Clinical tests predictive of temporary low back pain development during the prolonged standing test in physical therapy students.

Low back pain among physical therapists is a common musculoskeletal disorder that first occurs early in their career or as a student. This observational prospective study assessed the ability of hip and lumbopelvic neuromuscular control, endurance and hip range of motion tests to predict the development of transient low back pain development during a standing task. Seventy-two physical therapy students without low back pain completed nine performance tests and a 2-hour standing test on two separate days. Participants were classified as transient pain developers (PD) if they reported a ≥ 10mm increase in low back pain on a visual analog scale. Transient back pain was reported by 37.5% of students during the standing test. A cluster of three positive tests, self-rated active hip abduction (somewhat difficult or more), bilateral total hip internal rotation greater than 81 degrees, and non-dominant limb single-leg squat (moderate deviations), demonstrated an increased probability (94.9%) of identifying PDs. Negative findings on the same three tests decreased the probability to 10.7%. Overall, the classification accuracy for the three-test model was 72.2%. The sensitivity for the model was 63% and the specificity was 77.8%.

A 3-test cluster of poor hip and lumbopelvic neuromuscular control and increased hip internal rotation range of motion is an effective screening tool for identifying physical therapy students who are most likely and least likely to develop transient LBP during 2 hours of standing.

Is Real-Time Poolside Assessment of Upper Limb Errors in Front Crawl Swimming Technique Reliable and Equivalent to Video Analysis?

CONTEXT: Swimming technique is widely believed to influence performance, but this relationship has rarely been tested objectively using a real-time poolside assessment. OBJECTIVE: To determine the (1) test-retest reliability, interrater reliability, and criterion validity (live vs video) of real-time poolside assessment of upper limb (UL) errors in front crawl (FC) swimming technique and (2) the relationship between UL errors and FC swimming performance. DESIGN: Cross-sectional reliability, validity, and correlational study. SETTING: Swim team practice at a college natatorium. PARTICIPANTS: Thirty-nine Division III college swimmers (21 women and 18 men, age = 19 [1] y, swimming experience = 11 [3] y). MAIN OUTCOME MEASURES: Seven UL errors in FC swimming technique, many of which involved unnecessary vertical and mediolateral motions, were assessed in real time from outside the pool during swim practice. Test-retest reliability, interrater reliability, and criterion validity were calculated using Cohen kappa (κ) and weighted kappa (κw). Swimming performance was determined by the participants' best FC events relative to the conference records. The correlation between total UL errors and FC swimming performance was assessed with Pearson r. RESULTS: Cohen κ and κw were moderate for the majority of errors, with the following ranges: 0.46 to 0.90 (test-retest), -0.01 to 1.00 (interrater), and 0.36 to 0.66 (criterion validity). There was a significant correlation between total UL errors and FC swimming performance: r(24) = -.59 (P = .001, R2 = .35). CONCLUSIONS: Reliability and validity were moderate for the majority of errors. The fewer UL errors swimmers made while practicing FC, the faster their best FC race times tended to be relative to the conference record. UL errors in FC swimming technique explained 35% of the variance in performance.

Intrinsic Risk Factors for Noncontact Musculoskeletal Injury in Collegiate Swimmers: A Prospective Cohort Study.

