Counter-balanced Design Research Articles

(190) Effects of sleep continuity disruption on cold pain tolerance and accompanying pain catastrophizing in healthy, good sleepers

Chronic sleep problems, such as those associated with insomnia, have been shown to increase vulnerability for chronic pain at the population level. However, there is limited understanding of the mechanisms linking sleep and pain. Cold pain tolerance (CPT) is a predictor of clinical pain severity in chronic pain patients. Pain catastrophizing, a maladaptive cognitive coping strategy, is associated with lower pain tolerance and higher clinical pain. In the present study, we investigated the effects of sleep continuity disruption -- an experimental model of sleep deprivation with ecological validity for comorbid chronic pain and insomnia -- on CPT and accompanying catastrophizing cognitions. Healthy good sleepers underwent one night of uninterrupted sleep (US) and one night of forced awakenings (FA) in a randomized, within-person, counter-balanced design. On the day following each sleep condition, participants placed their dominant hand palm-down in a 4°C circulating water bath for a maximum of 300 seconds and were instructed to remove their hand when the pain became intolerable. CPT was measured as the time to withdrawal. Participants completed a self-report pain catastrophizing scale immediately following CPT. A total of 33 subjects provided usable data on these measures. Results indicated that CPT was significantly lower following FA compared to US (p<0.05). Pain catastrophizing was not significantly different between sleep conditions. Together these findings indicate that a single night of sleep continuity disruption is associated with a reduction in CPT that does not appear to be driven by catastrophizing. The present data suggest that the association of sleep continuity disruption and pain tolerance may be one avenue through which chronic sleep disorders, such as insomnia, increase vulnerability to chronic pain.

Amplified Striatal Responses to Near-Miss Outcomes in Pathological Gamblers.

Near-misses in gambling games are losing events that come close to a win. Near-misses were previously shown to recruit reward-related brain regions including the ventral striatum, and to invigorate gambling behavior, supposedly by fostering an illusion of control. Given that pathological gamblers are particularly vulnerable to such cognitive illusions, their persistent gambling behavior might result from an amplified striatal sensitivity to near-misses. In addition, animal studies have shown that behavioral responses to near-miss-like events are sensitive to dopamine, but this dopaminergic influence has not been tested in humans. To investigate these hypotheses, we recruited 22 pathological gamblers and 22 healthy controls who played a slot machine task delivering wins, near-misses and full-misses, inside an fMRI scanner. Each participant played the task twice, once under placebo and once under a dopamine D2 receptor antagonist (sulpiride 400 mg), in a double-blind, counter-balanced design. Participants were asked about their motivation to continue gambling throughout the task. Across all participants, near-misses elicited higher motivation to continue gambling and increased striatal responses compared with full-misses. Crucially, pathological gamblers showed amplified striatal responses to near-misses compared with controls. These group differences were not observed following win outcomes. In contrast to our hypothesis, sulpiride did not induce any reliable modulation of brain responses to near-misses. Together, our results demonstrate that pathological gamblers have amplified brain responses to near-misses, which likely contribute to their persistent gambling behavior. However, there is no evidence that these responses are influenced by dopamine. These results have implications for treatment and gambling regulation.

Abnormal modulation of reward versus punishment learning by a dopamine D2-receptor antagonist in pathological gamblers.

RationalePathological gambling has been associated with dopamine transmission abnormalities, in particular dopamine D2-receptor deficiency, and reversal learning deficits. Moreover, pervasive theoretical accounts suggest a key role for dopamine in reversal learning. However, there is no empirical evidence for a direct link between dopamine, reversal learning and pathological gambling.ObjectiveThe aim of the present study is to triangulate dopamine, reversal learning, and pathological gambling.MethodsHere, we assess the hypothesis that pathological gambling is accompanied by dopamine-related problems with learning from reward and punishment by investigating effects of the dopamine D2-receptor antagonist sulpiride (400 mg) on reward- and punishment-based reversal learning in 18 pathological gamblers and 22 healthy controls, using a placebo-controlled, double-blind, counter-balanced design.ResultsIn line with previous studies, blockade of D2 receptors with sulpiride impaired reward versus punishment reversal learning in controls. By contrast, sulpiride did not have any outcome-specific effects in gamblers.ConclusionThese data demonstrate that pathological gambling is associated with a dopamine-related anomaly in reversal learning from reward and punishment.Electronic supplementary materialThe online version of this article (doi:10.1007/s00213-015-3986-y) contains supplementary material, which is available to authorized users.

