Post-training Trials Research Articles

Training to Inhibit Negative Content Affects Memory and Rumination

Depressive rumination, the tendency to engage in repetitive self-focus in response to distress, seems to be affected by a variety of cognitive biases that in turn maintain negative emotional states. The current study examined whether the difficulty in inhibiting attention to negative information contributes to rumination and to rumination-related biases in memory. Seventy-nine ruminators underwent a 3-week computer-based training, designed to increase either inhibition of negative words or attention to them. On immediate post-training trials, as well as on 2-week follow-up tests, we found evidence for transfer of inhibition training. Training effects also occurred on session-by-session and post-training measures of state rumination, but not on a measure of trait rumination, assessed 2 weeks later. Finally, participants who were trained to inhibit negative material subsequently showed less negative bias on a memory test. These findings further establish the causal role of biased inhibition in rumination, and substantiate the view of rumination as a habit that encourages people to perceive, interpret, and remember events in a repetitive self-focused manner.

Predator avoidance training of the endangered lizard from El Hierro (Canary Islands): A new management strategy before reintroduction into the wild

Animals raised in captivity during several generations may not express appropriate antipredator behaviour when reintroduced into the wild. Here we present the results of experiments to enhance behavioural responses to predators in adult males of the endangered lizard Gallotia simonyi (El Hierro, Canary Islands). Individuals were subjected to a training procedure (control, pre-training, training and post-training phases) using stuffed specimens of a kestrel and a cat as predators. We filmed all trials and compared relative durations of the more common behaviour patterns shown by lizards, both among experimental phases and before and after presentation of the stuffed predator. Locomotion and Basking were significantly reduced in the training and post-training trials and also after stimulus presentation, suggesting that the training protocol induced lizard avoidance over both predator models. To our knowledge, this is the first time lizards have been trained to show antipredator avoidance and our results provide the basis for a new management strategy that could be useful for reintroduction of captive-bred individuals of endangered species.

Information about relative phase in bimanual coordination is modality specific (not amodal), but kinesthesis and vision can teach one another

How is information from different sensory modalities coordinated when learning an action? We tested two hypotheses. The first is that the information is amodal. The second is that the information is modality specific and one modality is used in first learning the action and then is used to teach the other modality. We investigated these hypotheses using a rhythmic coordination task. One group of participants learned to perform bimanual coordination at a relative phase of 90° using kinesthesis. A second group used vision to learn unimanual 90° coordination. After training, performance using the alternate modality was tested in each case. Snapp-Childs, Wilson, and Bingham (2015) had found transfer of 50% of learned performance of 90° coordination between the unimanual and bimanual tasks when each had included use of vision. Now, we found essentially no transfer (≈5%) indicating that the information was modality specific. Next, post-training trials performed using the untrained modality were alternated with trials in which kinesthesis and vision were used. The result was that performance using the untrained modality progressively improved. We concluded that trained modality was used to teach the untrained modality and that this likely represents the way information from different sensory modalities is coordinated in performance of actions.

Effect of Injury Prevention Training Program on Kinematics of Drop Jump Tasks: Evaluation with Landing Error Scoring System and Three-Dimensional Kinematic Analysis

