derived from the difference between the target and repositioning angle.

RESULTS

The ACL deficient patients had a greater error score (7.9 °±3.6) and hence poorer static proprioception ability that both the contra-lateral leg (2.0 °±1.6; p = 0.0001) and the control group (2.6 °±0.9; p = 0.0001). The standard error of the mean (SEM) of this JPS technique was 0.5 ° and 0.2 ° and the minimum detectable change (MDC) was 1.3 ° and 0.4 ° on asymptomatic and symptomatic subjects respectively.

CONCLUSION

This study confirms a static proprioceptive deficiency exists in the knee joint following ACL injury and rehabilitation, potentially due to a reduction in functioning mechanoreceptors in the ligament over time. The differences between the ACL deficient knee and the control group were above the SEMs and MDCs of the measurement which suggests clinical relevance. Longitudinal studies are needed to evaluate if patients who return to activity with a joint position sense deficiency develop secondary injuries.

LEVELS OF EVIDENCE

Individual Cohort Study (2b).

The effects of knee direction, physical activity and age on knee joint position sense

BACKGROUND

Previous research has suggested a decline in knee proprioception with age. Furthermore, regular participation in physical activity may improve proprioceptive ability. However, there is no large scale data on uninjured populations to confirm these theories. The aim of this study was to provide normative knee joint position data (JPS) from healthy participants aged 18-82years to evaluate the effects of age, physical activity and knee direction.

METHODS

A sample of 116 participants across five age groups was used. The main outcome measures were knee JPS absolute error scores into flexion and extension, Tegner activity levels and General Practitioner Physical Activity Questionnaire results.

RESULTS

Absolute error scores in to knee flexion were 3.6°, 3.9°, 3.5°, 3.7° and 3.1° and knee extension were 2.7°, 2.5°, 2.9°, 3.4° and 3.9° for ages 15-29, 30-44, 45-59, 60-74 and 75 years old respectively. Knee extension and flexion absolute error scores were significantly different when age group data were pooled. There was a significant effect of age and activity level on joint position sense into knee extension. Age and lower Tegner scores were also negatively correlated to joint position sense into knee extension.

CONCLUSIONS

The results provide some evidence for a decline in knee joint position sense with age. Further, active populations may have heightened static proprioception compared to inactive groups. Normative knee joint position sense data is provided and may be used by practitioners to identify patients with reduced proprioceptive ability.

Do changes in hand grip strength correlate with shoulder rotator cuff function?

BACKGROUND

Shoulder pain as a result of rotator cuff pathology is one of the most common musculoskeletal complaints presenting within primary care. Assessment of hand grip strength has been proposed as an indicator of rotator cuff function. This experimental study assessed the relationship between grip strength and shoulder lateral rotator muscle strength in a number of different shoulder positions, aiming to investigate whether such a relationship existed and whether grip strength could be used as a functional assessment tool for the posterior cuff.

METHODS

Twenty-seven healthy, physically active, volunteers (19 males, eight females) with no history of shoulder, upper limb or neck injury comprised the study group. The mean (SD) age was 19.8 (5.7) years (range 18 years to 23 years). Grip strength (measured with hand grip dynamometer) and lateral rotator strength (measured with a hand held dynamometer) was measured at neutral, 90° abduction, and 90° abduction with 90° external rotation.

RESULTS

The correlation between grip strength and shoulder lateral rotation strength ranged between r = 0.91 (r (2 )= 0.84) and r = 0.72 (r (2 )= 0.52) across all positions.

CONCLUSIONS

A strong correlation between grip strength and lateral rotator strength was shown at all positions for both left and right hands, suggesting that assessment of grip strength could be used as a rotator cuff monitor of recruitment function.

KINEMATIC ANALYSIS OF KNEE VALGUS DURING DROP VERTICAL JUMP AND FORWARD STEP-UP IN YOUNG BASKETBALL PLAYERS

PURPOSE/BACKGROUND

Lower limb asymmetry between dominant and nondominant limbs is often associated with injuries. However, there is a lack of evidence about frontal plane projection angle (FPPA) of the knee joint (knee valgus) during drop vertical jump (DVJ) and forward step-up tasks (FSUP) in young basketball players. Therefore, the purpose of this study was to assess the FPPA (i.e., dynamic knee valgus) via 2D video analysis during DVJ and FSUP tasks in the dominant and nondominant limbs of young male basketball players.