Core Muscle Activation During Unstable Leg Extension Using a Water-Filled Training Tube

Creating muscle instability may be an effective means of training for stability. Instability may be achieved using an unstable surface or load. PURPOSE: The purpose of this study was to assess the degree of muscle instability created during a seated leg extension using a novel unstable load (“slosh tube”) under three different conditions. METHODS: Eight men (age= 19.9± 1.6y, ht=178.8 ± 8.9cm, mass= 103.3 ± 48.5kg, Leg Ext 1RM= 136.5 ± 15.9kg ) and eight women (age= 20.1 ± 1.1y, ht=164.9 ± 9.8cm, mass= 62.9 ± 12.2kg, Leg Ext 1RM= 91.5 ± 15.5kg ) completed three, 30s trials of leg extension using an 11.4 kg tube partially filled with water. A central valve allowed three conditions of water movement: 50% open, 100% open, and a stable, balanced valve setting. The valve settings allowed for different water flow dynamics, creating movement during the lift. Subjects completed 8-10 repetitions (20 reps/min) within each condition using a counter-balanced design. Muscle activation was assessed on the right side, with bipolar surface electrodes placed over the vastus lateralis, vastus medialis, rectus abdominus and paraspinal muscles. Integrated EMG was measured (1,000Hz/s) for each repetition and converted to a %MVC for each muscle. Instability was determined using the coefficient of variation across repetitions. A two way repeated measures ANOVA (gender, condition, gender x condition) with post hoc t-tests was used to examine concentric contractions only. RESULTS: Percent MVC activated for the vastus lateralis was significantly greater in women (81.8 ±52.7%) compared to men (48.0 ±27.8%) across all conditions. No differences in % MVC were seen for vastus medialis, rectus abdominus, and paraspinal muscles. There were no differences in instability for any muscle or condition, however abdominal instability was trending toward differences between men( CV= 24.8 ±15.9) and women (CV= 30.5 ± 28.3 p= .06). CONCLUSIONS: We conclude that utilizing an 11.4kg unstable device during seated leg extension does not result in significant instability, however it does result in greater vastus lateralis activation in women compared to men. A heavier load may be required to create the desired unstable conditions for core muscle activation.

Core Muscle Activation During Unstable Bicep Curl Using a Water-Filled Training Tube

Stability and balance are essential components for functional movement. These components may developed by training with unstable surfaces, or unstable loads. PURPOSE: The purpose of this study was to use a novel unstable implement (“slosh tube”) and assess the degree of muscle instability created during a bicep curl. METHODS: Ten men (age= 21± 1.6y, ht=180.0 ± 3.3cm, mass= 87.4 ± 15.0kg) and ten women (age= 19.6± 1.3y, ht=161.4 ± 12.0cm, mass= 61.2 ± 7.4kg) completed three, 30s trials of a bicep curl using an 11.4 kg tube partially filled with water. A central valve allowed three conditions of water movement: 50% open, 100% open, and a balanced, closed valve setting. Subjects completed 8-10 repetitions within each condition (1.5s per rep) using a counter-balanced design. Muscle activation was assessed on the right side, using bipolar surface electrodes placed over the belly of the bicep, deltoid, rectus abdominus and paraspinal muscles. Integrated EMG was measured for each repetition and converted to a %MVC for each muscle. Instability was determined using the coefficient of variation across repetitions. A two way repeated measures ANOVA (gender, condition, gender x condition) with post hoc t-tests was used to examine concentric contractions only. RESULTS: Significant instability was seen in the paraspinal muscles for both genders at the 50% (CV= 26.5 ± 14.5) and 100% (CV= 27.1 ± 9.9) condition compared to stable (CV= 15.0 ± 9.1). Across all subjects the deltoid showed greatest instability at the 100% open setting (CV= 38.5 ± 23.2) compared to stable (CV= 21.0 ± 7.5). For the bicep, men showed greater overall instability (CV= 30.9 ± 17.0) compared to women (CV= 22.9 ± 8.4). There were no differences in abdominal activation in any condition. Percent MVC activated was significantly greater for women for the bicep (50= 97.7 ± 57.6, 100= 88.1 ± 55.6, stable= 87.0 ± 50.1) and paraspinal (50= 36.7 ± 22.3, 100= 47.5 ± 29.0, stable= 38.6 ± 23.9) compared to men (bicep 50= 39.5 ± 17.0, 100= 38.3 ± 18.3, stable= 31.8 ± 11.1) (paraspinal 50= 15.1 ± 10.0, 100= 16.2 ± 8.8, stable= 14.3 ± 9.6). No differences were seen for deltoid or abdominal. CONCLUSIONS: We conclude that a bicep curl using an unstable implement utilizing water inertia causes increased paraspinal and deltoid instability in men and women, with additional instability in the bicep for men.