The ACL injury prevention program we designed could effectively correct the risky motion pattern associated with increased risk for ACL injury. The Landing Error Scoring System (LESS) has been shown to be a reliable clinical screening tool that was developed to identify individuals at increased risk for noncontact anterior cruciate ligament (ACL) injury through evaluation of landing biomechanics during the drop vertical jump (DVJ) test. In the present study, we developed an ACL injury prevention training program and applied the program to the subjects. Kinematic characteristics during DVJ were assessed by LESS scoring and three dimensional motion analysis system before and after the training intervention. The purpose of this study was to examine whether the training intervention can correct (alter) the kinematics of jump-landing task using the two evaluation systems. Study subjects: Ten female healthy volunteers participated in the study (average age; 20.6 years). The injury prevention training program consisted of turn jump, plyometric exercise, and strengthening training (approximately 20 minutes for one set of exercise) was conducted 3 days a week for a period of 6 weeks. Kinematic analysis using LESS and motion analysis system was performed before and after completion of the whole training program. Jump-landing task according to the LESS protocol. All subjects performed 3 test DVJ trials according to the LESS protocol described by Padua et al. Analysis of video images for LESS scoring. Frontal and sagittal view video data were acquired using standard HD video camcorders (HDR-CX560, Sony, Tokyo, Japan) that were positioned according to the LESS protocol. Three-dimensional motion analysis using Point Cluster Technique Simultaneously, three-dimensional kinematics data were collected using an 8-camera motion analysis system (Vicon motion system, Oxford, UK) with ground reaction forces recorded using a force plate. In order to accurately analyze the sequential change in tibio-femoral spatial relationship at the knee, the Point Cluster Technique (PCT) was utilized. Testing procedure included attachment of multiple reflective markers and use of the special program to analyze the three-dimensional motion for extension/flexion, varus/valgus rotation, internal/external rotation of the tibia with respect to the femur. LESS score at the post-training trial (4.8) was significantly smaller than that for the Pre-training trial (6.2) (P < 0.05) (figure1). Regarding the motion analysis results, the peak knee valgus angle at the post-training trial (5.0°) was significantly smaller than that at the pre-training trial (8.2°) (P < 0.05) ; however, peak knee flexion and tibial rotation angles were not significantly different between pre- and post-training trials. As regards the correlation between the LESS and motion analysis results, significant correlation was found between peak knee valgus angle and LESS score at the pre-training trial (R=0.83, P < 0.05) and the post-training trial (R=0.95, P < 0.05). All subjects experienced internal tibial rotation after toe contact. In addition, there was a moderate correlation between the peak internal tibial rotation angle and the LESS score at both the pre-training and post-training trials (R=0.64 and 0.43 respectively). The results of the present study showed that The ACL injury prevention program successfully decreased knee valgus angle and LESS score. Therefore, the potential effectiveness of the training intervention was confirmed.

Endurance capacity and neuromuscular fatigue following high- vs moderate-intensity endurance training: A randomized trial.

High-intensity exercise induces significant central and peripheral fatigue; however, the effect of endurance training on these mechanisms of fatigue is poorly understood. We compared the effect of cycling endurance training of disparate intensities on high-intensity exercise endurance capacity and the associated limiting central and peripheral fatigue mechanisms. Twenty adults were randomly assigned to 6weeks of either high-intensity interval training (HIIT, 6-8×5minutes at halfway between lactate threshold and maximal oxygen uptake [50%Δ]) or volume-matched moderate-intensity continuous training (CONT, ~60-80minutes at 90% lactate threshold). Two time to exhaustion (TTE) trials at 50%Δ were completed pre- and post-training to assess endurance capacity; the two post-training trials were completed at the pretraining 50%Δ (same absolute intensity) and the "new" post-training 50%Δ (same relative intensity). Pre- and post-exercise responses to femoral nerve and motor cortex stimulation were examined to determine peripheral and central fatigue, respectively. HIIT resulted in greater increases in TTE at the same absolute and relative intensities as pre-training (148% and 43%, respectively) compared with CONT (38% and -4%, respectively) (P≤.019). Compared with pre-training, HIIT increased the level of potentiated quadriceps twitch reduction (-34% vs -43%, respectively, P=.023) and attenuated the level of voluntary activation reduction (-7% vs -3%, respectively, P=.047) following the TTE trial at the same relative intensity. There were no other training effects on neuromuscular fatigue development. This suggests that central fatigue resistance contributes to enhanced high-intensity exercise endurance capacity after HIIT by allowing greater performance to be extruded from the muscle.

The effects of two different correction strategies on the snatch technique in weightlifting

ABSTRACTImproving motor skills represents one of the major issues in motor control and motor learning literature. The aim of this study was to investigate which of two strategies, method of amplification of error (MAE) or direct instruction (DI), would be more beneficial for error correction of the snatch technique. Thirty well-trained male weightlifters were randomly assigned to one of three training conditions (MAE, DI and Control). The experiment took place in only one practice session in which each lifter performed 3 pretraining trials, 8 training intervention trials, and 3 post-training trials, and a retention test session after 1 week. An optoelectronic motion capture system was used to measure the kinematic parameters of the weightlifting performance. After the training intervention, data showed that the MAE group revealed a greater improvement in several kinematic parameters when compared to the DI and Control groups, and the benefits derived from its application were still present 1 week later in the retention test. Nevertheless, the findings of the present study should be interpreted with caution due to the relatively small sample size; further research will also be necessary to evaluate the effects of MAE with different ability levels and other sport skills. The present findings could have practical implications for sport psychology and physical education because while practice is obviously necessary for improving learning, the efficacy of the learning process is essential in enhancing learners’ motivation and sport enjoyment.