CONTEXT: Shoulder pain is pervasive in swimmers of all ages. However, given the limited number of prospective studies, injury risk factors in swimmers remain uncertain. OBJECTIVE: To determine the extent to which the risk factors of previous injury, poor movement competency, erroneous freestyle swimming technique, and low perceived susceptibility to sport injury were associated with noncontact musculoskeletal injury in collegiate swimmers. DESIGN: Prospective cohort study. SETTING: College natatorium. PATIENTS OR OTHER PARTICIPANTS: Thirty-seven National College Athletic Association Division III swimmers (21 females, 16 males; median age = 19 years [interquartile range = 3 years], height = 175 ± 10 cm; mass = 70.0 ± 10.9 kg). MAIN OUTCOME MEASURE(S): Participants completed preseason questionnaires on their previous injuries and perceived susceptibility to sport injury. At the beginning of the season, they completed the Movement System Screening Tool and the Freestyle Swimming Technique Assessment. Logistic regression was used to calculate odds ratios (ORs) with 95% CIs for the association between each risk factor and injury. RESULTS: Eleven of the 37 participants (29.7%) sustained an injury. Univariate analyses identified 2 risk factors: previous injury (OR = 8.89 [95% CI = 1.78, 44.48]) and crossover hand positions during the freestyle entry phase (OR = 8.50 [95% CI = 1.50, 48.05]). After adjusting for previous injury, we found that a higher perceived percentage chance of injury (1 item from the Perceived Susceptibility to Sport Injury) decreased the injury odds (adjusted OR = 0.11 [95% CI = 0.02, 0.82]). Poor movement competency was not associated with injury (P > .05). CONCLUSIONS: Previous injury, a crossover hand-entry position in freestyle, and a low perceived percentage chance of injury were associated with increased injury odds. Ascertaining injury histories and assessing for crossover positions may help identify swimmers with an elevated injury risk and inform injury-prevention strategies.

Workload and Noncontact Musculoskeletal Injury in Collegiate Swimmers: A Prospective Cohort Study.

CONTEXT: Swimmers are known for experiencing high training loads and a high incidence of overuse injuries, but few researchers have investigated the relationship between the two at the collegiate level. OBJECTIVE: To determine the association between workload and noncontact musculoskeletal injury in collegiate swimmers. DESIGN: Prospective cohort study. SETTING: College natatorium. PATIENTS OR OTHER PARTICIPANTS: A total of 37 National Collegiate Athletic Association Division III swimmers, 26 uninjured (age = 19 years [interquartile range = 3 years], height = 175 ± 11 cm, mass = 70.2 ± 10 kg) and 11 injured (age = 19 years [interquartile range = 3 years], height = 173 ± 9 cm, mass = 69.4 ± 13.5 kg) individuals. MAIN OUTCOME MEASURE(S): Logistic regression using generalized estimating equations was conducted to calculate odds ratios (ORs) with 95% CIs for injury relative to high workloads and high acute:chronic workload ratio (ACWRs). Injury rates for several ranges of workloads and ACWRs were also calculated. RESULTS: A total of 11 participants (29.7%) sustained 12 injuries, with 7 injuries occurring during the participants' winter training trip. Injury was associated with high acute workloads (OR = 27.1; 95% CI = 8.2, 89.8) and high ACWRs (OR = 25.1; 95% CI = 7.7, 81.4) but not high chronic (OR = 2.6; 95% CI = 0.3, 20.0) or overall (OR = 1.00; 95% CI = 0.99, 1.01) workloads. High acute workloads (>37.2 km/wk) and ACWRs (>1.56) increased the injury rate from ≤1% to 15% and 14%, respectively, compared with all lower acute workloads and ACWRs. CONCLUSIONS: Collegiate swimmers tolerated high workloads spread out during the season. However, caution should be used when prescribing high acute workloads and high ACWRs (eg, winter training trip) because of the increased odds of injury.

Comparison of core neuromuscular control and lower extremity postural stability in athletes with and without shoulder injuries.