Effects of Acute Exposure to Mild Simulated Hypoxia on Hormonal Responses to Low-intensity Resistance Exercise in Untrained Men

This study examined hormonal responses to low-intensity resistance exercise under mild simulated hypoxia. Ten resistance untrained men performed five sets of 15 repetitions of squat exercise at 30% of 1RM under normobaric hypoxia (FiO2 = 15%) and normoxia in a cross-over and counter-balanced design. Blood lactate (LAC), growth hormone (GH), total testosterone (T) and cortisol (C) were measured at pre-exercise, immediately post-exercise and 15 minutes post-exercise. LAC, GH and T significantly increased immediately after squat exercise in both trials (p < 0.05). While T returned to baseline, GH remained significantly greater at 15 minutes post-exercise. Cortisol significantly decreased immediately after and 15 minutes post-exercise in both trials (p < 0.05). No significant differences were observed between two trials in LAC, GH, T and C. It was concluded that low-intensity resistance exercise performed under mild simulated hypoxia does not induce greater anabolic hormonal responses in resistance untrained men.

Resistance Training Recovery

International Journal of Exercise Science 8(1) : 85-96, 2015. This study examined muscle recovery patterns between single-joint (SJ) versus multi-joint (MJ), and upper-body (UB) versus lower-body (LB) exercises and the utility of perceptual measures (ratings of perceived exertion (RPE) and perceived recovery scale (PRS)) to assess recovery status. A 10 rep max (10RM) was determined for 6 SJ and 4 MJ exercises (5 UB and 5 LB) for male recreational weightlifters (n = 10). Participants completed a baseline protocol including 8 repetitions at 85% of 10-RM followed by a set to failure with 100% of 10-RM. In a counter-balanced crossover design, participants returned at 24 or 48 h to repeat the protocol. PRS and RPE were assessed following the first and second sets of each exercise respectively. Wilcoxon matched pair signed-rank tests determined performance improved (p < 0.05) for every lift type category from 24 to 48 h, but the only difference in ∆ repetitions from baseline at the same time point was between MJ (-1.7 ± 1.5 repetitions ) and SJ (-0.5 ± 1.8 repetitions ) at 24 h (p = 0.037). Higher RPE and lower PRS estimations (p < 0.05) support the utility of perceptual measures to gauge recovery as the only between group differences were also found between MJ and SJ at 24 h. Eighty percent of participants completed within 1 repetition of baseline for all exercises at 48 h except bench press (70%) and deadlift (60%); suggesting 72 h of recovery should be implemented for multi-joint barbell lifts targeting the same muscle groups in slower recovering lifters.