METHODS

Twenty seven young male basketball players (age 14.5 ± 1.3 y, height 161.1 ± 4.1 cm, weight 64.2 ± 10.2 kg) participated in this study. The participants were asked to perform a bilateral DVJ and unilateral FSUP tasks. Kinematic analysis of FPPA was completed via a two-dimensional (2D) examination in order to evaluate the knee valgus alignment during the beginning of the concentric phase of each task. Knee valgus alignment was computed considering the angle between the line formed between the markers at the anterior superior iliac spine and middle of the tibiofemoral joint and the line formed from the markers on the middle of the tibiofemoral joint to the middle of the ankle mortise. Paired t-tests were used to evaluate differences in tasks. Standard error of measurement (SEM) was calculated to establish random error scores.

RESULTS

There was no difference in knee valgus angle during the DVJ task between dominant (20.2 ± 4.4 º) and nondominant legs (20 ± 4.1 º; p = 0.067). However, a significant difference was noted during FSUP between the non-dominant limb (18.7 ± 3.4 º) when compared to the dominant (21.7 ± 3.5 º; p = 0.001) limb.

CONCLUSION

Two dimensional kinematic analysis of knee FPPA may help coaches and other professionals to detect asymmetries between dominant and nondominant limbs, and to develop training programs with the goal of reducing overall lower extremity injury risk.

LEVEL OF EVIDENCE

2b.

Joint Kinetics and Kinematics During Common Lower Limb Rehabilitation Exercises

CONTEXT

Unilateral body-weight exercises are commonly used to strengthen the lower limbs during rehabilitation after injury, but data comparing the loading of the limbs during these tasks are limited.

OBJECTIVE

To compare joint kinetics and kinematics during 3 commonly used rehabilitation exercises.

DESIGN

Descriptive laboratory study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 9 men (age = 22.1 ± 1.3 years, height = 1.76 ± 0.08 m, mass = 80.1 ± 12.2 kg) participated.

INTERVENTION(S)

Participants performed the single-legged squat, forward lunge, and reverse lunge with kinetic data captured via 2 force plates and 3-dimensional kinematic data collected using a motion-capture system.

MAIN OUTCOME MEASURE(S)

Peak ground reaction forces, maximum joint angles, and peak sagittal-joint moments.

RESULTS

We observed greater eccentric and concentric peak vertical ground reaction forces during the single-legged squat than during both lunge variations (P ≤ .001). Both lunge variations demonstrated greater knee and hip angles than did the single-legged squat (P < .001), but we observed no differences between lunges (P > .05). Greater dorsiflexion occurred during the single-legged squat than during both lunge variations (P < .05), but we noted no differences between lunge variations (P = .70). Hip-joint moments were greater during the forward lunge than during the reverse lunge (P = .003) and the single-legged squat (P = .011). Knee-joint moments were greater in the single-legged squat than in the reverse lunge (P < .001) but not greater in the single-legged squat than in the forward lunge (P = .41). Ankle-joint moments were greater during the single-legged squat than during the forward lunge (P = .002) and reverse lunge (P < .001).

CONCLUSIONS

Appropriate loading progressions for the hip should begin with the single-legged squat and progress to the reverse lunge and then the forward lunge. In contrast, loading progressions for the knee and ankle should begin with the reverse lunge and progress to the forward lunge and then the single-legged squat.

Improving Single-Legged-Squat Performance: Comparing 2 Training Methods With Potential Implications for Injury Prevention

CONTEXT

Poor dynamic limb alignment during loading tasks has links to the development of knee injuries, including patellofemoral pain and anterior cruciate ligament injury. Therefore, modalities to improve limb alignment during loading tasks are thought to reduce loading through these structures and potentially prevent injury.

OBJECTIVE

To compare hip-strengthening and skill-acquisition training to examine if they can improve lower limb biomechanics, potentially preventing injury, and to examine whether changes demonstrated can be maintained after 6 weeks of no practice.

