Effects of Intravenous Cold Saline on Hyperthermic Athletes Representative of Large Football Players and Small Endurance Runners.

OBJECTIVE: To evaluate the cooling effects of intravenous (IV) cold normal (0.9%) saline on hyperthermic athletes. DESIGN: Randomized crossover study design. SETTING: Controlled research laboratory. PARTICIPANTS: Twelve male participants who were representative of a collegiate cross-country (6) and American football (6) population. INTERVENTIONS: Participants underwent body composition analysis using a BodPod. They were placed in an environmentally controlled chamber and brought to a Tc of 39.5°C with dynamic exercise. When temperatures were reached, they were treated with either 2 L of cold saline (CS) (4°C) or intravenous room temperature (22°C) saline (RS) over a ∼30-minute period. Tre was measured with a rectal temperature probe every minute during the treatment period. MAIN OUTCOME MEASURES: Total ΔTre (ending Tre - starting Tre) and cooling rate (total change in Tre/time) were measured for each condition, and body composition variables calculated included body surface area (BSA), BSA-to-mass ratio (BSA/mass), lean body mass, and body fat percentage (%BF) (P < 0.05). RESULTS: Statistically significant differences were found in the total ΔTre and cooling rate between the CS and RS trials. The cooling rate for the CS trials was significantly correlated to mass, BSA, BSA/mass, and %BF. CONCLUSIONS: In hyperthermic athletes, core temperature was reduced more effectively using chilled saline during IV infusion. Body composition had a significant impact on overall cooling revealing that the smaller and leaner participants cooled at a greater rate. When indicated, CS infusion could be considered for cooling hyperthermic individuals when other methods are not available.

Effects of Cardiovascular Fitness and Body Composition on Maximal Core Temperature in Collegiate Football Players During Preseason.

McClelland, JM, Godek, SF, Chlad, PS, Feairheller, DL, and Morrison, KE. Effects of cardiovascular fitness and body composition on maximal core temperature in collegiate football players during preseason. J Strength Cond Res 32(6): 1662-1670, 2018-This study evaluated the effects of body mass index (BMI) and aerobic fitness (V[Combining Dot Above]O2max) on maximal core temperature values (Tcmax) in 17 National Collegiate Athletic Association Division III football players during preseason. The subjects included 9 backs (BKs) and 8 linemen (LM). V[Combining Dot Above]O2max testing was performed 1 week before preseason. Core temperature was monitored by ingestible sensor every 10 minutes during practices on day 4 (D1), day 5 (D2), day 7 (D3), and postacclimatization on day 14 (D4). Wet bulb globe temperature (WBGT) was recorded on each collection day. Independent, paired t-tests and Pearson's correlations were performed (α = 0.05). There were no significant correlations between V[Combining Dot Above]O2max and Tcmax on D1 (WBGT = 29.07° C) or D2 (WBGT = 30.93° C), but on D3 (WBGT = 31.39° C) there was a nonsignificant moderate negative correlation (r = -0.564, p = 0.090). There were no significant correlations between BMI and Tcmax on D1 or D2, but on D3 there was a nonsignificant moderate positive correlation (r = 0.596, p = 0.069). Paired t-tests revealed that overall Tcmax (D1-3) (38.56 ± 0.32° C) was statistically higher (p = 0.002) than D4 (38.16 ± 0.30° C). Independent t-tests between groups showed that the Tcmax values during preacclimatization (D1-D3) were significantly higher in LM (38.50 ± 0.37° C) than BKs (38.16 ± 0.35° C) (p = 0.007). V[Combining Dot Above]O2max was significantly lower (p = 0.006) in LM (36.89 ± 6.40 ml·kg·min) than BKs (47.44 ± 7.09 ml·kg·min), and BMI was significantly higher (p = 0.019) in LM (35.59 ± 4.00 kg·m) than BKs (28.68 ± 3.38 kg·m). The results of this study demonstrate that LM are significantly less fit than BKs and have a greater BMI. When WBGT was the highest on D3, the results suggest that those with lower V[Combining Dot Above]O2max and higher BMI experienced a higher Tcmax.

