Edgar W. Shields

The relationship between subconcussive impacts and concussion history on clinical measures of neurologic function in collegiate football players.

Concussions sustained during college and professional football careers have been associated with both acute and chronic neurologic impairment. The contribution of subconcussive impacts to this impairment has not been adequately studied. Therefore, we investigated the relationship between subconcussive impacts and concussion history on clinical measures of neurologic function. Forty-six collegiate football players completed five clinical measures of neurologic function commonly employed in the evaluation of concussion before and after a single season. These tests included the Automated Neuropsychological Assessment Metrics, Sensory Organization Test, Standardized Assessment of Concussion, Balance Error Scoring System, and Graded Symptom Checklist. The Head Impact Telemetry (HIT) System recorded head impact data including the frequency, magnitude, and location of impacts. College football players sustain approximately 1,000 subconcussive impacts to the head over the course of a season, but for the most part, do not demonstrate any clinically meaningful changes from preseason to postseason on measures of neurologic function. Changes in performance were mostly independent of prior concussion history, and the total number, magnitude and location of sustained impacts over one season as observed R2 values ranged between 0.30 and 0.35. Repetitive subconcussive head impacts over a single season do not appear to result in short-term neurologic impairment, but these relationships should be further investigated for a potential dose–response over a player’s career.

The National Football League Combine: Performance Differences Between Drafted and Nondrafted Players Entering the 2004 and 2005 Drafts

The purpose of this study was to examine performance differences between drafted and nondrafted athletes (N = 321) during the 2004 and 2005 National Football League (NFL) Combines. We categorized players into one of 3 groups: Skill, Big skill, and Linemen. Skill players (SP) consisted of wide receivers, cornerbacks, free safeties, strong safeties, and running backs. Big skill players (BSP) included fullbacks, linebackers, tight ends, and defensive ends. Linemen (LM) consisted of centers, offensive guards, offensive tackles, and defensive tackles. We analyzed player height and mass, as well as performance on the following combine drills: 40-yard dash, 225-lb bench press test, vertical jump, broad jump, pro-agility shuttle, and the 3-cone drill. Student t-tests compared performance on each of these measures between drafted and nondrafted players. Statistical significance was found between drafted and nondrafted SP for the 40-yard dash (P < 0.001), vertical jump (P = 0.003), pro-agility shuttle (P < 0.001), and 3-cone drill (P < 0.001). Drafted and nondrafted BSP performed differently on the 40-yard dash (P = 0.002) and 3-cone drill (P = 0.005). Finally, drafted LM performed significantly better than nondrafted LM on the 40-yard dash (P = 0.016), 225-lb bench press (P = 0.003), and 3-cone drill (P = 0.005). Certified strength and conditioning specialists will be able to utilize the significant findings to help better prepare athletes as they ready themselves for the NFL Combine.

MEASUREMENT OF HEAD IMPACTS IN COLLEGIATE FOOTBALL PLAYERS: CLINICAL MEASURES OF CONCUSSION AFTER HIGH- AND LOW-MAGNITUDE IMPACTS

OBJECTIVEIt has been speculated that a theoretical injury threshold of 70 to 75 g may exist for concussions in football players. We aimed to investigate acute balance and neurocognitive performance after head impacts exceeding a theoretical injury threshold in the absence of both self-reported symptoms and a concussion diagnosis 24 hours before testing. METHODSForty-three Division I collegiate football players participated in this double-blind, repeated-measures study. Subjects participated in three test sessions (baseline, low impact, and high impact) separated by at least 2 weeks. The Head Impact Telemetry System (Simbex, Lebanon, NH) recorded real-time head impacts sustained during practices and games. The Automated Neuropsychological Assessment Metrics assessed neurocognitive performance. The NeuroCom Sensory Organization Test (NeuroCom International Inc., Clackamas, OR) assessed postural stability. The Graded Symptom Checklist evaluated symptom presence and severity in our participants. RESULTSAfter the low-impact test session (<60 g), we observed improvements in the Math Processing (F1, 26 = 9.797; P = 0.004), Matching to Sample (F1, 26 = 6.504; P = 0.017), and Sternberg Procedure (F1, 26 = 5.323; P = 0.030) Automated Neuropsychological Assessment Metrics test modules. Statistically significant differences were also observed after the high-impact test session (>90g) with improvements in Math Processing (F1, 22 = 16.629; P < 0.001), Procedural Reaction Time (F1, 22 = 14.668; P < 0.001), and the total number of symptoms reported (F1, 22 = 10.267; P = 0.004). Neurocognitive improvements were likely attributed to a learning effect. CONCLUSIONOur findings suggest that sustaining an impact greater than 90 g does not result in acute observable balance and neurocognitive deficits within 24 hours of sustaining the impact. Although previous studies have suggested a theoretical injury threshold, none have been founded on empirical data collected on the playing field in real-time. Future studies should consider the cumulative effects of impacts of varying magnitudes.

