Long-term effects of multiple concussions on prefrontal cortex oxygenation during a hypercapnic challenge in retired contact sport athletes.

This exploratory study aimed to investigate the long-term effects of multiple concussions on prefrontal cortex oxygenation during a five-minute hypercapnic challenge using Near Infrared Spectroscopy (NIRS). 55 physically active retired contact sport male athletes with three or more previous concussions (mTBI) were recruited along with 29 physically active males with no concussions history (CTRL). Participants completed five minutes of seated rest prior to the five-minute hypercapnic challenge (20-second breath-hold, 40-second recovery breathing; five times). NIRS measured right and left side oxygenated (O2Hb), deoxygenated (HHb), total (tHb) haemoglobin, and haemoglobin difference (HbDiff) with all parameters analysed through changes in average maximal and minimal values (ΔMAX), Z-scores, and standard deviations. Right prefrontal cortex HbDiff ΔMAX was significantly higher in the mTBI compared to CTRL (p = 0.045) group. Left prefrontal cortex O2Hb ΔMAX (p = 0.040), HHb Z-Scores (p = 0.008), and HbDiff ΔMAX(p = 0.014) were significantly higher in the mTBI group. Within-group right vs left analyses demonstrated significantly lower left HbDiff ΔMAX (p = 0.048) and HbDiff Z-scores (p = 0.002) in the mTBI group, while the CTRL group had significantly lower left HHb Z-scores (p = 0.003) and left tHb Z-scores (p = 0.042). This study provides preliminary evidence that athletes with a history of three or more concussions may have impaired prefrontal cortex oxygenation parameters during a hypercapnic challenge.

Long-term effects of multiple concussions on prefrontal cortex oxygenation during neurovascular coupling activation in retired male contact sport athletes.

Purpose: This study aimed to investigate the long-term effects of multiple concussions on prefrontal cortex oxygenation during a neurovascular coupling activating task using near infrared spectroscopy (NIRS). Methods: Self-reported physically active males who previously participated in contact team sports at various levels of competition and who previously had experienced at least 3 concussions (n = 55; mTBI) or had no history of concussions (n = 29; CTRL) were recruited. Participants completed a 5 min "Where's Waldo" object identification protocol which consisted of participants closing their eyes for 20-s followed by 40-s (repeated 5 times over 5-min) of searching a computer screen for "Waldo" hidden in a field of distractors. NIRS (µM) was used to measure right and left prefrontal cortex cerebral oxygenation. Oxygenated (O2Hb), deoxygenated (HHb), total (tHb) haemoglobin, and haemoglobin difference (HbDiff) were analysed through the change in average maximal and minimal values (ΔMAX), Z-scores, and standard deviations. Results: There were no significant differences in the relative change in cerebral oxygenation of the right prefrontal cortex between groups. In mTBI, left prefrontal cortex HHb ΔMAX (p = 0.031) and tHb ΔMAX (p = 0.044) were significantly lower than in the CTRL group. Within-group, right vs. left prefrontal cortex differences showed significantly lower values in left HbDiff Z-scores (p = 0.019) in only the mTBI group while the CTRL group showed significantly lower values in left HbDiff SD (p = 0.045). Conclusion: This preliminary study suggests that there are changes in prefrontal cortex oxygenation in males who had a history of experiencing multiple concussions in their past during a neurovascular coupling activating task. These changes may represent potential long-term effects in the brain's ability to adapt cerebral oxygenation during increased neural activity.

History of Brain Injury Alters Cerebral Haemodynamic Oscillations with Cardiac Influence.

