The effect of exercise intensity on coincidence anticipation performance at different stimulus speeds

Medium chain triglycerides with a C8:C10 ratio of 30:70 enhances cognitive performance and mitigates the cognitive decline associated with prolonged exercise in young and healthy adults

INTRODUCTION

Prolonged exercise has been linked to a decline in cognitive function due to a variety of factors, such as a drop in oxygen in the prefrontal cortex and an increase in stress hormones and neurotransmitters. Medium chain triglycerides (MCTs) may possibly offset this decline as they provide energy for the brain via both direct and indirect pathways, alongside promoting chronic physiological adaptations within the brain.

METHODS

Participants were divided into two groups; MCT (n = 9) and Placebo (n = 10). The MCT gels contained 6 g of MCT with a C8:C10 ratio of 30:70, whereas the placebo gels contained carbohydrates of similar calorific value to the MCT gels. Participants visited the laboratory on three occasions (familiarisation/fitness test, pre-supplementation, post-supplementation), during which they performed a battery of cognitive tasks assessing domains such as processing speed, working memory, selective attention, decision making and coordination, before and after a prolonged bout of exercise (60 mins at 90% gas exchange threshold (GET). A 2-week supplementation period between visits 2 and 3 involved the ingestion of 2 gels per day.

RESULTS

Exercise resulted in detriments in most cognitive tasks pre-supplementation for both groups, and post-supplementation for the Placebo group (main effect ps< 0.05). Post-supplementation, the effect of exercise was mediated in the MCT group for all cognitive tasks (main effect ps< 0.05), except for the Digit and Spatial Span Backwards test phases (main effect ps> 0.05). Furthermore, MCT supplementation enhanced before-exercise cognitive performance and in some measures, such as working memory, this was maintained after-exercise (interaction effect ps> 0.05).

CONCLUSIONS

Chronic MCT supplementation enhanced before-exercise cognitive performance and offset the cognitive decline caused by a prolonged bout of exercise. In some cases, improvements in before-exercise cognitive performance were maintained after-exercise.

Neurobehavioral measures of coincidence anticipation timing

Coincidence anticipation (CA) refers to the ability to coordinate responses to the arrival of a moving object. This study investigates the neurobehavioral processes that underlie CA through the measurement of electroencephalography (EEG) recorded during a CA task on a 17-foot plastic rail with evenly spaced LED lights. Participants responded at the anticipated moment a sequence of successively lit LEDs coincided with a stationary target. Healthy young adult participants (Mage = 21) performed six blocks with movement at 20, 30, or 40 mph and the direction either inbound or outbound relative to the participant. Behavioral results demonstrated a main effect of speed and an interaction between speed and direction, with outbound motion producing early responses and inbound motion producing delayed responses that increased at greater speeds. EEG demonstrated characteristic P1, N2, and P3-like visual evoked potentials (VEPs). VEP amplitudes revealed a significant direction by channel interaction for the P1, indicative of more medial responses for inbound motion. Significant laterality differences were present in the N2, whereas the P3 component produced significant main effects and interactions of speed and direction. This novel combination of three-dimensional CA with EEG demonstrates systematic brain responses that are tuned for motion speed and sensitive to different egocentric motion patterns thereby shedding new light on the mechanism of human visual-motor control.

Landing Posture in Elite Female Athletes During a Drop Vertical Jump Before and After a High-Intensity Ergometer Fatigue Protocol: A Study of 20 Japanese Women's Soccer League Players

Background

Even elite athletes, who usually show stable postural control, sometimes cannot control their posture after high-load training. This instability may contribute to anterior cruciate ligament injury.

Purpose/Hypothesis

The purpose of this study was to evaluate the landing posture of elite female soccer players before and after a novel high-intensity fatigue-inducing exercise protocol. We hypothesized that the landing posture will change before versus after the fatigue protocol.

Study Design

Descriptive laboratory study.

Method

The study participants were 20 female elite soccer players. All athletes performed 3 drop vertical jumps (DVJs), pedaled an ergometer 8 times with full force for 10 seconds each (fatigue protocol), and then repeated the 3 DVJs. We measured and compared the athletes' blood lactate levels before and after the fatigue protocol, as well as the hip flexion, knee flexion, and ankle dorsiflexion angles and final landing posture during the DJVs.