Aspirin ingestion does not alter the onset or slope of local sweat rate during whole‐body passive heat stress (1104.12)

Aspirin ingestion does not alter the onset or slope of local sweat rate during whole‐body passive heat stressStephen J. Carter, Robert L. Herron, S. Zeb Akers, Ann B. Collins, Jonathan E. Wingo. Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487Aspirin (acetylsalicylic acid; ASA) is a commonly prescribed over‐the‐counter drug. As a fever suppressant ASA may interfere with normal hypothalamic‐mediated temperature regulation. We sought to determine if varying doses of ASA would alter the onset and slope (i.e., sensitivity) of local sweat rate during whole‐body passive heating. Seven healthy men (mean ± SD; 28 ± 3 y) completed a counter‐balanced design to compare ASA treatments (single dose of non‐enteric coated 325‐mg ASA vs. 4 days of 81‐mg ASA) to a control trial. A 10 day washout period was given between ASA treatments. Participants were physically active, free from cardiovascular disease and refrained from vigorous physical activity 24 h prior to testing. Upon arrival, participants were outfitted with a heart rate monitor, rectal thermocouple, 6 skin thermocouples, and a ventilated capsule placed on the dorsal forearm to measure local sweat rate via capacitance hygrometry. To raise mean body temperature (Tb) participants rested supine while hot water (~49 °C) circulated through a tube‐lined suit. Body heating ensued until participants reached a 1.0 °C increase above baseline Tb. ASA did not affect Tb at baseline (P=0.14). The onset and slopes were unaffected by ASA use (P=0.33 and P=0.87, respectively). Additionally, ASA treatments did not alter peak sweat output (P=0.87). Aspirin ingestion did not appear to affect sweat responses in this cohort of men.

Evaluation of barefoot running in preadolescent athletes

PurposeThe literature shows few studies on shod and unshod running performance in athletes, with most limited to laboratory settings. The aim of this study was to evaluate preadolescent 1000 m running performance when barefoot and in running spikes or training shoes.MethodsA sample of 22 boys and 21 girls aged 10.6 ± 1.1 years was recruited. Anthropometric data and VO&lt;sub&gt;2max&lt;/sub&gt; were recorded when completing the three study protocols in a counter balanced design. Student’s t tests were applied to compare mean 1000 m finish times while ANOVA was used to evaluate sex differences between the protocols. Pearson's correlation analysis measured interactions between the finish times, anthropometric variables, and VO&lt;sub&gt;2max&lt;/sub&gt;.ResultsRunning performance with spikes (4.58 min) was significantly better than with training shoes (5.21 min) and barefoot (5.18 min). Male 1000 m times were overall better than the females. A substantial effect of VO&lt;sub&gt;2max&lt;/sub&gt; and body fat on performance was found in all protocols.ConclusionsPreadolescent endurance performance was not significantly different between training shoes and barefoot; this may serve as an incentive for future research on the training of developmental age runners.

The Use of an Indoor Rowing Ergometer Test for the Prediction of Maximal Oxygen Uptake

The Use of an Indoor Rowing Ergometer Test for the Prediction of Maximal Oxygen Uptake based version of the multi stage fitness test.Methods: Forty one participants (25 men, 16 women; mean ± SD; age 21 ± 5.3 years, height 175.4 ± 8.1cm, body mass 71.4 ± 12.6 kg) completed in a counter-balanced design: a treadmill running maximal oxygen uptake test (Treadmill - VO2max), a 2,000 m timed row and an incremental rowing maximal oxygen uptake test (IRT - VO2max) where stroke rate was increased by one stroke each minute. A student’s paired sample t-test was used to determine differences in maximal oxygen uptake (VO2max) and heart rate (HRmax) and a Pearson correlation coefficient to measure the relationships between VO2 during tests. Results: VO2max values were significantly higher in treadmill - VO2max (44.7 ± 6.5 ml•kg-1•min-1) than IRT - VO2max (42.2 ± 7.3 ml•kg-1•min-1; P<0.05). Maximum heart rate was significantly higher during the treadmill - VO2max (192 ± 10 beats.min-1) compared to the IRT - VO2max (184.3 ± 10.6 beats.min-1; P<0.05). A significant correlation was observed between treadmill - VO2max and the IRT - VO2max for VO2 (r=0.67). Gender specific linear regression equations were created to predict VO2max on the IRT from submaximal data (Males: Predicted VO2max (ml•kg-1•min-1)=2.30 (x) + 20.8, SEE=4.5; Females Predicted VO2max (ml•kg-1•min-1)=1.93(x) + 19.4, SEE=3.7). Conclusion: This new stroke rate based IRT provides a continuous test to exhaustion with minimal equipment which is suitable for the regular gym user to monitor their cardiorespiratory fitness.