DESIGN

Controlled laboratory study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 19 recreationally active individuals volunteered, and 17 (9 women: age = 27.9 ± 3.1 years, height = 165.4 ± 8.4 cm, mass = 60.5 ± 9.2 kg; 8 men: age = 30.4 ± 6.4 years, height = 181.4 ± 7.1 cm, mass = 69.8 ± 15.2 kg) completed the study. Nine participants were allocated to a hip-strengthening program; 8, to a skill-acquisition program.

INTERVENTION(S)

Participants performed a 6-week training program of either hip strengthening (n = 9) or skill acquisition (n = 8) 3 times per week.

MAIN OUTCOME MEASURE(S)

Measurements of clam-exercise strength, hip-abduction strength, frontal-plane projection angle, hip-adduction angle, and a qualitative score were taken at baseline, 6 weeks, and 12 weeks.

RESULTS

We observed improvements in frontal-plane projection angle (strength: t8 = 5.344, P = .001; skill: t7 = 4.393, P = .003), hip-adduction angle (strength: t8 = 3.597, P = .007; skill: t7 = 4.722, P = .002), and qualitative score (strength: t8 = 3.900, P = .005; skill: t7 = 8.283, P < .001) postintervention, which were retained at the 12-week retest in both groups.

CONCLUSIONS

A 6-week intervention of either hip-strengthening or skill-acquisition training improved lower limb biomechanics. The changes in biomechanics after skill training were retained at 12 weeks, suggesting a change in motor patterning that could be favorable to longer-term injury prevention.

An evidence-based review of current perceptions with regard to the subacromial space in shoulder impingement syndromes: Is it important and what influences it?

BACKGROUND

Reduction of the subacromial space as a mechanism in the etiology of shoulder impingement syndromes is debated. Although a reduction in this space is associated with shoulder impingement syndromes, it is unclear if this observation is cause or consequence.

METHOD

The purposes of this descriptive review are to provide a broad perspective on the current perceptions with regard to the pathology and pathomechanics of subacromial and internal impingement syndromes, consider the role of the subacromial space in impingement syndromes, describe the intrinsic and extrinsic mechanisms considered to influence the subacromial space, and critique the level of evidence supporting these concepts.

FINDING

Based on the current evidence, the hypothesis that a reduction in subacromial space is an extrinsic cause of impingement syndromes is not conclusively established and the evidence permits no conclusion.

INTERPRETATION

If maintenance of the subacromial space is important in impingement syndromes regardless of whether it is a cause or consequence, research exploring the correlation between biomechanical factors and the subacromial space, using the later as the outcome measure, would be beneficial.

Acromiohumeral Distance During Neuromuscular Electrical Stimulation of the Lower Trapezius and Serratus Anterior Muscles in Healthy Participants

CONTEXT

Compromise to the acromiohumeral distance has been reported in participants with subacromial impingement syndrome compared with healthy participants. In clinical practice, patients with subacromial shoulder impingement are given strengthening programs targeting the lower trapezius (LT) and serratus anterior (SA) muscles to increase scapular posterior tilt and upward rotation. We are the first to use neuromuscular electrical stimulation to stimulate these muscle groups and evaluate how the muscle contraction affects the acromiohumeral distance.

OBJECTIVE

To investigate if electrical muscle stimulation of the LT and SA muscles, both separately and simultaneously, increases the acromiohumeral distance and to identify which muscle-group contraction or combination most influences the acromiohumeral distance.

DESIGN

Controlled laboratory study.

SETTING

Human performance laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty participants (10 men and 10 women, age = 26.9 ± 8.0 years, body mass index = 23.8) were screened.

INTERVENTION(S)

Neuromuscular electrical stimulation of the LT and SA.

MAIN OUTCOME MEASURE(S)

Ultrasound measurement of the acromiohumeral distance.

RESULTS

Acromiohumeral distance increased during contraction via neuromuscular electrical stimulation of the LT muscle (t(19) = -3.89, P = .004), SA muscle (t(19) = -7.67, P = .001), and combined LT and SA muscles (t(19) = -5.09, P = .001). We observed no differences in the increased acromiohumeral distance among the 3 procedures (F(2,57) = 3.109, P = .08).

CONCLUSIONS

Our results supported the hypothesis that the muscle force couple around the scapula is important in rehabilitation and scapular control and influences acromiohumeral distance.

