A Field-expedient Arm Care Screening Tool Can Identify Musculoskeletal Risk Factors in Baseball Players.

BACKGROUND: Preseason movement screening can identify modifiable risk factors, deterioration of function, and potential for injury in baseball players. Limited resources and time prevent high school baseball coaches from performing movement screens on their players. HYPOTHESIS: The arm care screen (ACS) will be highly sensitive to detecting musculoskeletal risk factors. STUDY DESIGN: Cross-sectional. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 150 baseball players were independently scored on the ACS electronically by reviewing a video recording of each player's screening performance. Discriminability of the ACS was determined with a 2 × 2 contingency table dichotomizing musculoskeletal risk factors as present or absent based on a predetermined cutoff value and those who passed or failed the corresponding ACS subtest. RESULTS: High sensitivity was observed on the reciprocal shoulder mobility (0.89; 95% CI 0.81-0.94), 90/90 total body rotation (0.86; 95% CI 0.79-0.92), and lower body diagonal reach (0.85; 95% CI 0.78-0.91) tests of the ACS suggesting sufficient ability to identify musculoskeletal impairments and risk factors. CONCLUSION: The ACS is a simplistic screening tool that the coach can administer to discriminate between youth, high school, and college-level baseball players who possess musculoskeletal risk factors. The ACS subtests demonstrated high sensitivity for correctly identifying musculoskeletal risk factors common in baseball players and can be useful as a screening tool for baseball coaches developing arm care exercise programs. CLINICAL RELEVANCE: A field-expedient screen could provide coaches the ability to identify musculoskeletal risk factors that need to be addressed to minimize injury risk factors in a time-efficient manner.

The Intra- and Inter-rater Reliability of an Arm Care Screening Tool in High School Baseball Coaches.

BACKGROUND: Preseason movement screening can identify modifiable risk factors, deterioration of function, and potential for injury in baseball players. Limited resources and time intensive testing procedures prevent high school coaches from accurately performing frequent movement screens on their players. PURPOSE: To establish the intra-rater and inter-rater reliability of a novel arm care screening tool based on the concepts of the Functional Movement Screen (FMS™) and Selective Functional Movement Assessment (SFMA™) in high school coaches. STUDY DESIGN: Methodological intra- and inter-rater reliability study. METHODS: Thirty-one male high school baseball players (15.9 years ± 1.06) were independently scored on the Arm Care Screen (ACS) by three examiners (two coaches, one physical therapist) in real-time and again seven days later by reviewing video recordings of each players' initial screening performance. Results from each examiner were compared within and between raters using Cohen's kappa and percent absolute agreement. RESULTS: Substantial to excellent intra-rater and inter-rater reliability were established among all raters for each component of the ACS. The mean Cohen's kappa coefficient for intra-rater reliability was 0.76 (95% confidence interval, 0.54-0.95) and percent absolute agreement ranged from 0.82-0.94 among all raters. Inter-rater reliability demonstrated a mean Cohen's kappa value of 0.89 (95% confidence interval, 0.77-0.99) while percent absolute agreement between raters ranged from 0.81-1.00. Intra- and inter-rater reliability did not differ between raters with various movement screening experience (p>0.05). CONCLUSIONS: High school baseball coaches with limited experience screening movement can reliably score all three components of the ACS in less than three minutes with minimal training. LEVEL OF EVIDENCE: Level 3, Reliability study.

Current Concepts in Arm Care Exercise Programs and Injury Risk Reduction in Adolescent Baseball Players: A Clinical Review.