BACKGROUND: The kinetic chain theory is widely used as a rationale for the inclusion of core stability training in athletes. Core stability (muscle capacity and neuromuscular control) impairments may result in less than optimal performance and abnormal force dissipation to the shoulder complex that could lead to shoulder injuries. However, a paucity of literature exists to support this relationship, and no previous studies have investigated the relationship between isolated core neuromuscular control and shoulder injuries. Additionally, lower extremity postural stability has been associated with athletic function and may also be associated with shoulder injuries. The purpose of this study was to compare biomechanical measures of isolated core neuromuscular control and lower extremity postural stability between athletes with and without non-traumatic shoulder injuries. METHODS: Eighty athletes (55 males, age: 21.2 ± 3.3 years, 40 with a current shoulder injury) completed biomechanical measures of isolated core neuromuscular control and lower extremity postural stability. Athletes were matched by age, gender, body mass index, and sport type. MANOVAs were used to assess differences between measures of core neuromuscular control and lower extremity postural stability between groups. FINDINGS: There were no statistically significant differences between athletes with and without shoulder injuries for the static core neuromuscular control measures, F(4,75) = 0.45, P = 0.78, η2 = 0.02; dynamic core neuromuscular control measures, F(4,75) = 0.81, P = 0.52, η2 = 0.04; or lower extremity postural stability measures, F(8,61) = 0.85, P = 0.56, η2 = 0.10. INTERPRETATION: Although core stability is widely incorporated in rehabilitation of athletes with shoulder injuries, athletes with current non-traumatic shoulder injuries may not present with impairments in core neuromuscular control or lower extremity postural stability.

Comprehensive movement system screening tool (MSST) for athletes: Development and measurement properties.

OBJECTIVES: Non-traumatic extremity injuries are particularly common in sports, representing a significant economic, academic, and psychosocial burden on athletes. Proposed musculoskeletal risk factors for increased injury and decreased performance in athletes include movement pattern inefficiency, decreased regional stability, decreased mobility, and asymmetrical movement. The Movement System Screening Tool (MSST) is a comprehensive screening tool designed to assess these factors. Thus, the purpose of this study was to describe the development and determine the content and construct validity and inter-rater reliability of the MSST. METHODS: A modified Delphi panel of experts determined content validity. 80 athletes (40 with and 40 without a current non-traumatic shoulder injury) completed 21 clinical tests, with exploratory factor analysis and known group analysis performed to determine construct validity. Two independent raters were used to establish individual item and composite score inter-rater reliability. RESULTS: Exploratory factor analysis identified three of the four apriori constructs over 7 factors (14 tests), representing 63% of the variance. Known group analysis revealed a significantly lower composite score in athletes with vs. without a current non-traumatic shoulder injury (56.9±5.8 vs. 62.7±4.5, respectively). A preliminary cut score of 62 was chosen with sensitivity of 85% and specificity of 44%. Composite score inter-rater reliability was excellent ICC (2,1)=0.94, 95% CI (0.91, 0.96) and item reliability ranged from κ=.57 to 1.00. CONCLUSIONS: The MSST possesses constructs representative of injury risk and measurement properties acceptable for use in clinical settings. Comprehensive screens with construct validity and known measurement error are needed not only to identify athletes at risk of injury, but also provide an instrument that can be used in studies that seek to validate training approaches proposed to change movement impairment and injury risk in athletes.

Individuals With and Without Low Back Pain Use Different Motor Control Strategies to Achieve Spinal Stiffness During the Prone Instability Test.

BACKGROUND: The prone instability test is used to identify individuals with low back pain (LBP) who would benefit from trunk stabilization exercises. Although activity from muscles during the leg-raising portion of the prone instability test theoretically enhances spinal stiffness and reduces pain, evidence for this is lacking. OBJECTIVES: To compare and contrast (1) pain and stiffness changes between prone instability testing positions, and (2) muscle activation patterns during the prone instability test leg raise in individuals with and without LBP. METHODS: Participants with (n = 10) and without (n = 10) LBP participated in this laboratory case-control study. Spinal stiffness was measured using a beam-bending model and 3-D kinematic data. Stiffness changes were compared across the test positions and between groups. Surface electromyographic data were collected on trunk and limb musculature. Principal-component analysis was used to extract muscle synergies. RESULTS: Spinal stiffness increased across testing positions in all participants (P<.05). Participants with LBP experienced reduced pain during the test (P<.001). No between-group difference was found in spinal stiffness during leg raising during the test (P>.05). Participants without LBP used 3 muscle synergies during the leg raise and participants with LBP used 2 muscle synergies. CONCLUSION: Spinal stiffness increased in all participants; however, participants without LBP demonstrated a muscle synergy pattern where each synergy was associated with a distinct function of the prone instability test. Participants with LBP used a more global stabilization pattern, which may reflect a maladaptive method of enhancing spinal stability. J Orthop Sports Phys Ther 2019;49(12):899-907. Epub 3 Aug 2019. doi:10.2519/jospt.2019.8577.

