VOLUME TWELVE NUMBER FOUR

 
2017Masthead_V12N4_Cover

August 2017

ORIGINAL RESEARCH
The Dynamic Leap and Balance Test (DLBT): A Test-Retest Reliability Study.
Authors: Jaffri AH, Newman TM, Smith BI, Miller SJ
There is a need for new clinical assessment tools to test dynamic balance during typical functional movements. Common methods for assessing dynamic balance, such as the Star Excursion Balance Test, which requires controlled movement of body segments over an unchanged base of support, may not be an adequate measure for testing typical functional movements that involve controlled movement of body segments along with a change in base of support. The purpose of this study was to determine the reliability of the Dynamic Leap and Balance Test (DLBT) by assessing its test-retest reliability.  It was hypothesized that there would be no statistically significant differences between testing days in time taken to complete the test. Thirty healthy college aged individuals participated in this study. Participants performed a series of leaps in a prescribed sequence, unique to the DLBT test. Time required by the participants to complete the 20-leap task was the dependent variable. Subjects leaped back and forth from peripheral to central targets alternating weight bearing from one leg to the other. Participants landed on the central target with the tested limb and were required to stabilize for two seconds before leaping to the next target. Stability was based upon qualitative measures similar to Balance Error Scoring System. Each assessment was comprised of three trials and performed on two days with a separation of at least six days. A Two-way mixed ANOVA was used to analyze the differences in time to complete the sequence between the three trial averages of the two testing sessions. Intraclass Correlation Coefficient (ICC 3, 1) was used to establish between session test-retest reliability of the test trial averages. Significance was set a priori at p ≤0.05. No significant differences (p >0.05) were detected between the two testing sessions. The ICC was 0.93 with a 95% confidence interval from 0.84 to 0.96. The authors concluded that this test is a cost-effective, easy to administer, and clinically relevant novel measure for assessing dynamic balance that has excellent test-retest reliability. As a new measure of dynamic balance, the DLBT has the potential to be a cost-effective, challenging and functional tool for clinicians.
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Inter- and Intra-Rater Reliability of Performance Measures Collected with a Single-Camera Motion Analysis System.
Authors: Bates NA, McPherson AL, Berry JD, Hewett TE
Previous reliability investigations of single-camera three dimensional (3D) motion analysis systems have reported mixed results. The purpose of this study was to determine the intra- and inter-rater reliability of a single-camera 3D motion analysis system for subject standing height, vertical jump height, and broad jump length. Twelve subjects (age 20.6 ± 4.9 years) from a cohort that included high school to adult athletes who participated in sports at a recreational or competitive level entered and completed the study. Performance measurements were collected by a single-camera 3D motion analysis system and two human testers for standard clinical techniques. Inter- and intra-class correlation coefficients (ICC(2,k), ICC(2,1)) were determined. Intra-tester and inter-tester reliability were excellent (ICC ≥ 0.935) for single-camera system measured variables. Single-camera system measurements were slightly more reliable than clinical measurements for intra-tester ratings (ICC difference 0.020) for the standing broad jump. Single-camera system measurements were slightly less reliable than clinical measures for both intra- and inter-specimen standing height (mean ICC difference 0.003 and 0.043, respectively) and vertical jump height (mean ICC difference 0.017 and 0.036, respectively). The excellent reliability and previously demonstrated validity of the single-camera system along the anterior-posterior axis indicates that single-camera motion analysis may be a valid surrogate for clinically accepted manual measurements of performance in the horizontal plane. However, this single-camera 3D motion analysis system is likewise reliable, but inaccurate, for vertically oriented performance measurements.
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Validity of Athletic Task Performance Measures Collected with a Single-Camera Motion Analysis System as Compared to Standard Clinical Measurements.
