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1.  EFFECT OF ATHLETIC TAPING AND KINESIOTAPING® ON MEASUREMENTS OF FUNCTIONAL PERFORMANCE IN BASKETBALL PLAYERS WITH CHRONIC INVERSION ANKLE SPRAINS 
Background:
Chronic inversion ankle sprains are common in basketball players. The effect of taping on functional performance is disputed in the literature. Kinesiotaping® (KT®) is a new method that is being used as both a therapeutic and performance enhancement tool. To date, it appears that no study has investigated the effect of ankle KT® on functional performance.
Purpose:
To investigate the effects of different types of taping (KT® using Kinesio Tex®, athletic taping) on functional performance in athletes with chronic inversion sprains of the ankle.
Study Design:
Crossover Study Design
Methods:
Fifteen male basketball players with chronic inversion ankle sprains between the ages of 18 and 22 participated in this study. Functional performance tests (Hopping test by Amanda et al, Single Limb Hurdle Test, Standing Heel Rise test, Vertical Jump Test, The Star Excursion Balance Test [SEBT] and Kinesthetic Ability Trainer [KAT] Test) were used to quantify agility, endurance, balance, and coordination. These tests were conducted four times at one week intervals using varied conditions: placebo tape, without tape, standard athletic tape, and KT®. One-way ANOVA tests were used to examine difference in measurements between conditions. Bonferroni correction was applied to correct for repeated testing.
Results:
There were no significant differences among the results obtained using the four conditions for SEBT (anterior p=0.0699; anteromedial p=0.126; medial p=0.550; posteromedial p=0.587; posterior p=0.754; posterolateral p=0.907; lateral p=0.124; anterolateral p=0.963) and the KAT dynamic measurement (p=0.388). Faster performance times were measured with KT® and athletic tape in single limb hurdle test when compared to placebo and non-taped conditions (Athletic taping- placebo taping: p=0.03; athletic taping- non tape p=0.016;KT®- Placebo taping p=0.042; KT®-Non tape p=0.016). In standing heel rise test and vertical jump test, athletic taping led to decreased performance. (Standing heel rise test: Athletic taping- placebo taping p=0.035; athletic taping- non tape p=0.043; athletic tape- KT® p<0.001) (Vertical jump test: Athletic taping- placebo taping p=0.002: athletic taping- non tape p=0.002; KT®- athletic tape p<0.001)
Conclusion:
Kinesiotaping® had no negative effects on a battery of functional performance tests and improvements were seen in some functional performance tests.
Clinical Relevance:
Ankle taping using Kinesio Tex® Tape did not inhibit functional performance.
PMCID: PMC3325641  PMID: 22530190
Chronic inversion ankle sprain; functional performance tests; Kinesiotaping
2.  Using the Star Excursion Balance Test to Assess Dynamic Postural-Control Deficits and Outcomes in Lower Extremity Injury: A Literature and Systematic Review 
Journal of Athletic Training  2012;47(3):339-357.
Context:
A dynamic postural-control task that has gained notoriety in the clinical and research settings is the Star Excursion Balance Test (SEBT). Researchers have suggested that, with appropriate instruction and practice by the individual and normalization of the reaching distances, the SEBT can be used to provide objective measures to differentiate deficits and improvements in dynamic postural-control related to lower extremity injury and induced fatigue, and it has the potential to predict lower extremity injury. However, no one has reviewed this body of literature to determine the usefulness of the SEBT in clinical applications.
Objective:
To provide a narrative review of the SEBT and its implementation and the known contributions to task performance and to systematically review the associated literature to address the SEBT's usefulness as a clinical tool for the quantification of dynamic postural-control deficits from lower extremity impairment.
Data Sources:
Databases used to locate peer-reviewed articles published from 1980 and 2010 included Derwent Innovations Index, BIOSIS Previews, Journal Citation Reports, and MEDLINE.
Study Selection:
The criteria for article selection were (1) The study was original research. (2) The study was written in English. (3) The SEBT was used as a measurement tool.
Data Extraction:
Specific data extracted from the articles included the ability of the SEBT to differentiate pathologic conditions of the lower extremity, the effects of external influences and interventions, and outcomes from exercise intervention and to predict lower extremity injury.
Data Synthesis:
More than a decade of research findings has established a comprehensive portfolio of validity for the SEBT, and it should be considered a highly representative, noninstrumented dynamic balance test for physically active individuals. The SEBT has been shown to be a reliable measure and has validity as a dynamic test to predict risk of lower extremity injury, to identify dynamic balance deficits in patients with a variety of lower extremity conditions, and to be responsive to training programs in both healthy people and people with injuries to the lower extremity. Clinicians and researchers should be confident in employing the SEBT as a lower extremity functional test.
PMCID: PMC3392165  PMID: 22892416
clinical balance; functional tests; dynamic balance tests; dynamic postural-control tasks
3.  Improving Functional Performance and Muscle Power 4-to-6 Months After Anterior Cruciate Ligament Reconstruction 
The purpose of this study was to examine the effects of 8-week retraining programs, with either two or three training sessions per week, on measures of functional performance and muscular power in athletes with anterior cruciate ligament reconstruction (ACLR). Sixteen male athletes were randomly assigned to two groups after ACLR: a functional training group (FTG, n = 8) training 2 intense sessions per week (4hrs/week), and a control group (CG, n = 8) training 3 sessions per week with moderate intensity (6hrs/week). The two groups were assessed at four and six months post-ACLR and the effects of retraining were measured using the following assessments: the functional and the muscular power tests, and the agility T-test. After retraining, the FTG had improved more than the CG in the operated leg in the single leg hop test (+34.64% vs. +10.92%; large effect), the five jump test (+8.87% vs. +5.03%; medium effect), and single leg triple jump (+32.15% vs. +16.05%; medium effect). For the agility T-test, the FTG had larger improvements (+17.26% vs. +13.03%, medium effect) as compared to the CG. For the bilateral power tests, no significant training effects were shown for the two groups in the squat jump (SJ), the counter movement jump (CMJ) and the free arms CMJ (Arm CMJ). On the other hand, the unilateral CMJ test with the injured and the uninjured legs showed a significant increase for the FTG with respect to CG (p < 0.05). The present study introduces a new training modality in rehabilitation after ACLR that results in good recovery of the operated limb along with the contra-lateral leg. This may allow the athletes to reach good functional and strength performance with only two physical training sessions per week, better preparing them for a return to sport activity at 6 months post- ACLR and eventually sparing time for a possible progressive introduction of the sport specific technical training.
