McFadden, BA, Walker, AJ, Bozzini, BN, Sanders, DJ, and Arent, SM. Comparison of internal and external training loads in male and female collegiate soccer players during practices vs. games. J Strength Cond Res 34(4): 969–974, 2020—The purpose of this study was to compare the internal and external training loads (TLs) in men and women throughout a Division I soccer season during practices versus games. Players were evaluated during all practices and regulation game play using the Polar TeamPro system, utilizing Global Positioning Satellite technology and heart rate (HR) monitoring to determine TL, time spent in HR zones expressed as a percent of HRmax (HRZ1–Z5), calories expended per kilogram body mass (Kcal·kg−1), distance covered (DIS), sprints, average speed (SPDAVG), and distance covered in speed zones (DISZ1–Z5). During games, no significant differences were seen between men and women for TL, Kcal·kg−1, HRZ1–Z5, SPDAVG, DIS, DISZ1, DISZ3, and DISZ4. However, men accumulated a significantly greater number of sprints and DISZ5 (p < 0.05) during games, whereas women accumulated a greater DISZ2 (p < 0.05). During practice, no differences were observed for TL, DIS, sprints, Kcal·kg−1, DISZ2, DISZ3, HRZ1–Z5, but men exhibited higher SPDAVG, (p < 0.05), DISZ1 (p < 0.05), DISZ4 (p < 0.05), and DISZ5 (p < 0.05). The parallels in Kcal·kg−1, total DIS, HR, and TL indicate a similar relative workload between men and women. However, distance covered in higher speed zones was found to be greater in men than women across practice and games likely reflecting inherent sex differences in the ability to achieve those speeds. Monitoring techniques that track relative player workloads throughout practices and games may enhance player health and performance during the season. An individualized approach to tracking high-intensity running may improve workload prescriptions on a per player basis.

Bozzini, BN, McFadden, BA, Walker, AJ, and Arent, SM. Varying demands and quality of play between in-conference and out-of-conference games in Division I collegiate women's soccer. J Strength Cond Res 34(12): 3364–3368, 2020—The purpose of this study was to assess differences in physical workloads, physiological responses, and performance variables between in-conference (IC) and out-of-conference (OC) games during a collegiate women's soccer season. Female field players (N = 11), who played a minimum of 45 minutes for >50% of games, were evaluated using an integrative GPS and HR monitoring system to determine training load (TL), exercise energy expenditure (EEE), total distance covered (DIS), sprints, time spent in HR zones 4 and 5 (HRZ4 = 80–89% HRmax; HRZ5 = 90–100% HRmax), and distance covered in speed zones 4 and 5 (DISZ4 = 15.0–19.9 km·h−1; DISZ5 = ≥20 km·h−1). In addition, percent passing accuracy (PA%), dribbling success (DS%), tackling success (TS%), and challenges won (CW%) were generated for all games. Workload data were analyzed as a rate per minute playing time (PT) per game to account for differences in game duration and PT between OC (n = 7) and IC games (n = 11). Repeated-measures multivariate analyses of variance with univariate follow-ups and effect sizes (Hedges' g) were conducted to compare conditions (OC vs. CON) (p < 0.05). There were significantly greater TL, DIS, EEE, and HRZ5 per minute PT in OC versus IC games (Hedges' g: TL = 0.48; DIS = 0.20, EEE = 0.55; HRZ5 = 0.83; p < 0.05). Further analysis found significant differences in first half play favoring OC games (p < 0.05), but not second half play (p > 0.05). Based on these findings, OC games seem to be more demanding compared to IC, particularly during first half play. Emphasis should be placed on tailoring TL to the accumulating in-season demands through athlete-monitoring technology to prevent declines in performance in the latter half of the season.

Background This study evaluated the feasibility of a technology‐enhanced group‐based fitness intervention for adolescent and young adult (AYA) survivors of childhood cancer. Procedure AYA survivors ages 13‐25 years were randomized to the intervention (eight in‐person group sessions with mobile app and FitBit followed by 4 weeks of app and FitBit only) or waitlist control. Assessments were at 0, 2, 3, 6, and 9 months. Feasibility was evaluated by enrollment, retention, attendance, app engagement, and satisfaction. Secondary outcomes included physical activity, muscular strength/endurance, cardiorespiratory fitness, health‐related quality of life, and fatigue. Results A total of 354 survivors were mailed participation letters; 68 (19%) were screened, of which 56 were eligible and 49 enrolled (88% of those screened eligible, 14% of total potentially eligible). Forty‐nine survivors (Mage = 18.5 years, 49% female) completed baseline assessments and were randomized (25 intervention, 24 waitlist). Thirty‐seven (76%) completed the postintervention assessment and 32 (65%) completed the final assessment. On average, participants attended 5.7 of eight sessions (range 1‐8). Overall intervention satisfaction was high (M = 4.3, SD = 0.58 on 1‐5 scale). Satisfaction with the companion app was moderately high (M = 3.4, SD = 0.97). The intervention group demonstrated significantly greater improvement in lower body muscle strength compared to the waitlist postintervention, and small but not statistically significant changes in other secondary measures. Conclusions A group‐based intervention with a mobile app and fitness tracker was acceptable but has limited reach due to geographical barriers and competing demands experienced by AYA survivors.