Authors: McPherson AL, Berry JD, Bates, NA, Hewett TE
Previous investigations of single-camera 3D motion analysis camera systems validity have yielded mixed results for clinical applications. The purpose of this study was to determine the validity of a single-camera 3D motion analysis system for subject standing height, vertical jump height, and broad jump length. It was hypothesized that single-camera system values would demonstrate high correlation to the values obtained from accepted standard clinical measurements. Twelve subjects (age 20.6 ± 4.9 years) from a cohort that included high school to adult athletes who participate in sports at a recreational or competitive level entered and completed the study. Performance measurements for standing height, vertical jump height, and broad jump length were measured with standard clinical measurements and a single-camera 3D motion system. Single-camera system measurements were significantly different than clinical measures for standing height (p < 0.01) and vertical jump height (p < 0.01). There was no statistically significant difference between single-camera system measures and clinical measures for broad jump distance (p > 0.07). The relative performance of subjects was highly correlated between single-camera and clinical measurements (r2> 0.80).  Single-camera measurements lacked precision along the vertical axis of motion, but correlated well with clinically accepted measurements for standing height, broad jump length, and vertical jump height. The single-camera system may be capable of making accurate performance assessments in the horizontal plane, but should be limited to relative assessments along the vertical axis of motion. Additional refinement to increase the data reporting accuracy of the motion system along the vertical axis should be considered before relying on this single-camera 3D motion analysis system over clinical techniques to measure vertical jump and standing broad jump performances.
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Peak Hip Muscle Torque Measurements Are Influenced by Sagittal Plane Hip Position.
Authors: Bazett-Jones  DM, Tylinksi T, Krstic J, Stromquist A
An optimal position for strength testing of the hip musculature has not been identified. However, sagittal plane hip position during testing has been shown to influence hip external rotation strength.  The purpose of this study was to compare hip extension, external rotation, and abduction isometric torque at positions with differing degrees of hip flexion using a handheld dynamometer. Twenty-nine healthy and physically active females participated in this study. Peak isometric contractions were measured with a handheld dynamometer secured with a non-elastic strap and then converted to torque using segment lengths. Hip external rotation and extension were tested at 0°, 30°, and 90° of hip flexion. Hip abduction was tested at 0° and 30° of hip flexion and 5° of extension. Testing was randomized and counterbalanced. Repeated measures ANOVAs with Sidak’s test for multiple comparisons were used for statistical analysis. Significance was set at p<0.05. Significant main effects were found for hip extension (p<0.001) and external rotation (p<0.027), but not for abduction (p=0.085). Pairwise comparisons showed significant differences between all three testing positions for hip extension torque (0°v30°: p<0.001, 0°v90°: p<0.001, 30°v90°: p=0.002). Extension torque was highest in 90° of flexion (1.43±0.50 Nm/kg*m) and lowest in 0° of flexion (0.83±0.30 Nm/kg*m). Comparisons of hip external rotation torque tested at 0°v90° (p=0.096) and 30°v90° (p=0.080) were not significantly different but did have medium effect sizes. External rotation torque was highest in 90° of flexion (0.29±0.13 Nm/kg*m). Direct comparisons of torque values of hip extension and external rotation tested at different sagittal plane positions should be performed with caution due to differences. Hip extension and external rotation should be measured in consistent sagittal plane positions across examiners and testing sessions. Test position will be dependent upon the goals of strength testing.
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Building A Better Gluteal Bridge: Electromyographic Analysis of Hip Muscle Activity During Modified Single-Leg Bridges.
Authors: Lehecka BJ, Edwards M, Martin L, Porter K, Haverkamp R, Thatch K, Sack RJ, Hakansson NA
Gluteal strength plays a role in injury prevention, normal gait patterns, eliminating pain, and enhancing athletic performance. High gluteal muscle activity occurs during a single-leg bridge compared to other gluteal strengthening exercises; however, prior studies have primarily measured muscle activity with the active lower extremity starting in 90° of knee flexion with an extended contralateral knee. This standard position has caused reports of hamstring cramping, which may impede optimal gluteal strengthening. The purpose of this study was to determine which modified position for the single-leg bridge is best for preferentially activating the gluteus maximus and medius. Twenty-eight healthy males and females aged 18-30 years were tested in five different, randomized single-leg bridge positions. Electromyography (EMG) electrodes were placed on subjects’ gluteus maximus, gluteus medius, rectus femoris, and biceps femoris of their bridge leg (i.e., dominant or kicking leg), as well as the rectus femoris of their contralateral leg. Subjects performed a maximal voluntary isometric contraction (MVIC) for each tested muscle prior to performing five different bridge positions in randomized order. All bridge EMG data were normalized to the corresponding muscle MVIC data. A modified bridge position with the knee of the bridge leg flexed to 135° versus the traditional 90° of knee flexion demonstrated preferential activation of the gluteus maximus and medius compared to the traditional single-leg bridge. Hamstring activation significantly decreased (p = 0.05) when the dominant knee was flexed to 135° (23.49% MVIC) versus the traditional 90° (75.34% MVIC), while gluteal activation remained similarly high (51.01% and 57.81% MVIC in the traditional position, versus 47.35% and 57.23% MVIC in the modified position for the gluteus maximus and medius, respectively).  The authors concluded that modifying the traditional single-leg bridge by flexing the active knee to 135° instead of 90° minimizes hamstring activity while maintaining high levels of gluteal activation, effectively building a bridge better suited for preferential gluteal activation.
