Effectiveness of a Home-Based Eccentric-Exercise Program on the Torque-Angle Relationship of the Shoulder External Rotators: A Pilot Study

Context: The role of the rotator cuff is to provide dynamic stability to the glenohumeral joint. Human and animal studies have identified sarcomerogenesis as an outcome of eccentric training indicated by more torque generation with the muscle in a lengthened position. Objective: The authors hypothesized that a home-based eccentric-exercise program could increase the shoulder external rotators’ eccentric strength at terminal internal rotation (IR). Design: Prospective case series. Setting: Clinical laboratory and home exercising. Participants: 10 healthy subjects (age 30 ± 10 y). Intervention: All participants performed 2 eccentric exercises targeting the posterior shoulder for 6 wk using a home-based intervention program using side-lying external rotation (ER) and horizontal abduction. Main Outcome Measures: Dynamic eccentric shoulder strength measured at 60°/s through a 100° arc divided into 4 equal 25° arcs (ER 50–25°, ER 25–0°, IR 0–25°, IR 25–50°) to measure angular impulse to represent the work performed. In addition, isometric shoulder ER was measured at 5 points throughout the arc of motion (45° IR, 30° IR, 15° IR, 0°, and 15° ER). Comparison of isometric and dynamic strength from pre- to posttesting was evaluated with a repeated-measure ANOVA using time and arc or positions as within factors. Results: The isometric force measures revealed no significant differences between the 5 positions (P = .56). Analysis of the dynamic eccentric data revealed a significant difference between arcs (P = .02). The percentage-change score of the arc of IR 25–50° was found to be significantly greater than that of the arc of IR 0–25° (P = .007). Conclusion: After eccentric training the only arc of motion that had a positive improvement in the capacity to absorb eccentric loads was the arc of motion that represented eccentric contractions at the longest muscle length

Effectiveness of a Home-Based Eccentric-Exercise Program on the Torque-Angle Relationship of the Shoulder External Rotators: A Pilot Study

Context: The role of the rotator cuff is to provide dynamic stability to the glenohumeral joint. Human and animal studies have identified sarcomerogenesis as an outcome of eccentric training indicated by more torque generation with the muscle in a lengthened position. Objective: The authors hypothesized that a home-based eccentric-exercise program could increase the shoulder external rotators’ eccentric strength at terminal internal rotation (IR). Design: Prospective case series. Setting: Clinical laboratory and home exercising. Participants: 10 healthy subjects (age 30 ± 10 y). Intervention: All participants performed 2 eccentric exercises targeting the posterior shoulder for 6 wk using a home-based intervention program using side-lying external rotation (ER) and horizontal abduction. Main Outcome Measures: Dynamic eccentric shoulder strength measured at 60°/s through a 100° arc divided into 4 equal 25° arcs (ER 50–25°, ER 25–0°, IR 0–25°, IR 25–50°) to measure angular impulse to represent the work performed. In addition, isometric shoulder ER was measured at 5 points throughout the arc of motion (45° IR, 30° IR, 15° IR, 0°, and 15° ER). Comparison of isometric and dynamic strength from pre- to posttesting was evaluated with a repeated-measure ANOVA using time and arc or positions as within factors. Results: The isometric force measures revealed no significant differences between the 5 positions (P = .56). Analysis of the dynamic eccentric data revealed a significant difference between arcs (P = .02). The percentage-change score of the arc of IR 25–50° was found to be significantly greater than that of the arc of IR 0–25° (P = .007). Conclusion: After eccentric training the only arc of motion that had a positive improvement in the capacity to absorb eccentric loads was the arc of motion that represented eccentric contractions at the longest muscle length

The Relationship between Pitching Volume and Arm Soreness in Collegiate Baseball Pitchers