Intra- and Interrater Reliability and Concurrent Validity of a New Tool for Assessment of Breast Cancer-Related Lymphedema of the Upper Extremity.

OBJECTIVE: The goal of this study was to develop and assess intra- and interrater reliability and validity of a clinical evaluation tool for breast cancer-related lymphedema, for use in the context of outcome evaluation in clinical trials. DESIGN: Blinded repeated measures observational study. SETTING: Outpatient research laboratory. PARTICIPANTS: Breast cancer survivors with and without lymphedema (N=71). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The assessment of intraclass correlation coefficients (ICCs) for the Breast Cancer-Related Lymphedema of the Upper Extremity (CLUE) standardized clinical evaluation tool. RESULTS: Intrarater reliability for the CLUE tool was ICC: 0.88 (95% confidence interval [95% CI], 0.71-0.96). Interrater reliability for the CLUE tool was ICC: 0.90 (95% CI, 0.79-0.95). Concurrent validity of the CLUE score (Pearson r) was 0.79 with perometric interlimb difference and 0.53 with the Norman lymphedema overall score. CONCLUSIONS: The CLUE tool shows excellent inter- and intrarater reliability. The overall CLUE score for the upper extremity also shows moderately strong concurrent validity with objective and subjective measures. This newly developed clinical, physical assessment of upper extremity lymphedema provides standardization and a single score that accounts for multiple constructs. Next steps include evaluation of sensitivity to change, which would establish usefulness to evaluate intervention efficacy.

COMPARISON OF CORE STABILITY AND BALANCE IN ATHLETES WITH AND WITHOUT SHOULDER INJURIES.

BACKGROUND: Relationships between core stability and lower extremity injuries have been described in the literature; however, evidence of the relationship between upper extremity injuries and core stability and balance is limited. HYPOTHESIS/PURPOSE: The purpose of this study was to compare clinical measures of core stability and balance between athletes with and without non-traumatic shoulder injuries. STUDY DESIGN: Cross sectional. METHODS: Eighty athletes (54 males, age: 21.2 + 3.3 years) participated in this study. Forty athletes with a current shoulder injury were matched to healthy athletes by age, gender, BMI, and sport. Athletes completed clinical core stability tests including flexor and extensor endurance tests, double leg lower test (°) and balance tests including single leg stance under eyes open and eyes closed conditions, and the Y-balance test. MANOVAs were used to assess group differences. RESULTS: No statistically significant differences existed between athletes with and without shoulder injuries for clinical tests of core stability, F(1,78)=0.97, p=0.41; η2 = 0.04. No statistically significant differences existed between injured athletes with and without shoulder injuries for static and dynamic balance measures, F(1,78)=0.86, p=0.53; η2 = 0.07. CONCLUSIONS: Although core stability is widely incorporated in rehabilitation of athletes with shoulder injuries, performance on these clinical tests did not differ in the group of athletes assessed in this study. LEVEL OF EVIDENCE: 3.

Pectoralis minor muscle elongation and scapulothoracic motion do not differ in individuals with short versus typical resting pectoralis minor muscle length: a cross-sectional study.