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Effects Of A Band Loop On Lower Extremity Muscle Activity And Kinematics During The BarBell Squat.
Authors: Foley R, Bullbrook B, Button DC, Holmes MWR
Medial knee collapse can indicate an underlying movement issue that, if uncorrected, can lead to a variety of knee injuries. Placing a band around the distal thigh may act as a proprioceptive aid to minimize medial collapse of the knee during squats; however, little is known about muscle activity and biomechanics in trained and untrained individuals during the squat with an elastic band added. To investigate the effects of the TheraBand® Band Loop on kinematics and muscle activity of the lower extremity during a standard barbell back squat at different intensities in both trained and untrained individuals. Sixteen healthy, male, university aged-participants were split into two groups of eight, consisting of a trained and untrained group. Participants performed both a 3-repetition maximum (3-RM) and a bodyweight load squat for repetitions to failure. Lower extremity kinematics and surface electromyography of four muscles were measured bilaterally over two sessions, an unaided squat and a band session (band loop placed around distal thighs). Medial knee collapse, measured as a knee width index, and maximum muscle activity were calculated. During the 3-RM, squat weight was unaffected by band loop intervention (p=0.486) and the trained group lifted more weight than the untrained group (p<0.007). The trained group had a greater squat depth for both squat conditions, regardless of the band (p=0.0043). Knee width index was not affected by the band during the eccentric phase of bodyweight squats in the trained (band: 0.76 ± 0.08, no band: 0.73 ± 0.08) or untrained group (band: 0.77 ± 0.70, no band: 0.75 ± 0.13) (p=0.670). During the concentric phase, knee width index was significantly lower for 3-RM squats, regardless of group. Despite minimal changes in kinematics for the untrained group, increased muscle activity with the band loop may suggest that a training aid may, over time, lead to an increase in barbell squat strength by increasing activation of agonist muscles more than traditional, un-banded squats. Greater maximal muscle activity in most muscles during band loop sessions may provide enhanced knee stability via increased activation of stabilizing muscles.
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A Biomechanical Comparison Among Three Kinds of Rebound-Type Jumps in Female Collegiate Athletes.
Authors: Nariai M, Yoshida N, Imai A, Ae K, Ogaki R, Suhara H, Shiraki H
Single-legged drop jumps (SDJ), single-legged repetitive jumps (SRJ), and single-legged side hops (SSH) are often used as plyometric training and functional performance tests. Differences in the kinetics and kinematic characteristics of lower extremity joints during these jumps are unclear. The purpose of this study was to investigate the joint motion and mechanical work of the takeoff leg from foot contact to foot-off during SDJ, SRJ, and SSH in the sagittal and frontal planes in female athletes. It was hypothesized that the joint motion and mechanical work of the lower extremity joints during the SDJ and SRJ would be larger than the SSH in the sagittal plane, those during the SSH would be larger than the SDJ and SRJ in the frontal plane, and during SRJ would be larger than SDJ. Seventeen female collegiate athletes participated and performed the SDJ (0.15-m box height), and SRJ and SSH (by crossing two lines 0.3 m apart). Three-dimensional coordinate data and ground reaction forces were collected. Contact time, jump height, jump index (i.e., the jump height divided by the contact time) of the SDJ and SRJ, and the total times of the SSH were calculated. Range of motion (ROM) from touchdown to the lowest center of mass, and the positive and negative (mechanical) work from touchdown to foot-off were analyzed. There were no significant differences in jump performance variables. Compared to the SSH, the SDJ and SRJ had significantly larger ankle and knee ROM and positive and negative work at the lower extremity joints, except for positive work at the hip joint, in the sagittal plane (p < 0.05). Compared to the SDJ and SRJ, the SSH had a significantly larger ankle ROM and positive work at the knee joint in the frontal plane (p < 0.05). Compared to the SDJ, the SRJ had a significantly larger ROM and negative work at each lower extremity joint in the frontal plane (p < 0.05).  Although there were no significant differences in the jump performance variables, different characteristics of the takeoff leg ROM and mechanical work were found between three kinds of rebound-type jump tests. These findings may help clinicians choose jump methods to assess lower extremity function and to design plyometric training programs in sports and clinical fields.