The effects of an individualized exercise intervention on body composition in breast cancer patients undergoing treatment

CONTEXT AND OBJECTIVE Changes in metabolism have been reported in the majority of patients undergoing cancer treatment, and these are usually characterized by progressive change in body composition. The effects of aerobic exercise programs to combat the cancer and cancer treatment-related side effects, which include the negative changes in body composition, have been extensively reported in the literature. However, few resistance exercise intervention studies have hypothesized that breast cancer patients might benefit from this type of exercise. The purpose of this study was to determine whether exercise protocols that emphasize resistance training would change body composition and strength in breast cancer patients undergoing treatment. DESIGN AND SETTING Randomized controlled trial, at the Campus Recreation Center and Rocky Mountain Cancer Rehabilitation Institute of the University of Northern Colorado, and the North Colorado Medical Center. METHODS Twenty inactive breast cancer patients were randomly assigned to a 21-week exercise group (n = 10) or a control group (n = 10). The exercise group trained at low to moderate intensity for 60 minutes on two days/week. The primary outcome measurements included body composition (skinfold method) and muscle strength (one repetition maximum). RESULTS Significant differences in lean body mass, body fat and strength (p = 0.004, p = 0.004, p = 0.025, respectively) were observed between the groups at the end of the study. CONCLUSION The results suggest that exercise emphasizing resistance training promotes positive changes in body composition and strength in breast cancer patients undergoing treatment.

The effects of headache on clinical measures of neurocognitive function.

Objective:To examine effects of preseason baseline headache and posttraumatic headache (PTH) on neurocognitive function. Design:Retrospective repeated measures study with headache groups formed regarding baseline headache score (0 = negative headache; 1-6 = positive headache) and day 1 postinjury headache score (0 = no headache; 1-2 = mild headache; 3-6 = moderate-severe headache). Setting:Clinical athletic training setting and sports medicine research laboratory. Participants:High-school and collegiate athletes with a concussion. Independent Variables:Preseason baseline headache, PTH, test-day. Main Outcome Measures:A Graded Symptom Checklist (GSC) was used to assess symptoms. The Automated Neuropsychological Assessment Metrics (ANAM) and the Standardized Assessment of Concussion (SAC) were used to assess neuropsychological function and mental status. The Balance Error Scoring System (BESS) was used to assess postural stability. Results:Both baseline headache groups displayed a higher symptom endorsement and higher symptom severity at day 1 postinjury and improved by day 7 postinjury. The positive headache group reported an even greater increase in symptom severity and presence (P < 0.05). ANAM revealed deficits in both groups 1 day postinjury. All PTH headache groups displayed a difference in symptom number and severity with the increase being magnified by headache severity (P < 0.05). Individuals reporting moderate-severe PTH displayed increased deficits subacutely but improved by 5-7 days postinjury on overall neuropsychological performance, reaction time, and working memory (P < 0.05). Deficits were observed for all ANAM measures except simple reaction time 1 (SRT 1) and match to sample subacutely and improved over time (P < 0.05). The SAC yielded an interaction (P < 0.05) for baseline headache. The BESS yielded no significant findings. Conclusions:Clinicians should consider headache when assessing concussion and during preseason baseline assessments because headache may affect symptom presence and other clinical measures of concussion.