Response

Dear Editor-in-Chief We are pleased that our data have provided stimulus for further inquiry. Indeed, as Goulet et al. point out, although the majority of the scientific data clearly state that hypohydration decreases endurance exercise performance—especiallyin the heat (5)—some scientists are arguing that the greatest side effect of hypohydration is thirst (4). Laboratory findings Of course our data do not apply to all cycling events but could have application to intermittent events like criterium race, endurance track cycling, or breakaways. During the performance test in the laboratory, we used a simulated video while cyclists exercised on their own bikes to help them feel close to outdoor conditions. Moreover, a recent outdoor cycling study linked mild hypohydration to decreased performance (1). Cardiovascular strain Goulet et al. argue the absence of cardiovascular strain because heart rate during the cycling performance test was similar between trials. In our case, the same near-maximal heart rate was observed in both trials, although subjects were cycling faster (+4.6%) on greater power output. Although we did not measure cardiac output, we hypothesized that higher stroke volume with similar heart rate could be a potential cardiovascular explanation of our findings. Familiarization We do agree that familiarization is an important part of a performance-related study. However, the exercise protocol was already familiar to cyclist because they were regularly participating in similar criterium cycling races. Likewise, subjects regularly exercise on cycling ergometers similar tothe ones used in the experiment. In addition, statistical analysis for order effect ensured that protocol familiarity did not influence performance. Counterbalanced design The administration of experimental conditions in counterbalanced fashion is considered the best practice for controlling order effects in a repeated-measures design. This way, we made sure that half of the subjects performed first the euhydrated trial, while the other half performed first the hypohydrated trial. Fan cooling As stated in the manuscript, subjects were fan-cooled with an airflow of 3.2 m·s−1. Actually, convecting heat loss was insignificant because of the fact that air and skin temperatures were almost identical. In addition, because the walls and all the objects had reached ambient temperature, heat loss via radiation was minimal, making evaporation the only mechanism for heat dissipation. Hypohydration and endurance It seems that the supporting studies for the closing remark “hypohydration does not impair cycling or running endurance performance...” is based on two studies that have been misinterpreted. The study by Dugas et al. (2) nicely demonstrated that low versus high fluid intake induced hypohydration of −3.75% and −1.5%, respectively. The greater hypohydration was linked to lower power output, slower exercise performance, but similar core temperature. The study by Gigou et al. (3) investigated the effect of preexercise hyperhydration on running performance. Hypohydration by −3.1% versus −1.4% resulted in greater cardiovascular and thermoregulatory strain as indicated by elevated heart rate and core temperature. We thank Dr. Goulet and colleagues for helping us to clarify some issues in this very important field of hydration and performance. Stavros A. Kavouras, PhD Costas N. Bardis, PhD Human Performance Laboratory Department of Health, Human Performance, and Recreation University of Arkansas, Fayetteville, AR

Neck cooling and cognitive performance following exercise-induced hyperthermia

To assess the efficacy of neck cooling on cognitive performance following exertional hyperthermia. Twelve healthy men completed two experimental trials [control (CON) and neck cooling collar (NCC)] in a counter-balanced design. They ran on a treadmill at 70% VO2peak under warm and humid conditions (dry bulb temperature: 30.2 ± 0.3 °C, relative humidity: 71 ± 2 %) for 75 min or until volitional exhaustion. Gastrointestinal, neck and skin temperatures, heart rate and subjective ratings were assessed. Serum brain-derived neurotrophic factor (BDNF) levels were measured before and after each run. Cognitive performance comprising symbol digit matching, search and memory, digit span, choice reaction time and psychomotor vigilance test (PVT) were assessed before and after exercise. Mean gastrointestinal temperature was similar after exercise between trials (CON: 39.5 ± 0.4 °C vs. NCC: 39.6 ± 0.3 °C; p = 0.15). Mean neck temperature was lowered in NCC compared to CON after the run (36.4 ± 1.6 °C vs. NCC: 26.0 ± 0.3 °C; p < 0.001). Exercise-induced hyperthermia improved mean reaction time in the symbol digit matching test (-134 ± 154 ms; p < 0.05) and the PVT (-18 ± 30 ms; p < 0.05). Maximum span was increased in the digit span test (1 ± 2; p < 0.05). Application of NCC reduced the number of search errors made in level 3 of the search and memory test (p < 0.05). Mean serum BDNF levels were increased following exercise-induced hyperthermia in both trials (p < 0.05). Exercise-induced hyperthermia improves working memory and alertness. Neck cooling may only enhance performance in tasks of higher complexity.