CONTEXT: Awareness of important injury risk factors associated with excessive pitching volume has been highlighted in the literature, but injury rates remain high. Shoulder pain in baseball players is associated with various changes in musculoskeletal movements, which presents as measurable impairments throughout the kinetic chain. Baseball coaches and rehabilitation professionals have utilized exercise programs targeting strength and flexibility of the throwing arm to prevent injuries. The purpose of this review is to summarize the current evidence regarding the effectiveness of arm care exercise programs in reducing upper extremity injury rates in adolescent baseball players. EVIDENCE ACQUISITION: A search of electronic databases, including CINAHL with full text, MEDLINE, and SPORTDiscus was conducted to retrieve available articles in English from the years 2010 through 2020. The search terms injury prevention, exercise, and adolescent baseball were used. STUDY DESIGN: Clinical review. LEVEL OF EVIDENCE: Level 4. RESULTS: Improving shoulder internal rotation range of motion by stretching the posterior shoulder muscles daily was associated with a 36% risk reduction of shoulder and elbow injuries. Group-based arm care exercise programs that target multiple musculoskeletal impairments demonstrated an approximately 50% reduced risk of elbow injury. CONCLUSION: For adolescent baseball players, arm care injury prevention programs focusing on important musculoskeletal impairments are effective at reducing injury incidence rates. Multimodal injury prevention programs that improve multiple musculoskeletal impairments are more comprehensive and may result in better injury reduction than programs focusing on a singular impairment.

Glenohumeral instability and glenoid bone loss in a throwing athlete.

UNLABELLED: This case presents the challenges of management associated with a young throwing athlete presenting with a history of bilateral anterior shoulder instability. This athlete had multiple surgical interventions over a three-year period. The imaging modalities provided partial elucidation (at best) of the true picture of the pathology. This case report outlines the decision making process utilized to provide individualized care to a young throwing athlete with bilateral glenohumeral joint instability, recurrent dislocations, and resultant glenoid bone loss. LEVEL OF EVIDENCE: 5 (Single Case report).

Comparison of hip and knee strength and neuromuscular activity in subjects with and without patellofemoral pain syndrome.

PURPOSE/BACKGROUND: Historically, patellofemoral pain syndrome (PFPS) has been viewed exclusively as a knee problem. Recent findings have suggested an association between hip muscle weakness and PFPS. Altered neuromuscular activity about the hip also may contribute to PFPS; however, more limited data exist regarding this aspect. Most prior investigations also have not concurrently examined hip and knee strength and neuromuscular activity in this patient population. Additional knowledge regarding the interaction between hip and knee muscle function may enhance the current understanding of PFPS. The purpose of this study was to compare hip and knee strength and electromyographic (EMG) activity in subjects with and without PFPS. METHODS: Eighteen females with PFPS and 18 matched controls participated in this study. First, surface EMG electrodes were donned on the gluteus medius, vastus medialis, and vastus lateralis. Strength measures then were taken for the hip abductors, hip external rotators, and knee extensors. Subjects completed a standardized stair-stepping task to quantify muscle activation amplitudes during the loading response, single leg stance, and preswing intervals of stair descent as well as to determine muscle onset timing differences between the gluteus medius and vastii muscles and between the vastus medialis and vastus lateralis at the beginning of stair descent. RESULTS: Females with PFPS demonstrated less strength of the hip muscles. They also generated greater EMG activity of the gluteus medius and vastus medialis during the loading response and single leg stance intervals of stair descent. No differences existed with respect to onset activation of the vastus medialis and vastus lateralis. All subjects had a similar delay in gluteus medius onset activation relative to the vastii muscles. CONCLUSION: Rehabilitation should focus on quadriceps and hip strengthening. Although clinicians have incorporated gluteus medius exercise in rehabilitation programs, additional attention to the external rotators may be useful. LEVEL OF EVIDENCE: 4.

Reliability of electromyographic methods used for assessing hip and knee neuromuscular activity in females diagnosed with patellofemoral pain syndrome.

Patellofemoral pain syndrome (PFPS) is one of the most common, yet misunderstood, knee pathologies. PFPS is thought to result from abnormal patella tracking caused from altered neuromuscular control. Researchers have investigated neuromuscular influences from the gluteus medius (GM), vastus medialis (VM), and vastus lateralis (VL) but with inconsistent findings. A reason for these discrepancies may be from varying methodology. The purpose of this study was to determine the reliability of electromyographic (EMG) methods used to assess amplitudes and timing differences of the GM, VM, and VL in subjects with PFPS. Seven females with PFPS participated. GM, VM, and VL activity was assessed during the stance phase of a stair descent task on two separate occasions. Amplitudes during the different intervals of stance were recorded and expressed as a percent of each muscle's maximum voluntary isometric contraction. Muscle onsets at the beginning of stair descent were also determined. VM-GM, VL-GM, and VL-VM onset timing differences were quantified. Intraclass correlation coefficients (ICCs) and standard errors of measurement (SEMs) were calculated to assess between-day reliability. Most EMG measures had acceptable reliability (ICC(3,5)>or=0.70). Although some measures had moderate reliability (ICC<0.70), they had low SEMs, which suggested high measurement precision. These findings support using these methods for examining neuromuscular activity in subjects with PFPS.