Plantar pressure during running in subjects with chronic ankle instability.

BACKGROUND: It has been suggested that dynamic foot and ankle mechanics predispose individuals with CAI to repetitive episodes of the ankle ``giving way.'' Plantar pressure variations during a walking gait have been detected in those with CAI, but more dynamic conditions for analysis are needed. The purpose of this study was to evaluate plantar pressure distributions during a running gait in individuals with CAI, individuals who suffered a lateral ankle sprain, but did not develop CAI (AS), and subjects with no history of a lateral ankle sprain (CON). MATERIALS AND METHODS: Forty-five subjects [15 in each group, healthy males (18) and females (27), age 18 to 45] were recruited from University communities to participate in this study. Plantar pressure distributions were analyzed on a Tekscan© plantar pressure mat at 66 frames per second during a running gait at a controlled speed. The following variables were obtained: rearfoot medial/lateral (M/L) pressure ratio at foot strike (FS) and center-of-pressure (COP) trajectory during the initial loading response (heel strike to initial peak GRF). Separate one-way ANOVA with Tukey's post-hoc were used to test for group differences. The significance level was defined as p < 0.05. RESULTS: The CAI group had a significantly more lateral ratio (0.97 ± 0.12) at FS when compared to the CON (1.01 ± 0.13) and AS (1.11 ± 0.13) groups. The CAI subjects had a lateral COP trajectory during the loading phase (7.97 degrees ± 11.02), while both the AS (-3.68 degrees ± 10.24) and CON groups (-6.27 degrees ± 9.86) had medial trajectories. The difference was significant between the CAI group and both the AS and CON groups (all significant {\it p} values were less than 0.05). CONCLUSION: Our results confirm that CAI subjects have a more lateral foot positioning and loading pattern during a barefoot running gait when compared to both the CON and LAS groups. CLINICAL RELEVANCE: Clinicians treating patients with CAI should consider providing interventions to decrease the amount of rearfoot inversion at FS and during loading in order to create a more medial COP trajectory upon impact.

Cold-Water Immersion Cooling Rates in Football Linemen and Cross-Country Runners With Exercise-Induced Hyperthermia.

