Unaccounted for Pitch Volume Among Adolescent Baseball Pitchers During a Travel Baseball Season.

OBJECTIVE: The primary aim was to compare differences in live game pitch counts (LGPCs) with all pitch counts (APCs) over the course of a youth baseball season. DESIGN: Prospective longitudinal study. SETTING: Midwest youth travel baseball. PARTICIPANTS: Ten male baseball players part of a youth baseball travel team. VARIABLES: Demographic data, pitch counts (practice, game, warm-up, and bullpen), innings pitched, and recommended rest days. MAIN OUTCOME MEASURES: Live pitch counts compared with APCs and the relationship to recommended rest days. RESULTS: During the season, 7866 pitches were recorded among 9 pitchers. By using the LGPC method alone, 42.5% of the pitches were unaccounted for. When considering age-specific rest days suggested by Pitch Smart Guidelines (PSGs), there were 104 rest days unaccounted for by using the live game pitch method. CONCLUSION: There is a high number of unaccounted for pitches and an underestimation of rest days per outing when using live game methods. Revisions to the PSGs that include all pitches should be considered to accurately reflect pitching volume, which may be associated with the rising rate of injuries among these athletes.

Kinematic and Kinetic Differences Between Ball Rotational Exercises and the Throwing Motion in Collegiate Baseball Athletes.

ABSTRACT: Mylott, JA, Potts, EM, Wolf, JH, Bullock, GS, and Nicholson, KF. Kinematic and kinetic differences between ball rotational exercises and the throwing motion in collegiate baseball athletes. J Strength Cond Res XX(X): 000-000, 2024-The purpose of this study was to observe the associations that medicine ball pushes and chops have on the lower extremities regarding ground reaction forces (GRF) and lead knee flexion angles and to compare these values with a regular baseball overhead throw. Lower extremity kinetics and kinematics were obtained via force plates and marker motion capture. Subjects (n = 35) included baseball players (age 19.7 ± 1.5 years). Five medicine ball movements of each type along with at least 3 pitches or 5 throws off the mound were recorded for data collection. Statistical parametric mapping, including analysis of variance and 2-way t-tests, was used to compare the variables of interest between the movements for continuous time data. All kinematic and kinetic variables were significantly different (p < 0.05) for some time during the motion between the different trial types of medicine ball exercises and throws. A medicine ball chop can increase peak drive leg GRF, whereas a push can help an athlete keep greater driver leg GRF and maintain ground connection into foot plant. A push helps train lead leg deficiencies in the delivery. Both the medicine ball chop and push have benefits for training lead leg stabilization and extension.

Impact of Prolonged Sport Stoppage on Knee Injuries in High School Athletes: An Ecological Study.

CONTEXT: In March 2020, public health concerns resulted in school closure throughout the United States. The prolonged sport cessation may affect knee injury risk in high school athletes. The purpose of this study was to describe and compare risk of knee injuries in high school athletes during 2019-2020 and 2020-2021 academic years, and stratify by gender, severity, mechanism of injury, injury type, and knee anatomic region. DESIGN: Historical-prospective cohort study. METHODS: This historical-prospective cohort study included 176 schools in 6 states matched by sport participation in control and COVID years from July 1, 2019 to June 30, 2021. Injury rates per 1000 athletes per year were calculated with 95% confidence intervals. A negative binomial regression was performed to assess potential differences in knee injuries between academic years. RESULTS: 94,847 and 72,521 high school athletes participated in the 2019-2020 (19-20) and 2020-2021 (20-21) seasons. Knee injury risk was higher in the 20-21 season (19-20: 28.89% [27.82-29.96]; 20-21: 33.82% [32.50-35.14]). Risk increased for male athletes from 2019-2020 to 2020-2021 (19-20: 29.42% [28.01-30.83]; 20-21: 40.32% [38.89-41.75]). Female knee injury risk was similar between years (19-20: 25.78% [24.29-27.27]; 20-21: 26.03% [24.31-27.75]). Knee injuries increased by a ratio of 1.2 ([95% CI, 1.1-1.3], P < .001) during 2020-2021. CONCLUSIONS: Knee injury risk and relative risk increased among males in 2020-2021. Results indicate changes in knee injury risk following return from COVID shelter in place among high school athletes and implicate potential negative downstream effects of interrupted sports training and participation on high school injury risk.

