A Neuroscientific Approach to the Examination of Concussions in Student-Athletes

Concussions are occurring at alarming rates in the United States and have become a serious public health concern. The CDC estimates that 1.6 to 3.8 ...

Elon University

Developments relating to the control of application equipment can deliver improvements in pesticide use by better matching applications to target requirements. This may have components relating to the spatial distribution of a weed, pest or disease or methods by which the target, particularly a crop canopy, can be described with respect to a given application. Changes in application can relate to the dose and/or volume applied, but may also concern the way in which a treatment is delivered in terms of parameters such as spray trajectory angle and droplet size distribution. For many weed species there is evidence of patchy distributions in field situations. Studies have shown that savings of typically up to 40% in herbicide use can be achieved by adopting patch spraying approaches in such situations. Weed patch detection is key to the performance of such patch spraying systems. In widely spaced rowcrops such as vegetables, there is considerable scope for developing fully automated detection systems based on image analysis, and for the development of accurate guidance systems that apply pesticides only to the crop row. In crops with a relatively high plant density, weed detection in the medium/short term is likely to be based on manual discrimination. The costs of labour for manual weed patch mapping have been estimated at less than 1.50 ha(-1) pounds sterling. Potential savings in pesticide use can also be made if applications are matched to crop canopy structure. This is most important in bush and tree crops where savings of up to 75% in pesticide use could be achieved. In crops such as cereals, studies have shown that savings in fungicide use may be possible, particularly at earlier stages of growth by adjusting spray delivery to measured canopy characteristics. Key components of the performance of application systems concern the ability to deliver over a dose rate range of more than 3:1 while maintaining control of variables such as delivery trajectory angle and spray quality. Traceability and the effective monitoring of applications is likely to be a major driver influencing the uptake of more sophisticated control systems. Methods of labelling pesticides with systems that can be read by the application unit will be an important step in the development of recording and data handling systems that will operate safely with the minimum of operator input and enable the environmental advantages of targeted pesticide application to be monitored.

Patch spraying: future role of electronics in limiting pesticide use.

Protease supplementation has been shown to attenuate soft tissue injury resulting from intense exercise. The aim of this study was to evaluate the effects of protease supplementation on muscle soreness and contractile performance after downhill running. Ten matched pairs of male participants ran at a -10% grade for 30 min at 80% of their predicted maximal heart rate. The participants consumed two protease tablets (325 mg pancreatic enzymes, 75 mg trypsin, 50 mg papain, 50 mg bromelain, 10 mg amylase, 10 mg lipase, 10 mg lysozyme, 2 mg chymotrypisn) or a placebo four times a day beginning 1 day before exercise and lasting a total of 4 days. The participants were evaluated for perceived muscle soreness of the front and back of the dominant leg, pressure pain threshold by dolorimetry of the anterior medial, anterior lateral, posterior medial and posterior lateral quadrants of the thigh, and knee extension/flexion torque and power. The experimental group demonstrated superior recovery of contractile function and diminished effects of delayed-onset muscle soreness after downhill running when compared with the placebo group. Our results indicate that protease supplementation may attenuate muscle soreness after downhill running. Protease supplementation may also facilitate muscle healing and allow for faster restoration of contractile function after intense exercise.

The effects of protease supplementation on skeletal muscle function and DOMS following downhill running.

The problem of recognizing targets in nonoverlapping clutter using nonlinear N-ary phase filters is addressed. Using mathematical analysis, expressions were derived for an N-ary phase filter and the intensity variance of an optical correlator output. The N-ary phase filter was shown to consist of an infinite sum of harmonic terms whose periodicity was determined by N. For the intensity variance, it was found that under certain conditions the variance was minimized due to a previously undiscovered phase quadrature effect. Comparison showed that optimal real filters produced greater signal-to-noise-ratio values than the continuous phase versions as a consequence of this effect.

Signal-to-noise-ratio analysis for nonlinear N-ary phase filters.

The purpose of this investigation was to determine whether performance of a virtual environment (VE) task is influenced by exercise in the heat and carbohydrate supplementation.

Impact of prolonged exercise in the heat and carbohydrate supplementation on performance of a virtual environment task.