Age-Related Differences and Reliability on Computerized and Paper-and-Pencil Neurocognitive Assessment Batteries

CONTEXT Neurocognitive testing is a recommended component in a concussion assessment. Clinicians should be aware of age and practice effects on these measures to ensure appropriate understanding of results. OBJECTIVE To assess age and practice effects on computerized and paper-and-pencil neurocognitive testing batteries in collegiate and high school athletes. DESIGN Cohort study. SETTING Classroom and laboratory. PATIENTS OR OTHER PARTICIPANTS Participants consisted of 20 collegiate student-athletes (age = 20.00 ± 0.79 years) and 20 high school student-athletes (age = 16.00 ± 0.86 years). MAIN OUTCOME MEASURE(S) Hopkins Verbal Learning Test scores, Brief Visual-Spatial Memory Test scores, Trail Making Test B total time, Symbol Digit Modalities Test score, Stroop Test total score, and 5 composite scores from the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) served as outcome measures. Mixed-model analyses of variance were used to examine each measure. RESULTS Collegiate student-athletes performed better than high school student-athletes on ImPACT processing speed composite score (F(1,38) = 5.03, P = .031) at all time points. No other age effects were observed. The Trail Making Test B total time (F(2,66) = 73.432, P < .001), Stroop Test total score (F(2,76) = 96.85, P = < .001) and ImPACT processing speed composite score (F(2,76) = 5.81, P = .005) improved in test sessions 2 and 3 compared with test session 1. Intraclass correlation coefficient calculations demonstrated values ranging from 0.12 to 0.72. CONCLUSIONS An athletes neurocognitive performance may vary across sessions. It is important for clinicians to know the reliability and precision of these tests in order to properly interpret test scores.

Effect of exercise on the caloric intake of breast cancer patients undergoing treatment

The purpose of this study was to examine the effects of an exercise intervention on the total caloric intake (TCI) of breast cancer patients undergoing treatment. A secondary purpose was to determine whether or not a relationship existed between changes in TCI, body fat composition (%BF), and fatigue during the study, which lasted 6 months. Twenty females recently diagnosed with breast cancer, scheduled to undergo chemotherapy or radiation, were assigned randomly to an experimental (N = 10) or control group (N = 10). Outcome measures included TCI (3-day food diary), %BF (skinfolds), and fatigue (revised Piper Fatigue Scale). Each exercise session was conducted as follows: initial cardiovascular activity (6-12 min), followed by stretching (5-10 min), resistance training (15-30 min), and a cool-down (approximately 8 min). Significant changes in TCI were observed among groups (F1,18 = 8.582; P = 0.009), at treatments 2 and 3, and at the end of the study [experimental (1973 +/- 419), control (1488 +/- 418); experimental (1946 +/- 437), control (1436 +/- 429); experimental (2315 +/- 455), control (1474 +/- 294), respectively]. A significant negative correlation was found (Spearman rho(18) = -0.759; P < 0.001) between TCI and %BF and between TCI and fatigue levels (Spearman rho(18) = -0.541; P = 0.014) at the end of the study. In conclusion, the results of this study suggest that an exercise intervention administered to breast cancer patients undergoing medical treatment may assist in the mitigation of some treatment side effects, including decreased TCI, increased fatigue, and negative changes in body composition.

Application of Reliable Change Indices to Computerized Neuropsychological Measures of Concussion

Serial assessments of neurocognitive functioning in athletes with concussion are commonly used for return to play decisions. This study provides reliable change indices (RCIs) for computerized tests from 40 NCAA Division I collegiate athletes that suffered a sports-related concussion. The normative data that resulted from the RCIs and subsequent analyses of differences between improved and not improved athletes may aid both clinicians and researchers to assess whether observed change on neuropsychological measures is reliable change or change due simply to practice effects. Hence, the RCIs presented herein provide information that may be used judiciously by a clinician for assessing meaningful change.