The effects of individual upper alpha neurofeedback in ADHD: an open-label pilot study.

Standardized neurofeedback (NF) protocols have been extensively evaluated in attention-deficit/hyperactivity disorder (ADHD). However, such protocols do not account for the large EEG heterogeneity in ADHD. Thus, individualized approaches have been suggested to improve the clinical outcome. In this direction, an open-label pilot study was designed to evaluate a NF protocol of relative upper alpha power enhancement in fronto-central sites. Upper alpha band was individually determined using the alpha peak frequency as an anchor point. 20 ADHD children underwent 18 training sessions. Clinical and neurophysiological variables were measured pre- and post-training. EEG was recorded pre- and post-training, and pre- and post-training trials within each session, in both eyes closed resting state and eyes open task-related activity. A power EEG analysis assessed long-term and within-session effects, in the trained parameter and in all the sensors in the (1-30) Hz spectral range. Learning curves over sessions were assessed as well. Parents rated a clinical improvement in children regarding inattention and hyperactivity/impulsivity. Neurophysiological tests showed an improvement in working memory, concentration and impulsivity (decreased number of commission errors in a continuous performance test). Relative and absolute upper alpha power showed long-term enhancement in task-related activity, and a positive learning curve over sessions. The analysis of within-session effects showed a power decrease ("rebound" effect) in task-related activity, with no significant effects during training trials. We conclude that the enhancement of the individual upper alpha power is effective in improving several measures of clinical outcome and cognitive performance in ADHD. This is the first NF study evaluating such a protocol in ADHD. A controlled evaluation seems warranted due to the positive results obtained in the current study.

Skills Learning in Robot-Assisted Surgery Is Benefited by Task-Specific Augmented Feedback

Providing augmented visual feedback is one way to enhance robot-assisted surgery (RAS) training. However, it is unclear whether task specificity should be considered when applying augmented visual feedback. Twenty-two novice users of the da Vinci Surgical System underwent testing and training in 3 tasks: simple task, bimanual carrying (BC); intermediate task, needle passing (NP); and complex task, suture tying (ST). Pretraining (PRE), training, and posttraining (POST) trials were performed during the first session. Retention trials were performed 2 weeks later (RET). Participants were randomly assigned to 1 of 4 feedback training groups: relative phase (RP), speed, grip force, and video feedback groups. Performance measures were time to task completion (TTC), total distance traveled (D), speed (S), curvature, relative phase, and grip force (F). Significant interaction for TTC and curvature showed that the RP feedback training improved temporal measures of complex ST task compared to simple BC task. Speed feedback training significantly improved the performance in simple BC task in terms of TTC, D, S, curvature, and F even after retention. There was also a lesser long-term effect of speed feedback training on complex ST task. Grip force feedback training resulted in significantly greater improvements in TTC and curvature for complex ST task. For the video feedback training group, the improvements in most of the outcome measures were evident only after RET. Task-specific augmented feedback is beneficial to RAS skills learning. Particularly, the RP and grip force feedback could be useful for training complex tasks.

Effect of robotic performance-based error-augmentation versus error-reduction training on the gait of healthy individuals

Effective locomotion training with robotic exoskeletons requires identification of optimal control algorithms to better facilitate motor learning. Two commonly employed training protocols emphasize use of training stimuli that either augment or reduce performance errors. The current study sought to identify which of these training strategies promote better short-term modification of a typical gait pattern in healthy individuals as a framework for future application to neurologically impaired individuals. Ten subjects were assigned to each of a performance-based error-augmentation or error-reduction training group. All subjects completed a 45-min session of treadmill walking at their preferred speed with a robotic exoskeleton. Target templates prescribed an ankle path for training that corresponded to an increased step height. When subjects’ instantaneous ankle positions fell below the inferior virtual wall of the target ankle path, robotic forces were applied that either decreased (error-reduction) or increased (error-augmentation) the deviation from the target path. When the force field was turned on, both groups walked with ankle paths better approximating the target template compared to baseline. When the force field was removed unexpectedly during catch and post-training trials, only the error-augmentation group maintained an ankle path close to the target ankle path. Further investigation is required to determine if a similar training advantage is provided for neurologically impaired individuals.