The purpose of this study was to examine the influence of exercise order on blood lactate, perceptual, and affective responses to resistance exercise. Twenty-nine subjects (18 women, 11 men; 20.9 +/- 1.9 years) completed three sessions separated by a minimum of 48 hours. Session 1 determined the 10-repetition maximum (10RM) for nine resistance exercises. During sessions 2 and 3, exercises were completed in either a large to small or small to large muscle exercise order. The large to small muscle order was 1) chest press, 2) leg press, 3) rows, 4) leg extension, 5) overhead press, 6) hamstring curl, 7) biceps curl, 8) calve raise, and 9) triceps extension. Exercise order was reversed for the small to large condition. Participants performed two sets of each lift, with the first set being a warm-up at 80% 10RM, followed by one set at 100% 10RM with 1 minute of rest between each exercise. Rating of perceived exertion (RPE) was measured after completion of the second set. Blood lactate was recorded after exercises 1, 5, and 9. Affective measures were completed pre, during, post 0, and post 10 minutes. Lactate showed a significant time (p < 0.001) and condition x time interaction (p = 0.020). A significant difference was seen in average number of repetitions completed between sequences, with small to large performing more. There were no differences seen between exercise orders for average RPE. Analyses of Feeling Scale and Felt Arousal Scale scores showed only a significant main effect of time. A paired-sample t-test was conducted to examine differences in Feeling Scale for the two conditions at the different time points. Significant differences were found for Feeling Scale during exercise (after overhead press) and at post 10, with the small to large exercise order having greater Feeling Scale responses. No significant correlations were seen between blood lactate and perceptual or affective responses at any time point or in either exercise order. These findings may suggest that small to large exercise order may have beneficial physiological and psychological outcomes and potentially influence exercise adherence.

The influence of exercise order on blood lactate, perceptual, and affective responses.

Ratings of perceived exertion (RPE) are routinely used to monitor, assess, and prescribe aerobic exercise. Heart rate (HR) is another measure used to evaluate exercise intensity. Additionally, affective responses to aerobic exercise have been studied and seem to be influenced by the intensity of the exercise. The perceptual, HR, and affective responses to resistance exercise have not been effectively established. The purpose of this study was to examine whether differences in affect, RPE, and HR exist among college-aged women (n = 31) performing three different modes of resistance training: concentric (CE), eccentric (EE), and traditional concentric/eccentric (TE) performed at varying resistances. The women were asked to complete four sessions of resistance training on variable resistance machines: chest press, seated row, overhead press, and biceps curl. The first session was used to establish the 10-repetition maximum (RM) load for each station. Subsequent sessions involved the execution of training in one of the three test conditions: CE, EE, or TE. The participants performed three sets of each lift at 80% 10-RM, 100% 10-RM, and 120% 10-RM. The data revealed lower RPE during EE than the other test conditions. Similarly, EE elicited more mild HR response than either CE or TE. This finding is potentially important for the establishment of training programs, especially for those individuals recovering from an illness, who had been previously sedentary, and who are involved in rehabilitation of an injury.

The influence of muscle action on heart rate, RPE, and affective responses after upper-body resistance exercise.

The purpose of this study was to examine affective responses during and following resistance exercise in a mirrored environment. Thirty-two females completed three sessions. During session one, exercise intensity was determined for the subsequent two sessions. During the next two sessions participants performed eight exercises either with or without mirrors. Affect was measured prior to, during, immediately following and 15 minutes post-exercise. Affect was more pleasant and activated during and following exercise, but did not differ by condition. The inability to find a difference in mirrored condition may be a result of participants using the mirrors for technique as opposed to self-evaluation purposes.

Mirrors and resistance exercise, do they influence affective responses?