(1) Background: Cerebral autoregulation is altered during acute mild traumatic brain injury, or concussion. However, it is unknown how a history of concussion can impact cerebral haemodynamic activity during a task that elicits an autoregulatory response. (2) Methods: We assessed cerebral haemodynamic activity in those with a history of three or more concussions. The study included 44 retired athletes with concussion history and 25 control participants. We recorded participants' relative changes in right and left pre-frontal cortex oxygenation collected by near-infrared spectroscopy and continuous beat-to-beat blood pressure measured by finger photoplethysmography. Participants completed a 5-min seated rest followed by a 5-min repeated squat (10-s) stand (10-s) maneuver (0.05 Hz) to elicit a cerebral autoregulatory response. Wavelet transformation was applied to the collected signals, allowing separation into cardiac interval I (0.6 to 2 Hz), respiratory interval II (0.145 to 0.6 Hz), and smooth muscle cell interval III (0.052 to 0.145 Hz). (3) Results: Significant increases at cardiac interval I were found for the wavelet amplitude of oxy-haemoglobin and haemoglobin difference at the right pre-frontal cortex. No significant difference was found at the left pre-frontal cortex or the blood pressure wavelet amplitudes. (4) Conclusions: Contributions from cardiac activity to the pre-frontal cortex oxygenation are elevated when eliciting dynamic cerebral autoregulation in those with a history of three or more concussions.

Long-term effects of multiple concussions on prefrontal cortex oxygenation during repeated squat-stands in retired contact sport athletes.

BACKGROUND: This study investigated the long-term effects of multiple concussions on prefrontal cortex oxygenation using near-infrared spectroscopy (NIRS) during a squat-stand maneuver that activated dynamic cerebral autoregulation. METHODS: Active male retired contact sport athletes with a history of 3+ concussions (mTBI; n = 55), and active retired athletes with no concussion history (CTRL; n = 29) were recruited. Participants completed a 5-min squat-stand maneuve (10-s squat, 10-s stand, 0.05 Hz; 15 times). Oxygenated (O2Hb), deoxygenated (HHb), total (tHb) hemoglobin, and hemoglobin difference (HbDiff) were analyzed through the change in maximal and minimal values during the test (∆MAX), Z-scores, and standard deviations. RESULTS: mTBI group showed left prefrontal cortex O2Hb ∆MAX (p = 0.046) and HbDiff ∆MAX (p = 0.018) were significantly higher. Within-group analyses showed significantly higher left HHb ∆MAX (p = 0.003) and lower left HbDiff Z-scores (p = 0.010) only in the mTBI group. The CTRL group demonstrated significantly lower left HbDiff SD (p = 0.039), tHb Z-scores (p = 0.030), and HbDiff ∆MAX (p = 0.037) compared to right prefrontal cortex response. CONCLUSION: These preliminary results suggest changes in prefrontal cortex oxygenation potentially affecting the brain's ability to adapt to changing cerebral perfusion pressure after multiple previous concussions.

Effects of hydration status during heat acclimation on plasma volume and performance.

The impact of hydration status was investigated during a 5-day heat acclimation (HA) training protocol vs mild/cool control conditions on plasma volume (PV) and performance (20 km time-trial [TT]). Sub-elite athletes were allocated to one of two heat training groups (90 min/day): (a) dehydrated to ~2% body weight (BW) loss in heat (35°C; DEH; n = 14); (b) euhydrated heat (35°C; EUH; n = 10), where training was isothermally clamped to 38.5°C core temperature (Tc ). A euhydrated mild control group (22°C; CON; n = 9) was later added, with training clamped to the same relative heart rate (~75% HRmax ) as elicited during DEH and EUH; thus all groups experienced the same internal training stress (%HRmax ). Five-day total thermal load was 30% greater (P < 0.001) in DEH and EUH vs CON. There were significant differences in the average percentage of maximal work rate (%Wmax ) across all groups (DEH: 24 ± 6%; EUH: 34 ± 9%; CON: 48 ± 8%Wmax ) during training required to elicit the same %HRmax (77 ± 4% HRmax ). There were no significant differences pre-to post-HA between groups for PV (DEH: +1.7 ± 10.1%; EUH: +4.8 ± 10.2%; CON: +5.2 ± 4.0%), but there was a significant pooled group PV increase, as well as a 97% likely pooled improvement in TT performance (DEH: -1.8 ± 2.8%; EUH: -1.9 ± 2.1%, CON; -1.8 ± 2.8%; P = 0.136). Due to a lack of between-group differences for PV and TT, but pooled group increases in PV and 97% likely group increase in TT performance, over 5 days of intense training at the same average relative cardiac load suggests that overall training stress may also impact significant adaptations beyond heat and hydration stress.

