Rapid Weight Gain and Weight Differential Predict Competitive Success in 2100 Professional Combat-Sport Athletes.

PURPOSE: Combat-sport athletes commonly undergo rapid weight loss prior to prebout weigh-in and subsequently rapid weight gain (RWG) prior to competition. This investigation aimed to evaluate the effect of RWG and weight differential (WD) between opponents on competitive success. METHODS: A retrospective cohort study was performed using data from professional mixed martial arts (MMA) and boxing events held between 2015 and 2019. The primary outcome was RWG (relative and absolute) between weigh-in and competition stratified by bout winners and losers. Binary logistic regression was used to explore the relationships among bout outcome, RWG, and WD between competitors on the day of their bout. RESULTS: Among 708 MMA athletes included, winners regained more relative body mass (8.7% [3.7%] vs 7.9% [3.8%], P < .01) than losers. In 1392 included male boxers, winners regained significantly more relative body mass (8.0% [3.0%] vs 6.9% [3.2%], P < .01) than losers. Each percentage body mass increase resulted in a 7% increased likelihood of victory in MMA and a 13% increase in boxing. The relationship between RWG and competitive success remained significant in regional and male international MMA athletes, as well as boxers. WD predicted victory in international mixed martial artists and boxers. WD predicted victory by knockout or technical knockout in international MMA athletes and regional boxers. CONCLUSION: This analysis of combat-sport athletes indicates that RWG and WD influence competitive success. These findings raise fair-play and safety concerns in these popular sports and may help guide risk-mitigating regulation strategies.

Assessing Skill Acquisition in Anesthesiology Interns Practicing Central Venous Catheter Placement Through Advancements in Motion Analysis.

OBJECTIVES: The study authors hypothesized that a combination of previously used (path length, translational motions, and time) and novel (rotational sum) motion metrics could be used to analyze learning curves of anesthesiology interns (postgraduate year 1) practicing central venous catheter placement in the simulation setting. They also explored the feasibility of using segmented motion recordings to inform deliberate practice. DESIGN: A prospective cohort study. SETTING: A single academic medical center. PARTICIPANTS: Anesthesiology interns (postgraduate year 1). INTERVENTIONS: Anesthesiology interns underwent a 2-day training course in which they performed 9 central venous catheter placements, while attached to motion sensors on the dorsum of their dominant hand and ultrasound probe. MEASUREMENTS AND MAIN RESULTS: Motion metrics were analyzed using generalized estimating equations for both the overall procedure and predefined segments. Five attending anesthesiologists performed 3 trials each for comparison. Overall, there was a negative trend in path length, translational motions, rotational sum, and time (p < 0.001), with the exception of translational motions of the ultrasound probe. Interns reached within 1 standard deviation of the attending anesthesiologists by trials 7-to-8 for most metrics. Segmentation identified specific components of the procedure that were either significantly improved upon or required deliberate practice. The novel metric of rotational sum exhibited a moderate-to-strong positive correlation with other metrics (p < 0.001). CONCLUSIONS: A comprehensive series of motion metrics was able to describe the learning curves of novices training to perform central venous catheter placement in the simulation setting. Furthermore, it was determined that segmentation may provide additional insight into skill acquisition and inform deliberate practice.