The purpose of this study was to test the transient hypofrontality theory (Dietrich, 2003) by examining the influence of exercise intensity on executive control processes during and following submaximal exercise. Thirty participants (13 female) exercised for 30 min at ventilatory threshold (VT) or at 75% of VT. The Contingent Continuous Performance Task (CPT) and Wisconsin Card Sorting Test (WCST) were used as measures of executive control. They were administered before, during, immediately following, and 20 min after exercise. An increase in false alarms and unique errors (p < or = .05) occurred during both conditions. False alarms for the CPT and total and perseverative errors for the WCST remained elevated immediately following exercise at VT, but not at exercise below VT (p < or = .01). The decreased executive control function during exercise can be explained by the transient hypofrontality theory. Following VT, executive control performance remained poor possibly owing to an additional amount of time the brain needs to return to homeostasis following intense exercise.

Cognitive function during acute exercise: a test of the transient hypofrontality theory.

This study examined how exposure to media containing different body image content while exercising influenced exercise performance and feelings concerning appearance. 41 females completed two sessions of cycling (30 minutes). During exercise, participants viewed a television show that contained either media-portrayed ideal or neutral female body images. There were no differences in exercise performance between conditions. Physical appearance state anxiety (PASA) decreased post-exercise. After viewing ideal bodies, participants scored higher on appearance and comparison processing. The high internalization group scored higher on appearance and comparison processing and PASA increased following ideal body image content while the low internalization group decreased.

Viewing television shows containing ideal and neutral body images while exercising: does type of body image content influence exercise performance and body image in women?

Previous studies have shown changes in brain activity as a result of exercise; however, few studies have examined changes during exercise. The purpose of this study was to examine brain activity during a graded exercise test. Twenty male participants performed a graded exercise test on a recumbent cycle ergometer. Exercise intensity was set initially at 50W and was increased by 50W every 2 minutes until volitional fatigue was reached. Electroencephalography (EEG) was measured prior to the onset of exercise, during the last minute of each stage of exercise, immediately post-exercise, and 10 minutes into recovery. EEG was recorded from 8 scalp sites leading to analysis of alpha 1, alpha 2, beta 1, beta 2, and theta activities. Expired air was collected and analyzed for ventilation rate (VE), VO2, % of peak VO2, and Respiratory Exchange Ratio (RER). No differences were seen in EEG between the hemispheres of the brain. There was, however, a significant increase in brain activity across the spectrum occurring at 200 W through immediately post-exercise. Brain activity returned to pre- exercise levels by 10 minutes post. VO2, % of peak VO2 and RER increased linearly with exercise intensity. VE increased linearly through 200 W; however, a disproportionate increase was seen in VE from 200 W to peak exercise. The results of this investigation demonstrate that brain activity may be related to exercise intensity. Future research will want to examine how these changes in brain activity influence affective, perceptual and cognitive changes often associated with exercise. Efforts will also need to be made to determine if changes in brain activity during exercise are mediated by central (within the brain) or peripheral mechanisms. Key pointsEEG can be recorded during exercise.Brain EEG activity increases during exercise and may be related to exercise intensity.Brain EEG activity returns to resting levels quickly after the cessation of exercise.

Changes in EEG during graded exercise on a recumbent cycle ergometer.

Performance in fitness tests could depend on factors beyond the bioenergetic and skeletomuscular systems, such as individual differences in preference for and tolerance of different levels of exercise-induced somatosensory stimulation. Although such individual-difference variables could play a role in exercise testing and prescription, they have been understudied. The purpose of these studies was to examine the relationships of self-reported preference for and tolerance of exercise intensity with performance in fitness tests. Participants in study I were 516 men and women volunteers from a campus community, and participants in study II were 42 men recruit firefighters undergoing a 6-week training program. Both the Preference and Tolerance scores exhibited significant relationships with performance in several fitness tests and with body composition and physical activity participation. Preference and Tolerance did not change after the training program in study II, despite improvements in objective and perceived fitness, supporting their conceptualization as dispositional traits. Preference and Tolerance scores could be useful not only in ameliorating the current understanding of the determinants of physical performance, but also in personalizing exercise prescriptions and, thus, delivering exercise experiences that are more pleasant, tolerable, and sustainable.

Paul C. Miller

Department of Exercise Science

Elon University

A Neuroscientific Approach to the Examination of Concussions in Student-Athletes

Paul C. Miller

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Exercise Science

Elon University

A Neuroscientific Approach to the Examination of Concussions in Student-Athletes

Department of Exercise Science