Key pointsFunctional training (plyometrics, neuromuscular, proprioceptive and agility exercises) in athletes during 4th to 6th months post-ACLR further improved functional outcomes, compared to a conventional rehabilitation program.The former program was more time-efficient compared to the latter one as indicated by the weekly training duration (4hrs/week vs. 6hrs/week).This study provides evidence of the functional training in knee rehabilitation and provides important information that is highly relevant to clinicians, physiotherapists, coaches and trainers who are in charge of the injured athletes during the later phase of the rehabilitation after ACLR.
PMCID: PMC3761516  PMID: 24149555
ACL reconstruction; knee injury; retraining; agility; strength testing; power testing
4.  COMPARATIVE IMMEDIATE FUNCTIONAL OUTCOMES AMONG CRYOTHERAPEUTIC INTERVENTIONS AT THE ANKLE 
Purpose/Background:
There is a lack of evidence detailing the immediate effects of different cryotherapy interventions at the ankle on functional outcomes such as balance and jumping tasks in a physically active population; therefore, the purpose of the present study is to compare the immediate effects of varied modes of cryotherapy applications to the ankle joint on Star Excursion Balance Test and vertical jump height performance. The authors hypothesized that cryotherapy would acutely decrease performance when compared to a control, and that concomitant compression would further hinder outcomes.
Methods:
A crossover study was conducted in a controlled laboratory setting. Thirty (9 men, 21 women) participants (20.6 ± 1.0 years, 1.7 ± 0.1 m, 67.5 ± 11.7 kg) were enrolled. The independent variable was treatment mode; no ice, ice without compression and ice with compression. Dependent variables included center of pressure (COP) excursions, dynamic balance reach distances and vertical jump height for the dominant leg. Participants underwent three separate testing sessions separated by 72‐hour rest intervals. The order of treatment and performance measures was randomized to prevent order effects. Normalized dynamic balance reach distances were assessed using the reliable modified Star Excursion Balance Test (SEBT). Center of pressure path length was assessed via a force platform during a single‐legged static balance task under eyes‐open and eyes‐closed conditions. Relative vertical jump height was assessed using a single‐legged vertical hop test. Group means and standard deviations were calculated by treatment mode. One‐way analyses of variance with Tukey's post hoc test were used to calculate differences among treatment modes. p < 0.05 denoted statistical significance.
Results:
No statistically significant differences existed for all the performance measures among treatment modes.
Conclusions:
These findings suggest no immediate differences in lower extremity performance outcome measures between the respective treatment modes applied to the ankle in a young, healthy and physically active population. Additional investigation is warranted to study the related delayed effects of these interventions.
Levels of Evidence:
III
PMCID: PMC3867076  PMID: 24377069
Ankle; balance; cryotherapy; functional performance
5.  Landing Mechanics During Side Hopping and Crossover Hopping Maneuvers in Noninjured Women and Women With Anterior Cruciate Ligament Reconstruction 
Objective
To compare, landing mechanics and electromyographic activity of the lower extremities during side hopping and crossover hopping maneuvers, in noninjured women and women with anterior cruciate ligament (ACL) reconstruction.
Design
A case-control study.
Setting
A 3-dimensional motion analysis laboratory.
Participants
Twenty-eight young women (range, 21–35 years) (15 control subjects and 13 subjects with ACL reconstruction).
Patients and Methods
All participants performed a side-to-side hopping task that consisted of hopping single-legged 10 times consecutively from side to side across 2 lines marked 30 cm apart on 2 individual force plates. The task was designated as a side hopping when the hop was to the opposite side of the stance leg and as crossover hopping when the hop was toward the side of the stance leg.
Main Outcome Measurements
Peak hip-/knee-joint angles; peak knee extension/abduction joint moments; electromyographic studies of the gluteus maximus, gluteus medius, rectus femoris, and hamstring muscles; and quadriceps/hamstring co-contraction ratio were compared between the groups by means of 2 × 2 multivariate analysis of variance tests (group × maneuver).
Results
Noninjured women and women with ACL reconstruction exhibited similar hip-and knee-joint angles during both types of hopping. Hip-joint angles were greater during the crossover hopping in both groups, and knee-joint angles did not differ between the groups or hops. Knee-joint moments demonstrated a significant group × maneuver interaction. Greater knee extension and valgus moments were noted in the control group during crossover hopping, and greater knee abduction moments were noted in the ACL group during side hopping. Electromyographic data revealed no statistically significantly differences between the groups.
Conclusions
Women with ACL reconstruction exhibited the restoration of functional biomechanical movements such as hip-/knee-joint angles and lower extremity neuromuscular activation during side-to-side athletic tasks. However, not all biomechanical strategies are restored years after surgery, and women who have undergone a procedure such as ACL reconstruction may continue to exhibit knee-joint abduction moments that increase the risk of additional knee injury.
doi:10.1016/j.pmrj.2010.10.018
PMCID: PMC3087173  PMID: 21257128
6.  Efficacy of the Star Excursion Balance Tests in Detecting Reach Deficits in Subjects With Chronic Ankle Instability 
Journal of Athletic Training  2002;37(4):501-506.
Objective: Chronic instability after lateral ankle sprain has been shown to cause balance deficits during quiet standing. Although static balance assessment in those with ankle instability has been thoroughly examined in the literature, few researchers have studied performance on more dynamic tasks. Our purpose was to determine if the Star Excursion Balance Tests (SEBTs), lower extremity reach tests, can detect deficits in subjects with chronic ankle instability.
Design and Setting: We performed all testing in a university athletic training facility. We tested lower extremity reach using the SEBTs, which incorporates single-leg stance with maximal reach of the contralateral leg.
Subjects: Twenty subjects with unilateral, chronic ankle instability (age = 19.8 ± 1.4 years, height = 176.8 ± 4.5 cm, mass = 82.9 ± 21.2 kg) and 20 uninjured subjects matched by sex, sport, and position (age = 20.2 ± 1.4 years, height = 178.7 ± 4.1 cm, mass = 82.7 ± 19.9 kg).
Measurements: We measured the reach distances in centimeters (cm) and averaged 3 reaches in each of the 8 directions while the subjects stood on each leg for data analysis.
Results: The group with chronic ankle instability demonstrated significantly decreased reach while standing on the injured limb compared with the matched limb of the uninjured group (78.6 cm versus 82.8 cm). Additionally, subjects with chronic ankle instability reached significantly less when standing on their injured limbs as compared with their uninjured limbs (78.6 cm versus 81.2 cm).
Conclusions: The SEBTs appear to be an effective means for determining reach deficits both between and within subjects with unilateral chronic ankle instability.