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Cadaveric Evaluation of the Lateral Anterior Drawer Test for Examining Posterior Cruciate Ligament Integrity.
Authors: Seeber GH, Wilhelm MP, Windisch G, Coriolano HJA, Matthijs OC, Sizer PS
Common clinical tests often fail to identify posterior cruciate ligament (PCL) ruptures, leading to undetected tears and potential degenerative changes in the knee. The lateral-anterior drawer (LAD) test has been proposed but not yet evaluated regarding its effectiveness for diagnosing PCL-ruptures. The purpose of this study was to establish whether the LAD test sufficiently detects changes in in-vitro tibial translation when the PCL is disrupted. It was hypothesized that the LAD would show greater tibial translation values in lateral-anterior direction in a PCL-Cut condition compared to a PCL-Intact condition, thus serving as a useful test for clinical diagnosis of PCL integrity. Threaded markers were inserted into the distal femur and proximal tibia in eighteen cadaveric knees. Each femur was stabilized and the tibia translated in lateral-anterior direction for the LAD test versus in a straight posterior direction for the posterior sag sign (PSS). Each test was repeated three times with the PCL both intact and then cut, in that order. During each trial, digital images were captured at start and finish positions for the evaluation of tibial marker displacement. Tibial marker translation during each trial was digitally analyzed using photography. The PSS values served as a reference standard. The LAD tibial translation was significantly greater (U=-3.680; p<0.002) during the PCL-Cut (10.6±5.6mm) versus PCL-Intact (7.7±5.1mm) conditions. The PSS tibial translation was significantly greater (U=-3.724; p<0.002) during the PCL-Cut (11.0±5.3mm) versus PCL-Intact (6.4±3.5mm) conditions. There was no significant difference (t=2.029; p=0.07) in mean tibial translation in respective directions after PCL dissection during the LAD test (2.9±2.1mm) versus the PSS test (4.6±2.8mm). The LAD test detected changes in cadaveric tibial translation corresponding with changes in PCL integrity to a degree at least as effective for assessing PCL integrity as the PSS. Further clinical study will be required to assess the utility of the LAD as a physical examination tool for diagnosing PCL injuries.
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Relationships Among Common Vision and Vestibular Tests in Healthy Recreational Athletes.
Authors: Heick JD, Bay C, Dompier TP, McLeod TCV
Disruption of the visual and vestibular systems is commonly observed following concussion. Researchers have explored the utility of screening tools to identify deficits in these systems in concussed patients, but it is unclear if these tests are measuring similar or distinct phenomena. The purpose of this study was to determine the relationships between common vestibular tests including the King-Devick (K-D) test, Sensory Organization Test (SOT), Head Shake-Sensory Organization Test (HS-SOT), and Dynamic Visual Acuity (DVA) test, when administered contiguously, to healthy recreational athletes aged 14 to 24 years. Sixty participants (30 males, 30 females; mean age, 19.9±3.74 years) completed the four tests in a single testing session. The results did not support a relationship between any pair of the K-D, SOT, HS-SOT, and DVA tests. Pearson correlations between tests were poor, ranging from 0.14 to 0.20. As expected the relationship between condition 2 of the SOT and HS-SOT fixed was strong (ICC=0.81) as well as condition 5 of the SOT with HS-SOT sway (ICC=0.78). The test-retest reliability of all four tests were evaluated to ensure the relationships of the four tests were consistent between test trials and reliability was excellent with intraclass correlations ranging from 0.79 to 0.97. The authors concluded that the lack of relationships in these tests is clinically important because it suggests that the tests evaluate different aspects of visual and vestibular function.  Further, these results suggest that a comprehensive assessment of visual and vestibular deficits following concussion may require a multifaceted assessment.
