Body-worn inertial sensors have enabled motion capture outside of the laboratory setting. In this work, an inertial measurement unit was attached to the upper arm to track and discriminate between shoulder motion gestures in order to help prevent shoulder over-use injuries in athletics through real-time preventative feedback. We present a detection and classification approach that can be used to count the number of times certain motion gestures occur. The application presented involves tracking baseball throws and volleyball serves, which are common overhead movements that can lead to shoulder and elbow overuse injuries. Eleven subjects are recruited to collect training, testing, and randomized validation data, which include throws, serves, and seven other exercises that serve as a large null class of similar movements, which is analogous to a realistic usage scenario and requires a robust estimator.

Background: The 2020 Major League Baseball (MLB) season was drastically altered because of the COVID-19 pandemic. The changes included an extended layoff between March and July as well as a shortened preseason. Purpose/Hypothesis: To determine the incidence and epidemiology of MLB injuries in the abbreviated 2020 season compared with prior seasons. We hypothesized that there was an increase in the overall injury rate in the 2020 season compared with the 2018-2019 seasons and that it equally affected all body regions. Study Design: Descriptive epidemiology study. Methods: The MLB transactions database was queried to find players who had been placed on the injury list between 2018 and 2020. Injuries were categorized into upper extremity, lower extremity, spine/core, and other injuries. Incidence per 1000 athlete-exposures was calculated for the prior 2 seasons (2018-2019) and for the 2020 season separately. Incidence for each category was also calculated separately for pitchers and fielders. Incidence rate ratios (IRRs) and confidence intervals were used to compare injury rates in 2018-2019 versus 2020. The z test for proportions was used to determine significant differences between injury incidences. Results: In 2020, the overall incidence rate per 1000 athlete-exposures was almost twice the rate compared with the 2 seasons before COVID-19 (8.66 vs 5.13; IRR, 1.69 [95% CI, 1.53-1.87]; P < .001). Injury incidence increased similarly in 2020 for both pitchers (IRR, 1.68 [95% CI, 1.47-1.91]; P < .001) and fielders (IRR, 1.68 [95% CI, 1.45-1.96]; P < .001). Increases in injury incidence were seen in the upper extremity, spine/core, and other injury categories; however, the incidence of the lower extremity did not change significantly. Conclusion: There was a significant increase in injury incidence for both pitchers and fielders in 2020. Injury rates increased in anatomic zones of the upper extremity and spine/core but were not significantly changed in the lower extremity. The overall increase in injury rate suggests that irregular or insufficient sport-specific preparation prior to the start of the season placed athletes at a greater risk of injury when play resumed.

The purposes of this study were to: a) measure peak torque (PKT) at 60 and 180°/sec of angular velocity and work data at 180 /sec of angular velocity for isokinetic muscular performance during external/internal rotation (ER/IR) and modified abduction/ adduction (MOD-AB/AD) tests, b) compare the dominant and nondominant upper extremity data, and c) compare the relative peak torque between sexes. Twenty-one males and 20 females were tested isokinetically at 60 and 180 /sec in MOD-ABIAD and ERIIR. A significant difference did not exist behveen the dominant and nondominant shoulders for the PKT. A significant difference did exist between sexes when comparing PKT, total work, and power but not when comparing endurance and agonistlantagonist PKT and work ratios. The data described demonstrated large standard deviations suggesting the need for specific categorization of persons to establish normative values.

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 selfreported 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.

Scapular muscle weakness in patients with lateral elbow tendinopathy is an identified impairment and is part of a multimodal rehabilitation approach. The published literature provides little information regarding specific rehabilitation guidelines that address both the proximal scapular muscle weakness and local elbow/ wrist dysfunctions common in patients with lateral elbow tendinopathy. The purpose of this clinical commentary is to describe a comprehensive rehabilitation strategy for individuals with lateral elbow tendinopathy. This program emphasizes a phased therapeutic strategy that addresses proximal and local dysfunction along the kinetic chain. This clinical protocol is currently being tested for efficacy as part of a randomized controlled trial. The information in this commentary is intended to provide clinicians with sufficient detail to comprehensively guide the rehabilitation of a patient with lateral elbow tendinopathy.