Hip strength and hip and knee kinematics during stair descent in females with and without patellofemoral pain syndrome.

STUDY DESIGN: Cross-sectional. OBJECTIVE: To determine if females presenting with patellofemoral pain syndrome (PFPS) from no discernable cause other than overuse demonstrate hip weakness and increased hip internal rotation, hip adduction, and knee valgus during stair descent. BACKGROUND: Historically, PFPS has been viewed exclusively as a knee problem. Recent findings have indicated an association between hip weakness and PFPS. Researchers have hypothesized that patients who demonstrate hip weakness would exhibit increased hip internal rotation, hip adduction, and knee valgus during functional activities. To date, researchers have not simultaneously examined hip and knee strength and kinematics in subjects with PFPS to make this determination. METHODS AND MEASURES: Eighteen females diagnosed with PFPS and 18 matched controls participated. Strength measures were taken for the hip external rotators and hip abductors. Hip and knee kinematics were collected as subjects completed a standardized stair-stepping task. Independent t tests were used to determine between-group differences in strength and kinematics during stair descent. RESULTS: Subjects with PFPS generated 24% less hip external rotator (P = .002) and 26% less hip abductor (P =. 006) torque. No between-group differences (P > .05) were found for average hip and knee transverse and frontal plane angles during stair descent. CONCLUSION: Subjects with PFPS had significant hip weakness but did not demonstrate altered hip and knee kinematics as previously theorized. Additional investigations are needed to better understand the association between hip weakness and PFPS etiology.

Vastus medialis activation during knee extension exercises: evidence for exercise prescription.

CONTEXT: Knee extension exercise is an important part of knee rehabilitation. Clinicians prescribe non-weight bearing exercise initially and progress patients to weight bearing exercise once they can perform a straight leg raise (SLR). OBJECTIVE: Compare VM activation during a SLR and weight bearing exercises. DESIGN: One-way repeated measures design. SETTING: University Laboratory. SUBJECTS: Fifteen healthy subjects. INTERVENTION: One SLR exercise and 6 weight-bearing knee extension exercises. MAIN OUTCOME MEASURES: Electromyographic amplitudes for the VM expressed as a percent maximum voluntary isometric contraction. RESULTS: The SLR had greater activation than the single leg stance and bilateral squat exercises. The step-up and unilateral leg press exercises had the greatest activation. CONCLUSIONS: SLR performance can be an important indicator for exercise progression. These results provide foundational knowledge to assist clinicians with exercise prescription.

A comparison of select trunk muscle thickness change between subjects with low back pain classified in the treatment-based classification system and asymptomatic controls.

STUDY DESIGN: Cross-sectional descriptive. OBJECTIVES: To investigate if muscle thickness change, as measured with rehabilitative ultrasound imaging (RUSI), is different across subgroups of patients with low back pain (LBP), classified in the Treatment-Based Classification (TBC) system, when compared to controls. BACKGROUND: Researchers have demonstrated that subgroups of patients with LBP exist and respond differently to treatment, challenging the assertion that LBP is "nonspecific." The TBC system uses 4 categories (stabilization, mobilization, direction specific exercise, or traction) to subgroup patients. Recently, researchers have demonstrated impairments of the transverse abdominis (TrA) and lumbar multifidus (LM) in those with LBP, regardless of classification. Although distinct differences in impairments have been identified between subgroups, TrA and LM impairments have not been studied and may be present across categories of the TBC system. METHODS AND MEASURES: RUSI was utilized to measure percent thickness change from rest to contracted state during a voluntary task of the TrA and during an upper extremity task known to activate the LM in 56 subjects classified in the TBC system and 20 controls. RESULTS: During the prone upper extremity lifting task with a hand weight, there was a significant group difference for the LM at L4-L5 (P = .03) and at L5-S1 (P = .04), and during volitional activation for the TrA (P < .01). Post hoc testing revealed the differences were between controls and both the direction specific and stabilization categories at the L4-L5 level, between control and direction specific category for the L5-S1 level, and between controls and all 3 categories for the TrA. CONCLUSION: Deficits in the ability to generate muscle thickness changes in the TrA and LM occurred across categories of the TBC system. Intervention studies should be performed to determine if intervention can correct these deficits and if deficit corrections are related to outcomes.