Results

Blood lactate levels increased significantly pre- to postprotocol (from 2.7 ± 1.9 to 15.0 ± 3.6 mmol/L; P < .001), while there were decreases in hip flexion angle (from 35.0° ± 11.2° to 22.4° ± 8.8°; P < .001) and ankle dorsiflexion angle (from 26.4° ± 3.9° to 20.0° ± 3.7°; P < .001). The number of athletes who could not maintain a stable DVJ final landing posture increased from 10% before the fatigue protocol to 70% after.

Conclusion

The elite female athletes in our study showed significant decreases in hip flexion and ankle dorsiflexion angles in the DVJ landing after a fatigue-inducing protocol. Most elite athletes were unable to maintain a stable posture on the DVJ landing after the fatigue protocol.

Clinical Relevance

This study advances our understanding of how elite athletes land in a fatigued state.

Physical Stress and Determinants of Shooting Performance Among Norwegian Special Forces Operators

However, there is a lack of conceptual understanding of the factors influencing performance decrements in prone shooting. The present study examines how one can simulate a combat scenario by inducing acute physical stress, ultimately impacting one's shooting performance (SP). The relationship between participants' physical level and SP was measured in several ways. The SP of members of the Norwegian Navy Special Operations Forces (SOF) (N = 30) was measured before and directly after acute exercise-induced stress caused by a 200-m uphill run (90% HRmax). Under acute physical stress, participants took less time to fire five rounds (total 15.5 ± 10.9 s faster), and the probability of hitting the target was unaffected (92%). In terms of more sensitive measures, score was significantly reduced and shot-group dispersion increased (64 ± 90 cm2, p < 0.01, d = 0.72), mainly due to increased vertical dispersion (2.5 ± 4.6 cm, p < 0.01, d = 0.53). Age, trait somatic anxiety and the Big Five Inventory item "openness" explained 45.2% of the variance in shooting score in the pre-physical stress condition. In the post-physical stress condition, pre-test shooting score, the number of months deployed, and shooting time predicted 32.9% of the variance in shooting score. The change in SP (pre-post) showed the concentration disruption scale was the best predictor of the reduction in shot score (20.1%). From a practical point of view, maintaining the probability of hitting the target with reduced shooting time post-physical stress could be viewed as superior performance for SOF.

Does a relationship between handgrip strength and coincidence anticipation timing exist among young adults: a pilot study

The purpose of this investigation was to observe whether a strong to moderate relationship exists between maximal handgrip strength best score and best coincidence anticipation timing (CAT) score in young adults. Handgrip strength has demonstrated a strong relationship with high levels of activities of daily living (ADLs) and reduced injury potential. A one-shot case-study design was selected for this investigation. Twenty-three females and one male volunteered for this investigation (age 22.29 ± 4.71 years, height 63.78 ± 6.22 cm, mass 56.66 ± 8.25 kg) from a local higher education institution. Participants (n = 24) utilized the Bassin anticipation timing device (Lafayette Instruments, USA) and a Camry digital hand dynamometer (Model EH101, Camry LLC, El Monte, CA, USA) during the same time and recorded all scores. The Pearson correlation coefficient (r = -0.413; p = 0.04) indicated a medium effect relationship between best maximal handgrip strength and best CAT score.

Aerobic Exercise Attenuates Pain Sensitivity: An Event-Related Potential Study

In this study, electroencephalography (EEG) was utilized to explore the neurophysiological mechanisms of aerobic exercise-induced hypoalgesia (EIH) and provide a theoretical basis for the application of aerobic exercise in pain assessment and treatment. Forty-five healthy subjects were randomly divided into moderate-intensity aerobic exercise [70% heart rate reserve (HRR)], low-intensity aerobic exercise (50% HRR), or control groups (sitting). Aerobic exercise was performed with cycling. Pressure pain threshold (PPT), heat pain threshold (HPT), event-related potential (ERP) induced by contact heat stimulus and pain scoring were measured before and after the intervention. We found that moderate-intensity aerobic exercise can increase the PPT (rectus femoris: t = -2.71, p = 0.017; tibialis anterior muscle: t = -2.36, p = 0.033) and HPT (tibialis anterior muscle: t = -2.219, p = 0.044) of proximal intervention sites rather than distal sites, and decreased pain scorings of contact heat stimulus. After moderate-intensity aerobic exercise, alpha oscillation power reflecting the central descending inhibitory function was enhanced (t = -2.31, p < 0.05). Low-intensity aerobic exercise mainly reduced the pain unpleasantness rating (Block 1: t = 2.415, p = 0.030; Block 2: t = 3.287, p = 0.005; Block 4: t = 2.646, p = 0.019; Block 5: t = 2.567, p = 0.022). Aerobic exercise had an overall EIH effect. Its hypoalgesic effect was related to exercise intensity and affected by the site and type of pain stimulus. Moderate-intensity aerobic exercise effectively reduced the sensitivity to various painful stimuli, and low-intensity aerobic exercise selectively inhibited the negative emotional pain response. The hypoalgesic mechanism of aerobic exercise involves the enhancement of the central descending inhibitory function.

