BackgroundBall velocity, accuracy and game statistics represent three methods used to measure pitching performance. However, individual determinants of pitching performance are more elusive.ObjectivesThe aims of this study were to classify the performance factors associated with baseball pitchers, to identify the methods used to quantify their abilities through all features of the game and to document relationships between performance factors and indicators.DesignScoping review.Data sourcesElectronic searches of MEDLINE, Academic Search Complete, CINAHL, SportDiscus, PubMed, PsycINFO, Cochrane and of grey literature were undertaken from inception to January 2019.Eligibility criteria for selecting studiesCross-sectional studies that investigated the relationship between performance indicators and individual performance factors in healthy baseball pitchers were selected.ResultsThirty-four cross-sectional studies investigating individual potential factors of pitching performance met the inclusion criteria. The primary performance factors investigated were kinematic, kinetic, timing outcomes, personal characteristics, physical tests and range of motion. Shoulder horizontal adduction (SHA), upper torso forward flexion, maximal shoulder external rotation, upper torso rotation angle, upper torso lateral flexion, lead knee flexion (LKF) and forward trunk tilt (FTT) were identified as key kinematic features associated with increased ball velocity. Shoulder proximal force and peak elbow proximal forces were associated with greater ball velocity. Individual performances in jumping tests and body weight (BW) are also associated with pitching performance.Summary/conclusionBased on studies presenting low and moderate risk of bias, we conclude that BW, age and kinematics, such as FTT, LKF, SHA and lateral trunk tilt, are associated with pitching performance.

The aim of this study was to evaluate the effects of lumbar muscle delayed-onset muscle 2 soreness (DOMS) on the ability of the trunk muscles to reproduce different levels of force. 3 Methods: Twenty healthy adults (10 males and 10 females) were recruited for this study. Force reproduction in trunk extension and flexion was assessed at 50 and 75% of participants' maximal 5 isometric voluntary contraction in flexion and extension before and after a lumbar muscle DOMS 6 protocol. Trunk proprioception was evaluated and compared between these conditions using different 7 variables such as constant errors (CE), absolute errors (AE), variable errors (VE) and time to peak force 8 (TPF). For each variable, repeated measure ANOVAs were conducted. 9 Results: AE were higher when participants had to reach the target post-DOMS protocol in extension 10 compared to flexion and in presence of higher demand of force (p=0.02). For VE, results showed that 11 participants were more variable in extension than in flexion when the required force was higher (p=0.04). 12 CE variable was higher when participants had to reach the force target in extension compared to flexion 13 under the effect of DOMS (p=0.02). Results also showed that participants took less time to reach the force 14 target post-DOMS protocol in extension (0.62 ± 0.20 sec) and in flexion (0.53 ± 0.19 sec) than pre-DOMS 15 protocol in extension (0.55 ± 0.15) and in flexion (0.50 ± 0.20) (p<0.001). 16 Conclusion: Lumbar muscle DOMS affect trunk proprioception during force reproduction tasks 17 especially in trunk extension and at higher force.

Background: Spinal manipulations (SMT) and mobilizations (MOB) are interventions commonly performed by many health care providers to manage musculoskeletal conditions. The clinical effects of these interventions are believed to be, at least in part, associated with their force-time characteristics. Numerous devices have been developed to measure the force-time characteristics of these modalities. The use of a device may be facilitated or limited by different factors such as its metrologic properties.Objectives: This mixed-method scoping review aimed to characterize the metrologic properties of devices used to measure SMT/MOB force-time characteristics and to determine which factors may facilitate or limit the use of such devices within the context of research, education and clinical practice.Methods: This study followed the Joanna Briggs Institute's framework. The literature search strategy included four concepts: (1) devices, (2) measurement of SMT or MOB force-time characteristics on humans, (3) factors facilitating or limiting the use of devices, and (4) metrologic properties. Two reviewers independently reviewed titles, abstracts and full articles to determine inclusion. To be included, studies had to report on a device metrologic property (e.g., reliability, accuracy) and/or discuss factors that may facilitate or limit the use of the device within the context of research, education or clinical practice. Metrologic properties were extracted per device. Limiting and facilitating factors were extracted and themes were identified.Results: From the 8,998 studies initially retrieved, 46 studies were finally included. Ten devices measuring SMT/MOB force-time characteristics at the clinician-patient interface and six measuring them at patient-table interfaces were identified. Between zero and eight metrologic properties were reported per device: measurement error (defined as validity, accuracy, fidelity, or calibration), reliability/repeatability, coupling/crosstalk effect, linearity/correlation, sensitivity, variability, drift, and calibration. From the results, five themes related to the facilitating and limiting factors were developed: user-friendliness and versatility, metrologic/intrinsic properties, cost and durability, technique application, and feedback.Conclusion: Various devices are available to measure SMT/MOB force-time characteristics. Metrologic properties were reported for most devices, but terminology standardization is lacking. The usefulness of a device in a particular context should be determined considering the metrologic properties as well as other potential facilitating and limiting factors.