Time of day and athlete status effects on the modified clinical test of sensory integration and balance (mCTSIB) and stability evaluation test (SET).

BACKGROUND: Concussions or musculoskeletal injuries may impair postural control, which is one diagnostic to help determine return-to-activity decisions. Postural control may be affected by diurnal rhythm. RESEARCH QUESTION: Does time of day influence postural control as measured by two Neurocom Balance Master diagnostic protocols, the Modified Clinical Test of Sensory Interaction on Balance (mCTSIB) and the Stability Evaluation Test (SET)? METHODS: Following Institutional Review Board (IRB) approval, consented participants completed the SET and mCTSIB twice: between 0700 and 1000; and between 1600 and 1900. We randomized and balanced testing order. Familiarization trials were completed for the mCTSIB and SET. Assessments were completed in a controlled laboratory environment. We instructed participants to get a normal night's sleep prior to testing and refrain from caffeine use and exhaustive exercise on the day of testing. Sixty-nine participants (48 female, 21 male: age = 21.42±2.56 years, height = 168.20±7.53 cm, mass = 72.05±16.60 kg) completed the study. Thirty-one of the participants were National Association of Intercollegiate Athletes (NAIA) student-athletes from the sports of baseball, soccer and softball. Average postural sway velocity was measured and compared by time of day for each of the balance conditions in the mCTSIB and SET protocols. RESULTS: According to repeated measures ANOVA, there were no significant postural sway velocity main effects by time of day for any of the balance conditions. We found significant postural sway main effects by foam, stance and eyes. We also noted significant ANOVA between participants' differences for athlete status, but not for sex. SIGNIFICANCE: These results inform practitioners about the importance of controlling time-of-day between baseline and post-injury testing, which may allow for more flexible, accurate and reliable diagnosis and return-to-activity decisions. Athletes displayed better static postural control, possibly warranting different normative values for diagnostic comparison.

Quantifying head impacts and neurocognitive performance in collegiate boxers.

Head impacts and neurocognition were quantified in 27 intercollegiate male boxers engaged in two, two-minute sparring rounds. Head impacts were measured using Instrumented Boxing Headgear (IBH). Pre and post-sparring neurocognitive performance was compared using two computerized neuropsychological test batteries (CNTs): Immediate Post-concussion Assessment and Cognitive Testing (ImPACT™) and Automated Neuropsychological Assessment Metrics - Military Battery (ANAM4® MIL). An average of 27.63 ± 17.87 impacts above the 9.6 g IBH threshold were recorded per boxer, with average peak linear acceleration of 23.48 ± 15.20 g and average peak rotational acceleration of 1761.40 ± 1064.34 rad/s2. Small, but measurable declines in delayed memory and improvement in response time from pre- to post-bout were noted. Number of impacts and concussion history predicted degraded memory performance. This is a unique quantification of head impacts in collegiate boxing, which were similar in frequency and location, but lower in magnitude as compared to amateur boxing. Improved understanding of impact kinematics may enhance safety in boxing and other contact sports. Subtle post-bout decrements in delayed memory performance and mild improvement in response time reinforce prior research and provide evidence of congruence in our two CNT assessments, which may facilitate comparisons of outcomes across settings utilizing these tests.

Influence of carbon monoxide leaks on the measurement error of total haemoglobin mass.

Total haemoglobin mass (Hb(mass)) can be assessed with low measurement error using carbon monoxide (CO) rebreathing. However, variability in measurement error of Hb(mass) has been reported across laboratories and it has previously been suggested that CO leaks contribute to this variability. As a result of employing a standardized leak monitoring procedure using two CO detectors, we were able to retrospectively examine the impact of CO leaks on Hb(mass) values from past test-retest studies in our laboratory using the optimized CO rebreathing method. Test-retest data were collected to determine measurement error, with subjects tested twice within 5 days. Test-retest data were placed into separate categories based on magnitude and duration of CO leak observed during one of the two tests. The No Leak category contained test-retest data in which no leak occurred during either test. The Minor Leak category contained test-retest data in which one of the tests had a CO leak of magnitude less than 30 ppm and less than 5 seconds duration, whereas the Major Leak category included test-retest data in which a leak greater than this magnitude or duration occurred. Measurement error was lowest in the No Leak category (1.9%; 95%CI: 1.6-2.3%; n = 56), approximately doubled in the Minor Leaks category (3.6%; 95%CI: 2.6-6.1%; n = 13), and dramatically increased in the Major Leaks category (9.3%; 95%CI: 6.3-17.6%; n = 10). We recommend careful monitoring of potential CO leaks using multiple detectors. To minimize measurement error, tests in which any CO leak is detected should be excluded.

Hematological and physiological adaptations following 46 weeks of moderate altitude residence.