Effect of orthoses on postural stability in asymptomatic subjects with rearfoot malalignment during a 6-week acclimation period.

OBJECTIVE: To determine the effect of custom-fitted orthoses on postural sway over a 6-week acclimation period. DESIGN: Repeated-measures analysis of variance on postural sway measures with factors being group (control, malaligned), time (initial, 2 wk, 4 wk, 6 wk postintervention), and condition (with orthoses, without orthoses). For single-limb stance, side (right, left) was analyzed to determine bilateral differences. SETTING: Biodynamics laboratory. PARTICIPANTS: Twenty-one subjects, 11 asymptomatic with rearfoot malalignment and 10 asymptomatic with normal rearfoot alignment. INTERVENTIONS: Orthoses were prescribed and worn for 6 weeks. Balance testing was performed on 4 different dates with each subject tested in both orthotic conditions. Postural control was measured with three 10-second eyes-closed trials for single-limb stance, one 20-second eyes-closed bilateral stance with the platform moving, and one 20-second eyes-open bilateral stance with the platform and surroundings moving. MAIN OUTCOME MEASURES: Sway velocity (in deg/s) for single-limb stance and equilibrium score for bilateral stance. RESULTS: Postural sway measures were significantly decreased during single-limb testing with orthoses versus without orthoses, regardless of group. The orthotic intervention significantly improved bilateral stance equilibrium score in the malaligned group at weeks 2, 4, and 6 when compared with measures at the initial week. Equilibrium score of the malaligned group with orthoses at initial week was significantly lower (worse) than the control group with orthoses at initial week; however, these results were not repeated during measurements taken at weeks 2, 4, or 6. CONCLUSIONS: The application of orthoses decreased sway velocity for single-limb stance, improving postural stability regardless of group when visual feedback was removed. During bilateral stance, postural stability was initially worse for the malaligned group with and without orthoses when compared with the control group; however, improvements were seen by week 2 and continued throughout the remainder of testing. Clinically, the application of orthoses appears to improve postural control in people with rearfoot malalignment, particularly when vision is removed.

EMG analysis of shoulder muscle fatigue during resisted isometric shoulder elevation.

The purpose of this study was to determine if a difference existed in the rate of fatigue of select shoulder muscles during isometric shoulder elevation and if the measured rate of fatigue was consistent from day to day. Shoulder muscle fatigue has been associated with alterations in joint mechanics and possibly contributes to shoulder dysfunction. While research exists, there is limited information on an objective and reliable measure of shoulder fatigue. Sixteen asymptomatic subjects were evaluated. The subjects held a weight equivalent to 60% of his/her Maximum Voluntary Isometric Contraction (MVIC) while elevating in the scapular plane. Surface electrodes were applied to collect electromyographic activity from the upper trapezius, middle deltoid, serratus anterior, and lower trapezius muscles while the arm was held at 90 degrees elevation. Data collection ceased when the subject was no longer able to maintain 90 degrees of elevation. The subject then rested and a second trial performed. One week later, the two-trial procedure was repeated. A significant interaction of trial x day x muscle was found for the rate of fatigue. Post hoc analysis revealed that the rate of fatigue of the middle deltoid was significantly greater than the other muscles tested. The intraday reliability was good for all muscles but interday reliability was poor except for the middle deltoid. This study suggests that the middle deltoid appears to fatigue faster than the other shoulder muscles tested at the selected level of shoulder elevation. This should be considered in designing a rehabilitation program to develop a sequence that does not overly fatigue the middle deltoid.