A preliminary study into the effect of jumping-landing training and strength training on frontal plane projection angle

The presence of increased knee valgus angles during functional tasks has been associated with a range of knee pathologies. A number of different exercise interventions have been undertaken to improve knee alignment during functional tasks. The most successful of these interventions are multi-modal incorporating both strength and jump-landing training. Little research has been undertaken to compare these elements individually to assess if success is due to an individual element or the training as a whole. The study assessed the between group effects of strength training or jump-landing training alone on knee valgus alignment during a number of functional tasks, using a cohort specific treatment superiority design. Thirty asymptomatic female participants undertook a 6 week (minimum 15 sessions) strength or jump-landing programme, the effects of which were examined by assessing for any change in frontal plane projection angle (FPPA) during single leg squat and landing and bilateral drop jump landing. Both training methods had positive effects of FPPA during some but not all of the tasks. Strength training brought about significant changes in FPPA during single leg squat and landing, whilst jump-landing training significantly influenced single leg landing and drop jump landing performance. The changes reported, therefore appear to be related to the nature of the training and the tasks undertaken during that training. The findings indicating that a combined training protocol incorporating both strengthening and jump-landing training may bring about the greatest improvement across a spectrum of tasks for the patient, supporting the previous work on multimodal training.

Functional Performance Testing and Patient Reported Outcomes following ACL Reconstruction: A Systematic Scoping Review

Objective. A systematic scoping review of the literature to identify functional performance tests and patient reported outcomes for patients who undergo anterior cruciate ligament (ACL) reconstruction and rehabilitation that are used in clinical practice and research during the last decade. Methods. A literature search was conducted. Electronic databases used included Medline, PubMed, Cochrane Library, EMBASE, CINAHL, SPORTDiscus, PEDro, and AMED. The inclusion criteria were English language, publication between April 2004 and April 2014, and primary ACL reconstruction with objective and/or subjective outcomes used. Two authors screened the selected papers for title, abstract, and full-text in accordance with predefined inclusion and exclusion criteria. The methodological quality of all papers was assessed by a checklist of the Critical Appraisal Skills Programme (CASP). Results. A total of 16 papers were included with full-text. Different authors used different study designs for functional performance testing which led to different outcomes that could not be compared. All papers used a measurement for quantity of functional performance except one study which used both quantity and quality outcomes. Several functional performance tests and patient reported outcomes were identified in this review. Conclusion. No extensive research has been carried out over the past 10 years to measure the quality of functional performance testing and control stability of patients following ACL reconstruction. However this study found that the measurement of functional performance following ACL reconstruction consisting of a one-leg hop for a set distance or a combination of different hops using limb symmetry index (LSI) was a main outcome parameter of several studies. A more extensive series of tests is suggested to measure both the quantitative and qualitative aspects of functional performance after the ACL reconstruction. The KOOS and the IKDC questionnaires are both measures that are increasingly being used for ACL reconstruction throughout the last decade.

The effect of videotape augmented feedback on drop jump landing strategy: Implications for anterior cruciate ligament and patellofemoral joint injury prevention

BACKGROUND

Modification of high-risk movement strategies such as dynamic knee valgus is key to the reduction of anterior cruciate ligament (ACL) and patellofemoral joint (PFJ) injuries. Augmented feedback, which includes video and verbal feedback, could offer a quick, simple and effective alternative to training programs for altering high-risk movement patterns. It is not clear whether feedback can reduce dynamic knee valgus measured using frontal plane projection angle (FPPA).

METHODS

Vertical ground reaction force (vGRF), two-dimensional FPPA of the knee, contact time and jump height of 20 recreationally active university students were measured during a drop jump task pre- and post- an augmented feedback intervention. A control group of eight recreationally active university students were also studied at baseline and repeat test.

RESULTS

There was a significant reduction in vGRF (p=0.033), FPPA (p<0.001) and jump height (p<0.001) and an increase in contact time (p<0.001) post feedback in the intervention group. No changes were evident in the control group.

CONCLUSION

Augmented feedback leads to significant decreases in vGRF, FPPA and contact time which may help to reduce ACL and PFJ injury risk. However, these changes may result in decreased performance.

CLINICAL RELEVANCE

Augmented feedback reduces dynamic knee valgus, as measured via FPPA, and forces experienced during the drop jump task and therefore could be used as a tool for helping decrease ACL and PFJ injury risk prior to, or as part of, the implementation of injury prevention training programs.