Effects of Ball Size and Weight on Throwing Kinematics and Kinetics in Youth Baseball Athletes.

BACKGROUND: In baseball, youth athletes play on smaller fields with shorter distances between bases, shorter pitching distances, and smaller mounds. Despite this, youth athletes use baseballs weighing the same amount as those used at the professional level, possibly predisposing youth baseball players to injuries. PURPOSE: (1) To determine the effects of throwing a smaller, lighter, and both smaller and lighter baseball on throwing arm stress in youth athletes and (2) to also investigate how changing the ball size and weight would affect elbow varus torque, shoulder distraction force, and throwing arm internal rotation velocity during the throwing motion. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: This cross-sectional cohort study analyzed the kinematics and kinetics of 38 youth baseball players (mean age, 8.3 ± 0.8 years) throwing a baseball modified in size and weight. Three-dimensional motion data were collected using a retroreflective marker set and a 12-camera motion analysis system. Full-body kinematics and kinetics were calculated using commercial software. Participants threw 5 different types of baseballs 3 times each, in random order, with full effort from a pitching mound to a target 14 m away. The balls used were a 5-oz regular baseball, 5-oz (0.142-kg) baseball with a 5% reduced circumference, 4-oz (0.113-kg) baseball, 4-oz baseball with a 5% reduced circumference, and 3-oz (0.085-kg) baseball. Analysis of variance was used to determine statistical differences in elbow varus torque, shoulder distraction force, and throwing arm internal rotation velocity among baseball types. The Tukey post hoc test was used to further investigate differences between the ball groups, considering P < .05 to be significant. RESULTS: Analysis of variance detected a significant difference in elbow varus torque among ball groups (P = .024). The Tukey post hoc test revealed a moderate difference in elbow varus torque between the 5-oz baseball (4.73 ± 1.06 percentage body weight × height [%BW × H]) and 3-oz baseball (4.06 ± 0.83 %BW × H) (P = .017; d = 0.677 [95% CI, 0.08-1.27]). No significant differences were found in shoulder distraction force or throwing arm internal rotation velocity among ball groups. CONCLUSION: Compared with a 5-oz baseball, throwing a 3-oz baseball resulted in decreased elbow varus torque with a moderate effect size.

An Expedited Sling Immobilization Protocol After Isolated Biceps Tenodesis Results in Clinical and Patient-Reported Postoperative Outcomes Equivalent to a Standard Rehabilitation Protocol.

Purpose: To characterize clinical and patient-reported outcomes for patients after isolated biceps tenodesis (BT) who underwent either standard or expedited sling immobilization protocols following surgery. Methods: This retrospective cohort study compared patients who were assigned to use a sling for either 4 to 6 weeks (standard) or 0 to 2 weeks (expedited) following an isolated BT. Primary endpoint included rate of re-rupture, surgical revision, loss of fixation, and Popeye deformity. Secondary endpoints included shoulder range of motion (ROM) as well as pre- and postoperative patient-reported outcomes (PROs) of pain and function. Missing data were managed via multiple imputation with chained equations. Complication prevalence 95% confidence intervals were calculated using the Clopper Pearson method and a series of hierarchical mixed effects linear regressions were performed to assess differences between sling interventions in PROs and ROM. Results: The average age of the standard cohort (n = 66) was 49 years (±14 years), and the average age of the expedited cohort (n = 69) was 47 years (±14 years). The expedited and standardized cohorts demonstrated 0.4 and 0.3 complications per 10,000 exposure days, respectively, with no significant difference between groups (1.4 [95% confidence interval 0.2-10.0], P = .727). There was no demonstrated difference in forward flexion, abduction, or external ROM. The expedited group had less improvement in visual analog scale for pain scores that was not clinically significant and there were no differences in PROs of function. Conclusions: No statistically significant difference in the rate of re-rupture, surgical revision, loss of fixation, or Popeye deformity was noted between protocols after isolated BT. Furthermore, there were no clinically significant differences in ROM or PROs identified between protocols after isolated BT. This study suggests that patients who have undergone isolated BT may safely discontinue sling use within 2 weeks after surgery. Level of Evidence: Level III, retrospective comparative study.