PMCID: PMC164384  PMID: 12937574
functional reach; dynamic balance; postural control; ankle sprain
7.  Kinematic and Kinetic Reliability of Two Jumping and Landing Physical Performance Tasks in Young Adult Women 
Background
Jumping and landing tasks are commonly used functional measurement tools to assess lower extremity performance in female athletes. However, few studies have established the number of trials needed to achieve reliability of measurement for evaluating landing mechanics.
Objective
To determine the reliability of peak hip and knee joint angles and peak ground reaction forces during two anterior-posterior unilateral functional tasks performed by young women.
Methods
Sixteen young women (28.5 ± 4.2 years; 162.2 ± 4.8 cm; 59.5 ± 8.1 kg) participated in this investigation. Each participant performed five trials of a 40-cm single leg drop jump and two trials of a ten-repetition, 20-cm, single leg up-down hop task during the same session. Peak hip and knee joint angles, peak vertical ground reaction forces, and ground contact time were measured. Intraclass correlation coefficients (ICC), standard errors of measurement, and 95% confidence intervals were calculated for all variables measured during multiple trials for both tasks.
Results
The five-trial mean ICC values of the drop jump were ≥ 0.75 for all variables. The single and two to four-trial average ICC values yielded good reliability for only some variables. Single-trial and two-trial mean ICC values for the up down test were ≥ .77.
Discussion and Conclusion
The use of five-trial averages for the 40-cm drop jump and a single trial for the 20-cm, up-down hop task showed that for these functional tasks performed by young adult women, reliable measurement of lower extremity landing mechanics can be achieved.
PMCID: PMC2953289  PMID: 21522208
reliability; kinematics; landing; kinetics; hop test
8.  ASSOCIATIONS BETWEEN THREE CLINICAL ASSESSMENT TOOLS FOR POSTURAL STABILITY 
Study Design:
Clinical Measurement, Correlation, Reliability
Objectives:
To assess the relationship between the Single Leg Balance (SLB), modified Balance Error Scoring System (mBESS), and modified Star Excursion Balance (mSEBT) tests and secondarily to assess inter-rater and test-retest reliability of these tests.
Background:
Ankle sprains often result in chronic instability and dysfunction. Several clinical tests assess postural deficits as a potential cause of this dysfunction; however, limited information exists pertaining to the relationship that these tests have with one another.
Methods:
Two independent examiners measured the performance of 34 healthy participants completing the SLB Test, mBESS test, and mSEBT at two different time periods. The relationship between tests was assessed using the Pearson Correlation and Fisher's Exact Tests. Inter-rater and test-retest reliability were assessed using the intraclass correlation coefficient (ICC) and Kappa statistics.
Results:
A significant correlation (r = -0.35) was observed between the mSEBT and the mBESS. Fisher's Exact Test showed a significant association between the SLB Test and mBESS (P = .048), but no association between the SLB and mSEBT (P = 1.000). Inter-rater reliability was excellent for the mSEBT and fair for the mBESS (ICCs of .91 and .61 respectively). Excellent agreement was observed between raters for the SLB test (k = 1.00). Test-retest reliability was excellent for the mSEBT (ICC = 0.98) and fair for the mBESS (ICC = 0.74). There was poor test-retest agreement for the SLB test (k = .211).
Conclusion:
There was a significant relationship observed between the SLB Test, mBESS test, and mSEBT: however; strength of association measures showed limited overlap between these tests. This suggests that these tests are interrelated but may not assess equal components of postural stability.
PMCID: PMC2971643  PMID: 21589668
reliability; postural stability; star excursion balance test; single leg balance; balance error scoring system
9.  RELATIONSHIPS BETWEEN CORE STRENGTH, HIP EXTERNAL ROTATOR MUSCLE STRENGTH, AND STAR EXCURSION BALANCE TEST PERFORMANCE IN FEMALE LACROSSE PLAYERS 
Purpose/Background:
Female athletes have high rates of lower extremity (LE) injuries. Core strength (CS) and hip external rotator (HER) strength have been suggested to be factors that influence LE injury risk. Better balance has also been shown to decrease LE injury risk. Still, little research has examined whether core strength and hip muscle strength can influence LE balance. Therefore the purpose of the current study was to examine the relationships between core strength, hip ER strength and lower extremity balance as measured by the Star Excursion Balance Test (SEBT).
Methods:
CS was examined via the bent knee lowering test (BKLT) (grades 1‐5). Hip external rotator (HER) strength was measured singularly (HERL and HERR and combined (HERCOM) assessed via hand held dynamometry (reported in Newtons), and balance assessed via the SEBT expressed as % leg length, bilaterally in the postero‐medial, postero‐lateral, anterior directions and as a combined score (SEBTCOM). All outcomes were assessed in 45 female lacrosse players (16.0 ± 5.9 yrs, 65.1 ± 2.4 cm, 57.3 ± 7.4 kgs, experience=5.9 ± 2.9 yrs). Pearson product‐moment correlations examined relationships between the BKLT, HER and SEBT. Linear regression analyses examined possible influences of CS and HER on balance (p ≤ .05).
Results:
SEBTCOM was not correlated with BKLT [r(45)=–.20, p=.18] or HERCOM [r(45)=.20, p=.18]. There was no correlation between HER strength and CS (BKLT) [r(45)=.20, p=.20]. Overall scores on the BKLT were not correlated with any of the three balance SEBT scores. HERL [r(45)=.36, p=.02] and HERR [r(45)=.30, p=.05] were moderately positively correlated with left posteromedial SEBT direction. HERCOM and BKLT did not predict overall SEBTCOM balance scores (r2=.068, p=.23).
Conclusions:
BKLT scores and combined HER strength did not correlate with LE balance, as measured by the SEBT, in female lacrosse players. However, HER strength of both the left and right LE's (singularly) was moderately correlated with scores on one reach direction (left posteromedial) but not with combined SEBT scores. Researchers should continue to examine whether core and hip muscles influence LE balance.
Level of Evidence:
2b
PMCID: PMC3625788  PMID: 23593547
Balance; bent knee lowering test; hand held dynamometry; transversus abdominis
10.  Validity and inter-rater reliability of medio-lateral knee motion observed during a single-limb mini squat 
Background
Muscle function may influence the risk of knee injury and outcomes following injury. Clinical tests, such as a single-limb mini squat, resemble conditions of daily life and are easy to administer. Fewer squats per 30 seconds indicate poorer function. However, the quality of movement, such as the medio-lateral knee motion may also be important. The aim was to validate an observational clinical test of assessing the medio-lateral knee motion, using a three-dimensional (3-D) motion analysis system. In addition, the inter-rater reliability was evaluated.