The Effect of Feeding during Recovery from Aerobic Exercise on Skeletal Muscle Intracellular Signaling

We previously reported an increase in skeletal muscle protein synthesis during fasted and fed recovery from nonexhaustive aerobic exercise (Harber et al., 2010). The current study examined skeletal muscle intracellular signaling in the same subjects to further investigate mechanisms of skeletal muscle protein metabolism with and without feeding following aerobic exercise. Eight males (VO₂peak: 52 ± 2 ml⁻¹·kg⁻¹·min⁻¹) performed 60-min of cycle ergometry at 72 ± 1% VO₂peak on two occasions in a counter-balanced design. Exercise trials differed only in the postexercise nutritional intervention: EX-FED (5 kcal, 0.83 g carbohydrate, 0.37 g protein, 0.03 g fat per kg body weight) and EX-FAST (noncaloric, isovolumic placebo) ingested immediately and one hour after exercise. Muscle biopsies were obtained from the vastus lateralis at rest (on a separate day) and two hours postexercise to assess intracellular signaling via western blotting of p70S6K1, eEF2, 4EBP1, AMPKα and p38 MAPK. p70S6K1 phosphorylation was elevated (p < .05) in EX-FED relative to REST and EX-FAST. eEF2, 4EBP1, AMPKα and p38 MAPK signaling were unaltered at 2 h after exercise independent of feeding status when expressed as the ratio of phosphorylated to total protein normalized to actin. These data demonstrate that feeding after a nonexhaustive bout of aerobic exercise stimulates skeletal muscle p70S6K1 intracellular signaling favorable for promoting protein synthesis which may, as recent literature has suggested, better prepare the muscle for subsequent exercise bouts. These data provide further support into the role of feeding on mechanisms regulating muscle protein metabolism during recovery from aerobic exercise.

A comparison of data collection techniques used with discrete trial teaching

This study was designed to examine the comparative value of three discrete trial teaching data collection techniques: Continuous recording, time sample, and estimation. The data collection was conducted by behavior interventionists while teaching children diagnosed with autism spectrum disorder skills using discrete trial teaching. Utilizing a counter-balanced design, data collection techniques were examined in regards to their accuracy, that is, their correspondence to the independent measurement of a primary observer collecting contemporaneous trial-by-trial data. Also assessed were the relative impacts of the various techniques on efficiency of therapy and rate of children's acquisition. Finally, interventionists rated their preference of and satisfaction with each of the three techniques. Continuous recording was generally the most accurate, although the other methods were accurate to a degree when used by trained recorders to justify their usage in applied settings. Estimation was the most efficient and time sample was the most preferred.

The efficacy of the self-paced V̇O2max test to measure maximal oxygen uptake in treadmill running

The novel self-paced, cycle-based maximal oxygen uptake (V̇O2max) test (SPV) has been shown to produce higher V̇O2max values than standard graded exercise test (GXT) protocols. This study sought to ascertain whether these observations would also be apparent in a self-paced, treadmill-based test design. Fourteen trained male runners performed a standard GXT on a motorised treadmill and a self-paced V̇O2max test on a nonmotorised treadmill in a counter-balanced design. The GXT included a plateau verification and was designed to last between 8 and 12 min. The self-paced test included 5 × 2 min stages and allowed participants to set their own running speed based on fixed increments in rating of perceived exertion. Significantly higher V̇O2max values (t[13] = 3.71, p = 0.003) were achieved in the self-paced test (64.4 ± 7.3 mL · kg(-1) · min(-1)) compared with the GXT (61.3 ± 7.3 mL · kg(-1) · min(-1)), and 13 of the 14 participants achieved the same or higher V̇O2max values in the self-paced test. Higher (p = 0.01) maximum heart rates were observed in the GXT (191 ± 10 beats · min(-1) vs. 187 ± 7 beats · min(-1)), but no differences were observed in any other recorded variables. The self-paced V̇O2max test may provide a more valid means of measuring V̇O2max than the GXT and suggests that a V̇O2 plateau during a GXT does not always signify achievement of a definitive V̇O2max. These results provide further support that self-paced V̇O2max testing produces higher values for maximal oxygen uptake.