CONTEXT: Ideal and acceptable cooling rates in hyperthermic athletes have been established in average-sized participants. Football linemen (FBs) have a small body surface area (BSA)-to-mass ratio compared with smaller athletes, which hinders heat dissipation. OBJECTIVE: To determine cooling rates using cold-water immersion in hyperthermic FBs and cross-country runners (CCs). DESIGN: Cohort study. SETTING: Controlled university laboratory. PATIENTS OR OTHER PARTICIPANTS: Nine FBs (age = 21.7 ± 1.7 years, height = 188.7 ± 4 cm, mass = 128.1 ± 18 kg, body fat = 28.9% ± 7.1%, lean body mass [LBM] = 86.9 ± 19 kg, BSA = 2.54 ± 0.13 m2, BSA/mass = 201 ± 21.3 cm2/kg, and BSA/LBM = 276.4 ± 19.7 cm2/kg) and 7 CCs (age = 20 ± 1.8 years, height = 176 ± 4.1 cm, mass = 68.7 ± 6.5 kg, body fat = 10.2% ± 1.6%, LBM = 61.7 ± 5.3 kg, BSA = 1.84 ± 0.1 m2, BSA/mass = 268.3 ± 11.7 cm2/kg, and BSA/LBM = 298.4 ± 11.7 cm2/kg). INTERVENTION(S): Participants ingested an intestinal sensor, exercised in a climatic chamber (39°C, 40% relative humidity) until either target core temperature (Tgi) was 39.5°C or volitional exhaustion was reached, and were immediately immersed in a 10°C circulated bath until Tgi declined to 37.5°C. A general linear model repeated-measures analysis of variance and independent t tests were calculated, with P < .05. MAIN OUTCOME MEASURE(S): Physical characteristics, maximal Tgi, time to reach 37.5°C, and cooling rate. RESULTS: Physical characteristics were different between groups. No differences existed in environmental measures or maximal Tgi (FBs = 39.12°C ± 0.39°C, CCs = 39.38°C ± 0.19°C; P = .12). Cooling times required to reach 37.5°C (FBs = 11.4 ± 4 minutes, CCs = 7.7 ± 0.06 minutes; P < .002) and therefore cooling rates (FBs = 0.156°C·min-1 ± 0.06°C·min-1, CCs = .255°C·min-1 ± 0.05°C·min-1; P < .002) were different. Strong correlations were found between cooling rate and body mass (r = -0.76, P < .001), total BSA (r = -0.74, P < .001), BSA/mass (r = 0.73, P < .001), LBM/mass (r = 0.72, P < .002), and LBM (r = -0.72, P < .002). CONCLUSIONS: With cold-water immersion, the cooling rate in CCs (0.255°C·min-1) was greater than in FBs (0.156°C·min-1); however, both were considered ideal (≥0.155°C·min-1). Athletic trainers should realize that it likely takes considerably longer to cool large hyperthermic American-football players (>11 minutes) than smaller, leaner athletes (7.7 minutes). Cooling rates varied widely from 0.332°C·min-1 in a small runner to only 0.101°C·min-1 in a lineman, supporting the use of rectal temperature for monitoring during cooling.

Factors influencing help-seeking from informal networks among African American victims of intimate partner violence.

The purpose of this study was to gain an understanding of the challenges African-American women in abusive relationships face when they consider seeking-help from their informal networks. Data are reported from interviews with 15 African-American women who were self-identified as having survived physical intimate partner violence. A 13-item, semi-structured interview guide was developed in order to elicit information from participants. All of the interviews were audio-recorded, transcribed, and coded for analysis. This analysis revealed emergent themes from these interviews concerning the social factors and perceptions that influence help-seeking behavior. Participants perceived their informal networks as willing to offer instrumental support. However, informal networks were not emotionally supportive. Participants also noted that the African-American community at-large believes victims of violence to be "stupid" for remaining in violent relationships. Additional results are also discussed. Results may be used to help enhance efforts to reduce the rates of intimate partner violence among African-Americans.

Foot characteristics in association with inversion ankle injury.

OBJECTIVE: To review the literature that provides information to assist in analyzing the role of the foot in acute and chronic lateral ankle injury. DATA SOURCES: We searched MEDLINE, CINAHL, Institute for Scientific Information's Web of Science, and SPORT Discus from 1965-2005 using the terms lateral, ankle, ligament, injury, risk factors, foot, subtalar joint, talocrural joint, gait analysis, and foot biomechanics. DATA SYNTHESIS: We found substantial information on the incidence and treatment of lateral ankle sprains in sport but very few articles that focused on risk factors associated with these injuries and even less information on the foot as it relates to this condition. Moreover, little information was available regarding the risk factors associated with the development of chronic instability after a lateral ankle sprain. We critically analyzed the foot articulations and the foot's role in the mechanism of injury to assist our clinical synopsis. CONCLUSIONS/RECOMMENDATIONS: An in-depth review of the foot complex in relation to lateral ankle sprains strongly suggested its importance when treating and preventing inversion ankle trauma. Throughout the literature, the only static foot measurements that show a significant correlation to this condition are an identified cavovarus deformity, increased foot width, and increased calcaneal eversion range of motion. Authors also provided dynamic measurements of the foot, which produced several significant findings that we discuss. Although our findings offer some insight into the relationship between foot characteristics and lateral ankle injuries, future research is needed to confirm the results of this review and expand this area of investigation.