Methods
Twenty-five (17 women) non-injured participants (mean age 25.6 years, range 18-37) were included. Visual analysis of the medio-lateral knee motion, scored as knee-over-foot or knee-medial-to-foot by two raters, and 3-D kinematic data were collected simultaneously during a single-limb mini squat. Frontal plane 2-D peak tibial, thigh, and knee varus-valgus angles, and 3-D peak hip internal-external rotation, and knee varus-valgus angles were calculated.
Results
Ten subjects were scored as having a knee-medial-to-foot position and 15 subjects a knee-over-foot position assessed by visual inspection. In 2-D, the peak tibial angle (mean 89.0 (SE 0.7) vs mean 86.3 (SE 0.4) degrees, p = 0.001) and peak thigh angle (mean 77.4 (SE 1.0) vs mean 81.2 (SE 0.5) degrees, p = 0.001) with respect to the horizontal, indicated that the knee was more medially placed than the ankle and thigh, respectively. Thus, the knee was in more valgus (mean 11.6 (SE 1.5) vs 5.0 (SE 0.8) degrees, p < 0.001) in subjects with the knee-medial-to-foot than in those with a knee-over-foot position. In 3-D, the hip was more internally rotated in those with a knee-medial-to-foot than in those with a knee-over-foot position (mean 10.6 (SE 2.1) vs 4.8 (SE 1.8) degrees, p = 0.049), but there was no difference in knee valgus (mean 6.1 (SE 1.8) vs mean 5.0 (SE 1.2) degrees, p = 0.589). The kappa value and percent agreement, respectively, was >0.90 and 96 between raters.
Conclusions
Medio-lateral motion of the knee can reliably be assessed during a single-leg mini-squat. The test is valid in 2-D, while the actual movement, in 3-D, is mainly exhibited as increased internal hip rotation. The single-limb mini squat is feasible and easy to administer in the clinical setting and in research to address lower extremity movement quality.
doi:10.1186/1471-2474-11-265
PMCID: PMC2998461  PMID: 21080945
11.  Fatigue-Induced Alterations of Static and Dynamic Postural Control in Athletes With a History of Ankle Sprain 
Journal of Athletic Training  2013;48(2):203-208.
Context:
Sensorimotor control is impaired after ankle injury and in fatigued conditions. However, little is known about fatigue-induced alterations of postural control in athletes who have experienced an ankle sprain in the past.
Objective:
To investigate the effect of fatiguing exercise on static and dynamic balance abilities in athletes who have successfully returned to preinjury levels of sport activity after an ankle sprain.
Design:
Cohort study.
Setting:
University sport science research laboratory.
Patients or Other Participants:
30 active athletes, 14 with a previous severe ankle sprain (return to sport activity 6–36 months before study entry; no residual symptoms or subjective instability) and 16 uninjured controls.
Intervention(s):
Fatiguing treadmill running in 2 experimental sessions to assess dependent measures.
Main Outcome Measure(s):
Center-of-pressure sway velocity in single-legged stance and time to stabilization (TTS) after a unilateral jump-landing task (session 1) and maximum reach distance in the Star Excursion Balance Test (SEBT) (session 2) were assessed before and immediately after a fatiguing treadmill exercise. A 2-factorial linear mixed model was specified for each of the main outcomes, and effect sizes (ESs) were calculated as Cohen d.
Results:
In the unfatigued condition, between-groups differences existed only for the anterior-posterior TTS (P = .05, ES = 0.39). Group-by-fatigue interactions were found for mean SEBT (P = .03, ES = 0.43) and anterior-posterior TTS (P = .02, ES = 0.48). Prefatigue versus postfatigue SEBT and TTS differences were greater in previously injured athletes, whereas static sway velocity increased similarly in both groups.
Conclusions:
Fatiguing running significantly affected static and dynamic postural control in participants with a history of ankle sprain. Fatigue-induced alterations of dynamic postural control were greater in athletes with a previous ankle sprain. Thus, even after successful return to competition, ongoing deficits in sensorimotor control may contribute to the enhanced ankle reinjury risk.
doi:10.4085/1062-6050-48.1.08
PMCID: PMC3600922  PMID: 23672384
sensorimotor control; neuromuscular activity; copers; balance; time to stabilization; Star Excursion Balance Test
12.  Neuromuscular Training Improves Performance on the Star Excursion Balance Test in Young Female Athletes 
STUDY DESIGN
Controlled cohort repeated-measures experimental design.
OBJECTIVES
To determine if a neuromuscular training program (NMTP) focused on core stability and lower extremity strength would affect performance on the star excursion balance test (SEBT). We hypothesized that NMTP would improve SEBT performance in the experimental group and there would be no side-to-side differences in either group.
BACKGROUND
The SEBT is a functional screening tool that is used to assess dynamic stability, monitor rehabilitation progress, assess deficits following an injury, and identify athletes at high risk for lower extremity injury. The SEBT requires lower extremity coordination, balance, flexibility, and strength.
METHODS
Twenty uninjured female soccer players (13 experimental, 7 control) participated. Players trained together as a team, so group allocation was not randomized. The SEBT was administered prior to and following 8 weeks of NMTP in the experimental group and 8 weeks of no NMTP in the control group. A 3-way mixed-model ANOVA was used to determine the effect of group (experimental versus control), training (pretraining versus posttraining), and limb (right versus left).
RESULTS
After participation in a NMTP, subjects demonstrated a significant improvement in the SEBT composite score (mean ± SD) on the right limb (pretraining, 96.4% ± 11.7%; posttraining, 104.6% ± 6.1%; P = .03) and the left limb (pretraining, 96.9% ± 10.1%; posttraining, 103.4% ± 8.0%; P = .04). The control group had no change on the SEBT composite score for the right (pretraining, 95.7% ± 5.2%; posttraining, 94.4% ± 5.2%; P = .15) or the left (97.4% ± 7.2%; 93.6% ± 5.0%; P = .09) limb. Further analysis identified significant improvement for the SEBT in the posterolateral direction on both the right (P = .008) and left (P = .040) limb and the posteromedial direction of the left limb (P = .028) in the experimental group.
CONCLUSION
Female soccer players demonstrated an improved performance on the SEBT after NMTP that focused on core stability and lower extremity strength.
LEVEL OF EVIDENCE
Performance enhancement, level 2b-.
doi:10.2519/jospt.2010.3325
PMCID: PMC3439814  PMID: 20710094
core stability; core strengthening; injury prevention training; trunk neuromuscular control
13.  Intrarater Reliability of Functional Performance Tests for Subjects With Patellofemoral Pain Syndrome 
Journal of Athletic Training  2002;37(3):256-261.