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Comparison of a Head Mounted Impact Measurement Device to the Hybrid III Anthropomorphic Testing Device in a Controlled Laboratory Setting.
Authors: Schussler E, Stark D, Bolte JH, Kang YS, Onate JA
Prior reports estimate that 1.6 to 3.8 million cases of concussion occur in sports and recreation each year in the United States. Despite continued efforts to reduce the occurrence of concussion, the rate of diagnosis continues to increase. The mechanisms of concussion are thought to involve linear and rotational head accelerations and velocities. One method of quantifying the kinematics experienced during sport participation is to place measurement devices into the athlete's helmet or directly on the athlete's head. The purpose of this research was to determine the accuracy of a head mounted device for measuring the head accelerations experienced by the wearer. This was accomplished by identifying the error in Peak Linear Acceleration (PLA), Peak Rotational Acceleration (PRA) and Peak Rotational Velocity (PRV) of the device. A helmeted Hybrid III 50th percentile male headform was impacted via a pneumatic ram from the front, side, rear, front oblique and rear oblique at speeds from 1.5 to 5 m/s. The X2 Biosystems xPatch® (Seattle, WA) sensor was placed on the headform's right side at the approximate location of the mastoid process. Measures of PLA, PRA, PRV from the xPatch ® and Hybrid III were analyzed for Root Mean Square Error (RMSE), and Absolute and Relative Error (AE, RE). Seventy-six impacts were analyzed.  All measures of correlation, fixed through the origin, were found to be strong: PLA R2=0.967 p<0.01, PRA R2=0.933 p<0.01, PRV R2=0.999 p<0.00.  PLA RMSE was 34%, RE 31.0%±14.0, and AE 31.1%±13.7. PRA RMSE was 23.4%, RE -6.7±22.4 and AE 18.9%±13.8. PRV RMSE was 2.2%, RE 0.1±2.2, and AE 1.8±1.3. The authors concluded that without including corrections for effect of skin artifact, the xPatch® produces measurements highly correlated with the gold standard yet above the average error of testing devices in both PLA and PRA, but a low error in PRV. PLA measures from the xPatch® system demonstrated a high level of correlation with the PLA data from the Hybrid III mounted data collection system.  
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Transversus Abdominis Elasticity During Various Exercises: A Shear Wave Ultrasound Elastography Study.
Authors: Hirayama K, Akagi R, Moniwa Y, Okada J, Takahashi H
Although the transversus abdominis (TrA) is considered to play a significant role in maintaining trunk stability, there is little information regarding the type of exercise that best facilitates the development of tension in the TrA. Muscle elasticity shows a strong association with muscle tension. Shear wave ultrasound elastography provides a means by which the tension of TrA can be noninvasively estimated, by quantifying it’s elasticity. The purpose of this study was to examine the TrA elasticity during several exercises as measured by shear wave ultrasound elastography, and to determine which of the studied exercises demonstrated the greatest tension. Ten healthy men performed abdominal hollowing, abdominal bracing, a hanging deadlift, elbow–toe plank with contralateral arm and leg lift, and back bridge with single leg lift. During these exercises, TrA elasticity was measured using ultrasound elastography. The same measurements were performed at rest before and after these exercises. No significant difference was found for rest conditions measured before and after the exercises (p = 0.63). Abdominal bracing showed a significantly higher elasticity value than the other exercises (p < 0.05), except for hanging deadlift. Among the exercises, the authors concluded that abdominal bracing was the exercise that elevated the TrA tension the most. The present results also suggested that hanging deadlift also produced comparably high TrA tension with abdominal bracing.
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The Comparison of the Lumbar Multifidus Muscles Function between Gymnastic
Athletes with Sway-Back Posture and Normal Posture.