BACKGROUND: Individuals with short resting pectoralis minor muscle length have been shown to have aberrant scapulothoracic motion when compared to individuals with long resting pectoralis minor muscle length. However, the degree to which the pectoralis minor muscle can be lengthened and whether or not scapulothoracic motion differs between individuals with short and typical resting pectoralis minor muscle length is unknown. OBJECTIVES: To determine if: (1) pectoralis minor muscle elongation (percent pectoralis minor muscle can be actively and passively lengthened beyond resting length), (2) pectoralis minor muscle percent length change during overhead reaching, and (3) scapulothoracic motion during overhead reaching differ between individuals with short and typical resting pectoralis minor muscle length. DESIGN: Two group comparison. METHODS: Thirty healthy individuals were placed into a short or typical resting pectoralis minor muscle length group. A caliper was used to measure resting pectoralis minor muscle length and pectoralis minor muscle length during active and passive muscle lengthening. An electromagnetic tracking system was used to measure pectoralis minor muscle length change as well as scapular, humeral, and trunk motion during several arm elevation tasks. Pectoralis minor muscle elongation and length change during arm elevation tasks were compared between groups using independent t-tests. Two-factor mixed-model analyses of variance were used to compare scapulothoracic motion at arm elevation angles of 30°, 60°, 90°, and 120°. RESULTS: Pectoralis minor muscle elongation and pectoralis minor muscle length change during arm elevation did not differ between groups. Scapulothoracic motion did not differ between groups across arm elevation tasks. CONCLUSIONS: Although resting pectoralis minor muscle length differed between groups, pectoralis minor muscle lengthening and scapulothoracic motion were similar between participants with short and typical resting pectoralis minor muscle length. Additional studies are needed to better understand the role of pectoralis minor muscle elongation on scapulothoracic motion.

Agreement of Musculoskeletal Ultrasound and Clinical Assessment of Shoulder Impairment in Manual Wheelchair Users With Various Duration of Spinal Cord Injury.

OBJECTIVES: To determine (1) agreement of musculoskeletal ultrasound (MSK-US) findings of shoulder pathology and related shoulder special test results in individuals with varied durations of manual wheelchair (MWC) use after spinal cord injury (SCI); and (2) whether shoulder musculoskeletal impairments, per MSK-US and clinical examination, differed in individuals with SCI and varying durations of MWC use. DESIGN: Cross-sectional cohort study. SETTING: Laboratory setting. PARTICIPANTS: Adult volunteers (N=23) with SCI who used an MWC for community mobility. Individuals were stratified into 3 groups based on duration of MWC use: <5 years, 5 to 15 years, and >15 years. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Special tests for shoulder impingement and bicipital tendonitis were performed. Bilateral shoulder MSK-US was performed, with the Ultrasound Shoulder Pathology Rating Scale (USPRS) quantifying biceps tendon, supraspinatus tendon, and greater tuberosity cortical surface impairments. RESULTS: No agreement was found between MSK-US and related special tests. Special tests failed to identify impairment in 33.3% to 100% of those identified on MSK-US. The total USPRS score was highest in those with >15 years' MWC use. A higher proportion of dynamic impingement (supraspinatus and biceps) was found in those with >15 years' MWC use, with other MSK-US items having moderate effect sizes among duration-use groups. CONCLUSIONS: MSK-US identified shoulder impairments more frequently than commonly used special tests. A significant increase in the presence of MSK-US shoulder impairments was identified in the longest-duration group. This was not the case for special tests or pain. MSK-US is an easily administered, low-cost, noninvasive method for determining shoulder impairments and should be used in routine screening of individuals who use an MWC after SCI.

Intratester Reliability and Construct Validity of a Hip Abductor Eccentric Strength Test.