Effects of 2 ankle fatigue models on the duration of postural stability dysfunction.

CONTEXT: Muscle fatigue is generally categorized in 2 ways: that caused by peripheral weakness (peripheral fatigue) and that caused by a progressive failure of voluntary neural drive (central fatigue). Numerous variables have been studied in conjunction with fatigue protocols, including postural stability, maximum voluntary contraction force, and reaction time. When torque recordings fall below 50% of a maximum voluntary contraction, the muscle is described as fatigued, but whether this value is a good indicator of fatigue has not been studied. OBJECTIVE: To compare the effects of 2 ankle musculature fatigue protocols (30% and 50%) on the duration of postural stability dysfunction. DESIGN: To assess differences between the 30% and 50% fatigue protocols, we calculated a 1 between-groups factor (subjects) and 2 within-groups factors (fatigue, test) analysis of variance. SETTING: E.J. Nutter Athletic Training Facility. PATIENTS OR OTHER PARTICIPANTS: Twenty subjects (10 men, 10 women; age = 21.15 +/- 2.23 years; height = 172.97 +/- 9.86 cm; mass = 70.62 +/- 14.60 kg) volunteered for this study. Subjects had no history of lower extremity injury, vestibular or balance disorders, functional ankle instability, or head injury in the past 6 months. INTERVENTION(S): On separate days, subjects performed isokinetic fatiguing contractions of the plantar flexors and dorsiflexors in a 30% protocol (70% decrease in strength) and a 50% protocol (50% decrease in strength). MAIN OUTCOME MEASURE(S): Baseline and postfatigue postural stability scores were determined before and after the isokinetic fatiguing contractions. Plantar-flexion peak-torque measurements were obtained for the 2 fatiguing protocols. Three prefatigue and 12 postfatigue postural stability trials were recorded. Velocities for testing were 60 degrees /s for plantar flexion and 120 degrees /s for dorsiflexion. RESULTS: Sway velocity was significantly greater when the ankle was fatigued to 30% (1.56 degrees /s) than in the 50% condition (1.36 degrees /s). For the 30% protocol, sway was significantly impaired when the pretest condition (1.19 degrees /s) was compared with posttest trial 1 (2.34 degrees /s), trial 2 (2.37 degrees /s), and trial 3 (1.71 degrees /s). For the 50% protocol, sway was significantly impaired when the pretest condition (1.27 degrees /s) was compared with posttest trial 1 (2.02 degrees /s). CONCLUSIONS: The 30% fatigue protocol resulted in significantly longer impairment of postural stability than the 50% protocol. Because the 30% protocol resulted in a greater effect but was relatively short-lived (approximately 75 to 90 s), it is more useful for research purposes.

Plantar fasciitis and the windlass mechanism: a biomechanical link to clinical practice.

OBJECTIVE: Plantar fasciitis is a prevalent problem, with limited consensus among clinicians regarding the most effective treatment. The purpose of this literature review is to provide a systematic approach to the treatment of plantar fasciitis based on the windlass mechanism model. DATA SOURCES: We searched MEDLINE, SPORT Discus, and CINAHL from 1966 to 2003 using the key words plantar fasciitis, windlass mechanism, pronation, heel pain, and heel spur. DATA SYNTHESIS: We offer a biomechanical application for the evaluation and treatment of plantar fasciitis based on a review of the literature for the windlass mechanism model. This model provides a means for describing plantar fasciitis conditions such that clinicians can formulate a potential causal relationship between the conditions and their treatments. CONCLUSIONS/RECOMMENDATIONS: Clinicians' understanding of the biomechanical causes of plantar fasciitis should guide the decision-making process concerning the evaluation and treatment of heel pain. Use of this approach may improve clinical outcomes because intervention does not merely treat physical symptoms but actively addresses the influences that resulted in the condition. Principles from this approach might also provide a basis for future research investigating the efficacy of plantar fascia treatment.