Altered Movement Strategies during Triple Hop Test in Women With and Without Patellofemoral Pain

Research Review: Altered Movement Strategies during Triple Hop Test in Women With and Without Patellofemoral Pain

By Jinny McGivern PT, DPT, Certified Yoga Instructor

Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Dos Reis, A. C., Correa, J. C. F., Bley, A. S., Rabelo, N. D. D. A., Fukuda, T. Y., & Lucareli, P. R. G. (2015). Kinematic and Kinetic Analysis of the Single-Leg Triple Hop Test in Women With and Without Patellofemoral Pain. journal of orthopaedic & sports physical therapy, 45(10), 799-807. ABSTRACT

Image courtesy of: http://athletemovementindex.org/ami-tests/

Why is this relevant?: Dynamic knee valgus is a commonly observed weight-bearing, dysfunctional movement pattern. It has been associated with a multitude of injuries and pain in various segments of the lower extremity (LE). One assessment that is often used to evaluate knee function is the Single Leg Triple Hop Test (SLTHT). The authors of this paper examined the differences in mechanics between women with and without patellofemoral pain (PFP) and specifically focused on the movement events that occur between landing the first jump and completing take off for the second. In addition to analyzing the hip, knee and ankle segments, the authors included assessment of the trunk and pelvis, thus providing information about the integration between the LE kinetic chain and the trunk. This has implications for both prevention and intervention strategies related to knee pathomechanics and pain, specifically PFP.

Study Summary

http://www.runningwritings.com/2012/03/injury-series-uncovering-role-of-hip.html

Review & Commentary:

There were many strong components to the methodology of this research. The authors calculated an appropriate sample size for their findings to carry statistical significance prior to the start of recruitment. The authors used a previously researched method of 23 anatomical markers with an 8 camera system for kinematic analysis. Data on kinetics was collected from a force plate positioned such that the subject landed from the first jump on the plate. The researchers used the practice jumps to determine where the force plate needed to be positioned. While the researchers were not blinded to the group assignments, the subjects were not informed that the primary event of interest was the landing and take off between the first and second jumps. This helped to prevent the creation of a performance bias. The researchers standardized the hopping task by requiring subjects to perform the SLTHT barefoot and to cross their arms over their chest while hopping. This helped to eliminate the potentially confounding variables of variations in footwear as well as upper extremity compensations.

Kinematic and kinetic data was interfaced allowing the researchers to observe the interaction between body position and forces acting on/within it. In research focusing on dynamic valgus, the primary joints typically focused on are the hip, knee and ankle. The inclusion of the pelvis and trunk provided a wealth of additional information on other more proximal components of dynamic knee valgus. A single study is not necessarily enough to declare that certain trunk and pelvis motions are as characteristic of dynamic knee valgus as hip internal rotation and adduction, but the authors of this study do note that increasing numbers of researchers are observing the contralateral pelvis drop in conjunction with hip internal rotation and adduction. Finally, the inclusion of the time to peak joint angle outcome measure added a new dimension to the observation of joint motion and gave readers insight into some of the impaired timing of movement observed in dynamic knee valgus.

This research also had limitations. While the inclusion criteria for the PFPG was very specific, the criteria for recruiting members of the CONG appeared to be less so with the main requirement being the absence of knee pain. There was no assessment reported of whether or not these individuals demonstrated efficient knee tracking alignment in weight bearing, or if there has been any previous history of LE injury or pain in these individuals. It would have been beneficial if the authors could have included EMG analysis of key muscles of the LE to highlight neuromuscular changes that occur in PFP and dynamic knee valgus. Based on the kinematic data, we can make reasonable assumptions about what is happening in the muscular system, however these will remain guesses until future research confirms our hypothesis. Finally, the marker system was affixed to soft tissues which may move slightly differently than joints. Future research may want to consider the use of bone-in markers to reduce this potential source of error.

Because the authors provided both joint position and movement timing data, it became possible for the reader to visualize the dysfunctional movement demonstrated by the individuals with PFP. It was especially interesting to consider the inter-relationship between the quantity of excursion and the time to peak joint angle. There was a reduced quantity of ipsilateral trunk & pelvic rotation excursion, therefore it was not surprising that the time to peak joint angle was significantly faster than the CONG; there was less distance for those segments to travel in the PFPG. Similarly, there was also a significantly faster time to peak joint angle in knee flexion & ankle dorsiflexion, two segments that also demonstrated decreased excursion in the PFPG. Conversely, increased excursion was noted for hip internal rotation and ankle eversion, however these actions demonstrated faster times to peak joint angle. It is possible that this is the strategy that the subject used to initially stabilize themselves when landing out of the hop. There were also several variables which demonstrated significantly increased excursion, but slower time to peak joint angle. These included: anterior trunk lean, ipsilateral trunk lean, contralateral pelvic drop and hip adduction. It is possible that this group of movements makes up the compensation pattern adopted by the subjects due to impaired initiation of an efficient stabilization strategy. Generally speaking the researchers report decreased excursion in the sagittal plane at the hip, knee and ankle. It appears that the excessive movement in all other planes are all part of a compensation pattern to avoid pure sagittal plane movement.