CONTEXT: Side-lying hip abductor strength tests are commonly used to evaluate muscle strength. In a "break" test, the tester applies sufficient force to lower the limb to the table while the patient resists. The peak force is postulated to occur while the leg is lowering, thus representing the participant's eccentric muscle strength. However, it is unclear whether peak force occurs before or after the leg begins to lower. OBJECTIVES: To determine intrarater reliability and construct validity of a hip abductor eccentric strength test. DESIGN: Intrarater reliability and construct validity study. PARTICIPANTS: Twenty healthy adults (26 [6] y; 1.66 [0.06] m; 62.2 [8.0] kg) made 2 visits to the laboratory at least 1 week apart. MAIN OUTCOME MEASURES: During the hip abductor eccentric strength test, a handheld dynamometer recorded peak force and time to peak force, and limb position was recorded via a motion capture system. Intrarater reliability was determined using intraclass correlation, SEM, and minimal detectable difference. Construct validity was assessed by determining if peak force occurred after the start of the lowering phase using a 1-sample t test. RESULTS: The hip abductor eccentric strength test had substantial intrarater reliability (intraclass correlation(3,3) = .88; 95% confidence interval, .65-.95), SEM of 0.9 %BWh, and a minimal detectable difference of 2.5 %BWh. Construct validity was established as peak force occurred 2.1 (0.6) seconds (range: 0.7-3.7 s) after the start of the lowering phase of the test (P ≤ .001). CONCLUSION: The hip abductor eccentric strength test is a valid and reliable measure of eccentric muscle strength. This test may be used clinically to assess changes in eccentric muscle strength over time.

Kinematic characterization of clinically observed aberrant movement patterns in patients with non-specific low back pain: a cross-sectional study.

BACKGROUND: Clinical observation of aberrant movement patterns during active forward bending is one criterion used to identify patients with non-specific low back pain suspected to have movement coordination impairment. The purpose of this study was to describe and quantify kinematic patterns of the pelvis and trunk using a dynamics systems approach, and determine agreement between clinical observation and kinematic classification. METHOD: Ninety-eight subjects performed repeated forward bending with clinical observation and kinematic data simultaneously collected. Kinematic data were plotted using angle-angle, coupling-angle, and phase-plane diagrams. Accuracy statistics in conjunction with receiver operating characteristic curves were used to determine agreement between clinical observation and kinematic patterns. RESULTS: Kinematic patterns were consistent with clinical observation and definitions of typical and aberrant movement patterns with moderate agreement (kappa = 0.46-0.50; PABAK = 0.49-0.73). Early pelvic motion dominance in lumbopelvic coupling-angle diagram ≥59° within the first 38% of the movement represent observed altered lumbopelvic rhythm. Frequent disruptions in lumbar spine velocity represented by phase-plane diagrams with local minimum occurrences ≥6 and sudden decoupling in lumbopelvic coupling-angle diagrams with sum of local minimum and maximum occurrences ≥15 represent observed judder. CONCLUSION: These findings further define observations of movement coordination between the pelvis and lumbar spine for the presence of altered lumbopelvic rhythm and judder. Movement quality of the lumbar spine segment is key to identifying judder. This information will help clinicians better understand and identify aberrant movement patterns in patients with non-specific low back pain.

Association of Pectoralis Minor Muscle Extensibility, Shoulder Mobility, and Duration of Manual Wheelchair Use.

OBJECTIVE: To assess the relation of pectoralis minor muscle (PMm) length and extensibility to shoulder pain, shoulder girdle motion, and duration of manual wheelchair (MWC) use, and to compare differences in muscle length, muscle extensibility, peak humeral elevation, and pain among groups based on duration of wheelchair use. DESIGN: Cross-sectional cohort study. SETTING: Laboratory setting. PARTICIPANTS: Individuals with spinal cord injury (SCI) who used an MWC for daily community and home mobility (N=22; 18 men; mean age, 41.7y; duration wheelchair use, 14.6y). Participants were stratified into groups based on duration of wheelchair use: <5 years (n=6), 5 to 15 years (n=8), and >15 years (n=8). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Clinical measures of PMm length and extensibility, shoulder girdle motion, and shoulder pain (Wheelchair User's Shoulder Pain Index). RESULTS: Significant high correlations were found among duration of wheelchair use, passive PMm length, passive PMm extensibility, and peak humerothoracic elevation. Moderate correlation of peak humerothoracic elevation to pain was found. Individuals with >15 years wheelchair use had reduced PMm extensibility and reduced peak humerothoracic elevation than those with <5 years duration of use. CONCLUSIONS: To our knowledge, this is the first investigation to identify the association of reduced PMm extensibility with reduced shoulder girdle mobility, pain, and duration of wheelchair use in individuals with SCI.

