Allan G. Munro

Is There a Relationship Between Landing, Cutting, and Pivoting Tasks in Terms of the Characteristics of Dynamic Valgus?

Background: Anterior cruciate ligament (ACL) injuries are a major problem among female athletes. Screening for the risk of ACL injuries tends to focus on landing tasks, which may be limited in sports where changing direction is the main action involved in noncontact ACL injuries such as soccer. Purpose: To investigate whether there is a relationship between single-legged landing (SLL), cutting (90° cuts), and pivoting (180° turns) in terms of the characteristics of dynamic valgus. Study Design: Controlled laboratory study. Methods: Twenty female soccer players (mean ± SD: age, 21.0 ± 3.9 years; height, 1.65 ± 0.08 m; mass, 58.4 ± 6.4 kg) performed a minimum of 6 trials of SLL from a 0.3-m drop height and cutting and pivoting all on the right leg. Kinematics and kinetics were calculated from 3-dimensional motion analysis. Results: Strong correlations were found for peak knee abduction angles between tasks (R = 0.63-0.86, P < .01), whereas only moderate correlations between SLL and cutting (R = 0.46, P < .05), cutting and pivoting (R = 0.56, P < .05), and SLL and pivoting (R = 0.43, P > .05) were found between tasks for peak knee abduction moments. Conclusion: The results suggest that female athletes who exhibit poor SLL mechanics perform the same during various changing direction tasks. Clinical Relevance: The results support the use of existing screening tests that involve landing tasks to identify at-risk athletes for noncontact ACL injuries.

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.

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.

A Preliminary Investigation to Establish the Criterion Validity of a Qualitative Scoring System of Limb Alignment during Single Leg Squat and Landing

Objective: The present study aimed to investigate the criterion validity of a novel qualitative assessment scheme to assess limb alignment during single leg loading activities. Design and setting: Observational laboratory study Main outcome measures: Performance of 5 participant’s single leg squat and hop landing was assessed using 3-D motion capture and the findings of this compared to the qualitative scoring scheme. Results: The range of percentage of agreement between the qualitative and 3-D score was for all subjects across both tasks 95.6100%. The kappa measure of agreement was k = 0.9 for hop landing and k = 0.97 for single leg squat. Conclusion: The scores generated by the qualitative scoring scheme used showed excellent association with the corresponding data from 3-D motion capture, implying the measurement tool shows criterion validity.

Female soccer: Part 1 - a needs analysis

SUMMARY IT IS IMPERATIVE FOR STRENGTH AND CONDITIONING COACHES TO CONDUCT A DETAILED ANALYSIS OF THE DEMANDS OF A SPORT, IDENTIFYING NORMATIVE DATA WHERE POSSIBLE TO PERMIT AN EVIDENCE-BASED EVALUATION OF AN ATHLETE’S CURRENT PERFORMANCE STATUS AND TO INFORM THE DEVELOPMENT OF SPECIFIC GOALS FOR THE ATHLETES’ DEVELOPMENT. PART ONE OF THIS ARTICLE REVIEWS THE DEMANDS OF FEMALE SOCCER AND PROVIDES NORMATIVE DATA FROM PUBLISHED RESEARCH IDENTIFYING SPECIFIC AREAS THAT REQUIRE DEVELOPMENT IN FEMALE SOCCER PLAYERS. PART TWO RECOMMENDS EVIDENCE-BASED APPROACHES INTEGRATED TO ATHLETE DEVELOPMENT AND INJURY PREVENTION STRATEGIES, AS A RESULT OF THE NEEDS ANALYSIS.

The Relationship Between 2-Dimensional Knee-Valgus Angles During Single-Leg Squat, Single-Leg-Land, and Drop-Jump Screening Tests

CONTEXT Injuries to the anterior cruciate ligament (ACL) and patellofemoral joint (PFJ) are a significant problem in female athletes. A number of screening tasks have been used in the literature to identify those at greatest risk of injury. To date, no study has examined the relationship in 2-dimensional (2D) knee valgus between common screening tasks to determine whether individuals exhibit similar movement patterns across tasks. OBJECTIVE To establish whether frontal-plane projection angle (FPPA) during the single-leg squat (SLS), single-leg land (SLL), and drop jump (DJ) are related. DESIGN Cross-sectional study. SETTING University laboratory. PARTICIPANTS 52 national-league female football players and 36 national-league female basketball players. MAIN OUTCOME MEASURES 2D FPPA during the SLS, SLL, and DJ screening tasks. RESULTS Significant correlations were found between tasks. FPPA in the SLS was significantly correlated with SLL (r = .52) and DJ (r = .30), whereas FPPA in the SLL was also significantly correlated to DJ (r = .33). FPPA was significantly greater in the SLS than in the SLL (P < .001) and DJ (P < .001) and in the SLL than in the DJ (P < .001). CONCLUSION The results showed that 2D FPPA is correlated across the SLS, SLL, and DJ tasks. However, significantly greater FPPA values in the unilateral tasks suggest that the DJ may not identify risk of injury in sports where primary injury mechanisms are during unilateral loading tasks. Therefore, it is recommended that both unilateral and bilateral tasks be included when screening for ACL and PFJ injury risk.

Female Soccer: Part 2 – training considerations and recommendations

SUMMARY PART 1 OF THIS ARTICLE IDENTIFIED THE DEMANDS OF FEMALE SOCCER AND THE SPECIFIC AREAS OF DEVELOPMENT REQUIRED TO OPTIMIZE PERFORMANCE AND REDUCE THE RISK OF COMMON INJURIES. INCREASES IN AEROBIC CAPACITY, STRENGTH, AND LOWER LIMB CONTROL WERE REQUIRED TO IMPROVE PERFORMANCE AND REDUCE THE RISKS OF COMMON INJURIES. THE AIMS OF PART 2 ARE TO PROVIDE EXAMPLES OF EVIDENCE-BASED INTEGRATED STRATEGIES TO ADDRESS THE ISSUES IDENTIFIED IN PART 1 AND TO ENSURE NOT ONLY ENHANCED PERFORMANCE BUT ALSO A REDUCED INCIDENCE OF COMMON INJURIES IN FEMALE SOCCER PLAYERS.