Objective: Patellofemoral pain syndrome (PFPS) is a common clinical entity seen by the sports medicine specialist. The ultimate goal of rehabilitation is to return the patient to the highest functional level in the most efficient manner. Therefore, it is necessary to assess the progress of patients with PFPS using reliable functional performance tests. Our purpose was to evaluate the intrarater reliability of 5 functional performance tests in patients with PFPS.
Design and Setting: We used a test-retest reliability design in a clinic setting.
Subjects: Two groups of subjects were studied: those with PFPS (n = 29) and those with no known knee condition (n = 11). The PFPS group included 19 women and 10 men with a mean age of 27.6 ± 5.3 years, height of 169.80 ± 10.5 cm, and weight of 69.59 ± 15.8 kg. The normal group included 7 women and 4 men with a mean age of 30.3 ± 5.2 years, height of 169.55 ± 9.9 cm, and weight 69.42 ± 14.6 kg.
Measurements: The reliability of 5 functional performance tests (anteromedial lunge, step-down, single-leg press, bilateral squat, balance and reach) was assessed in 15 subjects with PFPS. Secondly, the relationship of the 5 functional tests to pain was assessed in 29 PFPS subjects using Pearson product moment correlations. The limb symmetry index (LSI) was calculated in the 29 PFPS subjects and compared with the group of 11 normal subjects.
Results: The 5 functional tests proved to have fair to high intrarater reliability. Intrarater reliability coefficients (ICC 3,1) ranged from .79 to .94. For the PFPS subjects, a statistical difference existed between limbs for the anteromedial lunge, step-down, single-leg press, and balance and reach. All functional tests correlated significantly with pain except for the bilateral squat; values ranged from .39 to .73. The average LSI for the PFPS group was 85%, while the average LSI for the normal subjects was 97%.
Conclusions: The 5 functional tests proved to have good intrarater reliability and were related to changes in pain. Future research is needed to examine interrater reliability, validity, and sensitivity of these clinical tests.
PMCID: PMC164353  PMID: 12937582
step-down; squat; limb symmetry; knee
14.  The Reliability of an Instrumented Device for Measuring Components of the Star Excursion Balance Test 
Background
The Star Excursion Balance Test (SEBT) is a dynamic test that requires strength, flexibility, and proprioception and has been used to assess physical performance, identify chronic ankle instability, and identify athletes at greater risk for lower extremity injury. In order to improve the repeatability in measuring components of the SEBT, the Y Balance Test™ has been developed.
Objective
The purpose of this paper is to report the development and reliability of the Y Balance Test™.
Methods
Single limb stance excursion distances were measured using the Y Balance Test™ on a sample of 15 male collegiate soccer players. Intraclass Correlation Coefficients (ICC) were used to determine the reliability of the test.
Results
The ICC for intrarater reliability ranged from 0.85 to 0.91 and for interrater reliability ranged from 0.99 to 1.00. Composite reach score reliability was 0.91 for intrarater and 0.99 for interrater reliability.
Discussion
This study demonstrated that the Y Balance Test™ has good to excellent intrarater and interrater reliability. The device and protocol attempted to address the common sources of error and method variation in the SEBT including whether touch down is allowed with the reach foot, where the stance foot is aligned, movement allowed of the stance foot, instantaneous measurement of furthest reach distance, standard reach height from the ground, standard testing order, and well defined pass/fail criteria.
Conclusion
The Y Balance Test™ is a reliable test for measuring single limb stance excursion distances while performing dynamic balance testing in collegiate soccer players.
PMCID: PMC2953327  PMID: 21509114
Y Balance Test; lower extremity; postural stability
15.  THE EFFECT OF KINESIO® TAPE ON VERTICAL JUMP AND DYNAMIC POSTURAL CONTROL 
Introduction and Background:
Ankle injuries are one of the most common injuries among physically active individuals. The role of prophylactic ankle taping and bracing has been studied extensively. Kinesio® Tape (KT) is a somewhat new type of taping technique gaining popularity as both treatment and performance enhancement tool. However, there is limited research on the effect of KT on functional performance.
Purpose:
The purpose of this study was to determine whether the application of Kinesio Tex® Tape had an effect on vertical jump and dynamic postural control in healthy young individuals.
Methods:
52 healthy subjects free of ankle or lower extremity problems (28 males and 24 females; age: 22.12±2.08 years; height: 170.77±8.69 cm; weight: 69.90±12.03 kg) participated in the study. Subjects were randomly assigned to either the experimental group (KT with tension) or the control group (KT without tension). Vertical jump was measured using the VertiMetric device and dynamic postural control was assessed using the Star Excursion Balance Test (SEBT) under three conditions: (1) without taping; (2) immediately after taping; (3) 24 hours after taping with the taping remaining in situ.
Results:
Three-way repeated measure ANOVA was conducted in order to identify differences between the experimental and the control group during the three conditions. Overall, there were no differences between groups in vertical jump maximum height, vertical jump average height, or the SEBT scores for the three time periods (pre-test, post-test, 24hrs-post-test). However, the main effect of KT was moderated by a significant gender interaction, resulting in a statistically significant effect of KT for the SEBT scores in the posterior-medial direction, F(1.72, 82.57) = 4.50, p = 0.018 and the medial direction, F(1.75, 83.81) = 4.27, p = 0.021. Follow-up analyses indicated that female subjects in the KT group had increased SEBT scores between three time periods when compared to the placebo group.
Discussion:
KT application on the ankle neither decreased nor increased vertical jump height in healthy non-injured young individuals, but did increase dynamic postural control in females for certain directions. Additional study is warranted using different measures of balance to further investigate the effect of KT on dynamic postural control.
Level of Evidence:
2b
PMCID: PMC3812836  PMID: 24175126
Dynamic postural control; Kinesio taping; vertical jump
16.  Patellar Taping, Patellofemoral Pain Syndrome, Lower Extremity Kinematics, and Dynamic Postural Control 
Journal of Athletic Training  2008;43(1):21-28.
Context: Patellar taping has been a part of intervention for treatment of patellofemoral pain syndrome (PFPS). However, research on the efficacy of patellar taping on lower extremity kinematics and dynamic postural control is limited.
Objective: To evaluate the effects of patellar taping on sagittal-plane hip and knee kinematics, reach distance, and perceived pain level during the Star Excursion Balance Test (SEBT) in individuals with and without PFPS.
Design: Repeated-measures design with 2 within-subjects factors and 1 between-subjects factor.
Setting: The University of Toledo Athletic Training Research Laboratory.
Patients or Other Participants: Twenty participants with PFPS and 20 healthy participants between the ages of 18 and 29 years.
Intervention(s): The participants performed 3 reaches of the SEBT in the anterior direction under tape and no-tape conditions on both legs.