Background: Excessive baseball pitch volume has been associated with increased risk of injury in adolescents. However, many collegiate athletes report non-time loss injuries over the course of the season. It is unknown how pitch volume throughout a collegiate baseball season affects arm soreness. Purpose: The primary purpose of this study was to determine the relationship between pitch volume and self-reported arm soreness. A secondary purpose was to determine the relationship between change in pitch volume and change in arm soreness over the course of the season for collegiate baseball pitchers. Study Design: Prospective Cohort. Methods: Seven collegiate baseball pitchers volunteered to participate in a yearlong prospective study. The seven pitchers reported daily pitch volume and level of soreness from the fall through spring collegiate baseball season during practices and games. The athletic trainer, a member of the research team, tracked athletic exposures and injuries for the entire season. Frequency counts of athletic exposures were categorized by game, practice, conditioning and injury status. Frequency counts of pitch volume was categorized by game, game bullpen, practice bullpen, flat ground, long toss and warm-up pitches. The pitch volume and soreness levels for each athlete were used to determine the relationship between these two variables using a Pearson correlation. Results: The seven pitchers were involved with 1,256 athletic exposures and a total of 54,151 throws, averaging 7,735 throws per player for the entire season. The pitch volume and self-reported arm soreness for the entire season revealed a correlation of r = .72 (p = .004). The relationship between change in pitch volume and change in arm soreness was r = .635 (p = .001) over the season. Conclusion: There was a moderate significant correlation between arm soreness and pitch volume across the whole season. This relationship was maintained when evaluating weekly changes. Level of Evidence: 4

Reliability of the Myotonometer for Assessment of Posterior Shoulder Tightness

BACKGROUND/PURPOSE: The Myotonometer® is an electronic tissue compliance meter that has been used to quantify the compliance of soft tissues. The Myotonometer® may be a valuable tool to measure the effectiveness of interventions commonly used to increase tissue compliance in individuals with posterior shoulder tightness (PST). Limited data exist on reliability and responsiveness of the Myotonometer® for assessment of soft tissues about the shoulder; therefore, the purpose of this study is to determine the intra- and inter-session reliability and responsiveness of the Myotonometer® in measuring tissue compliance of the posterior shoulder musculature in asymptomatic subjects with PST. METHODS: Fifteen asymptomatic subjects with unilateral shoulder range of motion deficits attended two measurement sessions to assess the compliance of the tissues overlying the posterior deltoid, infraspinatus, and teres musculature. Analyses of reliability and responsiveness were conducted using intra-class correlation coefficients (ICCs) and the determination of minimal detectible change (MDC). RESULTS: Intra-session ICC values ranged from 0.69 to 0.91 for all muscles with MDC never exceeding 1.0 mm. Inter-session ICC values were best for the posterior deltoid, which averaged 0.82, compared to the infraspinatus and the teres complex, which averaged 0.42 and 0.5 respectively. Inter-session MDC ranged from 0.55 to 1.20 mm across all muscles. CONCLUSIONS: Clinicians can reliably detect relatively small changes in tissue compliance within a single treatment session utilizing the Myotonometer®. The Myotonometer® can reliably detect changes between sessions for tissues overlying the posterior deltoid; however, observed change in the infraspinatus and teres musculature must be above 1 mm to achieve meaningful change and account for decreased inter-session reliability. LEVEL OF EVIDENCE: 3

Neuromuscular Alterations After Ankle Sprains: An Animal Model to Establish Causal Links After Injury

Context: The mechanisms that contribute to the development of chronic ankle instability are not understood. Investigators have developed a hypothetical model in which neuromuscular alterations that stem from damaged ankle ligaments are thought to affect periarticular and proximal muscle activity. However, the retrospective nature of these studies does not allow a causal link to be established. Objective: To assess temporal alterations in the activity of 2 periarticular muscles of the rat ankle and 2 proximal muscles of the rat hind limb after an ankle sprain. Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Five healthy adult male Long Evans rats (age = 16 weeks, mass = 400.0 ± 13.5 g). Intervention(s): Indwelling fine-wire electromyography (EMG) electrodes were implanted surgically into the biceps femoris, medial gastrocnemius, vastus lateralis, and tibialis anterior muscles of the rats. We recorded baseline EMG measurements while the rats walked on a motor-driven treadmill and then induced a closed lateral ankle sprain by overextending the lateral ankle ligaments. After ankle sprain, the rats were placed on the treadmill every 24 hours for 7 days, and we recorded postsprain EMG data. Main Outcome Measure(s): Onset time of muscle activity, phase duration, sample entropy, and minimal detectable change (MDC) were assessed and compared with baseline using 2-tailed dependent t tests. Results: Compared with baseline, delayed onset time of muscle activity was exhibited in the biceps femoris (baseline = −16.7 ± 54.0 milliseconds [ms]) on day 0 (5.2 ± 64.1 ms; t4 = −4.655, P = .043) and tibialis anterior (baseline = 307.0 ± 64.2 ms) muscles on day 3 (362.5 ± 55.9 ms; t4 = −5.427, P = .03) and day 6 (357.3 ± 39.6 ms; t4 = −3.802, P = .02). Longer phase durations were observed for the vastus lateralis (baseline = 321.9 ± 92.6 ms) on day 3 (401.3 ± 101.2 ms; t3 = −4.001, P = .03), day 4 (404.1 ± 93.0 ms; t3 = −3.320, P = .048), and day 5 (364.6 ± 105.2 ms; t3 = −3.963, P = .03) and for the tibialis anterior (baseline = 103.9 ± 16.4 ms) on day 4 (154.9 ± 7.8 ms; t3 = −4.331, P = .050) and day 6 (141.9 ± 16.2 ms; t3 = −3.441, P = .03). After sprain, greater sample entropy was found for the vastus lateralis (baseline = 0.7 ± 0.3) on day 6 (0.9 ± 0.4; t4 = −3.481, P = .03) and day 7 (0.9 ± 0.3; t4 = −2.637, P = .050) and for the tibialis anterior (baseline = 0.6 ± 0.4) on day 4 (0.9 ± 0.5; t4 = −3.224, P = .03). The MDC analysis revealed increased sample entropy values for the vastus lateralis and tibialis anterior. Conclusions: Manually inducing an ankle sprain in a rat by overextending the lateral ankle ligaments altered the complexity of muscle-activation patterns, and the alterations exceeded the MDC of the baseline data

