Relationships between External, Wearable Sensor-Based, and Internal Parameters: A Systematic Review

Micro electro-mechanical systems (MEMS) are used to record training and match play of intermittent team sport athletes. Paired with estimates of internal responses or adaptations to exercise, practitioners gain insight into players' dose-response relationship which facilitates the prescription of the training stimuli to optimize performance, prevent injuries, and to guide rehabilitation processes. A systematic review on the relationship between external, wearable-based, and internal parameters in team sport athletes, compliant with the PRISMA guidelines, was conducted. The literature research was performed from earliest record to 1 September 2020 using the databases PubMed, Web of Science, CINAHL, and SportDISCUS. A total of 66 full-text articles were reviewed encompassing 1541 athletes. About 109 different relationships between variables have been reviewed. The most investigated relationship across sports was found between (session) rating of perceived exertion ((session-)RPE) and PlayerLoad™ (PL) with, predominantly, moderate to strong associations (r = 0.49-0.84). Relationships between internal parameters and highly dynamic, anaerobic movements were heterogenous. Relationships between average heart rate (HR), Edward's and Banister's training impulse (TRIMP) seem to be reflected in parameters of overall activity such as PL and TD for running-intensive team sports. PL may further be suitable to estimate the overall subjective perception. To identify high fine-structured loading-relative to a certain type of sport-more specific measures and devices are needed. Individualization of parameters could be helpful to enhance practicality.

Seasonal Training Load Quantification and Comparison in College Male Soccer Players

Ryan, GA, Snarr, RL, Eisenman, ML, and Rossi, SJ. Seasonal training load quantification and comparison in college male soccer players. J Strength Cond Res XX(X): 000-000, 2020-Monitoring and quantification of training load (TL) throughout a competitive soccer season is important to ensure players are able to perform throughout the season. The intent of this study was to examine the positional demands and patterns of select measures of TL during a 14-week season in collegiate male soccer players. Heart rate (HR), running performance (SZ), and perceived recovery data were collected daily using a bioharness for each subject (n = 21). Data were grouped into 2- to 3-week training blocks (Pre1, Pre2, In1, In2, In3, and In4). Continuous variables were analyzed using a multivariate analysis of variance, with post hoc Least Squared Difference pairwise comparisons. Significant positional differences were observed across the season. During Pre1, center midfielders (CM) spent more time in %HRlow compared to center backs (CB) (p < 0.01), wide midfielders (p < 0.01), and center forwards (p = 0.04). Center midfielders spent greater time in SZlower than CB (p < 0.01) and wide backs (WB) (p = 0.01). Wide backs spent greater time in SZupper compared to other positions (all p < 0.01). During Pre2, WB spent more time in %HRhigh and SZupper compared to other positions (all p < 0.01). Positional differences were more varied throughout in-season comparisons, but generally, WB and CB demonstrated higher intensities in variables compared to other positions. Tracking variations in positional TLs across the season is important for coaching and training staffs to determine player readiness and plan future training sessions, while helping to mitigate overuse injuries during a long competitive season.

Monitoring Internal Training Load, Stress-Recovery Responses, and Immune-Endocrine Parameters in Brazilian Jiu-Jitsu Training

Campos, F, Molina Correa, JC, Canevari, VCM, Branco, BHM, Andreato, LV, and de Paula Ramos, S. Monitoring internal training load, stress-recovery responses, and immune-endocrine parameters in Brazilian jiu-jitsu training. J Strength Cond Res XX(X): 000-000, 2020-This study aimed to evaluate the relationship between training loads, stress, and immune-endocrine markers during a precompetitive period in Brazilian jiu-jitsu (BJJ) athletes. For this, 12 athletes were submitted to 1 physical and 1 technical-tactical training session per day, 5 days a week, for 7 weeks. The saliva sampling and physical tests (countermovement jump [CMJ] and squat jump [SJ]) were performed before starting the training period (pre) and at the fourth week (4-week) and eighth week (post). Session rating of perceived exertion (sRPE) and the Recovery-Stress Questionnaire-Sport (RESTQ) were applied, and the training load was calculated weekly. Repeated-measures analysis of variance and the Friedman test were used, with significance levels set at p < 0.05. Increased training loads were recorded by the sRPE method in technical-tactical training sessions (p < 0.05). Higher physical loads were reported by athletes during weeks 1-4, contributing to overall higher training load, monotony, and strain during this period (p < 0.05). Increased perception of stress, by the RESTQ, and cortisol were detected, whereas decreased salivary testosterone and salivary immunoglobulin A were observed at 4 weeks (p < 0.05). No significant differences were detected in CMJ and SJ tests, suggesting that training neither elicited significant fatigue and underperformance nor improved strength performance. However, decreasing physical training loads appeared to reduce symptoms of stress and improved recovery, favoring immune recovery and anabolic balance. Thus, the sRPE seems to be a reliable and simple method to monitor training loads in BJJ athletes because variation in values was related to the RESTQ and physiological responses to training loads.