Short-term exercise training does not improve whole-body heat loss when rate of metabolic heat production is considered

We evaluated the effects of an 8-week exercise training program in previously sedentary individuals on whole-body heat balance during exercise at a constant rate of metabolic heat production. Prior to and after 8 weeks of training, ten participants performed 60-min of cycling exercise at a constant rate of heat production (approximately 450 W) followed by 60-min of recovery, at 30 degrees C and 15% relative humidity. Rate of total heat loss was measured directly by whole-body calorimetry, while rate of metabolic heat production was measured simultaneously by indirect calorimetry. Esophageal (T(es)), skin blood flow (SkBF) and local sweat rate (LSR) were also measured continuously. The 8-week exercise training program elicited a 10% increase in maximal aerobic capacity (P < 0.001). Furthermore, exercise training reduced (P <or= 0.05) baseline (37.10 +/- 0.28 vs. 36.95 +/- 0.24 degrees C) and end-exercise (37.85 +/- 0.30 vs. 37.55 +/- 0.20 degrees C) values for T (es) as well as onset thresholds for LSR (37.23 +/- 0.26 vs. 36.96 +/- 0.22 degrees C, P < 0.001) and SkBF (37.16 +/- 0.38 vs. 36.83 +/- 0.26 degrees C, P < 0.001). However, these improvements in thermoregulatory function did not translate into a greater rate of total heat loss between the pre- and post-training exercise trials (P = 0.762). Furthermore, there were no differences in SkBF (P = 0.546) and LSR (P = 0.475) from pre- to post-training. Although physical training resulted in significant improvements of cardiorespiratory and thermoregulatory functions, these adaptations did not improve whole-body and local heat loss responses during exercise performed at a given rate of metabolic heat production.

Substantial working muscle glycerol turnover during two-legged cycle ergometry

We combined tracer and arteriovenous (a-v) balance techniques to evaluate the effects of exercise and endurance training on leg triacylglyceride turnover as assessed by glycerol exchange. Measurements on an exercising leg were taken to be a surrogate for working skeletal muscle. Eight men completed 9 wk of endurance training [5 days/wk, 1 h/day, 75% peak oxygen consumption (Vo(2peak))], with leg glycerol turnover determined during two pretraining trials [45 and 65% Vo(2peak) (45% Pre and 65% Pre, respectively)] and two posttraining trials [65% of pretraining Vo(2peak) (ABT) and 65% of posttraining Vo(2peak) (RLT)] using [(2)H(5)]glycerol infusion, femoral a-v sampling, and measurement of leg blood flow. Endurance training increased Vo(2peak) by 15% (45.2 +/- 1.2 to 52.0 +/- 1.8 mlxkg(-1)xmin(-1), P < 0.05). At rest, there was tracer-measured leg glycerol uptake (41 +/- 8 and 52 +/- 15 micromol/min for pre- and posttraining, respectively) even in the presence of small, but significant, net leg glycerol release (-68 +/- 19 and -50 +/- 13 micromol/min, respectively; P < 0.05 vs. zero). Furthermore, while there was no significant net leg glycerol exchange during any of the exercise bouts, there was substantial tracer-measured leg glycerol turnover during exercise (i.e., simultaneous leg muscle uptake and leg release) (uptake, release: 45% Pre, 194 +/- 41, 214 +/- 33; 65% Pre, 217 +/- 79, 201 +/- 84; ABT, 275 +/- 76, 312 +/- 87; RLT, 282 +/- 83, 424 +/- 75 micromol/min; all P < 0.05 vs. corresponding rest). Leg glycerol turnover was unaffected by exercise intensity or endurance training. In summary, simultaneous leg glycerol uptake and release (indicative of leg triacylglyceride turnover) occurs despite small or negligible net leg glycerol exchange, and furthermore, leg glycerol turnover can be substantially augmented during exercise.