Authors: Mahdavie E, Rezasoltani A, Simorgh L
The prevalence of sway back posture (SBP) is very high among elite gymnasts. This posture may be partly due to the improper function of lumbar multifidus muscles (LMM) as lumbar stabilizers muscles.  The aim of this study was to compare the thicknesses of LMM measured at rest and during the contraction elicited during an arm lift between elite gymnasts with SBP and normal posture. The participants consist of twenty gymnasts between the ages of 17 and 30 who had trained in gymnastics for more than ten years. They were assigned to two groups: SBP (n=10) and control (n=10). Posture analysis with grid paper and plumb line was performed for all subjects. The thickness of LMM on dominant side of spinal column was measured by a real-time ultrasound at five lumbar levels. The thickness of the LMM was measured both at rest and during the contraction elicited during an arm lift. The variation between the LMM thickness between the muscle at rest and muscle at the peak of contraction was regarded as LMM muscle function. The thickness of LMM was less in SBP group than the control group at all lumbar segments. The variation in LMM thickness between the state of rest and muscle contraction was significantly less in athletes with SBP than controls when compared at all levels of the lumbar spine (p < 0.05). The authors concluded that the function of LMM may be disturbed in athletes with SBP as demonstrated by decreased thicknesses of LMM found in gymnasts with SBP. Additionally, the thickness of the LMM as a strong antigravity and stabilizing muscle group was decreased during arm raising in gymnasts with SBP.
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Can Runners Perceive Changes In Heel Cushioning As The Shoe Ages With Increased Mileage?  
Authors: Cornwall MW, McPoil TG
For those runners who utilize footwear and have a rearfoot strike pattern, the durability of the midsole heel region has been shown to deteriorate as shoe mileage increases. The purpose of this study was threefold: 1) to determine if the runner can self-report changes in heel cushioning properties of the midsole after an extended period of distance running, 2) to determine if force and plantar pressures measured in the heel region of the midsole using a capacitance sensor insole change after running 640 km, and 3) to determine if a durometer could be used clinically to objective measure changes in the hardness of the material in the heel region of the midsole. Fifteen recreational runners voluntarily consented to participate and were provided with a new pair of running shoes. Each participant’s running style was observed and classified as having a rearfoot strike pattern. Inclusion criteria included running at least 24 km per week, experience running on a treadmill, no history of lower extremity congenital or traumatic deformity, or acute injury six months prior to the start of the study. The ability of each participant to self-perceive changes in shoe cushioning, comfort and fit was assessed using the Footwear Comfort Assessment Tool (FCAT). In-shoe plantar pressures and vertical forces were assessed using a capacitance sensor insole while runners ran over a 42-meter indoor runway. A Shore A durometer was used to measure the hardness of the midsole in the heel region. All measures were completed at baseline (zero km) and after running 160, 320, 480, and 640 km. In addition to descriptive statistics, a repeated measures analysis of variance was used to determine if the FCAT, pressures, forces, or midsole hardness changed because of increased running mileage. While plantar pressures and vertical forces were significantly reduced in the midsole heel region, none of the runners self-reported a significant reduction in heel cushioning based on FCAT scores after running 640 km. The use of a durometer provided an objective measure of the changes in the heel region of the midsole that closely matched the reductions observed in pressure and force values. The results indicated that runners who have a rearfoot strike pattern will have a 16% to 33% reduction in the amount of cushioning in the heel region of the midsole after running 480 km. Although there were significant reductions in heel cushioning, the experienced recreational runners in this study were not able to self-perceive these changes after running 640 km.  In addition, the use of a durometer provides a quick and accurate way to assess changes in the hardness of the heel region of the midsole as running mileage increases.
