Access to athletic trainers and sex as modifiers of time to reach clinical milestones after sport-related concussion in collegiate athletes.

OBJECTIVE: Investigate whether an athlete's biological sex and exposure to a dedicated athletic trainer (AT) were related to clinical milestones after a sports-related concussion (SRC). DESIGN: Retrospective chart review. METHODS: Medical charts of collegiate athletes (n = 196 [70.9% female]) diagnosed with SRC were reviewed to extract: biological sex, dedicated AT exposure for their sport (yes/no), and time (days) to reaching clinical milestones (diagnosis, symptom resolution, unrestricted return to sport [RTS]). Mann-Whitney U tests were used to determine whether time to clinical milestones differed by sex, AT exposure, or their interaction. Proportions of same-day diagnoses and times to diagnosis, symptom resolution, and unrestricted RTS were evaluated with chi-squared and spearman's rank correlations, respectively. RESULTS: There were no significant differences in times to reaching any clinical milestone by sex, AT exposure, or their interaction (ps > 0.05). Forty-three percent of participants were diagnosed on the day of their SRC. This did not differ by sex or AT exposure (ps > 0.29). Longer times to SRC diagnosis were associated with more days to symptom resolution (ρ = 0.236, p = 0.001) and unrestricted RTS (ρ = 0.223, p < 0.001). CONCLUSIONS: Athlete sex and AT exposure were not associated with times to reach any clinical milestone; however, delayed diagnosis was associated with longer times to reach clinical recovery.

Concussion diagnosis and recovery in relation to collegiate athletic department classification: a LIMBIC MATARS consortium investigation.

PURPOSE: We investigated time to reach concussion diagnosis and recovery milestones in collegiate athletes relative to their schools' National Collegiate Athletic Association (NCAA) classification. METHODS: We retrospectively examined 849 (43.1% female) concussion cases from 11 NCAA institutions (Division I Power 5 [n = 4], Division I Non-Power 5 [n = 4], and Division II/III [n = 3]) from the 2015-16 to 2019-20 athletic seasons. Our primary outcome measures were days to reach specific clinical milestones following concussion. RESULTS: Median (IQR) time from injury to diagnosis was significantly longer at Division II/III institutions (1 [0-4] days) compared to Division I Power 5 (0 [0-1] days) and Division I Non-Power 5 (0 [0-1] days) institutions (p < 0.001). Likewise, Division II/III athletes (15 [11-22] days) took significantly longer to return to sport after concussion than Division I Power 5 (10 [7-16] days) and Division I Non-Power 5 (11 [7-18.5] days) athletes (p < 0.001). CONCLUSION: Division II/III athletes had delayed concussion diagnoses and return to sport timelines compared to Division I athletes. Our results suggest that differences in sports medicine resources across NCAA divisions may influence injury recognition and recovery in collegiate athletes with concussion.

Sport Type and Risk of Subsequent Injury in Collegiate Athletes Following Concussion: a LIMBIC MATARS Consortium Investigation.

OBJECTIVE: To investigate the association between sport type (collision, contact, non-contact) and subsequent injury risk following concussion in collegiate athletes. MATERIALS AND METHODS: This retrospective chart review of 248 collegiate athletes with diagnosed concussions (age: 20.0 ± 1.4 years; height: 179.6 ± 10.9 cm; mass: 79.0 ± 13.6 kg, 63% male) from NCAA athletic programs (n = 11) occurred between the 2015-2020 athletic seasons. Acute injuries that occurred within six months following concussion were evaluated. Subsequent injuries were grouped by lower extremity, upper extremity, trunk, or concussion. The independent variable was sport type: collision, contact, non-contact. A Cox proportional hazard model was used to assess the risk of subsequent injury between sport types. RESULTS: Approximately 28% (70/248) of athletes sustained a subsequent acute injury within six months post-concussion. Collision sport athletes had a significantly higher risk of sustaining any injury (HR: 0.41, p < 0.001, 95% CI: 0.28, 0.62), lower extremity (HR: 0.55, p = 0.04, 95% CI: 0.32, 0.97), and upper extremity (HR: 0.41, p = 0.01, 95% CI: 0.20, 0.81) injuries following concussion. No differences between sport types were observed for other injuries. CONCLUSION: Collision sport athletes had a higher rate of any subsequent injury, lower, and upper extremity injuries following concussion. Future research should focus on sport-specific secondary injury prevention efforts.