Although acclimatization to moderate altitude (MA) is thought to be unnecessary or to require minimal adaptation, retrospective data from the U.S. Air Force Academy (USAFA), a military college located at 2210 m, suggested otherwise. To further examine the utility of USAFA as a model for MA acclimatization, a longitudinal experimental design was prospectively utilized to determine the magnitude and time course of selected hematological and performance parameters following 46 weeks at this unique MA setting. Incoming USAFA male freshmen (n=55) were divided into experimental groups based on prior residence at sea level (SL) or MA. Hematological and performance parameters were repeatedly assessed during their entire first year at MA. Hematological data consisted of a complete blood count (CBC) with reticulocyte parameters, as well as determination of serum levels of ferritin, erythropoietin, and soluble transferrin receptor (sTfR). Performance testing included aerobic (1.5-mile run) and physical (push-ups, sit-ups, pull-ups, and standing long jump) fitness tests, maximal aerobic capacity, and running economy. Significant (p<0.05; main effect) hematological differences between SL and MA subjects were observed for the majority of the study. MA subjects had a significantly higher hemoglobin concentration ([Hb], +5.5%), hematocrit (+2.8%), and serum ferritin (+59.0%) and significantly lower sTfR (-11.4%) values than their SL peers. Although both serum ferritin and sTfR demonstrated a significant altitude group x time interaction, [Hb] and hematocrit did not. A significant main effect of altitude without interaction was also observed for performance parameters, with SL subjects having a significantly lower Vo2peak (-5.9%), slower 1.5- mile run time (+5.4%), poorer running economy (+6.6%), and lower composite physical fitness test score (-13.9%) than MA subjects. These results suggest that complete acclimatization to 2210 m by former SL residents may require lengthy physiological adaptations, as both hematological and physical performance differences persisted between groups. Further research at this uniquely well controlled MA setting is warranted.

Determination of functional strength imbalance of the lower extremities.

The purposes of this study were (a) to determine whether a significant strength imbalance existed between the left and right or dominant (D) and nondominant (ND) legs and (b) to investigate possible correlations among various unilateral and bilateral closed kinetic chain tests, including a field test, and traditional isokinetic dynamometry used to determine strength imbalance. Fourteen Division I collegiate women softball players (20.2 +/- 1.4 years) volunteered to undergo measures of average peak torque for isokinetic flexion and extension at 60 degrees .s(-1) and 240 degrees .s(-1); in addition, measures of peak and average force of each leg during parallel back squat, 2-legged vertical jump, and single-leg vertical jump and performance in a 5-hop test were examined. Significant differences of between 4.2% and 16.0% were evident for all measures except for average force during single-leg vertical jump between the D and ND limbs, thus revealing a significant strength imbalance. The 5-hop test revealed a significant difference between D and ND limbs and showed a moderate correlation with more sophisticated laboratory tests, suggesting a potential use as a field test for the identification of strength imbalance. The results of this study indicate that a significant strength imbalance can exist even in collegiate level athletes, and future research should be conducted to determine how detrimental these imbalances could be in terms of peak performance for athletes, as well as the implications for injury risk.

Caffeinated tube food effect on pilot performance during a 9-hour, simulated nighttime U-2 mission.

INTRODUCTION: Interventions to maintain performance are necessary to meet demanding mission requirements during sustained and surge aviation operations. Tube foods are the only foods that can be consumed during a U-2 mission due to the confining and encapsulating nature of required support equipment. Caffeine is a safe and effective strategy to enhance cognitive performance and is an ingredient in some tube foods. The objective of this study was to determine whether moderate doses of caffeinated tube foods would enhance performance in a simulated U-2 mission. METHODS: Volunteers were 12 healthy USAF male pilots. The study used a double blind, placebo-controlled, two-factor, repeated-measures (five iterations per night) design. Caffeinated (200 mg each) or placebo tube food was consumed at 00:00 and 04:00. Dependent measures assessed included standardized tests of cognitive performance, vigilance, and mood designed to simulate the demands of a nighttime U-2 mission. RESULTS: Statistically significant (p < 0.05) improvements in performance due to caffeine administration compared with placebo were present in all five cognitive tasks either as main effects, interactions, or absence of significant degradation in the caffeine treatment condition compared with the placebo condition. A majority of sleep deprivation-induced performance decrements were attenuated by 200 mg of caffeine in tube food consumed every 4 h, and in some cases, performance was improved beyond baseline levels. CONCLUSIONS: Caffeinated tube food maintained cognitive performance representative of U-2 long-duration mission tasks at or near baseline levels for a 9-h overnight period in qualified USAF pilots. Side effects were minor and did not differ between placebo and caffeine conditions.

Effects of physical conditioning on intercollegiate golfer performance.