Influence of Single Bouts of Aerobic Exercise on Dual-Tasking Performance in Healthy Adults

Dual-tasking performance (DTP) is critical for most real-life activities. Interventions to improve DTP would be clinically valuable. This study investigated effects of single-bouts of two different aerobic exercises on the performance of Extended cognitive Timed-Up and Go (ETUGcog), a dual-task test involving concurrent performance of a physical (ETUG) and cognitive (counting backwards serial 7 s) task. Twenty-two adults performed single bouts of high-intensity interval training (HIIT) and moderate-intensity exercise (MIE), separately. ETUGcog was performed before, immediately following, and 24 hours after each exercise. Number and rates of correct serial 7 s were significantly higher 24 hours after HIIT, with no difference in times to complete ETUGcog. No such effects were found for MIE. Single bouts of HIIT could provide delayed improvements in DTP.

Shoulder Muscular Fatigue From Static Posture Concurrently Reduces Cognitive Attentional Resources

OBJECTIVE

The goal of this work is to determine whether muscular fatigue concurrently reduces cognitive attentional resources in technical tasks for healthy adults.

BACKGROUND

Muscular fatigue is common in the workplace but often dissociated with cognitive performance. A corpus of literature demonstrates a link between muscular fatigue and cognitive function, but few investigations demonstrate that the instigation of the former degrades the latter in a way that may affect technical task completion. For example, laparoscopic surgery increases muscular fatigue, which may risk attentional capacity reduction and undermine surgical outcomes.

METHOD

A total of 26 healthy participants completed a dual-task cognitive assessment of attentional resources while concurrently statically fatiguing their shoulder musculature until volitional failure, in a similar loading pattern observed in laparoscopic procedures. Continuous and discrete monitoring task performance was recorded to reflect attentional resources.

RESULTS

Electromyography of the anterior deltoid and descending trapezius, as well as self-assessment surveys indicated fatigue occurrence; continuous tracking error, tracking velocity, and response time significantly increased with muscular fatigue.

CONCLUSION

Muscular fatigue concurrently degrades cognitive attentional resources.

APPLICATION

Complex tasks that rely on muscular and cognitive performance should consider interventions to reduce muscular fatigue to also preserve cognitive performance.

Effects of exercise intensity on anticipation timing performance during a cycling task at moderate and vigorous intensities in children aged 7-11 years

This study examined coincidence anticipation timing performance at moderate and fast stimulus speeds before, during, and after a 15 minute cycling task. In a within-subject design, 24 children (18 males and 6 females) exercised on a cycle ergometer under two experimental conditions: exercise intensities of 50% (moderate) and 75% (vigorous) heart rate reserve. Coincidence anticipation timing was measured using the Bassin Anticipation Timer at stimulus speeds of 5 and 8 mph. A 2 (intensity) × 3 (time) repeated measures ANOVA was conducted to evaluate the effect of exercise intensity on coincidence anticipation performance before, during, and immediately after the cycling task. Results indicated that for absolute error there was no significant main effect for time (p = .633) or experimental condition (p = .782) at the 5 mph stimulus speed. However, there was a significant interaction effect between experimental condition and time (p = 0.026) at the 5 mph stimulus speed. At the 8 mph stimulus speed, there was no significant main effect for time (p = .910) or condition (p = .938), or interaction effect between experimental condition and time (p = .591). Cycling exercise at moderate intensity appears to influence anticipation timing performance during and immediately after exercise in children, but only when stimulus speeds are moderate in nature.