Physical activity and recovery following concussion in collegiate athletes: a LIMBIC MATARS Consortium Investigation.

OBJECTIVE: To investigate whether routine daily activities (RDA), non-prescribed exercise (Non-ERx), or prescribed exercise (ERx) were associated with recovery from sport-related concussion (SRC) in collegiate athletes. MATERIALS AND METHODS: Data for this cross-sectional, retrospective chart review of collegiate athletes diagnosed with SRC (n = 285[39.6% female], age = 19.5 ± 1.4 years) were collected during the 2015-16 to 2019-20 athletic seasons. The independent variable was group (RDA, Non-ERx, ERx). Dependent variables included days from date of diagnosis to symptom resolution (Dx-SR) and SR to return to sport (SR-RTS). RESULTS: Those in the Non-ERx group took nearly 1.3 times longer to achieve SR (IRR = 1.28, 95% CI: 1.11, 1.46) and, 1.8 times longer for RTS (IRR = 1.82, 95% CI: 1.11, 2.71) when compared to those in the RDA group. No other comparisons were significant. CONCLUSION: Collegiate athletes in the Non-ERx group took approximately 1 week longer to achieve SR as compared to the RDA and ERx groups. Our findings suggest that if exercise is recommended following SRC, it must be clearly and specifically prescribed. If exercise parameters cannot be prescribed, or monitored, RDA appear to be similarly beneficial during recovery for collegiate athletes with concussion.

Impacts of circulating microRNAs in exercise-induced vascular remodeling.

Cardiovascular adaptation underlies all athletic training modalities, with a variety of factors contributing to overall response during exercise-induced stimulation. In this regard the role of circulating biomarkers is a well-established and invaluable tool for monitoring cardiovascular function. Specifically, novel biomarkers such as circulating cell free DNA and RNA are now becoming attractive tools for monitoring cardiovascular function with the advent of next generation technologies that can provide unprecedented precision and resolution of these molecular signatures, paving the way for novel diagnostic and prognostic avenues to better understand physiological remodeling that occurs in trained versus untrained states. In particular, microRNAs are a species of regulatory RNAs with pleiotropic effects on multiple pathways in tissue-specific manners. Furthermore, the identification of cell free microRNAs within peripheral circulation represents a distal signaling mechanism that is just beginning to be explored via a diversity of molecular and bioinformatic approaches. This article provides an overview of the emerging field of sports/performance genomics with a focus on the role of microRNAs as novel functional diagnostic and prognostic tools, and discusses present knowledge in the context of athletic vascular remodeling. This review concludes with current advantages and limitations, touching upon future directions and implications for applying contemporary systems biology knowledge of exercise-induced physiology to better understand how disruption can lead to pathology.

Evaluation of the Functional Movement Screen and a Novel Basketball Mobility Test as an Injury Prediction Tool for Collegiate Basketball Players.

Bond, CW, Dorman, JC, Odney, TO, Roggenbuck, SJ, Young, SW, and Munce, TA. Evaluation of the functional movement screen and a novel basketball mobility test as an injury prediction tool for collegiate basketball players. J Strength Cond Res 33(6): 1590-1601, 2019-Identifying injury risk and implementing preventive measures can assist in reducing injury occurrence and may ultimately improve athletic performance. Improper movement patterns often contribute to musculoskeletal (MSK) injuries. The validity of the Functional Movement Screen (FMS) as an injury prediction tool for athletes remains unclear. We designed the Basketball-Specific Mobility Test (BMT) to represent the neuromuscular demands of basketball and identify deficiencies that may be indicative of greater MSK injury risk while playing this sport. The aim of this study was to examine the association of FMS and BMT scores with injury occurrence in collegiate basketball players. We hypothesized that the BMT would be a better predictor of injury risk than the FMS, and that scores from both tests would have a higher association with severe MSK injuries than minor, non-MSK injuries. One-hundred nineteen male and female collegiate basketball players from 4 Upper Midwest universities were assessed preseason (PRE) and postseason (POST) using the FMS and BMT. In-season injury records were collected from the schools' athletic trainers and were classified by type and severity. During the season, 56 of 119 players were injured, resulting in 96 total injuries. Injured athletes' PRE FMS scores demonstrated negligible effects compared with uninjured athletes' PRE scores (d < 0.20), whereas some BMT scores showed potentially meaningful effects (d > 0.20). Although specificity of the FMS and BMT to predict injury was relatively high (FMS 85.7-87.6; BMT 42.0-88.0), sensitivity (FMS 14.2-22.7; BMT 11.6-39.1), odds ratios (FMS 1.00-2.08; BMT 0.47-1.06), and injury prediction capacities (area under the curve; FMS 0.43-0.49; BMT 0.49-0.59) of the tests were low. Although the FMS and BMT may be suitable for identifying MSK deficiencies, they do not accurately determine injury risk in collegiate basketball players. Injury risk assessments may be improved by targeting specific injury mechanisms and the conditions in which they occur.