Main Outcome Measure(s): The participants' hip and knee sagittal-plane kinematics were measured using the electromagnetic tracking system. Reach distance was recorded by hand and was normalized by dividing the distance by the participants' leg length (%MAXD). After each taping condition on each leg, the participants rated the perceived pain level using the 10-cm visual analog scale.
Results: The participants with PFPS had a reduction in pain level with patellar tape application compared with the no-tape condition (P = .005). Additionally, participants with PFPS demonstrated increased %MAXD under the tape condition compared with the no-tape condition, whereas the healthy participants demonstrated decreased %MAXD with tape versus no tape (P = .028). No statistically significant differences were noted in hip flexion and knee flexion angles.
Conclusions: Although patellar taping seemed to reduce pain and improve SEBT performance of participants with PFPS, the exact mechanisms of these phenomena cannot be explained in this study. Further research is warranted to investigate the effect of patellar taping on neuromuscular control during dynamic postural control.
PMCID: PMC2231393  PMID: 18335009
anterior knee pain; McConnell taping
17.  The Relationship Between Maximum Unilateral Squat Strength and Balance in Young Adult Men and Women 
The purpose of this study was to determine the relationship between unilateral squat strength and measures of static balance to compare balance performance between the dominant and non-dominant leg. Seventeen apparently healthy men (mean mass 90.5 ± 20.9 kg and age 21.7 ± 1.8 yrs) and 25 women (mean mass 62.2 ± 14.5 kg and age 21.9 ± 1.3 yrs) completed the study. Weight bearing unilateral strength was measured with a 1RM modified unilateral squat on the dominant and non-dominant leg. The students completed the stork stand and wobble board tests to determine static balance on the dominant and non-dominant leg. Maximum time maintained in the stork stand position, on the ball of the foot with the uninvolved foot against the involved knee with hands on the hips, was recorded. Balance was measured with a 15 second wobble board test. No significant correlations were found between the measurements of unilateral balance and strength (r values ranged between -0.05 to 0.2) for the men and women. Time off balance was not significantly different between the subjects’ dominant (men 1.1 ± 0.4 s; women 0.3 ± 0.1 s) and non-dominant (men 0.9 ± 0.3 s; women 0.3 ± 0.1 s) leg for the wobble board. Similar results were found for the time balanced during the stork stand test on the dominant (men 26.4 ± 6.3 s; women 24.1 ± 5.6 s) and non-dominant (men 26.0 ± 5.7 s; women 21.3 ± 4.1 s) leg. The data indicate that static balance and strength is unrelated in young adult men and women and gains made in one variable after training may not be associated with a change in performance of the other variable. These results also suggest that differences in static balance performance between legs can not be determined by leg dominance. Similar research is needed to compare contralateral leg balance in populations who participate in work or sport activities requiring repetitive asymmetrical use. A better understanding of contralateral balance performance will help practitioners make evaluative decisions during the rehabilitation process.
Key Points1RM unilateral squat strength is unrelated to measures of unilateral static balance in young adult men and womenStatic balance is similar between the dominant and non-dominant leg in young adult men and womenSide-to-side differences in balance warrant assessment and training to correct imbalances prior to participation in activities that present a high risk for injury.
PMCID: PMC3827570  PMID: 24260001
Single-leg strength; closed kinetic chain; unilateral balance; resistance exercise
18.  Lower Limb Kinematics and Dynamic Postural Stability in Anterior Cruciate Ligament-Reconstructed Female Athletes 
Journal of Athletic Training  2013;48(2):172-185.
Context:
Deficits in lower limb kinematics and postural stability are predisposing factors to the development of knee ligamentous injury. The extent to which these deficits are present after anterior cruciate ligament (ACL) reconstruction is still largely unknown.
The primary hypothesis of the present study was that female athletes who have undergone ACL reconstruction and who have returned to sport participation would exhibit deficits in dynamic postural stability as well as deficiencies in hip- and knee-joint kinematics when compared with an age-, activity-, and sex-matched uninjured control group.
Objective:
To investigate dynamic postural stability as quantified by the Star Excursion Balance Test (SEBT) and simultaneous hip- and knee-joint kinematic profiles in female athletes who have undergone ACL reconstruction.
Design:
Descriptive laboratory study.
Setting:
University motion-analysis laboratory.
Patients or Other Participants:
Fourteen female athletes who had previously undergone ACL reconstruction (ACL-R) and 17 age- and sex-matched uninjured controls.
Intervention(s):
Each participant performed 3 trials of the anterior, posterior-medial, and posterior-lateral directional components of the SEBT.
Main Outcome Measure(s):
Reach distances for each directional component were quantified and expressed as a percentage of leg length. Simultaneous hip- and knee-joint kinematic profiles were recorded using a motion-analysis system.
Results:
The ACL-R group had decreased reach distances on the posterior-medial (P < .01) and posterior-lateral (P < .01) directional components of the SEBT. During performance of the directional components of the SEBT, ACL-R participants demonstrated altered hip-joint frontal-, sagittal-, and transverse-plane kinematic profiles (P < .05), as well as altered knee-joint sagittal-plane kinematic profiles (P < .05).
Conclusions:
Deficits in dynamic postural stability and concomitant altered hip- and knee-joint kinematics are present after ACL reconstruction and return to competitive activity. The extent to which these deficits influence potential future injury is worthy of investigation.
doi:10.4085/1062-6050-48.2.05
PMCID: PMC3600919  PMID: 23672381
anterior cruciate ligament; reconstruction; kinematics; postural stability
19.  Immediate Effects of Lumbopelvic Manipulation and Lateral Gluteal Kinesio Taping on Unilateral Patellofemoral Pain Syndrome 
Sports Health  2013;5(3):214-219.
Objectives:
To determine the immediate effects of Kinesio taping directed to the hip and manipulation directed to the lumbopelvic region in individuals with unilateral patellofemoral pain syndrome (PFPS).
Background:
PFPS affects up to 25% of the general population. Despite the high prevalence, this condition is not clearly understood, as evidenced by the numerous proposed causes and recommended treatments. Notwithstanding, recent evidence suggests that treatments directed at the hip or spine may lead to beneficial results.
Methods:
A convenience sample of 18 participants (12 men and 6 women, 19.5 ± 1.15 years old) with unilateral PFPS was recruited. Participants were randomized by sex to 1 of 3 groups: Kinesio taping, manipulation, and control taping. The main outcome measures included the Y-balance test, squatting range of motion (ROM), and the Lower Extremity Functional Scale.
Results:
Compared with the lumbopelvic manipulation and control groups, those in the Kinesio taping group performed significantly better on the Y-balance test (F = 5.59, P = 0.02) and with squatting ROM (F = 3.93, P = 0.04). The Kinesio taping and lumbopelvic groups were also significantly better than the control (sham) group with double-leg squatting ROM performance 3 days later.