Reliability and validity of active and passive pectoralis minor muscle length measures.

BACKGROUND: Pectoralis minor muscle length is believed to play an important role in shoulder pain and dysfunction. Current clinical procedures for assessing pectoralis minor muscle length may not provide the most useful information for clinical decision making. OBJECTIVE: To establish the reliability and construct validity of a novel technique to measure pectoralis minor muscle length under actively and passively lengthened conditions. DESIGN: Cross-sectional repeated measures. METHODS: Thirty-four healthy adults (age: 23.9, SD=1.6 years; 18 females) participated in this study. Pectoralis minor muscle length was measured on the dominant arm in three length conditions: resting, actively lengthened, and passively lengthened. Based upon availability, two raters, out of a pool of five, used a caliper to measure the distance between the coracoid process and the 4th rib. The average of two pectoralis minor muscle length measures was used for all muscle length conditions and analyses. Intraclass correlation coefficients determined intra-and inter-rater reliability, and measurement error was determined via standard error of measurement and minimal detectable change. Construct validity was assessed by ANOVA to determine differences in muscle length across the three conditions. RESULTS: Our intra- and inter-rater reliability values across all three conditions ranged from 0.84 to 0.92 and from 0.80 to 0.90, respectively. Significant differences (p<0.001) in muscle length were found among all three conditions: rest-active (3.66; SD=1.36cm), rest-passive (4.72, SD=1.41cm), and active-passive (1.06, SD=0.47cm). CONCLUSIONS: The techniques described in this study for measuring pectoralis minor muscle length under resting and actively and passively lengthened conditions have acceptable reliability for clinical decision making.

Critical review of the impact of core stability on upper extremity athletic injury and performance.

BACKGROUND: Programs designed to prevent or rehabilitate athletic injuries or improve athletic performance frequently focus on core stability. This approach is based upon the theory that poor core stability increases the risk of poor performance and/or injury. Despite the widespread use of core stability training amongst athletes, the question of whether or not sufficient evidence exists to support this practice remains to be answered. OBJECTIVES: 1) Open a dialogue on the definition and components of core stability. 2) Provide an overview of current science linking core stability to musculoskeletal injuries of the upper extremity. 3) Provide an overview of evidence for the association between core stability and athletic performance. DISCUSSION: Core stability is the ability to control the position and movement of the trunk for optimal production, transfer, and control of forces to and from the upper and lower extremities during functional activities. Muscle capacity and neuromuscular control are critical components of core stability. A limited body of evidence provides some support for a link between core stability and upper extremity injuries amongst athletes who participate in baseball, football, or swimming. Likewise, few studies exist to support a relationship between core stability and athletic performance. CONCLUSIONS: A limited body of evidence exists to support the use of core stability training in injury prevention or performance enhancement programs for athletes. Clearly more research is needed to inform decision making when it comes to inclusion or emphasis of core training when designing injury prevention and rehabilitation programs for athletes.

Critical review of the impact of core stability on upper extremity athletic injury and performance

BACKGROUND: Programs designed to prevent or rehabilitate athletic injuries or improve athletic performance frequently focus on core stability. This approach is based upon the theory that poor core stability increases the risk of poor performance and/or injury. Despite the widespread use of core stability training amongst athletes, the question of whether or not sufficient evidence exists to support this practice remains to be answered.OBJECTIVES: 1) Open a dialogue on the definition and components of core stability. 2) Provide an overview of current science linking core stability to musculoskeletal injuries of the upper extremity. 3) Provide an overview of evidence for the association between core stability and athletic performance.DISCUSSION: Core stability is the ability to control the position and movement of the trunk for optimal production, transfer, and control of forces to and from the upper and lower extremities during functional activities. Muscle capacity and neuromuscular control are critical components of core stability. A limited body of evidence provides some support for a link between core stability and upper extremity injuries amongst athletes who participate in baseball, football, or swimming. Likewise, few studies exist to support a relationship between core stability and athletic performance.CONCLUSIONS: A limited body of evidence exists to support the use of core stability training in injury prevention or performance enhancement programs for athletes. Clearly more research is needed to inform decision making when it comes to inclusion or emphasis of core training when designing injury prevention and rehabilitation programs for athletes.