More Than Skin Deep: Patient-Provider Racial and Ethnic Concordance and Discordance in Collegiate Athletics and Concussion Management.

CONTEXT: There is strong evidence that racial and ethnic disparities exist in multiple arenas of health and wellness. The causes of racial and ethnic differences in healthcare are multi- dimensional, one factor that may impact injury/illness communication, interactions, and outcomes is patient-provider racial and ethnic concordance. At present, it is unclear what role patient-provider racial and ethnic concordance and discordance plays in facilitating concussion care for collegiate athletes. OBJECTIVE: Investigate the presence of athlete-athletic trainer (AT) racial and ethnic concordance and discordance amongst diagnosed concussion cases, and examine if racial and ethnic concordance and discordance influences time (in days) until diagnosis, symptom resolution, or return-to-sport clinical milestones in collegiate athletes. DESIGN: Retrospective cohort study. SETTING: Collegiate athletics. PATIENTS OR OTHER PARTICIPANTS: A total of 694 concussion cases [38.6% (n=268) sustained by women, 61.4% (n=426) sustained by men] that occurred within the 2015-2016 through 2019- 2020 sport seasons at 9 institutions. MAIN OUTCOME MEASURE(S): The number of days from date of injury to diagnosis, symptom resolution, and return-to-sport; and from date of diagnosis to symptom resolution and return-to- sport. RESULTS: Overall, 68.4% (n=475) of concussion cases had patient-provider racial and ethnic concordance and 31.6% (n =219) were discordant. All concordant pairs included a White athlete and White AT. Time to diagnosis differed between the concordant and discordant groups (median[IQR]=1[0,2] versus 0[0,1], respectively) only in the model adjusted for sex, sport-type, and availability of an AT (OR[CI95]=1.46[1.07, 1.85]). There were no other group differences. CONCLUSIONS: One-third of concussion cases had athlete-AT racial and ethnic discordance. While this group was diagnosed with a concussion 1-day sooner than the concordant group, no differences were observed for any concussion recovery milestones. These findings suggest that patient-provider racial and ethnic concordance may play a minor role in concussion recognition or reporting, but not necessarily in the management and recovery thereafter.

Sport concussion knowledge base, clinical practises and needs for continuing medical education: a survey of family physicians and cross-border comparison.

CONTEXT: Evolving concussion diagnosis/management tools and guidelines make Knowledge Transfer and Exchange (KTE) to practitioners challenging. OBJECTIVE: Identify sports concussion knowledge base and practise patterns in two family physician populations; explore current/preferred methods of KTE. DESIGN: A cross-sectional study. SETTING: Family physicians in Alberta, Canada (CAN) and North/South Dakota, USA. PARTICIPANTS: CAN physicians were recruited by mail: 2.5% response rate (80/3154); US physicians through a database: 20% response rate (109/545). INTERVENTION/INSTRUMENT: Online survey. MAIN AND SECONDARY OUTCOME MEASURES: Diagnosis/management strategies for concussions, and current/preferred KTE. RESULTS: Main reported aetiologies: sports/recreation (52.5% CAN); organised sports (76.5% US). Most physicians used clinical examination (93.8% CAN, 88.1% US); far fewer used the Sport Concussion Assessment Tool (SCAT1/SCAT2) and balance testing. More US physicians initially used concussion-grading scales (26.7% vs 8.8% CAN, p=0.002); computerised neurocognitive testing (19.8% vs 1.3% CAN; p<0.001) and Standardised Assessment of Concussion (SAC) (21.8% vs 7.5% CAN; p=0.008). Most prescribed physical rest (83.8% CAN, 75.5% US), while fewer recommended cognitive rest (47.5% CAN, 28.4% US; p=0.008). Return-to-play decisions were based primarily on clinical examination (89.1% US, 73.8% CAN; p=0.007); US physicians relied more on neurocognitive testing (29.7% vs 5.0% CAN; p<0.001) and recognised guidelines (63.4% vs 23.8% CAN; p<0.001). One-third of Canadian physicians received KTE from colleagues, websites and medical school training. Leading KTE preferences included Continuing Medical Education (CME) courses and online CME. CONCLUSIONS: Existing published recommendations regarding diagnosis/management of concussion are not always translated into practise, particularly the recommendation for cognitive rest; predicating enhanced, innovative CME initiatives.