Conclusion:
Kinesio taping may facilitate gluteus medius activation and improve postural stability and a double-leg squat.
Clinical Relevance:
The improvement in affected limb reach and double-leg squatting ROM highlights the potential for Kinesio taping to improve gluteus medius activation. Lumbopelvic manipulation may also immediately improve rehabilitation programs for PFPS.
doi:10.1177/1941738112473561
PMCID: PMC3658409  PMID: 24427391
patellofemoral pain; Kinesio tape; lumbopelvic manipulation; Y-balance
20.  RELIABILITY AND VALIDITY OF FUNCTIONAL PERFORMANCE TESTS IN DANCERS WITH HIP DYSFUNCTION 
Study Design:
Quasi-experimental, repeated measures.
Purpose/Background:
Functional performance tests that identify hip joint impairments and assess the effect of intervention have not been adequately described for dancers. The purpose of this study was to examine the reliability and validity of hop and balance tests among a group of dancers with musculoskeletal pain in the hip region.
Methods:
Nineteen female dancers (age: 18.90±1.11 years; height: 164.85±6.95 cm; weight: 60.37±8.29 kg) with unilateral hip pain were assessed utilizing the cross-over reach, medial triple hop, lateral triple hop, and cross-over hop tests on two occasions, 2 days apart. Test-retest reliability and comparisons between the involved and uninvolved side for each respective test were determined.
Results:
Intra-class correlation coefficients for the functional performance tests ranged from 0.89-0.96. The cross-over reach test had a SEM of 2.79 cm and a MDC of 7.73 cm. The medial and lateral triple hop tests had SEM values of 7.51 cm and 8.17 cm, and MDC values of 20.81 cm and 22.62 cm, respectively. The SEM was 0.15 seconds and the MDC was 0.42 seconds for the cross-over hop test. Performance on the medial triple hop test was significantly less on the involved side (370.21±38.26 cm) compared to the uninvolved side (388.05±41.49 cm); t(18) = −4.33, p<0.01. The side-to-side comparisons of the cross-over reach test (involved mean=61.68±10.9 cm; uninvolved mean=61.69±8.63 cm); t(18) = −0.004, p=0.99, lateral triple hop test (involved mean=306.92±35.79 cm; uninvolved mean=310.68±24.49 cm); t(18) = −0.55, p=0.59, and cross-over hop test (involved mean=2.49±0.34 seconds; uninvolved mean= 2.61±0.42 seconds; t(18) = −1.84, p=0.08) were not statistically different between sides.
Conclusion:
The functional performance tests used in this study can be reliably performed on dancers with unilateral hip pain. The medial triple hop test was the only functional performance test with evidence of validity in side-to-side comparisons. These results suggest that the medial triple hop test may be a reliable and valid functional performance test to assess impairments related to hip pain among dancers.
Level of Evidence:
3b. Non-consecutive cohort study
PMCID: PMC3812843  PMID: 24175123
Hop test; reach test; reliability; validity
21.  Functional and Neuromuscular Changes in the Hamstrings After Drop Jumps and Leg Curls 
The purpose of this study was to use a holistic approach to investigate changes in jumping performance, kinaesthesia, static balance, isometric strength and fast stepping on spot during a 5-day recovery period, following an acute bout of damaging exercise consisted of drop jumps and leg curls, where specific emphasis was given on the hamstring muscles. Eleven young healthy subjects completed a series of highly intensive damaging exercises for their hamstring muscles. Prior to the exercise, and during the 5-day recovery period, the subjects were tested for biochemical markers (creatine kinase, aspartate aminotransferase, and lactate dehydrogenase), perceived pain sensation, physical performance (squat jump, counter movement jump, maximal frequency leg stamping, maximal isometric torque production and maximally explosive isometric torque production), kinaesthesia (active torque tracking) and static balance. We observed significant decreases in maximal isometric knee flexion torque production, the rate of torque production, and majority of the parameters for vertical jump performance. No alterations were found in kinaesthesia, static balance and fast stepping on spot. The highest drop in performance and increase in perceived pain sensation generally occurred 24 or 48 hours after the exercise. Damaging exercise substantially alters the neuromuscular functions of the hamstring muscles, which is specifically relevant for sports and rehabilitation experts, as the hamstrings are often stretched to significant lengths, in particular when the knee is extended and hip flexed. These findings are practically important for recovery after high-intensity trainings for hamstring muscles.
Key PointsHamstring function is significantly reduced following specifically damaging exercise.It fully recovers 120 hours after the exercise.Prevention of exercise-induced muscle damage is cruicial for maintaining normal training regime.
PMCID: PMC3772585  PMID: 24149148
Isometric strength; stamping; balance; kinaesthesia; DOMS; EIMD
22.  Jump Kinetic Determinants of Sprint Acceleration Performance from Starting Blocks in Male Sprinters 
The purpose of this research was to identify the jump kinetic determinants of sprint acceleration performance from a block start. Ten male (mean ± SD: age 20 ± 3 years; height 1.82 ± 0.06 m; weight 76.7 ± 7.9 kg; 100 m personal best: 10.87 + 0.36 s {10.37 - 11.42}) track sprinters at a national and regional competitive level performed 10 m sprints from a block start. Anthropometric dimensions along with squat jump (SJ), countermovement jump (CMJ), continuous straight legged jump (SLJ), single leg hop for distance, and single leg triple hop for distance measures of power were also tested. Stepwise multiple regression analysis identified CMJ average power (W/kg) as a predictor of 10 m sprint performance from a block start (r = 0.79, r2 = 0.63, p<0.01, SEE = 0.04 (s), %SEE = 2.0). Pearson correlation analysis revealed CMJ force and power (r = -0.70 to -0.79; p = 0.011 - 0.035) and SJ power (r = -0.72 to -0.73; p = 0.026 - 0.028) generating capabilities to be strongly related to sprint performance. Further linear regression analysis predicted an increase in CMJ average and peak take-off power of 1 W/kg (3% & 1.5% respectively) to both result in a decrease of 0.01 s (0.5%) in 10 m sprint performance. Further, an increase in SJ average and peak take-off power of 1 W/kg (3.5% & 1.5% respectively) was predicted to result in a 0.01 s (0.5%) reduction in 10 m sprint time. The results of this study seem to suggest that the ability to generate power both elastically during a CMJ and concentrically during a SJ to be good indicators of predicting sprint performance over 10 m from a block start.