Previous Knee Surgery, Anteromedial Portal Drilling, Quadriceps Tendon Autograft, and Meniscal Involvement Associated With Delayed Return to Sport After Anterior Cruciate Ligament Reconstruction in Amateur Athletes.

Purpose: To identify prognostic factors associated with a delayed return-to-sport (RTS) time in amateur athletes who return to full participation after a primary isolated anterior cruciate ligament (ACL) reconstruction. Methods: A retrospective review was performed among athletes who underwent ACL reconstruction between October 2014 and October 2021. Inclusion criteria were any amateur athletes with an ACL reconstruction who had a documented RTS and greater than 1-year follow-up. Nonathletes, those with multiligamentous knee injury, and those missing documented RTS timelines were excluded. RTS was defined as participation in athletics at a level equivalent to or greater than the preinjury level participation. Demographic and prognostic factors, including previous knee surgery, meniscal involvement, level of participation, surgical approach, and graft type, were recorded along with RTS time and analyzed via Poisson regression. Results: In total, 91 athletes, average age 18.8 (± 6.7) years, who underwent ACL reconstruction at a single institution from 2014 to 2021 were identified with an average follow-up time of 4.6 (± 2.5) years (range 1.1, 9.0). Meniscal involvement (1.11; 95% confidence interval [CI] 1.08-1.15, P < .001) and previous knee surgery (1.43; 95% CI 1.29-1.58; P < .001) were related to a delayed RTS. Quadriceps tendon and bone-patellar tendon-bone autografts, as well as allograft, showed a significant association with a longer RTS time when compared with hamstring autograft (1.16, 95% CI 1.13-1.20, P < .001; 1.04, 95% CI 1.01-1.07, P = .020; 1.11, 95% CI 1.03-1.19, P = .004, respectively), as did anteromedial portal drilling, when compared with the outside in approach for femoral drilling (1.19, 95% CI 1.16-1.23, P < .001). Conclusions: Previous knee surgery, anteromedial femoral drilling, quadriceps tendon autograft, and meniscus tear were most associated with a delayed timeline for RTS among young athletes who were able to return. Level of Evidence: Level IV, prognostic case series.

Feasibility of Implementing Patient-Reported and Physical Performance Measures to Identify and Manage Fall Risk in Older Adults Within a Secondary Fracture Clinic.

The purpose of this study was to assess the feasibility of implementing both electronic and in-person assessments to assess falls risk in an older adult secondary fracture clinic. Electronic data capture feasibility was defined as the proportion of patients that completed the electronic questionnaires prior to their clinic visit. In-clinic feasibility was defined in two ways: (1) the proportion of patients that consented to participate at their clinic visit; (2) time to complete testing. Patients were contacted electronically through their health system portal for electronic consent. Patients were invited to complete consent, the STopping Elderly Accidents, Deaths, and Injuries (STEADI) falls risk assessment tool, and the visual analog scale (VAS) for pain. The Short Physical Performance Battery (SPPB) was performed at the clinic visit. A total of 310 patients were contacted electronically. No patients (0%) provided consent through their health portal. Of the 310 patients, 200 (65%) consented in person (Ineligible: 67 [21%]; Declined: 43 [14%]), resulting in an 82% response rate. In-person data collection took a median of 38.48 (Range: 12.34-54.30) minutes to complete. It was not feasible to contact and collect older adult patient data electronically prior to clinic; but, was feasible to obtain these patient-reported outcomes and physical performance data in person.