Contributions of working muscle to whole body lipid metabolism are altered by exercise intensity and training

To evaluate the contribution of working muscle to whole body lipid oxidation, we examined the effects of exercise intensity and endurance training (9 wk, 5 days/wk, 1 h, 75% Vo(2 peak)) on whole body and leg free fatty acid (FFA) kinetics in eight male subjects (26 +/- 1 yr, means +/- SE). Two pretraining trials [45 and 65% Vo(2 max) (45UT, 65UT)] and two posttraining trials [65% of pretraining Vo(2 peak) (ABT), and 65% of posttraining Vo(2 peak) (RLT)] were performed using [1-(13)C]palmitate infusion and femoral arteriovenous sampling. Training increased Vo(2 peak) by 15% (45.2 +/- 1.2 to 52.0 +/- 1.8 ml.kg(-1).min(-1), P < 0.05). Muscle FFA fractional extraction was lower during exercise (EX) compared with rest regardless of workload or training status ( approximately 20 vs. 48%, P < 0.05). Two-leg net FFA balance increased from net release at rest ( approximately -36 micromol/min) to net uptake during EX for 45UT (179 +/- 75), ABT (236 +/- 63), and RLT (136 +/- 110) (P < 0.05), but not 65UT (51 +/- 127). Leg FFA tracer measured uptake was higher during EX than rest for all trials and greater during posttraining in RLT (716 +/- 173 micromol/min) compared with pretraining (45UT 450 +/- 80, 65UT 461 +/- 72, P < 0.05). Leg muscle lipid oxidation increased with training in ABT (730 +/- 163 micromol/min) vs. 65UT (187 +/- 94, P < 0.05). Leg muscle lipid oxidation represented approximately 62 and 30% of whole body lipid oxidation at lower and higher relative intensities, respectively. In summary, training can increase working muscle tracer measured FFA uptake and lipid oxidation for a given power output, but both before and after training the association between whole body and leg lipid metabolism is reduced as exercise intensity increases.

Tracer Measured glucose uptake by the leg demonstrates dynamic kinetics across the working muscle

We compared two methods measuring glucose uptake, tracer measured (TMGU) and net balance (NGU). As part of a larger study, we examined the effects of exercise intensity and a 9-week leg cycle ergometer training program (5 d/w, 1 hr, 75% VO2peak) on glucose uptake by working muscles in 8 healthy male subjects (25.9±1.4 yr, 77.4±3.7 kg). Two pre-training trials (45% and 65% VO2peak, UT) and two post-training trials (same absolute workload as 65%UT VO2peak [ABT], and same relative-65% of post-training VO2peak [RLT]) were performed with the infusion of [6, 6D2] glucose. Subjects were studied 3-hr post-absorptive for 90 min at rest and during 1 hr of leg cycling exercise. Training increased VO2peak 15% (45.2±1.2 vs. 52.0±1.8 ml·kg−1·min−1, p<0.05). Glucose uptake in the leg increased from rest to exercise (P<0.05) regardless of method used (TMGU, rest=0.23 +/− 0.7, ex=2.1+/−2, NGU, rest=0.18+/−.4 ex=1.8+/−1mmol/kg/min). The methods were correlated (r=0.699, P<0.05) and TMGU is predicted 13% higher than NGU (TMGU = 1.13*NGU, P=0.01). The large between subject and time variability in measures demonstrates that glucose kinetics of working muscle is highly dynamic. Our results indicate that using TMGU is preferable when describing glucose flux across the working muscle, as the NGU method my underestimate glucose uptake. Supported by NIH, AR42906 to GAB.

The efficacy of training for three manual handling strategies based on the observation of expert and novice workers

Objectives. To evaluate the efficacy of training for three manual handling strategies, i.e. load tilting/hands positioning, shoulders positioning and feet orientation based on the observation of the contrasted strategies of expert and novice workers and free practice using a search approach. Design. Ten novice male workers were tested at pre-training (one trial) and post-training with homogeneous boxes (three trials) and heterogeneous boxes (two trials) sampled from two sessions. Training took place with homogeneous boxes whereas heterogeneous boxes were new situations. Background. The effectiveness of training programs in safe handling and the repetition of specified techniques are contested; they should rather be based on expert workers’ strategies. Methods. Pre-training and post-training trials were analyzed with five video cameras and a large force plate. The biomechanical variables included three safety criteria: net 3D resulting moments at L5/S1, asymmetry of posture/efforts at L5/S1 and mechanical work on load; kinematics and ergonomic variables were used as explicative variables. Results. Training produced safer strategies by reducing mechanical work and back extensor moments; this occurred in both load conditions, an indication of the transfer of knowledge. These strategies consisted of changes in load maneuvers (tilting/hand positioning) and feet orientation. Conclusions. Training programs should be based on observations of workers. Relevance These results may guide the specialists involved in training programs. Training based on a search approach by the learner and anchored on observations of contrasted strategies (load tilts/hands positioning and feet orientation) by experts and novices appears promising for safe handling.