Sequential alterations in catabolic and anabolic gene expression parallel pathological changes during progression of monoiodoacetate-induced arthritis

Chronic inflammation is one of the major causes of cartilage destruction in osteoarthritis. Here, we systematically analyzed the changes in gene expression associated with the progression of cartilage destruction in monoiodoacetate-induced arthritis (MIA) of the rat knee. Sprague Dawley female rats were given intra-articular injection of monoiodoacetate in the knee. The progression of MIA was monitored macroscopically, microscopically and by micro-computed tomography. Grade 1 damage was observed by day 5 post-monoiodoacetate injection, progressively increasing to Grade 2 by day 9, and to Grade 3-3.5 by day 21. Affymetrix GeneChip was utilized to analyze the transcriptome-wide changes in gene expression, and the expression of salient genes was confirmed by real-time-PCR. Functional networks generated by Ingenuity Pathways Analysis (IPA) from the microarray data correlated the macroscopic/histologic findings with molecular interactions of genes/gene products. Temporal changes in gene expression during the progression of MIA were categorized into five major gene clusters. IPA revealed that Grade 1 damage was associated with upregulation of acute/innate inflammatory responsive genes (Cluster I) and suppression of genes associated with musculoskeletal development and function (Cluster IV). Grade 2 damage was associated with upregulation of chronic inflammatory and immune trafficking genes (Cluster II) and downregulation of genes associated with musculoskeletal disorders (Cluster IV). The Grade 3 to 3.5 cartilage damage was associated with chronic inflammatory and immune adaptation genes (Cluster III). These findings suggest that temporal regulation of discrete gene clusters involving inflammatory mediators, receptors, and proteases may control the progression of cartilage destruction. In this process, IL-1β, TNF-α, IL-15, IL-12, chemokines, and NF-κB act as central nodes of the inflammatory networks, regulating catabolic processes. Simultaneously, upregulation of asporin, and downregulation of TGF-β complex, SOX-9, IGF and CTGF may be central to suppress matrix synthesis and chondrocytic anabolic activities, collectively contributing to the progression of cartilage destruction in MIA

Long-Lasting Impairments in Quadriceps Mitochondrial Health, Muscle Size, and Phenotypic Composition Are Present After Non-Invasive Anterior Cruciate Ligament Injury