Key PointsThe relative explosive ability of the hip and knee extensors during a countermovement jump can predict 10 m sprint performance from a block start.The relative power outputs of male competitive sprinters during a squat jump can predict 10 m sprint performance from a block start.
PMCID: PMC3827579  PMID: 24260010
Anthropometry; horizontal jumps; sprint performance; vertical jumps
23.  Validity and Reliability of Nintendo Wii Fit Balance Scores 
Journal of Athletic Training  2012;47(3):306-313.
Context:
Interactive gaming systems have the potential to help rehabilitate patients with musculoskeletal conditions. The Nintendo Wii Balance Board, which is part of the Wii Fit game, could be an effective tool to monitor progress during rehabilitation because the board and game can provide objective measures of balance. However, the validity and reliability of Wii Fit balance scores remain unknown.
Objective:
To determine the concurrent validity of balance scores produced by the Wii Fit game and the intrasession and intersession reliability of Wii Fit balance scores.
Design:
Descriptive laboratory study.
Setting:
Sports medicine research laboratory.
Patients or Other Participants:
Forty-five recreationally active participants (age  =  27.0 ± 9.8 years, height  =  170.9 ± 9.2 cm, mass  =  72.4 ± 11.8 kg) with a heterogeneous history of lower extremity injury.
Intervention(s):
Participants completed a single-limb–stance task on a force plate and the Star Excursion Balance Test (SEBT) during the first test session. Twelve Wii Fit balance activities were completed during 2 test sessions separated by 1 week.
Main Outcome Measure(s):
Postural sway in the anteroposterior (AP) and mediolateral (ML) directions and the AP, ML, and resultant center-of-pressure (COP) excursions were calculated from the single-limb stance. The normalized reach distance was recorded for the anterior, posteromedial, and posterolateral directions of the SEBT. Wii Fit balance scores that the game software generated also were recorded.
Results:
All 96 of the calculated correlation coefficients among Wii Fit activity outcomes and established balance outcomes were interpreted as poor (r < 0.50). Intrasession reliability for Wii Fit balance activity scores ranged from good (intraclass correlation coefficient [ICC]  =  0.80) to poor (ICC  =  0.39), with 8 activities having poor intrasession reliability. Similarly, 11 of the 12 Wii Fit balance activity scores demonstrated poor intersession reliability, with scores ranging from fair (ICC  =  0.74) to poor (ICC  =  0.29).
Conclusions:
Wii Fit balance activity scores had poor concurrent validity relative to COP outcomes and SEBT reach distances. In addition, the included Wii Fit balance activity scores generally had poor intrasession and intersession reliability.
PMCID: PMC3392161  PMID: 22892412
center of pressure; Star Excursion Balance Test; interactive gaming; rehabilitation
24.  Lower extremity joint kinetics and lumbar curvature during squat and stoop lifting 
Background
In this study, kinematics and kinetics of the lower extremity joint and the lumbar lordosis during two different symmetrical lifting techniques(squat and stoop) were examined using the three-dimensional motion analysis.
Methods
Twenty-six young male volunteers were selected for the subjects in this study. While they lifted boxes weighing 5, 10 and 15 kg by both squat and stoop lifting techniques, their motions were captured and analyzed using the 3D motion analysis system which was synchronized with two forceplates and the electromyographic system. Joint kinematics was determined by the forty-three reflective markers which were attached on the anatomical locations based on the VICON Plug-in-Gait marker placement protocol. Joint kinetics was analyzed by using the inverse dynamics. Paired t-test and Kruskal-Wallis test was used to compare the differences of variables between two techniques, and among three different weights. Correlation coefficient was calculated to explain the role of lower limb joint motion in relation to the lumbar lordosis.
Results
There were not significant differences in maximum lumbar joint moments between two techniques. The hip and ankle contributed the most part of the support moment during squat lifting, and the knee flexion moment played an important role in stoop lifting. The hip, ankle and lumbar joints generated power and only the knee joint absorbed power in the squat lifting. The knee and ankle joints absorbed power, the hip and lumbar joints generated power in the stoop lifting. The bi-articular antagonist muscles' co-contraction around the knee joint during the squat lifting and the eccentric co-contraction of the gastrocnemius and the biceps femoris were found important for maintaining the straight leg during the stoop lifting. At the time of lordotic curvature appearance in the squat lifting, there were significant correlations in all three lower extremity joint moments with the lumbar joint. Differently, only the hip moment had significant correlation with the lumbar joint in the stoop lifting.
Conclusion
In conclusion, the knee extension which is prominent kinematics during the squat lifting was produced by the contributions of the kinetic factors from the hip and ankle joints(extensor moment and power generation) and the lumbar extension which is prominent kinematics during the stoop lifting could be produced by the contributions of the knee joint kinetic factors(flexor moment, power absorption, bi-articular muscle function).
doi:10.1186/1471-2474-10-15
PMCID: PMC2651112  PMID: 19183507
25.  Osteoarthritis and meniscus disorders of the knee as occupational diseases of miners 
Aim: To determine whether kneeling or squatting for prolonged periods is sufficiently causally associated with an increased risk of injury or degenerative disease of the knee joint as to meet the classic criteria to be considered an occupational disease of coal miners for whom these are or have been routine working postures.
Method: Systematic literature searches were made for studies relating to kneeling and squatting as part of the working environment of coal mines and the role of these postures in causation of knee disorders in coal miners, analogous occupations, populations, and communities. The working environment and potentially damaging forces on the knee when kneeling or squatting were described. Papers on the incidence or prevalence of knee disorders in occupational and other groups were scored against five criteria independently by each author, and from this a single consensus score representing the overall strength of evidence given by the research was awarded. The evidence was then weighed against the criteria for an occupational disease.
Results: Nineteen published papers were scored, the majority of which focussed on osteoarthritis as the outcome of interest. Few of the studies found focussed specifically on miners, and those that did tended to involve small numbers of subjects and were carried out before 1960, when the mining population was at its largest but epidemiological evidence of the risk factors for knee disorders was not well established. The non-mining studies in the review represent groups of workers with a similar or lesser kneeling content in their work.
Conclusion: The papers reviewed provide sufficient evidence to conclude that work involving kneeling and/or squatting is causally associated with an increased risk of osteoarthritis of the knee. In some of the more recent epidemiologically sound studies, frequent or prolonged kneeling or squatting doubles the general risk of osteoarthritis of the knees found in the general population. This may be of particular importance in welfare and medico-legal situations. There was also evidence to suggest that lifting, in combination with kneeling/squatting, an activity also performed by miners in the course of their work, is associated with an excess risk of osteoarthritis above that attributed to kneeling/squatting alone.
doi:10.1136/oem.2004.017137
PMCID: PMC1741064  PMID: 16046610

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