Preseason Functional Movement Screen Predicts Risk of Time-Loss Injury in Experienced Male Rugby Union Athletes.

The purpose of this study was to determine the relationship between Functional Movement Screen (FMS) score and the risk of time-loss injury in experienced male rugby union athletes. A secondary purpose was to determine the relationship between FMS-determined asymmetries and the risk of time-loss injury in these athletes. Functional Movement Screen scores were collected from male rugby union athletes (n = 73) during preseason and half-way through one 8-month season. Time-loss injury data were collected throughout the full season. A receiver-operator characteristic curve was created for each half of the season to identify FMS composite and asymmetry cut-off scores associated with increased likelihood of injury and determined odds ratios, sensitivity, and specificity in evaluating FMS as a predictor of injury risk. Odds ratio analyses revealed that when compared with those scoring >14, athletes with an FMS ≤14 were 10.42 times more likely (95% confidence interval [CI]: 1.28-84.75, p = 0.007) to have sustained injury in the first half of the season and 4.97 times (95% CI: 1.02-24.19, p = 0.029) more likely in the second half of the season. The presence of asymmetries was not associated with increased likelihood of injury. Experienced male rugby union athletes with FMS composite scores ≤14 are significantly more likely to sustain time-loss injury in a competitive season than those scoring >14. The quality of fundamental movement, as assessed by the FMS, is predictive of time-loss injury risk in experienced rugby union athletes and should be considered an important preseason assessment tool used by strength and conditioning and medical professionals in this sport with inherently high injury rates.

Hydration status and fluid and sodium balance in elite Canadian junior women's soccer players in a cool environment.

Dehydration can impair mental and on-field performance in soccer athletes; however, there is little data available from the female adolescent player. There is a lack of research investigating fluid and electrolyte losses in cool temperatures. Therefore, the purpose of this study was to investigate the pretraining hydration status, fluid balance, and sweat sodium loss in 34 female Canadian junior elite soccer athletes (mean age ± SD, 15.7 ± 0.7 years) in a cool environment. Data were collected during two 90 min on-field training sessions (9.8 ± 3.3 °C, 63% ± 12% relative humidity). Prepractice urine specific gravity (USG), sweat loss (pre- and post-training body mass), and sweat sodium concentration (regional sweat patch method) were measured at each session. Paired t tests were used to identify significant differences between training sessions and Pearson's product moment correlation analysis was used to assess any relationships between selected variables (p ≤ 0.05). We found that 45% of players presented to practice in a hypohydrated state (USG > 1.020). Mean percent body mass loss was 0.84% ± 0.07% and sweat loss was 0.69 ± 0.54 L. Although available during each training session, fluid intake was low (63.6% of players consumed <250 mL). Mean sweat sodium concentration was 48 ± 12 mmol·L⁻¹. Despite low sweat and moderate sodium losses, players did not drink enough to avoid mild fluid and sodium deficits during training. The findings from this study highlights the individual variations that occur in hydration management in athletes and thus the need for personalized hydration guidelines.

Nutrition needs assessment of young Special Olympics participants.

BACKGROUND: Children with intellectual disability (ID) are at increased risk for obesity and nutrition-related health concerns, yet there is a paucity of data describing their nutrition status. The purpose of this study was to evaluate nutritional challenges of young participants (2?10 years of age) enrolled in Special Olympics Canada (SOC) programs. METHOD: A validated nutrition screening tool was mailed to 52 parents/caregivers of participants across 18 SOC programs in British Columbia, Canada. RESULTS: Of the 29 (55.8%) questionnaires returned, 62.1% scored as "high" nutrition risk. Nutrition concerns included feeding (84.2%), oral motor (57.9%), and dental problems (26.3%), food allergies/intolerances (26.3%), constipation (15.8%), anaemia (10.3%), and diarrhoea (5.3%). Body mass index (BMI) for age data classified 16.7% of participants as overweight/obese and 22.2% as underweight. CONCLUSIONS: This study identifies some of the unique nutrition issues faced by children with ID. These data can help inform future ID health-related nutrition, prevention, and treatment programs.

