The Impact of Early Morning Training Sessions on Total Sleep Time in Collegiate Athletes

International Journal of Exercise Science 15(6): 423-433, 2022. Early morning training sessions may affect sleep quantity in athletes. The purpose of this study is to examine differences in total sleep time of collegiate athletes on nights prior to early morning training sessions relative to non-training nights. Wristwatch monitors equipped with photoplethysmography and accelerometer technology were worn by 18 NCAA Division III collegiate athletes (Age: 20.1 ± 1.6 years, Height: 1.81 ± 0.02 m, Body Mass: 91.2 ± 6.5 kg, Body Fat %: 20.8 ± 1.6%) during a two-week period of training to monitor total sleep times. Athletes recorded time in and out of bed using a sleep diary, anxiety levels due to having to wake up in the morning, and perceived recovery status (PRS) upon waking the next day. The data were divided into: nights before non-training days (NT) and Training days (TD). Data were analyzed using univariate analysis. All athletes obtained significantly less total sleep on nights before TD relative to NT (NT: 8:15 ± 1:03 vs. TD: 6:08 ± 0:59 hh:mm; p \u3c 0.05). There was a positive relationship between total sleep time and recovery status (p \u3c 0.01). Anxiety scores were inversely related to total sleep time (p \u3c 0.01). Next-day recovery status was inversely related to anxiety scores (p \u3c 0.001). College athletes obtained significantly less total sleep time on nights before early morning training sessions (\u3c 0700) during the off-season, regardless of sex and sport. Coaches should consider later training sessions or promote optimal sleep quantity in order to minimize the risks associated to early morning training sessions

Examining Changes in Shoulder Strength, Lower Body Power, and Body Composition among Collegiate Baseball Players after Completion of a Summer Baseball League Season

The strength of the shoulder musculature involved with internal rotation and arm extension plays an important role in the overhead throwing motion for baseball athletes, both for throwing-related performance and injury risk. The maintenance of shoulder strength is a high priority for baseball athletes throughout a season; however, little is known in regards to the expected changes in strength throughout a season. To examine pre-post changes in shoulder strength, lower body power, and body composition among collegiate baseball players after the completion of a summer baseball league season. Amateur baseball players (n = 12; age: 20.9 ± 1.0 years.; height: 181.6 ± 5.6 cm; body mass: 86.4 ± 11.1 kg; BMI: 26.0 ± 2.6 kg/m2) participated in the current study. Pre- and post-competitive season, the participants completed shoulder strength assessments and body composition and countermovement vertical jump (CMJ) tests. An upper-body isometric test (athletic shoulder [ASH] test) was used to evaluate shoulder strength for each arm. Each subject completed maximal isometric contractions for both the throwing and non-throwing arms at four separate angles of abduction (180°, ‘I’; 135°, ‘Y’; 90°, ‘T’; and −180°, ‘A’) while lying in a prone position. For shoulder strength, the primary dependent variable of interest was a composite measure that represented the average of the forces produced across all four positions of the ASH test (I, Y, T, A). For the ASH test composite measure, there was a trend toward a significant arm-by-time interaction effect (p = 0.08), as shoulder strength decreased by 9.03% for the throwing arm (ES = 0.72; 95% CI = [−0.27, −0.01]), compared to only 2.03% for the non-throwing arm (ES = 0.15; 95% CI = [−0.16, 0.09]), over the course of the season. The main effects of time (p = 0.16) and arm (p = 0.58) were not significant for the ASH test composite measure. There was no relationship between lower body power and throwing arm strength at baseline (r = 0.20, p = 0.56), and only a non-significant weak relationship at post-test (r = 0.28, p = 0.41). Throughout a season, baseball players may experience reductions in shoulder strength of the throwing arm with minimal changes in shoulder strength in the non-throwing arm

Systems approach to designing a maritime Phase Zero Force for the year 2020

Includes supplementary materialThis report details the construct of a maritime force designed solely for the accomplishment of Phase Zero missions. Accomplishment of Phase Zero missions will increase a region's stability thus decreasing the spread of radical ideologies that could spawn large scale terrorist attacks and prevent smaller conflicts from growing into larger more expensive ones. To devise this force the integrated study team had to take the broad idea of Phase Zero operations and determine which specific missions contribute to the completion of what they defined as the overall Phase Zero mission. Based on these missions, the integrated study team built scenarios that were representative of the entire Phase Zero mission area. These scenarios were used to establish what capabilities were important to a maritime Phase Zero Force. With these capabilities in mind, the team constructed maritime forces and then evaluated them against the same scenarios to determine which ones performed better. The recommended force can be fielded for an annual cost of $360 million and could accomplish all of the Phase Zero scenarios that the integrated study team built.http://archive.org/details/systemspproachto109456941N