Development of an exercise therapy referral clinical support tool for patients with osteoporosis at risk for falls.

BACKGROUND: The purpose of this study was to develop a clinical support tool for osteoporosis clinic providers to support risk assessment and referrals for evidence-based exercise therapy programs. METHODS: A sequential Delphi method was used with a multidisciplinary group of national falls experts, to provide consensus on referral to exercise therapy for patients at risk for falls. The Delphi study included a primary research team, expert panel, and clinical partners to answer the questions: (1) "What patient characteristics are needed to develop a clinical support tool?"; (2) "What are the recommended exercise referrals for patients with osteoporosis at risk for falls?" The consensus process consisted of two rounds with 8 weeks between meetings. Two qualitative researchers analyzed the data using a modified version of a matrix analysis approach. RESULTS: The following were the most important variables to include when determining exercise therapy referrals for patients with osteoporosis: Patient history and demographics, falls history over the last year, current physical function and balance, caregiver and transportation status, socioeconomic and insurance status, and patient preference. Potential exercise therapy referrals included one-on-one physical therapy, group physical therapy, home health, community-based exercise programs, and not acceptable for exercise therapy. CONCLUSIONS: Patient characteristics including patient history, physical function and balance performance, socioeconomic and insurance status, and patient preference for exercise therapy are important to inform both the medical provider and patient with osteoporosis to choose the most appropriate exercise therapy referral. Adoption of the algorithmic suggestions may have a significant impact on uptake and adherence to exercise therapy, ultimately improving patient physical function and reducing falls risk.

The Impact of Drive Leg Impulse and Slope on Throwing Velocity and Kinematics in the Competitive Throwing Athlete.

BACKGROUND: Multiple studies have analyzed pitching kinematics using motion analysis technology, but lower extremity drive leg impulse (DLI) and drive leg slope (DLS) are not as well characterized. The purpose of this study was to investigate associations between DLI and DLS and pitch velocity as well as angular velocity of the pelvis, trunk, and humerus. HYPOTHESIS: Increased DLI and DLS will be correlated positively with pitch velocity and associated with increased angular velocities in the humerus, trunk, and pelvis. STUDY DESIGN: Retrospective case series. LEVEL OF EVIDENCE: Level 4. METHODS: Three-dimensional motion analyses data from 174 pitchers (age, 17.0 ± 1.0 years; height, 1.82 ± 0.07 m; weight, 80.0 ± 11.3 kg) throwing combined 613 fastball pitches were included. Pitchers threw 2 to 5 pitches, and the variables collected between pitches were averaged and recorded. Statistical analysis was performed using linear regressions to determine the association between DLS as well as DLI and pitch velocity and angular velocities of the pelvis, trunk, and humerus. RESULTS: Pitchers with higher DLI were associated with lower pitch velocities (ß = -22.32; 95% CI, -32.75 to -11.88, P < 0.01). There were no significant associations for DLS and velocity (ß = -0.60; 95% CI, -1.48 to 0.29, P = 0.18) or DLS and DLI with rotational velocities except for DLI and trunk kinematics (ß = -0.60; 95% CI, -1.48 to 0.29, P = 0.18). CONCLUSION: In the combined cohort, DLI correlated negatively with pitch velocity, although this relationship does not exist in the subgroup analysis. Higher DLS was found in pitchers with slower pitch velocities in the elite, high school, and youth groups, although not statistically significant. No associations were found with DLS and any angular velocities between any level of play analyzed in this study, suggesting no consistent association regardless of playing level.

On-Field Evaluation of Mouthpiece-and-Helmet-Mounted Sensor Data from Head Kinematics in Football.