Head Impact Exposure of a Youth Football Team over Eight Consecutive Seasons.

PURPOSE: This study examined HIE of middle school football players over multiple seasons. METHODS: Head impact exposure was evaluated in 103 football players (11-14 yr) who participated in a community-based youth tackle football program, up to 2 yr, with the same coaching staff over eight consecutive seasons (2012-2019). Head impact exposure was assessed using the Head Impact Telemetry System. Median of individual mean head impacts per session (HIPS) and median of individual 50th and 95th percentile head impact magnitudes were compared across seasons. RESULTS: There were 33,519 head impacts measured throughout the study. Median HIPS for all sessions decreased every year, with a significant reduction from 2012 to 2019 (11.1 vs 2.3 HIPS; P < 0.05). Median game HIPS were significantly reduced in 2019 compared with 2012-14 (5.00 vs 16.30-17.75 HIPS; P < 0.05). Median practice HIPS were reduced by 81.3%, whereas median game HIPS were reduced by 69.3%. Median 50th and 95th percentile linear and rotational acceleration were lower in 2019 compared with some earlier years but remained unchanged during games. CONCLUSIONS: Head impacts incurred by youth football players decreased substantially over eight seasons, with players in the final year sustaining approximately one fifth the HIPS as players experienced during the first year. The most prominent decline occurred in practices, although players also had much fewer head impacts in games. These results suggest that coaches' and/or players' behavior can be modified to greatly reduce the head impact burden in youth football.

Subconcussive changes in youth football players: objective evidence using brain vital signs and instrumented accelerometers.

Brain vital signs, measured by EEG, were used for portable, objective, neurophysiological evaluation of cognitive function in youth tackle football players. Specifically, we investigated whether previously reported pre- and post-season subconcussive changes detected in youth ice hockey players were comparably detected in football. The two objectives were to: (i) replicate previously published results showing subconcussive cognitive deficits; and (ii) the relationship between brain vital sign changes and head-impact exposure. Using a longitudinal design, 15 male football players (age 12.89 ± 0.35 years) were tested pre- and post-season, with none having a concussion diagnosis during the season. Peak latencies and amplitudes were quantified for Auditory sensation (N100), Basic attention (P300) and Cognitive processing (N400). Regression analyses tested the relationships between these brain vital signs and exposure to head impacts through both number of impacts sustained, and total sessions (practices and games) participated. The results demonstrated significant pre/post differences in N400 latencies, with ∼70 ms delay (P < 0.01), replicating prior findings. Regression analysis also showed significant linear relationships between brain vital signs changes and head impact exposure based on accelerometer data and games/practices played (highest R = 0.863, P < 0.001 for overall sessions). Number of head impacts in youth football (age 12-14 years) findings corresponded most closely with prior Junior-A ice hockey (age 16-21 years) findings, suggesting comparable contact levels at younger ages in football. The predictive relationship of brain vital signs provided a notable complement to instrumented accelerometers, with a direct physiological measure of potential individual exposure to subconcussive impacts.

Dynamic Postural Stability in Active, Adolescent Males Following Repeated Bouts of Aerobic Exercise in Hot and Temperate Environments: A Pilot Study.