THE EFFECT OF EIGHT WEEKS OF VIRTUAL REALITY TRAINING ON THE METABOLIC EFFICIENCY OF MOVEMENT PATTERNS OF COLLEGE STUDENTS.

Exposure to computer interaction has never been greater for the general population. However the use of computer interaction to facilitate exercise compliance is still a novel activity. College age students exposed to Trazer (a virtual reality game) revealed highly absorbed participants exercising at a relatively high intensity. PURPOSE: To determine if chronic exposure to whole body virtual reality training can change the metabolic efficiency of movement patterns and alter stimulus intensity. METHODS: Ten college students (age 22.1 ± 1.2 yr., ht. 173 ± 1.2 cm., mass 68.2 ± 5.8 kg.), participated in eight weeks of virtual reality (Trazer) training for a duration of 30 minutes and a frequency of three sessions/week. A Trazer beacon attached to the subject, tracked interactive movements relative to power (P), speed (S)(m/sec), and distance (D)(meters) throughout each trial. In addition, metabolic efficiency was measured by open circuit spirometry during pre- and post-training trials. Performance was measured during a Trap Attack trial at a low intensity (L2) and a moderate intensity (L5). RESULTS: Statistical analysis by paired t-test (*p < .05) revealed significant pre-post differences in metabolic cost at the L5 trial, which indicates an attenuated metabolic cost despite better performance and an identical distance displacement. Relative intensity of L5 declined from 85% to 77% max HR. CONCLUSION: The low intensity (60% HR max) may be a neglible stimulus for movement pattern changes in a relatively young, healthy population. Moderate intensity virtual reality exercise can improve movement pattern efficiency in college age participants.Table

Information Processing Changes following Extended Stress

Extended periods of stress are associated with subjective fatigue and performance deterioration. Psychological state and cognitive performance were assessed before and after one week of field training at a Navy Survival, Evasion, Resistance and Escape School. Subjective discomfort increased, but average cognitive performance deterioration was limited to increased Simple Reaction Time. Considering that decrements in complex performance are commonly associated with fatigue, the stability or improvement of the more complex cognitive tasks was unexpected. Given that increasing effort is required to maintain performance as time-on-task increases, performance changes within pre and post-training trials were compared. While performance was stable or improved in the pre-training session, complex task performance deteriorated during post-training trials. The results are consistent with the hypotheses that fatigued individuals maintain complex cognitive task performance by exerting increased effort, but that increasing effort becomes increasingly difficult even during brief assessments.

LACK OF TRAINING EFFECT ON EPINEPHRINE AND NOREPINEPHRINE CONCENTRATION DURING MODERATE AND HARD EXERCISE IN MEN 1153

We investigated the effects of exercise intensity and endurance training on plasma epinephrine (Epi) and norepinephrine (NE) concentrations. Epi and NE were measured at rest and steady state exercise during two pre-training trials(45% and 65% of VO2peak), and two post-training trials (65% of pre-training VO2peak-same absolute workload, and 65% of post-training VO2peak-same relative workload). At rest, Epi and NE concentrations were similar in untrained (UT) and trained (T) conditions [47.4±29.4(UT) vs. 74.2±38.6 (T) pg/ml]. Epi concentrations were not different in the UT trials [134.1±100.6 (45%) vs. 148.2±93.8 (65%) pg/ml], however, NE concentrations were higher (P > 0.05) at 65% VO2peak than 45% VO2peak [1178.3±663 vs. 1882.5±763 pg/ml]. Epi concentrations were similar in T and UT subjects at the same relative intensity [218.2±93 (UT) vs. 213.9±225 (T) pg/ml]. Likewise, training did not alter NE [1786.5±816 (UT) vs. 1650.6±968 (T) pg/ml] at the same relative intensity. At the same absolute workload, NE or Epi concentrations in the T were not significantly lower [NE: 1790.9±814 (UT) vs. 1470.3±790 (T) pg/ml, E: 148.2±93(UT) vs. 218.9±225 (T) pg/ml] in T subjects. These data are interpreted to suggest that endurance training has no significant effect on plasma Epi and NE concentrations during exercise at intensities less than 65% of VO2peak.