Introduction: Despite rigorous rehabilitation aimed at restoring muscle health, anterior cruciate ligament (ACL) injury is often hallmarked by significant long-term quadriceps muscle weakness. Derangements in mitochondrial function are a common feature of various atrophying conditions, yet it is unclear to what extent mitochondria are involved in the detrimental sequela of quadriceps dysfunction after ACL injury. Using a preclinical, non-invasive ACL injury rodent model, our objective was to explore the direct effect of an isolated ACL injury on mitochondrial function, muscle atrophy, and muscle phenotypic transitions. Methods: A total of 40 male and female, Long Evans rats (16-week-old) were exposed to non-invasive ACL injury, while 8 additional rats served as controls. Rats were euthanized at 3, 7, 14, 28, and 56 days after ACL injury, and vastus lateralis muscles were extracted to measure the mitochondrial respiratory control ratio (RCR; state 3 respiration/state 4 respiration), mitochondrial reactive oxygen species (ROS) production, fiber cross sectional area (CSA), and fiber phenotyping. Alterations in mitochondrial function and ROS production were detected using two-way (sex:group) analyses of variance. To determine if mitochondrial characteristics were related to fiber atrophy, individual linear mixed effect models were run by sex. Results: Mitochondria-derived ROS increased from days 7 to 56 after ACL injury (30–100%, P \u3c 0.05), concomitant with a twofold reduction in RCR (P \u3c 0.05). Post-injury, male rats displayed decreases in fiber CSA (days 7, 14, 56; P \u3c 0.05), loss of IIa fibers (day 7; P \u3c 0.05), and an increase in IIb fibers (day 7; P \u3c 0.05), while females displayed no changes in CSA or phenotyping (P \u3e 0.05). Males displayed a positive relationship between state 3 respiration and CSA at days 14 and 56 (P \u3c 0.05), while females only displayed a similar trend at day 14 (P = 0.05). Conclusion: Long-lasting impairments in quadriceps mitochondrial health are present after ACL injury and play a key role in the dysregulation of quadriceps muscle size and composition. Our preclinical data indicate that using mitoprotective therapies may be a potential therapeutic strategy to mitigate alterations in muscle size and characteristic after ACL injury

YeATS - a tool suite for analyzing RNA-seq derived transcriptome identifies a highly transcribed putative extensin in heartwood/sapwood transition zone in black walnut

The transcriptome provides a functional footprint of the genome by enumerating the molecular components of cells and tissues. The field of transcript discovery has been revolutionized through high-throughput mRNA sequencing (RNA-seq). Here, we present a methodology that replicates and improves existing methodologies, and implements a workflow for error estimation and correction followed by genome annotation and transcript abundance estimation for RNA-seq derived transcriptome sequences (YeATS - Yet Another Tool Suite for analyzing RNA-seq derived transcriptome). A unique feature of YeATS is the upfront determination of the errors in the sequencing or transcript assembly process by analyzing open reading frames of transcripts. YeATS identifies transcripts that have not been merged, result in broken open reading frames or contain long repeats as erroneous transcripts. We present the YeATS workflow using a representative sample of the transcriptome from the tissue at the heartwood/sapwood transition zone in black walnut. A novel feature of the transcriptome that emerged from our analysis was the identification of a highly abundant transcript that had no known homologous genes (GenBank accession: KT023102). The amino acid composition of the longest open reading frame of this gene classifies this as a putative extensin. Also, we corroborated the transcriptional abundance of proline-rich proteins, dehydrins, senescence-associated proteins, and the DNAJ family of chaperone proteins. Thus, YeATS presents a workflow for analyzing RNA-seq data with several innovative features that differentiate it from existing software

YeATS - a tool suite for analyzing RNA-seq derived transcriptome identifies a highly transcribed putative extensin in heartwood/sapwood transition zone in black walnut [version 2; referees: 3 approved]

The transcriptome provides a functional footprint of the genome by enumerating the molecular components of cells and tissues. The field of transcript discovery has been revolutionized through high-throughput mRNA sequencing (RNA-seq). Here, we present a methodology that replicates and improves existing methodologies, and implements a workflow for error estimation and correction followed by genome annotation and transcript abundance estimation for RNA-seq derived transcriptome sequences (YeATS - Yet Another Tool Suite for analyzing RNA-seq derived transcriptome). A unique feature of YeATS is the upfront determination of the errors in the sequencing or transcript assembly process by analyzing open reading frames of transcripts. YeATS identifies transcripts that have not been merged, result in broken open reading frames or contain long repeats as erroneous transcripts. We present the YeATS workflow using a representative sample of the transcriptome from the tissue at the heartwood/sapwood transition zone in black walnut. A novel feature of the transcriptome that emerged from our analysis was the identification of a highly abundant transcript that had no known homologous genes (GenBank accession: KT023102). The amino acid composition of the longest open reading frame of this gene classifies this as a putative extensin. Also, we corroborated the transcriptional abundance of proline-rich proteins, dehydrins, senescence-associated proteins, and the DNAJ family of chaperone proteins. Thus, YeATS presents a workflow for analyzing RNA-seq data with several innovative features that differentiate it from existing software