Walker, AJ, McFadden, BA, Sanders, DJ, Bozzini, BN, Conway, SP, and Arent, SM. Early season hormonal and biochemical changes in Division I field hockey players: is fitness protective? J Strength Cond Res 34(4): 975–981, 2020—The purpose was to evaluate changes in hormonal and biochemical markers as a result of the accumulated stress of the initial 4-week training block in field hockey players. Women's Division I field hockey players (N = 22; Mage = 19.7 ± 1.1 years) performed testing before the start of preseason (A1) that included body composition (%BF), vertical jump, and V̇o 2max. Blood draws were conducted at A1 to assess creatine kinase (CK), iron (Fe), hemoglobin (HGB), hematocrit (HCT), percent saturation (%sat), total cortisol (TCORT), free cortisol (FCORT), interleukin-6 (IL-6), sex hormone–binding globulin (SHBG), prolactin (PRL), vitamin D (vitD), and thyroxine (T3). Blood draws were repeated 4 weeks later (A2). Athletes were monitored during this training block, which included 2 weeks of preseason and the first 2 weeks of the season, using heart rate monitors to determine energy expenditure (Kcal) and training load. There were significant disruptions in TCORT, FCORT, T3, CK, Fe, and SHBG (p < 0.05) from A1 to A2. V̇o 2max accounted for 31% (p < 0.05) of the variance in TCORT and %BF accounting for an additional 20.1% (p < 0.05). V̇o 2max accounted for 32.7% (p < 0.05) of the variance in FCORT. %BF accounted for 48.9% (p < 0.05) of the variance in T3. Kcal was positively correlated with V̇o 2max (p < 0.05) and negatively correlated with %BF (p < 0.05). Athletes with higher V̇o 2max and lower %BF may be capable of a higher work output and therefore more likely to experience increased physiological disruptions during intense training. The high-volume nature of preseason and differences in athlete fitness capabilities require coaches to manage players at an individual level to maintain athlete readiness.

The purpose of this study was to evaluate the effects of a competitive soccer season on biomarkers and performance metrics in order to determine the correlation between changes in biomarkers, body composition, and performance outcomes. Twenty-one Division 1 female collegiate soccer players were monitored throughout the 16-week season. Player workload was measured using heart rate and Global Position Satellite systems at all practices and games. Performance testing, including vertical jump, VO 2max , and 3-repetition maximum testing for bench press, squat and deadlift, occurred prior to pre-season and immediately post-season. Blood draws occurred prior to preseason and every 4-weeks thereafter, following a game. Body composition was assessed prior to the start of season (week 0) and weeks 6, 10, 14, and 17 (post-season). Delta area under the curve was calculated for biomarkers and body composition variables to account for seasonal changes adjusted for baseline. Pearson-product moment correlations were used to assess relationships with significance set at p < 0.05. Trends were considered p ≤ 0.10. No significant time main effects were seen for anabolic biomarkers (p > 0.05). Significant time effects were seen for catabolic biomarkers throughout the season (p = 0.001). No changes in body weight, VO 2max , vertical jump, and deadlift occurred. Squat and bench press improved (p = 0.01 and p = 0.02, respectively) with a decline in percent body fat (p = 0.03) and a trend for increased fat free mass (p = 0.09). Additionally, total cortisol (TCORT) negatively correlated with fat free mass (r = −0.48; p = 0.03) and positively correlated with VO 2max (r = 0.47; p = 0.04). A trend was shown for a positive correlation between both TCORT and free cortisol (FCORT) and percent body fat (r = 0.39; r = 0.40; p = 0.08, respectively). IGF-1 and growth hormone positively correlated to deadlift (r = 0.57; P = 0.02 and r = 0.59; p = 0.03), whereas creatine kinase showed a trend for a positive correlation with deadlift (r = 0.49; p = 0.06). IL-6 negatively correlated with bench press (r = −0.53; p = 0.03). McFadden et al. Biomarkers Correlate With Performance These findings support a relationship between biomarkers, performance outcomes, and body composition. Biomarker monitoring may be useful to detect individual player's physiological response to an athletic season and may help provide insights in efforts to optimize performance outcomes.