INTRODUCTION: Proper jump-landing neuromuscular control is crucial in mitigating lower-extremity musculoskeletal injuries. The presence of fatigue, especially in extreme environments, may degrade dynamic postural stability (DPS) and result in lower-extremity injuries. This study aimed to evaluate the influence of moderate intensity exercise in hot (HOT) and temperate (TEMP) ambient temperatures and residual effects of a previous bout on DPS during a single-legged jump-landing. It was hypothesized that the participants would display worse DPS after HOT compared to TEMP. METHODS: Six recreationally active young males (16.8 ± 0.7 year, 1.88 ± 0.12 m, 83.8 ± 19.8 kg) completed two, 60-minute bouts of exercise with 60 minutes of rest between bouts in both HOT (35°C) and TEMP (22.2°C). Heart rate and core body temperature (Tc) were monitored continuously, and DPS was assessed before and after each bout. RESULTS: The DPS time and condition effects were not identified (p > 0.05), but HOT elicited some notable (d > 0.20) increases in heart rate, Tc, and DPS compared to TEMP. CONCLUSIONS: The DPS decrements varied between subjects suggesting individual-specific etiology. Repeated bouts of exercise in HOT may place an individual at a greater risk for injury than TEMP if proper prevention strategies are not used.

Sex differences in voluntary fluid intake by older adults during exercise.

PURPOSE: This study compared the voluntary fluid intake behavior of older men and women (54-70 yr) when provided cold, palatable beverages and ample opportunity to drink between repeated bouts of exercise in the heat. METHODS: Thirteen men and 14 women performed four bouts of 15-min cycling at 65% VO2peak followed by 15 min of rest at 30 degrees C and 50% relative humidity. In separate trials, subjects drank either a carbohydrate-electrolyte solution (CES) or water ad libitum during the rest periods and were unaware that their fluid intake was being measured. RESULTS: Fluid intake behavior was repeatable (intraclass correlation coefficient = 0.75), and subjects drank enough of either beverage to match sweating rates and maintain their body mass (BM). Fluid intake per kilogram of BM was greater with CES (18.7 +/- 2.2 vs 15.1 +/- 2.1 mL x kg(-1); P < 0.05), and plasma volume (PV) was better maintained during the CES trials (-1.3 +/- 1.1 vs -4.2 +/- 1.1% during the second half of the session). Women drank significantly more water than the men on a per kilogram basis (17.2 +/- 2.9 vs 12.8 +/- 1.7 mL x kg(-1) BM), and one woman (BM = 45.7 kg) became hyponatremic (S(NA) = 126 mmol x L(-1)) with symptoms during the water trial. CONCLUSION: Older adults drank enough to maintain fluid balance when palatable fluid was readily available; however, CES promoted greater voluntary fluid intake and restored PV losses faster than water. In addition, older women drank more water than men during interval exercise in the heat, which may put smaller women at an increased risk for developing hyponatremia.

An exercise trial targeting posterior shoulder strength in manual wheelchair users: pilot results and lessons learned.

PURPOSE: Because wheelchair users are unable to use standard fitness equipment such as treadmills and bikes, we developed an upper body rowing ergometer (UBRE) that can be retrofitted onto a standard stationary cycle and used to perform a rowing exercise. We validated a graded exercise testing protocol utilizing the UBRE and completed a 12-week pilot intervention to compare the training effects of the UBRE to a standard arm cycle ergometer (ACE) in manual wheelchair users. METHODS: Repeat graded exercise tests were compared on the two pieces of equipment. Twenty-seven manual wheelchair users participated in the intervention. Outcomes included pre- versus post-test change in shoulder pain, strength and cardiorespiratory fitness measures. RESULTS: Testing results obtained with the UBRE were comparable to those on the ACE. In the exercise intervention, most outcome measures did not change significantly, but individuals assigned to the UBRE were able to increase their peak exercise test power by 31 W and duration by 3.6 min. CONCLUSION: There is biomechanical reason to believe that rowing exercises may improve shoulder muscle balance in this population, which could reduce the risk of impingement. This may be of benefit to manual wheelchair users, who are at high risk for shoulder injury. Implications for Rehabilitation Regular exercise improves cardiorespiratory fitness and did not exacerbate shoulder pain in this group of manual wheelchair users. Exercises that target posterior shoulder muscle groups, such as rowing, may improve muscle balance and reduce the risk of shoulder impingement. Participation in exercise is hindered in this population by a high rate of secondary health conditions and difficulty accessing facilities and equipment.