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There Are No Biomechanical Differences Between Groups Classified By The Functional Movement Screen.™
Authors: de Oliveira RR, Chaves SF, Lima YL, Bezerra A, Almeida GPL, Lima PO
Running has been one of the main choices of physical activity in people seeking an active lifestyle. The Functional Movement Screen (FMS™) is a screening tool that aims to discern movement competency.  The purposes of this study were to compare biomechanical characteristics between two groups rated using the composite FMS™ score, and to analyze the influence of specific individual tests. The hypothesis was that the group that scored above 14 would demonstrate better performance on biomechanical tests than the group that scored below 14. Runners were screened using the FMS™ and were dichotomized into groups based on final score: Functional, where the subjects scored a 14 or greater (G≥14, n=16) and dysfunctional, when the subjects scored less than 14 (G< 14, n=16). All runners were evaluated using measures for flexibility, postural balance, muscle strength, knee dynamic valgus during forward step down test and time for the electromyographic response of the transversus abdominis and fibularis longus muscles. All data were analyzed with SPSS (p≤0.05) and the index of asymmetry (IS) was calculated with the mean score of nondominant limb divided by the mean score of the dominant limb, multiplied by 100. There were no statistically significant differences in flexibility, muscle strength, knee dynamic valgus, or myoelectric response time of the transversus abdominis and long fibular muscles. Index of asymmetry (IS) of global stability was 3.26±26.79% in G≥14 and 31.72±52.69% in G<14 (p=0.02). In-line lunge and active straight-leg raise tests showed no significant difference between the groups (p>0.05). The authors concluded that overall, there were no biomechanical differences between the groups of runners as classified by the FMS™. In addition, in-line lunge and active strength-leg raise tests did not influence on the FMS™ final score.
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Running Injury Development: The Attitudes of Middle- and Long-Distance Runners and Their Coaches.
Authors: Johansen KK, Hulme A, Damsted C, Ramskov D, Nielsen RO
Behavioral science methods have rarely been used in running injury research. Therefore, the attitudes amongst runners and their coaches regarding factors leading to running injuries warrants formal investigation. The purpose of this study was to investigate the attitudes of middle- and long-distance runners able to compete in national championships and their coaches about factors associated with running injury development. A link to an online survey was distributed to middle- and long-distance runners and their coaches across 25 Danish Athletics Clubs. The main research question was: “Which factors do you believe influence the risk of running injuries?”. In response to this question, the athletes and coaches had to click “Yes” or “No” to 19 predefined factors. In addition, they had the possibility to submit a free-text response. A total of 68 athletes and 19 coaches were included in the study. A majority of the athletes (76% [95%CI: 66%; 86%]) and coaches (79% [95%CI: 61%; 97%]) reported “Ignoring pain” as a risk factor for running injury. A majority of the coaches reported “Reduced muscle strength” (79% [95%CI: 61%; 97%]) and “high running distance” (74% [95%CI: 54%; 94%]) to be associated with injury, while half of the runners found “insufficient recovery between running sessions” (53% [95%CI: 47%; 71%]) important. The authors concluded that runners and their coaches emphasize ignoring pain as a factor associated with injury development. The question remains how much running, if any at all, runners having slight symptoms or mild pain, are able to tolerate before these symptoms develop into a running-related injury.
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Cavitation Sounds During Cervicothoracic Spinal Manipulation.

Authors: Dunning J, Mourad F, Zingoni A, Iorio R, Perreault T, Zacharko N, de las Penas CF, Butts R, Cleland J
No study has previously investigated the size, duration or number of audible cavitation sounds during high-velocity low-amplitude (HVLA) thrust manipulation to the cervicothoracic spine. The primary purpose of this study was to determine which side of the spine cavitates during cervicothoracic junction (CTJ) HVLA thrust manipulation. Secondary aims were to calculate the average number of cavitations, the duration of cervicothoracic thrust manipulation, and the duration of a single cavitation. Thirty-two patients with upper trapezius myalgia received two cervicothoracic HVLA thrust manipulations targeting the right and left T1-2 articulation, respectively. Two high sampling rate accelerometers were secured bilaterally 25 mm lateral to midline of the T1-2 interspace. For each manipulation, two audio signals were extracted using Short-Time Fourier Transformation (STFT) and singularly processed via spectrogram calculation in order to evaluate the frequency content and number of instantaneous energy bursts of both signals over time for each side of the CTJ. Unilateral cavitation sounds were detected in 53 (91.4%) of 58 cervicothoracic HVLA thrust manipulations and bilateral cavitation sounds were detected in just five (8.6%) of the 58 thrust manipulations; that is, cavitation was significantly (p<0.001) more likely to occur unilaterally than bilaterally. In addition, cavitation was significantly (p<0.0001) more likely to occur on the side contralateral to the clinician’s short-lever applicator. The mean number of audible cavitations per manipulation was 4.35 (95% CI 2.88, 5.76). The mean duration of a single manipulation was 60.77 ms (95% CI 28.25, 97.42) and the mean duration of a single audible cavitation was 4.13 ms (95% CI 0.82, 7.46). In addition to single-peak and multi-peak energy bursts, spectrogram analysis also demonstrated high frequency sounds, low frequency sounds, and sounds of multiple frequencies for all 58 manipulations. Cavitation was significantly more likely to occur unilaterally, and on the side contralateral to the short-lever applicator contact, during cervicothoracic HVLA thrust manipulation. The authors concluded that clinicians should expect multiple cavitation sounds when performing HVLA thrust manipulation to the CTJ. Due to the presence of multi-peak energy bursts and sounds of multiple frequencies, the cavitation hypothesis (i.e. intra-articular gas bubble collapse) alone appears unable to explain all of the audible sounds during HVLA thrust manipulation, and the possibility remains that several phenomena may be occurring simultaneously.
