Background and objectives: Research investigating hydration strategies specialized for women’s soccer players is limited, despite the growth in the sport. The purpose of this study was to determine the effects of fluid balance and electrolyte losses in collegiate women’s soccer players. Materials and Methods: Eighteen NCAA Division I women’s soccer players were recruited (age: 19.2 ± 1.0 yr; weight: 68.5 ± 9.0 kg, and height: 168.4 ± 6.7 cm; mean ± SD), including: 3 forwards (FW), 7 mid-fielders (MD), 5 defenders (DF), and 3 goalkeepers (GK). Players practiced outdoor during spring off-season training camp for a total 14 practices (WBGT: 18.3 ± 3.1 °C). The main outcome measures included body mass change (BMC), sweat rate, urine and sweat electrolyte concentrations, and fluid intake. Results: Results were analyzed for comparison between low (LOW; 16.2 ± 2.6° C, n = 7) and moderate risk environments for hyperthermia (MOD; 20.5 ± 1.5 °C, n = 7) as well as by field position. The majority (54%) of players were in a hypohydrated state prior to practice. Overall, 26.7% of players had a %BMC greater than 0%, 71.4% of players had a %BMC less than −2%, and 1.9% of players had a %BMC greater than −2% (all MD position). Mean %BMC and sweat rate in all environmental conditions were −0.4 ± 0.4 kg (−0.5 ± 0.6% body mass) and 1.03 ± 0.21 mg·cm⁻²·min⁻¹, respectively. In the MOD environment, players exhibited a greater sweat rate (1.07 ± 0.22 mg·cm⁻²·min⁻¹) compared to LOW (0.99 ± 0.22 mg·cm⁻²·min⁻¹; p = 0.02). By position, DF had a greater total fluid intake and a lower %BMC compared to FW, MD, and GK (all p < 0.001). FW had a greater sweat sodium (Na+) (51.4 ± 9.8 mmol·L⁻¹), whereas GK had the lowest sweat sodium (Na+) (30.9 ± 3.9 mmol·L⁻¹). Conclusions: Hydration strategies should target pre-practice to ensure players are adequately hydrated. Environments deemed to be of moderate risk of hyperthermia significantly elevated the sweat rate but did not influence fluid intake and hydration status compared to low-risk environments. Given the differences in fluid balance and sweat responses, recommendations should be issued relative to soccer position.

This study aimed to describe the physical demands of American football players using novel performance analysis techniques. Heart rate (HR) and accelerometer-based activity levels were observed across two pre-season scrimmages in 23 Division I collegiate football players (age: 19 ± 1 y, height: 1.90 ± 0.06 m, weight: 116.2 ± 19.4 kg). Data were analyzed using a MATLAB program and inter-rater reproducibility assessed using inter-class correlations (ICC). Players were analyzed by side (offense/defense) and position (skill/non-skill). Performance variables assessed in bursts of activity included burst duration, HR_mean and HR_max (bpm), and mean activity (vector magnitude units [vmu]). Exercise intensity was categorized as time spent in % HRmax in 5% increments. The burst duration (8.1±3.9 min, ICC = 0.72), HR_mean (157 ± 12 bpm, ICC = 0.96) and mean activity (0.30 ± 0.05 vmu, ICC = 0.86) were reproducible. HR_mean (p = 0.05) and HR_max (p = 0.001) were greater on defense. Offense spent more time at 65–70% HR_max (p = 0.01), 70–75% HR_max (p = 0.02) while defense spent more time 90–95% HR_max and ≥95% HR_max (p = 0.03). HR_mean (p = 0.70) and HR_peak (p = 0.80) were not different between positions across both sides. Skilled players demonstrated greater mean activity (p = 0.02). The sport-specific analysis described HR and activity level in a reproducible manner. Automated methods of assessing HR may be useful in training and game time performance but ultimately provides support to coaching decision making.

Background/Objectives: Exertional rhabdomyolysis (ER) is a possibly fatal condition resulting from extreme or novel exercise that causes substantial muscle breakdown. ER has been observed during preseason football; however, prospective research has yet to characterize normal versus ER responses using a repeated measures design. This study characterized ER biomarker responses related to muscle damage, and renal and hepatic stress, after two NCAA Division I preseason football scrimmages. Methods: Following a prospective, repeated measures design, blood and urine samples from 17 players were collected immediately (IPS) and 24 h post-scrimmage (24hPS). A subset (n = 13) provided samples after 48 h of rest as a non-exertion (NE) comparator group. A Comprehensive Metabolic Panel was run on serum samples, and urine samples were analyzed for myoglobin and creatinine. Values were compared with reference ranges, mixed models evaluated time effects, and linear regressions examined associations between CPK and renal and hepatic biomarkers. Results: No participants were diagnosed with ER. A time effect was observed for CPK (p < 0.01), with CPK greater IPS (991.6 ± 560.8 IU/L) compared to NE (267.7 ± 205.3 IU/L), and remaining elevated above reference ranges at 24hPS (739.2 ± 442.6 IU/L). Similar time effects were observed with LDH, AST, and ALT (p < 0.01). Serum creatinine increased above reference values and NE concentrations (p < 0.01). CPK correlated (p < 0.01 for all) with LDH (r = 0.69), serum myoglobin (r = 0.57), creatinine (r = 0.42), AST (r = 0.77), and ALT (r = 0.38). Conclusions: Biomarkers of muscle damage, renal stress, and liver function were higher IPS, with only partial recovery by 24hPS. These findings provide preliminary reference patterns for biomarker fluctuations and support individualized, serial monitoring to identify abnormal responses and promote early detection of ER.

Background: Symptom scales are routinely used in sport during concussion screening and return-to-play. Limited research has explored the presence of concussion symptoms in the absence of a diagnosed concussion. This study analyzed concussion symptom scores in concussed vs. non-concussed football players after football activities and evaluated the effect of field of play variables. Methods: NCAA Division I football players with (n = 9) and without (n = 30) diagnosed concussion completed concussion symptom scales (C3 Logix) following practice for 1 week. Wet bulb globe temperature (WBGT), play duration, equipment, and location (inside/outside) were recorded. Mixed models analyzed the effect of day, WBGT, equipment, location, and play duration on concussion-like symptoms in non-concussed players and determined the time course of symptom relief in concussed players. Results: Fatigue or low energy (27.6%), neck pain (16.8%), feeling slowed down (14.8%), and headache (12.8%) were most reported. In non-concussed players, total symptoms scores were higher early in the week (Monday/Tuesday) and decreased throughout the week (p < 0.01). No effect of play duration (p = 0.49), WBGT (p = 0.12), equipment (p = 0.40), or location (p = 0.83) was found. Symptom scores were greater in the concussed vs. non-concussed groups on days 1–3. Conclusions: Football players report concussion-like symptoms in the absence of a concussion diagnosis, particularly following the first few practices after a game.