Using kinematics and a dynamical systems approach to enhance understanding of clinically observed aberrant movement patterns.

The objective of this technical paper is to demonstrate how graphing kinematic data to represent body segment coordination and control can assist clinicians and researchers in understanding typical and aberrant human movement patterns. Aberrant movements are believed to be associated with musculoskeletal pain and dysfunction. A dynamical systems approach to analysing movement provides a useful way to study movement control and coordination. Continuous motion angle-angle and coupling angle-movement cycle graphs provide information about coordinated movement between body segments, whereas phase-plane graphs provide information about neuromuscular control of a body segment. Examples demonstrate how a dynamical systems approach can be used to represent (1) typical movement patterns of the lumbopelvic and shoulder regions; (2) aberrant coordination in an individual with low back pain who presented with altered lumbopelvic rhythm; and (3) aberrant control of shoulder movement in an individual with observed scapular dysrhythmia. Angle-angle and coupling angle-movement cycle graphs were consistent with clinical operational definitions of typical and altered lumbopelvic rhythm. Phase-plane graphs illustrated differences in scapular control between individuals having typical scapular motion and an individual with scapular dysrhythmia. Angle-angle, coupling angle-movement cycle, and phase-plane graphs provide information about the amount and timing of segmental motion, which clinicians assess when they observe movements. These approaches have the potential to (1) enhance understanding of typical and aberrant movement patterns; (2) assist with identifying underlying movement impairments that contribute to aberrant movements: and (3) improve clinicians' ability to visually assess and categorize functional movements.

Shoulder impairments and their association with symptomatic rotator cuff disease in breast cancer survivors.

Over 2.6 million breast cancer survivors currently reside in the United States. While improvements in the medical management of women diagnosed with breast cancer have resulted in a 5-year survival rate of 89%, curative treatments are associated with a high prevalence of shoulder and arm morbidity, which, in turn, can negatively impact a woman's quality of life. Breast cancer survivors frequently experience shoulder and arm pain, decreased range of motion, muscle weakness, and lymphedema. These symptoms can lead to difficulties with daily activities ranging from overhead reaching and carrying objects to caring for family and returning to work. Despite health care professionals awareness of these problems, a significant number of breast cancer survivors are confronted with long-term, restricted use of their affected shoulder and upper extremity. This problem may partially be explained by: (1) an incomplete understanding of relevant impairments and diagnoses associated with shoulder/arm pain and limited upper extremity use, and (2) the limited effectiveness of current rehabilitation interventions for managing shoulder pain and decreased upper extremity function in breast cancer survivors. Because breast cancer treatment directly involves the neuromusculoskeletal tissues of the shoulder girdle, it is understandable why breast cancer survivors are likely to develop shoulder girdle muscle weakness and fatigue, decreased shoulder motion, altered shoulder girdle alignment, and lymphedema. These impairments can be associated with diagnoses such as post-mastectomy syndrome, adhesive capsulitis, myofascial dysfunction, and brachial plexopathy, all of which have been reported among breast cancer survivors. It is our belief that these impairments also put women at risk for developing symptomatic rotator cuff disease. In this paper we set forth the rationale for our belief that breast cancer treatments and subsequent impairments of shoulder girdle neuromusculoskeletal tissues place breast cancer survivors at risk for developing symptomatic rotator cuff disease. Additionally, we identify knowledge gaps related to the current understanding of relevant shoulder girdle impairments and their association with symptomatic rotator cuff disease in breast cancer survivors. Ultimately, information from studies designed to meet these gaps will provide a scientific basis for the development of new, or refinement of existing, examination, intervention, and prevention techniques, which should lead to improved clinical outcomes in this population.