Head Impact Exposure and Neurologic Function of Youth Football Players.

UNLABELLED: Football players are subjected to repetitive impacts that may lead to brain injury and neurologic dysfunction. Knowledge about head impact exposure (HIE) and consequent neurologic function among youth football players is limited. PURPOSE: This study aimed to measure and characterize HIE of youth football players throughout one season and explore associations between HIE and changes in selected clinical measures of neurologic function. METHODS: Twenty-two youth football players (11-13 yr) wore helmets outfitted with a head impact telemetry (HIT) system to quantify head impact frequency, magnitude, duration, and location. Impact data were collected for each practice (27) and game (9) in a single season. Selected clinical measures of balance, oculomotor performance, reaction time, and self-reported symptoms were assessed before and after the season. RESULTS: The median individual head impacts per practice, per game, and throughout the entire season were 9, 12, and 252, respectively. Approximately 50% of all head impacts (6183) had a linear acceleration between 10g and 20g, but nearly 2% were greater than 80g. Overall, the head impact frequency distributions in this study population were similar in magnitude and location as in high school and collegiate football, but total impact frequency was lower. Individual changes in neurologic function were not associated with cumulative HIE. CONCLUSION: This study provides a novel examination of HIE and associations with short-term neurologic function in youth football and notably contributes to the limited HIE data currently available for this population. Whereas youth football players can experience remarkably similar head impact forces as high school players, cumulative subconcussive HIE throughout one youth football season may not be detrimental to short-term clinical measures of neurologic function.

Tracking postural stability of young concussion patients using dual-task interference.

OBJECTIVES: This study examined the diagnostic benefit of using dual-task interference balance testing in young concussion patients and the longitudinal changes in postural stability that occur relative to other standard clinical assessments of concussion injury. DESIGN: Longitudinal, case-control. METHODS: Eighteen patients (16.6 (1.6)y) diagnosed with a concussion provided 22 separate ratings to characterize the severity of their current concussion-related symptoms and were evaluated for postural stability at each of four clinical visits. Twenty-six injury-free adolescents (17 (2.8)y) performed balance testing on two occasions, separated by ∼1 week. RESULTS: There was a progressive decrease in self-reported symptoms from visit 1 to visit 4 (P<0.0001-0.001). A similar improvement occurred in postural stability, indicated by 95% ellipse area and velocity. However, the differences in ellipse area and velocity were significant only between visit 1 and the rest of the visits as a whole (P<0.0001-0.05). There was a significant difference between concussion patients and healthy, injury-free participants in ellipse area and velocity during visit 1. A group difference was also observed in ellipse area on visit 2, but only during the two balance tests that involved a concomitant secondary cognitive task. CONCLUSIONS: Improvements in postural stability coincide with reductions in reported symptoms, though apparent recovery of these selected measures of postural stability seemingly occurs sooner. Because of the distinguishing time course of recovery indicated by dual-task interference balance testing, this type of balance testing assessment may be particularly valuable in evaluating integrated functional impairment and recovery in young concussion patients.

Age-specific skin blood flow responses to acute capsaicin.

Local skin blood flow (SkBF) responses can be modified by vasoactive neurotransmitters released from sensory nerves, notably, capsaicin-sensitive primary afferents (CSPAs). Age-specific CSPA function was examined in this study by assessing the SkBF response to acute capsaicin (CPZ). Eight young (18-30 years), 8 middle-aged (40-55 years), and 9 older (65-80 years) healthy men participated in the study. Treatment patches of varying CPZ concentration (ethanol and 0.001%-10.0% CPZ) were applied to sites on the ventral forearm. SkBF was measured with a laser Doppler imager. There were significant (p <.001) age-specific differences in the SkBF response to CPZ. In the older group, SkBF was reduced at least 2-fold at all concentrations of CPZ compared with the younger group. The middle-aged group showed an intermediate response. SkBF was significantly elevated above that obtained with a vehicle solution when sites were treated with CPZ concentrations > or = 0.1% in middle-aged and younger skin, whereas a significant elevation in SkBF was only achieved with 10% CPZ in older skin. The elevated SkBF in the young and middle-aged groups at higher concentrations of CPZ was the result of both an increased area of vasodilation and an increased magnitude of vasodilation within the vasodilated areas. In the older group, the increase in cutaneous vascular conductance at the highest concentration of CPZ was entirely the result of an increased area of vasodilation. These results suggest impaired CSPA function in aged skin and age-specific differences in the ability of sensory nerves to modify local inflammatory SkBF responses.