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CASE STUDIES
Return to Running Following a Knee Disarticulation Amputation: A Case Report.
Authors: Diebal-Lee AR, Kuenzi RS, Rabago CA
The evolution of running-specific prostheses has empowered athletes with lower extremity amputations to run farther and faster than previously thought possible; but running with proper mechanics is still paramount to an injury-free, active lifestyle. The purpose of this case report was to describe the successful alteration of intact limb mechanics from a rearfoot striking (RFS) to a non-rearfoot striking (NRFS) pattern in an individual with a knee disarticulation amputation, the associated reduction in Average Vertical Loading Rate (AVLR), and the improvement in functional performance following the intervention.
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The Effects of a Multimodal Rehabilitation Program on Pain, Kinesiophobia and Function in a Runner with Patellofemoral Pain: A Case Report.
Authors: Passigli A, Capacci P, Volpi E
Multimodal interventions possess the strongest evidence in the long-term management of patellofemoral pain, but despite receiving evidence-based treatments that are initially effective, many patients report recurrent or persistent symptoms for years after the initial diagnosis. Untreated psychological factors could be a possible explanation for persistent symptoms and poor treatment outcome. The purpose of this case report was to describe and evaluate the effects of a multimodal rehabilitation program that included pain education, a graded program of lower limb strengthening, and running retraining on pain, kinesiophobia, and function in a runner with patellofemoral pain.
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CLINICAL COMMENTARY
A Four-Phase Physical Therapy Regimen for Returning Athletes to Sport Following Hip Arthroscopy for Femoroacetabular Impingement with Routine Capsular Closure.

Authors: Kuhns BD, Weber AE, Batko B, Nho SJ, Stegemann C
Hip preservation surgery has become more common over the past decade and is now a preferred treatment modality for an increasingly diverse array of pathology in the young, active patient with hip pain. In particular, hip arthroscopy has become an increasingly popular treatment choice for active patients diagnosed with femoroacetabular impingement (FAI). Appropriate postoperative rehabilitation is critical for overall patient success and optimal long-term outcome. As surgical techniques continue to evolve, rehabilitation protocols must adapt to accommodate changes in the surgical procedure and ultimately provide the safest and fastest recovery of function for the patient. One such surgical modification has been the incorporation of routine capsular closure as part of the treatment of FAI in the young, active patient. The purpose of this clinical commentary is to present a four-phase rehabilitation protocol for returning to sport following arthroscopic correction of FAI with routine capsular closure.
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Energy System Development and Load Management through the Rehabilitation and Return to Play Process.
Authors: Morrison S, Ward P, duManoir GR
Return-to-play from injury is a complex process involving many factors including the balancing of tissue healing rates with the development of biomotor abilities. This process requires interprofessional cooperation to ensure success. An often-overlooked aspect of return-to-play is the development and maintenance of sports specific conditioning while monitoring training load to ensure that the athlete’s training stimulus over the rehabilitation period is appropriate to facilitate a successful return to play. The purpose of this clinical commentary is to address the role of energy systems training as part of the RTP process. Additionally the aim is to provide practitioners with an overview of practical sports conditioning training methods and monitoring strategies to allow them to direct and quantify the return-to-play process.
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