ENDURANCE TRAINING ALTERS GLUCOSE KINETICS IN RESPONSE TO THE SAME ABSOLUTE, BUT NOT THE SAME RELATIVE WORKLOAD 619

We examined the hypothesis that exercise intensity and a 10 week cycle ergometry endurance training program (5 d/w, 1 hr, 75% VO2peak) would affect glucose kinetics in 10 healthy, sedentary male subjects. Two pre-training (PE) trials (45% and 65% of VO2peak) and two post-training(PO) trials (same absolute workload-65% of old VO2peak, and same relative-65% of new VO2peak) were performed using a primed, continuous infusion of [1-13C] and [6,6-2H]glucose. Subjects were studied in the morning, post-absorptive for 90 min. of rest and 1 hour of cycling exercise. The subjects remained weight stable throughout the training program, but did demonstrate significant increases in VO2peak (9.4±1.5%). Arterial glucose concentration was not different between trials and remained stable (4.7±0.16mM) during steady state exercise. The PE intensity effect on glucose kinetics was evident with rate of appearance (Ra: 5.72±0.14 mg/kgmin vs. 4.32±0.17), disappearance (Rd: 5.59±0.15 mg/kgmin vs. 4.34±0.17), oxidation (Rox: 5.36±0.15 mg/kgmin vs. 3.41±0.23) and metabolic clearance (MCR: 6.79±0.92 ml/kgmin vs. 4.33±0.23) of glucose being significantly greater (p≤0.05) at 65% than 45%. When Ra was expressed as a% of total energy expenditure (RaE), there was no difference between the 45%(17.06±0.94) and 65% (15.65±0.42) intensities. Training did significantly reduce kinetic values to Ra (4.47±0.32), Rd(4.47±0.32), MCR (5.01±0.44), Rox (3.77±0.43), and RaE(12.84±0.80) when tested at the same absolute workload (p≤0.05). However, when subjects were tested at the same relative workload, Ra, Rd, MCR, RaE were not different, although Rox was significantly lower PO(5.36±0.15 vs. 4.41±0.42, p≤0.05). These results show: 1) glucose use is directly related to exercise intensity, 2) training decreases glucose flux for a given power output, 3) when expressed as relative exercise intensity, training does not affect glucose use.

A color-contingent prism displacement aftereffect.

Observers were trained to point with feedback to red and blue dots whose images had been laterally displaced in opposite directions by a reversible prism. On pretraining and posttraining trials the red and blue dots were aligned vertically in the absence of visual orientation cues. The alignment was modified by the pointing training on the posttraining trials. The colors were aligned in the direction of their prior prismatic displacement. One control experiment showed that the alignment aftereffect requires feedback during the pointing task. Another experiment in which observers pointed to the red and blue dots with opposite arms showed that pointing to both dots with the same arm was necessary to produce the alignment aftereffect. Changes in the perceived position of objects in the visual field occur when changes in perceived limb position cannot compensate for a sensorimotor conflict. Eye torsion or fixation displacements are proposed as alternative mechanisms mediating the aftereffect.

The effects of symmetry and contour on recognition memory in children

Children in prekindergarten, kindergarten, and second grade were tested on a delayed match-to-sample task using abstract visual patterns. The patterns varied both in type of visual organization (unstructured, diagonally symmetrical, vertically symmetrical, and horizontally symmetrical) and in amount of contour. Following the initial memory task, we attempted to train half of the children at each grade by directing their attention to axes of symmetry; the other half of the children received a control task. Subsequently, the subjects were given a second delayed match-to-sample test. On both pre- and post-training trials, structure influenced performance, especially in the two younger groups. Vertical and horizontal symmetry generally facilitated performance in the prekindergarteners, while all three types of symmetry facilitated performance in the kindergarteners. In addition, children generally responded more accurately to patterns with lower levels of contour. They also made more like-contour than unlike-contour confusions, indicating that quantitative aspects of patterns were encoded. Group differences suggested that both processing capacity and memory increase during the age range studied. Finally, there was no indication that training improved performance at any age.