Prediction of Rowing Performance by Using Critical Thresholds in Elite Female Rowers

The purpose of this study was to compare the different critical thresholds, critical velocity (CV) and critical power (CP), combining with anaerobic power and energy expenditure to predict the 2,000m indoor performance of female rowers in Taiwan. Fifteen elite female rowers (age 20.7±1.4 years, height 164±3.5cm, weight 56.6±4.4kg) were recruited for this study. By using counter-balanced design order, 4 time-trials on 90s, 240s, 600s and 1,200s were underwent to determine the CP (139.5±20.4W), whereas CV (4.0±0.1 m/s) was derived by 400m, 600m, 800m and 1,000m distance-trials on different days by using linear distance-time model. Maximal oxygen uptake (VO2peak=2.5±0.5L/min) and anaerobic threshold (AT4=157.8±22.1W) were obtained from an incremental exercise test. Further, anaerobic capacity (6,912.1±895.6W), mean power (323.2±26.7W) and fatigue index (3.8±2.6%) were obtained using a modified Wingate protocol on rowing ergometer followed by a 2,000 m time-trial. The results showed that CV, CP as well as VO2peak and AT4 were significantly correlated with 2,000 m indoor rowing performance. Stepwise regression analysis indicated CV and fatigue index (FI) were most important determinants in establishing predicting model of 2,000 m indoor rowing performance (T2000=-131.44 CV-89.57 FI+1022.27, SEE=4.08s). This study concludes that both CV and CP were significant correlated with 2,000m indoor rowing performance. CV and FI constructed the best predicting model for indoor rowing performance of female rowers in Taiwan.

Effect of instruction in appropriate rubato usage on performances of Mozart and Bach: Replication and extension

The purpose of this study was to investigate how instruction in the use of rhythmic nuances influences subsequent timings of a musical performance. Volunteer participants were asked to listen to and alter a performance of an excerpt from Mozart’s Concerto for Horn and Orchestra No. 2 and Bach’s Suite Number 3 for Violoncello solo, Bourrèe Number 1. They used recently-developed software that allowed them to control the rhythmic timing of each of the performances without changing any other musical attribute. Forty music majors served as participants for both excerpts in a counter-balanced design. When, after practice, participants generated a performance with which they were pleased, it was saved as a pretest. Students in the treatment group for each piece were taught the rhythmic tendencies that have been identified in the finest performances of these excerpts and practiced them until they felt they were prepared to make a second recording, which was saved as the posttest. Control participants were instructed simply to practice more and to make another, better recording. All note onset data were calculated and analyzed to determine if the experimental groups had successfully integrated the given rhythmic tendencies into their performances. Results indicated that students in the experimental groups did indeed more closely reflect the model professional performances in their posttest performances of both experiments.

Effects of Swimming Exercise on Post-Exercise Cardiac Compensation in Healthy Middle-Aged Adults