Cross-disciplinary thermoregulation and sweat analysis laboratory experiences for undergraduate Chemistry and Exercise Science students.

Cross-disciplinary (CD) learning experiences benefit student understanding of concepts and curriculum by offering opportunities to explore topics from the perspectives of alternate fields of study. This report involves a qualitative evaluation of CD health sciences undergraduate laboratory experiences in which concepts and students from two distinct disciplines [chemistry (CHEM) and exercise physiology (EPHE)] combined to study exercise thermoregulation and sweat analysis. Twenty-eight senior BSc Kinesiology (EPHE) students and 42 senior BSc CHEM students participated as part of their mutually exclusive, respective courses. The effectiveness of this laboratory environment was evaluated qualitatively using written comments collected from all students as well as from formal focus groups conducted after the CD laboratory with a representative cohort from each class (n = 16 CHEM students and 9 EPHE students). An open coding strategy was used to analyze the data from written feedback and focus group transcripts. Coding topics were generated and used to develop five themes found to be consistent for both groups of students. These themes reflected the common student perceptions that the CD experience was valuable and that students enjoyed being able to apply academic concepts to practical situations as well as the opportunity to interact with students from another discipline of study. However, students also reported some challenges throughout this experience that stemmed from the combination of laboratory groups from different disciplines with limited modification to the design of the original, pre-CD, learning environments. The results indicate that this laboratory created an effective learning opportunity that fostered student interest and enthusiasm for learning. The findings also provide information that could inform subsequent design and implementation of similar CD experiences to enhance engagement of all students and improve instructor efficacy.

Prospective evaluation of a 12-week walking exercise program and its effect on fatigue in prostate cancer patients undergoing radical external beam radiotherapy.

OBJECTIVE: To evaluate tolerability and compliance to a walking exercise program and its effect on fatigue during and after radical external beam radiation therapy (EBRT) for prostate cancer. METHODS: A total of 50 subjects with prostate cancer undergoing EBRT over 6 to 8 weeks were prospectively accrued to an exercise intervention group, matched for age and clinical characteristics to 30 subjects in a historical control group who underwent EBRT with no specific exercise intervention. Starting 1 week before EBRT, exercise participants performed moderate-intensity walking targeting 60% to 70% age-predicted maximum heart rate, at least 20 min/d, 3 d/wk over 12 weeks. The Brief Fatigue Inventory was administered at baseline, mid-EBRT (week 3-4), end-EBRT (week 6-8), and 6 months post-EBRT. RESULTS: Of 50, 42 (84%) of exercise participants completed the walking program. There were no cardiovascular complications, musculoskeletal injuries, or other adverse events. A total of 89% subjects reported "Good-Excellent" satisfaction during and up to 6 months post-EBRT. Fatigue in control subjects escalated from baseline to end-EBRT, remaining high at 6 months post-EBRT (P[r] = 0.03). In contrast, mean total fatigue scores in exercise subjects were stable from baseline up to 6 months post-EBRT (P = 0.52). Trends for higher fatigue interference with quality of life were observed in the control group as compared with the exercise group. CONCLUSIONS: Moderate-intensity walking exercise during radical EBRT is safe and feasible. The high convenience and satisfaction ratings, in conjunction with the observed fatigue trends, indicate that this activity has the potential to attenuate fatigue and improve quality of life for patients with localized prostate cancer undergoing curative therapy.

Habitual moderate-to-vigorous physical activity is inversely associated with insulin resistance in Canadian first nations youth.