Speed, resistance, and unexpected accelerations modulate feed forward and feedback control during a novel weight bearing task

We developed a method to investigate feed-forward and feedback movement control during a weight bearing visuomotor knee tracking task. We hypothesized that a systematic increase in speed and resistance would show a linear decrease in movement accuracy, while unexpected perturbations would induce a velocity-dependent decrease in movement accuracy. We determined the effects of manipulating the speed, resistance, and unexpected events on error during a functional weight bearing task. Our long term objective is to benchmark neuromuscular control performance across various groups based on age, injury, disease, rehabilitation status, and/or training. Twenty-six healthy adults between the ages of 19-45 participated in this study. The study involved a single session using a custom designed apparatus to perform a single limb weight bearing task under nine testing conditions: three movement speeds (0.2, 0.4, and 0.6Hz) in combination with three levels of brake resistance (5%, 10%, and 15% of individual's body weight). Individuals were to perform the task according to a target with a fixed trajectory across all speeds, corresponding to a∼0 (extension) to 30° (flexion) of knee motion. An increase in error occurred with speed (p<0.0001, effect size (eta²): η²=0.50) and resistance (p<0.0001, η²=0.01). Likewise, during unexpected perturbations, the ratio of perturbed/non-perturbed error increased with each increment in velocity (p<0.0014, η²=0.08), and resistance (p<0.0001, η²=0.11). The hierarchical framework of these measurements offers a standardized functional weight bearing strategy to assess impaired neuro-muscular control and/or test the efficacy of therapeutic rehabilitation interventions designed to influence neuromuscular control of the knee.

Effects of oncoming target velocities on rapid force production and accuracy of force production intensity and timing

The present study aimed to clarify the effects of oncoming target velocities on the ability of rapid force production and accuracy and variability of simultaneous control of both force production intensity and timing. Twenty male participants (age: 21.0 ± 1.4 years) performed rapid gripping with a handgrip dynamometer to coincide with the arrival of an oncoming target by using a horizontal electronic trackway. The oncoming target velocities were 4, 8, and 12 m · s^-1, which were randomly produced. The grip force required was 30% of the maximal voluntary contraction. Although the peak force (Pf) and rate of force development (RFD) increased with increasing target velocity, the value of the RFD to Pf ratio was constant across the 3 target velocities. The accuracy of both force production intensity and timing decreased at higher target velocities. Moreover, the intrapersonal variability in temporal parameters was lower in the fast target velocity condition, but constant variability in 3 target velocities was observed in force intensity parameters. These results suggest that oncoming target velocity does not intrinsically affect the ability for rapid force production. However, the oncoming target velocity affects accuracy and variability of force production intensity and timing during rapid force production.

The influence of cycling intensity upon cognitive response during inferred practice and competition conditions

In many sport and exercise situations, cognitive performance is required under conditions of high physiological load and high cognitive anxiety. However, few studies have assessed all these components in situ. The current study sought to address this issue. Fourteen adults (9 males, 5 females) completed 2 incremental exercise trials (perceived competition or perceived practice) in a counterbalanced order. Cognitive performance, via a test of visual discrimination, rating of perceived exertion (RPE), heart rate (HR), blood lactate (Bla), and anxiety scores, was recorded at rest, 70% [Formula: see text] and 90% [Formula: see text]. Visual discrimination response times were faster at rest compared to 70% (P = 0.001) and 90% [Formula: see text] (P = 0.002) and at 70% compared to 90% [Formula: see text] (P = 0.04) in the competitive condition. HR post-instructions (P = 0.0001), at 70% (P = 0.001) and 90% [Formula: see text] (P = 0.0001), was significantly higher in competition compared to practice. RPE was higher in the competitive condition compared to the practice condition (P = 0.023). Cognitive anxiety intensity was significantly higher in the competitive condition, at 70% and 90% [Formula: see text] (P = 0.001). This study suggests that cognitive performance is more negatively affected when physiological arousal and cognitive anxiety are at their highest. Coaches and athletes should be mindful of such effects and seek to develop skills to offset such responses or to structure training to better represent competition.

The effect of badminton-specific exercise on badminton short-serve performance in competition and practice climates

This study examined the effects of changes in physiological and psychological arousal on badminton short-serve performance in competitive and practice climates. Twenty competitive badminton players (10 males and 10 females) volunteered to participate in the study following ethics approval. After familiarisation, badminton short-serve performance was measured at rest, mid-way through and at the end of a badminton-specific exercise protocol in two conditions; competition vs. practice. Ratings of cognitive and somatic anxiety were assessed at three time points prior to badminton short-serve performance using the Mental Readiness Form 3. Heart rate and rating of perceived exertion (RPE) were assessed during the exercise protocol. Results indicated that better short-serve performance was evident in practice compared to competition (P = .034). RPE values were significantly higher in the competition condition compared to practice (P = .007). Cognitive anxiety intensity was significantly lower post-exercise in the practice condition compared to competition (P = .001). Cognitive anxiety direction showed greater debilitation post-exercise in the competition condition compared to practice (P = .01). Somatic anxiety intensity increased from pre-, to mid- to post-exercise (P = .001) irrespective of condition. This study suggests that badminton serve performance is negatively affected when physiological arousal, via badminton-specific exercise, and cognitive anxiety, via perceived competition, are high.