Post-exercise cardiac compensation is closely associated with cardiovascular health. Swimming exercise could elicit different post-exercise physiological responses compared to land-based exercise due to the environment and posture differences. The purpose of this study was to examine the effect of swimming exercise at two different intensities on post-exercise cardiac compensation in healthy middle-aged adults. Eight male (50.1 ± 3.1 yr) and 9 female (53.9 ± 2.2 yr) subjects were recruited for this study. Each subject completed an initial graded exercise test to determine individual maximal heart rate (HRmax) followed by a 30-min swimming exercise at low (40% HRR, LE), moderate (70% HRR, ME) intensities, and a sham control (CON) by using counter-balanced design. Hemodynamic variables were obtained at 1, 2, 3, 4, 12, and 24-h after exercise by using a 24-h ambulatory blood pressure monitor. Three-way analysis of variance (ANOVA) was used to assess the differences, main effects and interaction (gender × intensity × time) between controlled variables. We found no significant difference in stroke volume (SV), left ventricular ejection time (LV ejection time) and LV dp/dt Max after LE and ME. However, heart rate was significantly increased one hour after exercise in ME compared to LE (82.2 ± 2.8 vs. 75.8 ± 2.3 beats/ min), and both ME and LE showed higher than CON (66 ± 1.8 beats/min). The main effect on cardiac output was reached significantly higher in both ME (4.6 ± 0.2 L/min) and LE (4.5 ± 0.2 L/min) than CON (4.2 ± 0.2 L/min). Our findings conclude that cardiac compensation was still observed during 4-h recovery after 30-min swimming exercise at 40% HRR as well as 70% HRR without any gender difference.

Effects of AZD3480, a neuronal nicotinic acetylcholine receptor agonist, and donepezil on dizocilpine-induced attentional impairment in rats

Nicotinic acetylcholine systems play major roles in cognitive function. Nicotine and a variety of nicotinic agonists improve attention, and nicotinic antagonist exposure impairs it. This study was conducted to investigate the effect of a novel nicotinic receptor agonist at α4β2 nicotinic receptors (AZD3480) on attention and reversal of pharmacologically induced attentional impairment produced by the NMDA glutamate antagonist dizocilpine (MK-801). Adult female Sprague-Dawley rats were trained to perform an operant visual signal detection task to a stable baseline of accuracy. The rats were then injected subcutaneously following a repeated measures, counter-balanced design with saline, AZD3480 (0.01, 0.1, and 1 mg/kg), dizocilpine (0.05 mg/kg), or their combinations 30 min before the test. The effect of donepezil on the same pharmacologically induced attentional impairment was also tested. A separate group of rats was injected with donepezil (0.01, 0.1, and 1 mg/kg), dizocilpine (0.05 mg/kg), or their combinations, and their attention were assessed. Saline was the vehicle control. Dizocilpine caused a significant (p < 0.0005) impairment in percent correct performance. This attentional impairment was significantly (p < 0.0005) reversed by 0.01 and 0.1 mg/kg of AZD3480. AZD3480 by itself did not alter the already high baseline control performance. Donepezil (0.01-1.0 mg/kg) also significantly (p < 0.005) attenuated the dizocilpine-induced attentional impairment. AZD3480, similar to donepezil, showed significant efficacy for counteracting the attentional impairment caused by the NMDA glutamate antagonist dizocilpine. Low doses of AZD3480 may provide therapeutic benefit for reversing attentional impairment in patients suffering from cognitive impairment due to glutamatergic dysregulation and likely other attentional disorders.

Importance of Pharmacokinetic Profile and Timing of Coadministration of Short– and Long–Acting Formulations of Methylphenidate on Patterns of Subjective Responses and Abuse Potential

Objective: Subjective responses (ie, liking, disliking) to stimulants are thought to be proxies for abuse potential. Greater subjective responses have been documented in formulations that are more rapidly absorbed. However, repeat dosing has not been examined. Methods: Subjective responses on the Drug Rating Questionnaire were compared in 26 healthy adults after administration of short– (immediate–release [IR] methylphenidate [MPH]) and long– (osmotically controlled—release oral delivery system [OROS] MPH) acting stimulant formulations. The second dose was administered 4 hours after initial dosing. All subjects received all 5 conditions (ie, placebo to placebo; IR–MPH to IR–MPH; IR–MPH to OROS–MPH; OROS–MPH to IR–MPH; or OROS–MPH to OROS–MPH) in a double–blind, counter–balanced design on 5 separate days. Results: Plasma levels and subjective patterns of detection were higher when an IR formulation was administered during the ascending phase of a first–administered long–acting dose (OROS). Conclusion: These results emphasize the critical role that formulation type (IR vs OROS) and timing of administration (ascending vs descending phase) play when short– and long–acting formulations are coadministered. Such knowledge provides important information for clinicians about the safety and tolerability of the timing of repeat dosing of various permutations of coadministration of MPH formulations.