The effects of resistance training on muscular strength and fatigue levels in breast cancer patients

The effects of generalized exercise programs to combat cancer and cancer treatment-related side effects have been extensively reported in the literature. The purpose of this study was to examine the effects of an individualized exercise program with emphasis on resistance exercise, changes in muscular strength and fatigue in breast cancer female patients under treatment. Twenty subjects were randomly divided in two groups: an experimental (57.5 ± 23.0 years) and a control (56.6 ± 16.0 years) group. A twenty-one week intervention involving preand post-functional assessments, prescriptive exercise, and three moments of fatigue measures was used. The experimental group exercised at a low to moderate-intensity for sixty minutes two days a week beginning after surgery. Significant differences in overall muscular strength were observed between groups post-intervention (p = 0.025). Fatigue was also significantly different between groups at treatment one (p = 0.001), treatment two (p = 0.005) and post-intervention (p = 0.001). The results of this study suggest that an emphasis on resistance training should be utilized to combat fatigue and to increase muscular strength in breast cancer patients undergoing treatment.ABSTRACTThe effects of resistance training on muscular strength andfatigue levels in breast cancer patients The effects of generalized exercise programs to combat cancerand cancer treatment-related side effects have been extensivelyreported in the literature. The purpose of this study was to exami-ne the effects of an individualized exercise program with empha-sis on resistance exercise, changes in muscular strength and fati-gue in breast cancer female patients under treatment. Twentysubjects were randomly divided in two groups: an experimental(57.5 ± 23.0 years) and a control (56.6 ± 16.0 years) group. A twen-ty-one week intervention involving pre- and post-functional asses-sments, prescriptive exercise, and three moments of fatigue me-asures was used. The experimental group exercised at a low tomoderate-intensity for sixty minutes two days a week beginningafter surgery. Significant differences in overall muscular strengthwere observed between groups post-intervention (p = 0.025). Fa-tigue was also significantly different between groups at treatmentone (p = 0.001), treatment two (p = 0.005) and post-intervention(p = 0.001). The results of this study suggest that an emphasis onresistance training should be utilized to combat fatigue and to in-crease muscular strength in breast cancer patients undergoing tre-atment.The effects of resistance training on muscular strength and fatigue levels in breast cancer patients The effects of generalized exercise programs to combat cancer and cancer treatment-related side effects have been extensively reported in the literature. The purpose of this study was to examine the effects of an individualized exercise program with emphasis on resistance exercise, changes in muscular strength and fatigue in breast cancer female patients under treatment. Twenty subjects were randomly divided in two groups: an experimental (57.5 ± 23.0 years) and a control (56.6 ± 16.0 years) group. A twenty-one week intervention involving preand post-functional assessments, prescriptive exercise, and three moments of fatigue measures was used. The experimental group exercised at a low to moderate-intensity for sixty minutes two days a week beginning after surgery. Significant differences in overall muscular strength were observed between groups post-intervention (p = 0.025). Fatigue was also significantly different between groups at treatment one (p = 0.001), treatment two (p = 0.005) and post-intervention (p = 0.001). The results of this study suggest that an emphasis on resistance training should be utilized to combat fatigue and to increase muscular strength in breast cancer patients undergoing treatment.

Assessing explosive power production using the backward overhead shot throw and the effects of morning resistance exercise on afternoon performance.

Abstract Ekstrand, LG, Battaglini, CL, McMurray, RG, and Shields, EW. Assessing explosive power production using the backward overhead shot throw and the effects of morning resistance exercise on afternoon performance. J Strength Cond Res 27(1): 101–106, 2013—The purpose of this study was to determine if performing a morning total-body resistance exercise workout affects explosive power in an afternoon session. The secondary goal was to assess the usefulness of the backward overhead shot throw (BOST) as a measure of explosive power in experienced thrower in the sport of athletics. Throwers (N = 14) performed 1 control and 1 experimental trial on separate days. The control consisted of BOST and a vertical jump (VJ) testing performed in the afternoon. For the experimental trial, the participants reported for a short resistance training session in the morning then repeating the BOST and VJ testing 4–6 hours later. The BOST distance (meters) and VJ peak power (watts) were correlated in both trials (r ∼ 0.64, p < 0.05). The BOST distance improved in experimental trial over control (p < 0.05), but VJ power failed to improve. The results indicate that a morning resistance exercise bout can improve competitive throwing performance later on the same day. The results also suggest that BOST may be a useful performance testing tool for throwers in the sports of athletics.