The effect of exercise intensity on cognitive performance during short duration treadmill running

This study examined the effect of short duration, moderate and high-intensity exercise on a Go/NoGo task. Fifteen, habitually active (9 females and 6 males aged 28 ± 5 years) agreed to participate in the study and cognitive performance was measured in three sessions lasting 10 min each, performed at three different exercise intensities: rest, moderate and high. Results indicated significant exercise intensity main effects for reaction time (RT) (p = 0.01), the omission error rate (p = 0.027) and the decision error rate (p = 0.011), with significantly longer RTs during high intensity exercise compared to moderate intensity exercise (p = 0.039) and rest (p = 0.023). Mean ± SE of RT (ms) was 395.8 ± 9.1, 396.3 ± 9.1 and 433.5 ± 16.1 for rest, moderate and high intensity exercise, respectively. This pattern was replicated for the error rate with a significantly higher omission error and decision error rate during high intensity exercise compared to moderate intensity exercise (p = 0.003) and rest (p = 0.001). Mean ± SE of omission errors (%) was 0.88 ± 0.23, 0.8 ± 0.23 and 1.8 ± 0.46% for rest, moderate and high intensity exercise, respectively. Likewise, mean ± SE of decision errors (%) was 0.73 ± 0.24, 0.73 ± 0.21 and 1.8 ± 0.31 for rest, moderate and high intensity exercise, respectively. The present study’s results suggest that 10 min workout at high intensity impairs RT performances in habitually active adults compared to rest or moderate intensity exercise.

Coincidence Anticipation Timing Performance during an Acute Bout of Brisk Walking in Older Adults: Effect of Stimulus Speed

This study examined coincidence anticipation timing (CAT) performance at slow and fast stimulus speeds before, during, and after an acute bout of walking in adults aged 60–76 years. Results from a series of repeated measures ANOVAs indicated significant rest versus exercise × stimulus speed × time interactions for absolute and variable errors (both P = 0.0001) whereby absolute and variable error scores, when stimulus speed was slow, improved as the duration of exercise increased. When stimulus speed was fast there were significantly greater absolute and variable errors at 18 minutes of the walking bout. There was also greater error at 18 minutes during walking compared to rest. These results suggest that, in a task involving walking and CAT, stimulus speeds plays an important role; specifically walking (exercise) enhances CAT performance at slow stimulus speeds but reduces CAT performance at fast stimulus speeds. The implications are that in everyday situations, where events require dual-task responses to be made at different speeds, for example, walking on the pavement whilst avoiding a crowd, compared to crossing a busy road, an understanding of how different stimulus speeds influence dual-task performance is extremely important, particularly in the older adult population.

Assessment of the ergogenic effect of caffeine supplementation on mood, anticipation timing, and muscular strength in older adults

The effect of caffeine to promote improvements in mood, cognition, and exercise performance has been well established in young and athletic adults. However, little is known about whether such nutritional ergogenic aids are effective in enhancing psychological well-being, physiological or cognitive performance in older adults. This study assesses the ergogenic effect of caffeine on mood, perceptual-motor coupling, and muscular strength in an older human population. Following a familiarization session, 12 apparently healthy volunteers (nine females and three males; 69 ± 6 years) completed two laboratory visits. “Pre ingestion” trials of mood state Brunel Mood State Inventory (BRUMS) and coincidence anticipation performance (Bassin anticipation timer) at slow (3 mph) and fast (8 mph) stimulus speeds were completed on both visits. Using a randomized, double-blind, cross-over design, participants consumed either caffeine (3 mg/kg body mass) or a placebo. Sixty minutes postingestion participants repeated the trials before completing a set of 10 consecutive repetitions of maximal knee extension using isokinetic dynamometry. Rating of perceived exertion (RPE) was assessed following the fifth and final repetition. Caffeine ingestion significantly improved mood state scores for vigor by 17% (P = 0.009) and reduced absolute error by 35% (P = 0.045) during coincidence anticipation assessment at 8 mph compared to placebo. There were no other significant effects. Caffeine ingestion failed to augment maximal voluntary contraction of the knee extensors and RPE did not prove to be significantly different to from placebo (P > 0.33 in each case). Acute caffeine ingestion may not be an effective ergogenic aid for improving muscular strength in older adults but could possibly be used as a nutrition supplement for enhancing mood and improving cognitive performance in daily living tasks where interceptive timing skills are required.