With respect to the kinetic data, note that all of the joint power absorption variables were decreased in PFPG group with the exception of hip flexion, which was not statistically different, and knee abduction which was significantly greater. It appears that all of the stress of landing out of the hop is concentrated at the medial knee. This is not an efficient strategy for shock absorption which should ideally take place over several joints to distribute the load.

Why is this study important?

This study provides evidence to support the concept of regional interdependence between the hip, knee and ankle, as well as the pelvis and the trunk. It also indicates that knee pain may not be an issue isolated to dysfunction of the knee. The knee may be the most observable sign of dysfunction, as well as the location of tissue breakdown and pain; however, potential drivers of dysfunction as well as additional compensations may be both distal and proximal to the knee. Furthermore, this research highlights that dysfunctional movement patterns are not solely a product of impaired joint positions, but that a timing component may contribute as well. It is important to consider which muscles are activated first to stabilize or generate movement and to incorporate efficient timing strategies into rehabilitation and performance enhancement.

How does it affect practice?

This research supports the use of "full body" functional movements for movement assessment. This may include walking, squatting or stairclimbing at the lower impact level of the spectrum. In more active and athletic populations, it is essential to also assess higher impact activities such as jumping, hopping and running. While it is important to also assess the painful or dysfunctional segment in greater detail, it is possible that other components of the dysfunction may be missed if one is only looking in the location of pain.

This research also supports the use of exercises that focus on the integration of the trunk with the extremities. The individuals with PFP in this research demonstrated excessive movement of the trunk and pelvis in the frontal and sagittal planes, however reduced movement of both of these segments in the transverse plane. It is possible that the synergistic groups of muscles that cross the trunk and extremities, the subsystems , were not functioning efficiently in the individuals with PFP. Whether this was a pre-disposing factor or a result of pain and dysfunction cannot be ascertained from this study; however, recovery will be challenging if efficient hip and knee alignment is not addressed in conjunction with the ability to stabilize the trunk and pelvis during dynamic activities.

How does it relate to Brookbush Institute Content?

This research supports the Brookbush's Institute's approach the use of a dynamic movement such as a squat for movement assessment, its approach to addressing postural dysfunction , and its sequencing of a corrective exercise routine. The dysfunctional movement pattern described in this research closely relates to both Lower Leg Dysfunction (LLD) and Lumbopelvic Hip Complex Dysfunction (LPHD) . The Overhead Squat Assessment (adapted from the National Academy of Sports Medicine) is a useful functional movement assessment to identify signs relating to both of these dysfunctions. The "knees in" sign is the sign that most directly relates to this research. The Overhead Squat Assessment includes modifications (heel lift) to differentiate if the knee valgus is being driven by dysfunction of the ankle and lower leg or the lumbopelvic hip complex to allow the human movement professional to prioritize the activities that will make up a corrective exercise plan.

Many previous research reviews on this site explore the details of specific mobilization and isolated activation techniques. Following activities designed to reduce the activity of certain muscles (namely for dynamic knee valgus the typical culprits may include gastrocnemius /soleus complex, the fibularis group, the TFL , the adductors , biceps femoris , quadratus lumborum ) and increase the activity of other muscles (usually the tibialis anterior , tibialis posterior , gluteus medius , gluteus maximus , hip external rotators , transverse abdominis ) the Brookbush Institute recommends the performance of full body integration activities. This research supports the use of "subsystem integration " activities designed to connect the extremities of the body to the trunk.

The videos below highlight information about the "knees in" sign in the Overhead Squat Assessment , as well as provide examples of subsystem integration activities, an essential component of any corrective exercise routine (assuming that isolated activated activities have been performed earlier in the sequence).

Intro to the Overhead Squat Assessment

Overhead Squat Assessment 6: Knees Bow In Breakdown

Review of Core Subsystems

Anterior Oblique Subsystem Integration (step up to chest press)

Posterior Oblique Subsystem Integration

Side Step and Step Up with Shoulder Series for Lateral Subsystem Integration

© 2015 Brent Brookbush

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