This investigation was conducted to determine the effects of a physical conditioning program on clubhead speed, consistency, and putting distance control in 10 men and 6 women National Collegiate Athletic Association Division I golfers. Supervised strength, power, and flexibility training was performed 3 times per week for 11 weeks. Performance tests were conducted before and after the training period. Significant (p < 0.05) increases were noted for all strength, power, and flexibility tests from pre- to posttraining of between 7.3 and 19.9%. Clubhead speed increased significantly (1.6%), equating to approximately a 4.9-m increase in driving distance. Putting distance control significantly improved for the men-only group (29.6%), whereas there was no significant difference in putting distance control for the total and women-only groups. Eleven weeks of golf-specific physical conditioning increased clubhead speed without a negative effect on consistency or putting distance control in intercollegiate men and women golfers.

Assessing psychoactive pharmaceuticals and transitioning pharmacological fatigue countermeasures into operational environments.

Herein we summarize a discussion on the topic of how psychopharmaceuticals for potential military operational use may be evaluated based on their effects on performance and safety, and introduce two manuscripts: the first (Caldwell and Caldwell; 1) addressing the operational use of fatigue countermeasures; and the second (Rowland; 3) discussing the potential operational use and limitations of ketamine as a field analgesic. Fatigue countermeasures are usually employed by a relatively small number of military members engaged in sustained or continuous operations when sleep is not an option. Clinical treatments are available at any time as required to treat medical conditions. The issue of importance for the operational community, with regard to both clinical use of psychopharmaceuticals and performance maintenance through fatigue countermeasures, should be whether the medication impairs operationally relevant performance, assuming the disorder for which the medication is prescribed does not in itself prohibit operational duties. Applied research paradigms are generally discussed for assessing and transitioning pharmaceutical compounds from the laboratory to the operational environment. Tier 1 focuses on quantifying the impact of stressors and interventions in healthy members of the general population, while Tier 2 testing would use military or operationally matched volunteers in simulated or actual field environments. The section papers address two areas of operational relevance--the Caldwell and Caldwell paper presents guidelines for the use of fatigue countermeasures, and the Rowland paper discusses the potential effects of ketamine, an agent intended to replace morphine as a battlefield analgesic, on cognition.

Evaluation of a lower-body compression garment.

The aims of this study were to determine how custom-fit compression shorts affect athletic performance and to examine the mechanical properties of the shorts. Ten male and 10 female track athletes on a university's nationally competitive track team, specializing in sprint or jump events, participated in the study. Testing utilized the compression shorts with loose-fitting gym shorts as the control garment. Several significant effects were revealed for the custom-fit compressive garment. Although 60 m sprint time was not affected, hip flexion angle was reduced. Skin temperature increased more and at a faster rate during a warm-up protocol. Muscle oscillation was decreased during vertical jump landing. Countermovement vertical jump height increased when the participants were wearing the custom-fit compression garment. In materials testing, the elasticity of the compressive garment provides increased flexion and extension torque at the end range of extension and flexion, respectively, and may assist the hamstrings in controlling the leg at the end of the swing phase in sprinting. The compressive garment significantly reduced impact force by 27% compared with American football pants alone. Through various mechanisms, these findings may translate into an effect on athletic performance and a reduction in injuries.

The effects of a 10-kilometer run on muscle strength and power.

Recovery of maximal force and power following a 10-km race has not been widely studied in the scientific literature. Ten healthy men who were experienced distance runners participated in this investigation. Data were collected prerace, immediate postrace, and 48 hours postrace to examine the effect of a 10-km race on muscle force production in the lower body. Maximal peak torque was measured via an isokinetic dynamometer at 30 degrees, 180 degrees, and 300 degrees.s-1. A significant (p

Effects of increased eccentric loading on bench press 1RM.

The purpose of this study was to measure the effects of additional eccentric loading on subsequent concentric strength. Eight subjects with some experience in weight training volunteered to perform maximal attempts in the barbell bench press using detaching hooks that allowed them to lower 105% of their concentric 1 repetition maximum (RM) and raise 100%. The detaching hooks allowed attachment of extra weight to the bar and would release from the bar at the bottom of the lift, reducing the weight lifted during the concentric phase of the lift. After determining their 1RM for the bench press, the subjects attempted to increase their performance by using a heavier eccentric load with the detaching hooks. All 8 subjects who completed the study increased their 1RMs by 5 to 15 pounds. The use of additional eccentric loading significantly (p = 0.008) increased the weight that could be lifted on the subsequent concentric phase and therefore 1RM performance. This phenomenon was a result of the enhancement of stretch-shortening cycle performance by the increased eccentric load. Athletes who are interested in developing 1RM strength in the bench press may benefit from the use of additional eccentric loading.