Bozzini, BN, McFadden, BA, Scruggs, SK, and Arent, SM. Evaluation of performance characteristics and internal and external training loads in female collegiate beach volleyball players. J Strength Cond Res 35(6): 1559–1567, 2021—Although women's beach volleyball is the fastest growing collegiate sport, the training demands and performance characteristics have yet to be determined. The purpose of this study was to evaluate internal and external training loads throughout a competitive season and to quantify the performance characteristics of National Collegiate Athletic Association Division I women's beach volleyball players. Female beach volleyball players (N = 20) were monitored throughout the 6-week competitive season (T1-T6) using integrative global positioning systems (GPS) and heart rate (HR)–monitoring technology, which was individualized based on preseason testing, for the determination of workload metrics. In addition to team data, all variables were analyzed between travel (n = 11, regular match participation) and non-travel (n = 7) squad athletes (p < 0.05). Team performance metrics demonstrated the explosive power emphasis of the sport, with travel squad players exhibiting significantly greater vertical jump and jump velocity abilities than their non-travel counterparts (p < 0.05). Although few time main effects from T1 to T6 were observed for team workload metrics, follow-ups revealed significant time × group interactions for training load (TL), exercise energy expenditure (EEE), total distance covered, and minutes spent in HR zones (HRZ1-Z5) over the season (p < 0.05). Finally, although average workloads were greater in practices than in matches, when accounting for pre-match warm-ups, competition load was greater than practice (p < 0.05). National Collegiate Athletic Association Division I women's beach volleyball is a demanding, explosive power sport characterized by overall large TL and EEE, particularly in-season when athletes compete in 4 matches per weekend. The workloads observed point to the need to assess and manage training loads and fueling requirements to optimize performance and decrease injury risk.

McFadden, BA, Walker, AJ, Bozzini, BN, Hofacker, M, Russell, M, and Arent, SM. Psychological and physiological changes in response to the cumulative demands of a women's division I collegiate soccer season. J Strength Cond Res 36(5): 1373–1382, 2022—This study sought to determine the effects of a women's collegiate soccer season on psychological markers, biomarkers, sleep, and performance. Athletes participated in maximal countermovement vertical jump height (CMJ) assessments and biomarker monitoring in conjunction with subjective measures of psychological wellness and sleep questionnaires before preseason (S1) and every 4 weeks following (S2, S3, and S4). Training was monitored during practices and games using global positioning satellite systems and heart rate technology. Total training load was highest from S1 to S2, decreased from S2 to S3 (effect size [ES] = -2.5; p < 0.001), and remained stable from S3 to S4. CMJ declined at S2 (ES1-2 = −0.51; p = 0.001) and returned to baseline at S3. Increases from S1 to S2 were seen for creatine kinase (ES1-2 = 1.74), free testosterone (ES1-2 = 1.27), total testosterone (ES1-2 = 3.5), and free cortisol (ES1-2 = 0.88) (p < 0.03) before returning to baseline by S3 and S4 (free cortisol). Total cortisol was elevated throughout the season before declining at S4 (ES1-4 = −0.41; p = 0.03). Iron declined from S1 to S2 (ES1-2 = −0.73; p = 0.01) and returned to baseline values at S4, whereas growth hormone declined at S2 (ES1-2 = −0.50; p = 0.01) and remained depressed. Interleukin-6 increased at S4 (ES1-4 = 0.71; p = 0.02). Total training distress decreased from S1 to S2 (ES1-2 = −0.38; p = 0.02), returned to baseline by S3, and increased by S4 (ES1-4 = 0.57; p = 0.01). No changes were observed in markers of sleep (p > 0.05). Biomarkers showed notable changes after the highest workload period (S1-S2), which coincided with CMJ decrements. Biomarker perturbations preceded declines in subjective psychological wellness (S4) which occurred in the latter half of the season, indicating an accumulation of fatigue as the season progressed.

High training demands throughout the competitive season in female collegiate soccer players have been shown to induce changes in biomarkers indicative of stress, inflammation, and reproduction, which may be exacerbated in athletes using oral contraceptives (OCs). Purpose: To compare biomarkers and body composition between OC-using and non-using (CON) female soccer players throughout a competitive season. Methods: Female collegiate soccer players were stratified into two groups based on their reported OC use at the start of pre-season (OC: n=6; CON: n=17). Prior to the start of pre-season and immediately post-season, athletes underwent a battery of performance tests. Blood draws and body composition assessments were performed prior to pre-season, on weeks 2, 4, 8, and 12 of the season, and post-season. Results: Area-under-the-curve ratios (OCAUC:CONAUC) indicated the OC group were exposed to substantially higher levels of sex-hormone binding globulin (AUCratio=1.4, probability=p>0.999), total cortisol (1.7; p>0.999), c-reactive protein (5.2; p>0.999), leptin (1.4; p=0.990), growth hormone (1.5; p=0.97), but substantively lower amounts of estradiol (0.36; p<0.001), progesterone (0.48; p=0.008), free testosterone (0.58; p<0.001), follicle-stimulating hormone (0.67; p<0.001) and creatine kinase (0.33, p<0.001) compared with the CON across the season. Both groups increased fat free mass over the season, but CON experienced a greater magnitude of increase along with decreased body fat percentage. Conclusion: Although similar training loads were observed between groups over the season, the elevated exposure to stress, inflammatory, and metabolic biomarkers over the competitive season in OC users may have implications on body composition, training adaptations, and recovery in female athletes.