PURPOSE: Wearable sensors are used to measure head impact exposure in sports. The Head Impact Telemetry (HIT) System is a helmet-mounted system that has been commonly utilized to measure head impacts in American football. Advancements in sensor technology have fueled the development of alternative sensor methods such as instrumented mouthguards. The objective of this study was to compare peak magnitude measured from high school football athletes dually instrumented with the HIT System and a mouthpiece-based sensor system. METHODS: Data was collected at all contact practices and competitions over a single season of spring football. Recorded events were observed and identified on video and paired using event timestamps. Paired events were further stratified by removing mouthpiece events with peak resultant linear acceleration below 10 g and events with contact to the facemask or body of athletes. RESULTS: A total of 133 paired events were analyzed in the results. There was a median difference (mouthpiece subtracted from HIT System) in peak resultant linear and rotational acceleration for concurrently measured events of 7.3 g and 189 rad/s2. Greater magnitude events resulted in larger kinematic differences between sensors and a Bland Altman analysis found a mean bias of 8.8 g and 104 rad/s2, respectively. CONCLUSION: If the mouthpiece-based sensor is considered close to truth, the results of this study are consistent with previous HIT System validation studies indicating low error on average but high scatter across individual events. Future researchers should be mindful of sensor limitations when comparing results collected using varying sensor technologies.

Anterior Cruciate Ligament Return to Sport after Injury Scale (ACL-RSI) Scores over Time After Anterior Cruciate Ligament Reconstruction: A Systematic Review with Meta-analysis.

BACKGROUND: Psychological readiness is an important consideration for athletes and clinicians when making return to sport decisions following anterior cruciate ligament reconstruction (ACLR). To improve our understanding of the extent of deficits in psychological readiness, a systematic review is necessary. OBJECTIVE: To investigate psychological readiness (measured via the Anterior Cruciate Ligament-Return to Sport after Injury scale (ACL-RSI)) over time after ACL tear and understand if time between injury and surgery, age, and sex are associated with ACL-RSI scores. METHODS: Seven databases were searched from the earliest date available to March 22, 2022. Articles reporting ACL-RSI scores after ACL tear were included. Risk of bias was assessed using the ROBINS-I, RoB-2, and RoBANS tools based on the study design. Evidence certainty was assessed for each analysis. Random-effects meta-analyses pooled ACL-RSI scores, stratified by time post-injury and based on treatment approach (i.e., early ACLR, delayed ACLR, and unclear approach). RESULTS: A total of 83 studies were included in this review (78% high risk of bias). Evidence certainty was 'weak' or 'limited' for all analyses. Overall, ACL-RSI scores were higher at 3 to 6 months post-ACLR (mean = 61.5 [95% confidence interval (CI) 58.6, 64.4], I2 = 94%) compared to pre-ACLR (mean = 44.4 [95% CI 38.2, 50.7], I2 = 98%), remained relatively stable, until they reached the highest point 2 to 5 years after ACLR (mean = 70.7 [95% CI 63.0, 78.5], I2 = 98%). Meta-regression suggests shorter time from injury to surgery, male sex, and older age were associated with higher ACL-RSI scores only 3 to 6 months post-ACLR (heterogeneity explained R2 = 47.6%), and this reduced 1-2 years after ACLR (heterogeneity explained R2 = 27.0%). CONCLUSION: Psychological readiness to return to sport appears to improve early after ACL injury, with little subsequent improvement until ≥ 2-years after ACLR. Longer time from injury to surgery, female sex and older age might be negatively related to ACL-RSI scores 12-24 months after ACLR. Due to the weak evidence quality rating and the considerable importance of psychological readiness for long-term outcomes after ACL injury, there is an urgent need for well-designed studies that maximize internal validity and identify additional prognostic factors for psychological readiness at times critical for return to sport decisions. REGISTRATION: Open Science Framework (OSF), https://osf.io/2tezs/ .