Age-specific modification of local cutaneous vasodilation by capsaicin-sensitive primary afferents.

Age-related changes in neurogenic vasodilation mediated by sensory nerves may alter local skin blood flow (SkBF) responses in older individuals. The purpose of this study was to determine the age-specific modification of cutaneous vasodilation by capsaicin-sensitive primary afferent (CSPA) nerves during local heating. Nine young (18-30 yr), eight middle-aged (40-55 yr), and eight older (65-80 yr) healthy men participated in the experiments. Two local-heating protocols (rapid and slow) were performed before and after 1 wk of capsaicin pretreatment (CP), used to desensitize CSPAs. All temperatures were below those that elicit pain. SkBF was measured with a laser-Doppler imager and indexed to percentage of maximal cutaneous vascular conductance (%CVCmax). CP caused a significant reduction in %CVCmax in the middle-aged and older groups during slow heating (P < 0.05), without affecting %CVCmax in the young group. During rapid heating, CP significantly reduced (53.9 +/- 4.4 vs. 74.4 +/- 7.4% CVCmax, P < 0.05), but did not abolish, the initial sensory nerve-mediated rise in SkBF in the young group. No significant effects of CP on SkBF were observed during rapid heating in the middle-aged or older groups. These results indicate that, with advanced age, CSPA activity is more important to the maximal SkBF response during prolonged local heating, whereas it has a reduced role in the initial SkBF peak elicited by rapid local heating. In summary, CSPA activity contributes modestly to the overall SkBF response to local heating in an age-specific manner.

Invited review: aging and human temperature regulation.

This mini-review focuses on the effects of aging on human temperature regulation. Although comprehensive reviews have been published on this topic (Kenney WL. Exercise and Sport Sciences Reviews, Baltimore: Williams & Wilkins, 1997, p. 41-76; Pandolf KB. Exp Aging Res 17: 189-204, 1991; Van Someren EJ, Raymann RJ, Scherder EJ, Daanen HA, and Swaab DF. Ageing Res Rev 1: 721-778, 2002; and Young AJ. Exp Aging Res 17: 205-213, 1991), this mini-review concisely summarizes the present state of knowledge about human temperature regulation and aging in thermoneutral conditions, as well as during hypo- and hyperthermic challenges. First, we discuss age-related effects on baseline body core temperature and phasing rhythms of the circadian temperature cycle. We then examine the altered physiological responses to cold stress that result from aging, including attenuated peripheral vasoconstriction and reduced cold-induced metabolic heat production. Finally, we present the age-related changes in sweating and cardiovascular function associated with heat stress. Although epidemiological evidence of increased mortality among older adults from hypo- and hyperthermia exists, this outcome does not reflect an inability to thermoregulate with advanced age. In fact, studies that have attempted to separate the effects of chronological age from concurrent factors, such as fitness level, body composition, and the effects of chronic disease, have shown that thermal tolerance appears to be minimally compromised by age.

Effects of youth football on selected clinical measures of neurologic function: a pilot study.

We assessed 10 youth football players (13.4 ± 0.7 y) immediately before and after their season to explore the effects of football participation on selected clinical measures of neurologic function. Postseason postural stability in a closed-eye condition was improved compared to preseason (P = .017). Neurocognitive testing with the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery revealed that reaction time was significantly faster at postseason (P = .015). There were no significant preseason versus postseason differences in verbal memory (P = .507), visual memory (P = .750), or visual motor speed (P = .087). Oculomotor performance assessed by the King-Devick test was moderately to significantly improved (P = .047-.115). A 12-week season of youth football did not impair the postural stability, neurocognitive function, or oculomotor performance measures of the players evaluated. Though encouraging, continued and more comprehensive investigations of this at-risk population are warranted.