The aim of this study was to explore the relationship between insulin resistance (IR) and objectively measured habitual moderate-to-vigorous physical activity (MVPA) in First Nations youth. A cross-sectional study was conducted in 2 rural villages in northern British Columbia, Canada. Thirty-nine healthy youth (16 males and 23 females; age = 11.8 yrs +/- 2.2; range = 8.8-18.5 yrs) participated. PA was measured with ActiGraph GT1M accelerometers. The homeostasis model assessment estimate of IR (HOMA-IR) was used to define IR. Duration of MVPA was inversely related to HOMA-IR (r = -.44, p < .01). From the regression model, 30 min of habitual MVPA corresponded to HOMA-IR levels that were 15% lower. In conclusion, these findings suggest that active First Nations youth have lower HOMA-IR values.

Progressive resistance training in breast cancer: a systematic review of clinical trials.

BACKGROUND: Progressive resistance training (PRT) may be effective for targeting the sequelae of breast cancer and its treatment given the unique anabolic nature of this exercise modality. Therefore, our objectives were: (1) to systematically review studies that have prescribed PRT after breast cancer surgery, (2) to summarize the efficacy of PRT in this cohort, and (3) to delineate areas for future investigations. METHOD: A systematic review using computerized databases was performed. RESULTS: The systematic review located 10 trials: Four uncontrolled trials, one controlled trial and five randomized controlled trials (RCTs). PRT was prescribed with aerobic training in 8/10 trials reviewed, and in isolation in 2/10 trials reviewed. Upper body PRT was prescribed in 7/10 trials, including 4/5 RCTs. No exacerbation of objectively measured or subjectively reported lymphedema symptoms was reported in any of these trials. Adverse events were rare, generally musculoskeletal in nature, and were managed effectively by conservative means. Overall, the studies we reviewed suggest that women surgically treated for breast cancer can derive health-related and clinical benefits by performing PRT after breast cancer surgery. Further research may be required to stimulate greater advocacy for PRT among oncologists, and in community care settings. CONCLUSIONS: Robustly designed RCTs prescribing targeted PRT regimens throughout various phases of breast cancer treatment are warranted. RCTs with thorough, standardized reporting of interventions and adverse events are required to establish the efficacy of this intervention for the post-treatment management of breast cancer patients and survivors as a means to improve health status and quality of life.

Reliability and validity testing of the Patient and Observer Scar Assessment Scale in evaluating linear scars after breast cancer surgery.

BACKGROUND: The Patient and Observer Scar Assessment Scale is a promising new method incorporating observer and patient ratings in evaluating burn scars. The authors compared this tool to the Vancouver Scar Scale in a cohort of women with linear scars from breast cancer surgery. METHODS: Twenty women with newly diagnosed breast cancer were prospectively accrued. Thirty-one scars were evaluated. The median time from surgery to scar assessment was 8 weeks (range, 3 to 25 weeks). Observer assessment was performed by three independent raters using the Vancouver scale and the observer component of the new tool. Patient self-assessment was performed using the patient component of the tool. Internal consistency, interobserver reliability, and convergent validity were examined. RESULTS: Internal consistency was acceptable for the Vancouver scale and both components of the new tool (Cronbach's alpha, 0.71, 0.74, and 0.77, respectively). Interobserver reliability was substantial with both the Vancouver scale and the observer tool (average measure intraclass coefficient correlation, 0.78 and 0.60, respectively). The observer tool and Vancouver scale correlated significantly with each other (p < 0.001), but only the observer tool correlated well with patients' ratings (p = 0.04). CONCLUSIONS: In surgical scar assessment, the new Patient and Observer Scar Assessment Scale and Vancouver Scar Scale were both associated with acceptable internal consistency and interobserver reliability. The new tool is more comprehensive and has higher correlation with patients' ratings. These findings support the use of the new tool as a reliable, valid, and comprehensive approach to assess linear surgical scars.

Prospective evaluation of the prevalence and severity of fatigue in patients with prostate cancer undergoing radical external beam radiotherapy and neoadjuvant hormone therapy.

OBJECTIVE: To prospectively evaluate the prevalence and severity of fatigue and its impact on quality of life (QOL) during and after radical external beam radiotherapy (RT) for prostate cancer. METHOD AND MATERIALS: Twenty-eight men with prostate cancer undergoing RT over 6-8 consecutive weeks were prospectively accrued. The Brief Fatigue Inventory (BFI), a validated fatigue assessment tool, was administered at five time points: baseline (week 1), middle of RT (week 3-4), end of RT (last week of RT), and follow-up (median 6.5 weeks after RT). The BFI contained nine questions, each using 0-10 ratings to quantify fatigue severity and interference with six QOL domains. The prevalence of moderate-severe fatigue was plotted as a function of time. Mean sum and subscale scores at each time point were compared to baseline scores using Wilcoxon tests. Linear regression analyses were performed to assess associations between fatigue scores and age, tumor and treatment characteristics. RESULTS: The median age was 69 years (range 57-84), Gleason score 7 (range 6-10), and presenting PSA 9.0 ng/mL (range 2.5 ng/mL-103.0 ng/mL). Patients were treated once daily to a median dose of 74 Gy (range 60 Gy-78 Gy) over a median of 37 fractions (range 30-39). Hormone therapy was used in all patients (median duration 12.2 months). The prevalence of moderate-severe present fatigue increased from 7% at baseline to 8% at mid-RT and 32% at RT completion. Compared to baseline (mean score 11.5), fatigue increased significantly mid-RT (mean score 14.6, p = 0.03) and peaked at the end of RT (mean score 23.5, p = 0.001). Fatigue significantly interfered with walking ability, normal work, daily chores, and enjoyment of life only at the end of RT. After RT completion, fatigue improved but remained higher compared to baseline at 6.5 weeks of follow-up (mean score 15.0, p = 0.02). On linear regression analysis, age, Gleason score, PSA, T-stage, hormone therapy duration, RT dose and fractions were not significantly associated with mean fatigue scores. CONCLUSION: Patients undergoing 6-8 weeks of RT experienced significant fatigue adversely affecting QOL persisting after therapy completion. Since walking ability was not affected until the end of RT, a walking exercise intervention to combat fatigue is likely feasible and is being investigated.

Full-body exercise training improves fitness and quality of life in survivors of breast cancer.

This study evaluated the safety and effectiveness of an 8-week full-body resistance and aerobic exercise program for 27 survivors of breast cancer (age, 57.7 +/- 7.2 years; years posttreatment, 0.8- 21.0) with prior upper-body conditioning. Physical fitness and quality-of-life (QOL) measures were obtained before and after the training period. Lymphedema, evaluated via arm volume measurement at baseline, was self-monitored throughout the trial. Sum of skinfolds, waist girth, and hip girth were significantly reduced posttraining (p < 0.01), although body weight did not change. Significant improvements (p < 0.01) were observed in upper-body strength (35.6 +/- 16.4%) and endurance (167.4 +/- 55.4%), lower-body strength (50.7 +/- 32.3%) and endurance (273.1 +/- 120.7%), Vo(2peak), trunk flexibility, and flexibility of the ipsilateral (surgical) and contralateral shoulder joint. Psychological QOL and overall QOL, evaluated via the World Health Organization Quality of Life Assessment Scale-Abbreviated Version. Inventory also improved significantly (p < 0.01). No incidents of lymphedema or injury were reported. These findings suggest that survivors of breast cancer can safely benefit from engaging in a full-body exercise regimen.

Imagery as a Method of Enhancing Transfer From Trailing to Performance.

This study investigated the effect of engaging in imagery in conjunction with nonspecific training on the transfer of the training to performance. Forty subjects were pretested on a Wingate cycle ergometer test for peak power and a 40-m sprint. Subjects were assigned to one of four groups: imagery training (IT), power training (PT), imagery and power training (DPT), and control (C). Following a 6-week training period, all subjects were retested. Although a MANOVA revealed no significant difference between groups on any variable, the groups-by-time interaction was significant. Therefore an analysis of difference scores on both tests was performed. This analysis revealed that although both the IPT and the PT group significantly improved in peak power, only the IPT group improved significantly on the sprint. The results indicate that imagery coupled with nonspecific training contributes to the enhancement of subsequent performance significantly better than does nonspecific training alone.