Significant Main Effect Of Condition Research Articles

Acute effects of ballistic and non-ballistic conditioning activities on the punching impact of amateur boxers

Objectives This study investigated the postactivation performance enhancement (PAPE) effects of medicine ball throwing (MBT) and bench pressing (BP) on punching impact at different recovery times. Methods Fourteen amateur boxers performed three lead-hand (lead-hand) and rear-hand straight punches (rear-hand) at 3, 6, 9, 12, and 15 min after MBT or BP exercise. Peak force, time to the peak force, and rate of force development (RFD) of each punch was measured by a force plate. Results There was no significant condition × time interaction effect for any variables (lead-hand: F = 0.744–0.913, p = 0.448–0.542; rear-hand: F = 0.240–1.355, p = 0.245–0.944). No significant main effect for condition for any variables (lead-hand: F = 0.103–0.219, p = 0.644–0.751; rear-hand: F = 0.070–0.459, p = 0.504–0.793). The time effect was significant on peak force ( F = 4.411, p = 0.005) and RFD ( F = 5.002, p = 0.002) of lead-hand, time to the peak force ( F = 5.791, p = 0.001) and RFD ( F = 5.514, p = 0.001) of rear-hand. Peak force and RFD of the lead-hand, as well as time to the peak force and RFD of the rear-hand enhanced significantly at 6–15 min ( p = 0.001–0.042), compared to the baseline. Conclusions MBT and BP may equally enhance punching impact for amateur boxers; moreover, there was no difference in recovery time between conditioning activities.

Emotional Dysregulation and Altered Reward Processing in Self-Harm

IntroductionSelf-Harm (SH) is any act of self-injury carried out by somebody irrespective of motivation. SH most commonly functions to relieve negative affect (NA). Tentative evidence suggests reward processing is altered in SH. NA may trigger reward hypersensitivity and therefore SH. Whether NA influences reward processing in SH remains unclear.ObjectivesTo investigate whether self-harmers differ in motivation to obtain SH stimuli than healthy controls (HCs) following NA induction.HypothesisAfter NA induction, SH participants will have a significantly shorter reaction latency (RL) and greater reaction accuracy (RA) than HCs in the SH condition of the Incentive Delay (ID) task.Methods16-25-year-old SH (n=35) and HC (n=20) participants were recruited online and underwent the Trier Social Stress Test, to induce NA, followed by the ID task, where participants were cued to respond to a target as quickly as possible. On responding, an image of either a SH act (SH Condition), people socializing (Social Condition) or money (Monetary Condition) appeared. Each condition included control trials showing a neutral image. RA was the percentage of trials responded to within the target’s presentation time. RL was the time (seconds) between target appearance and participants’ response.ResultsThere was no significant main effect of group, condition or group x condition interaction for RL. There was a significant main effect of condition (p < 0.05) but not of group nor a group x condition interaction for RA.ConclusionsReward processing did not differ in the SH group compared to HCs post-NA induction. Future studies could investigate reward processing in longitudinal and larger SH samples.DisclosureNo significant relationships.

Emotional Dysregulation and Altered Reward Processing in Self-Harm

AimsSelf-Harm (SH) is defined as “any act of self-injury or poisoning carried out by a person irrespective of their motivation”. SH increases the risk of adverse outcomes including suicide attempts, necessitating early intervention. The most widely reported reason for SH is to relieve negative affect (NA), with NA precipitating SH engagement. SH participants show altered reward processing, particularly reward hypersensitivity. NA could trigger reward hypersensitivity and therefore SH engagement. However, the interaction between NA and reward processing in SH remains unclear.Aim: To investigate whether those who SH show differences in processing SH stimuli compared to healthy controls (HCs) following NA induction.Hypothesis: NA induction will result in SH participants having significantly shorter reaction latency (RL) and significantly greater reaction accuracy (RA) in the SH condition of the Incentive Delay task (IDT) than HCs.Methods16–25-year-old SH (n = 35) and HC (n = 20) participants were recruited on social media. Participants completed the Trier Social Stress Test, to induce NA, followed by the IDT. In the latter, participants were cued to respond to a target as quickly as possible, and on responding were shown images of either a SH act (SH condition), people socializing (social condition) or money (monetary condition), where each condition had control trials where a neutral image was shown, which participants also had to respond to (SH neutral, social neutral and monetary neutral conditions respectively). RA was the percentage of IDT trials in which participants responded within the target's presentation time. RL in the IDT was the time (seconds) between the target appearance and the participant's response.ResultsA linear mixed effects model showed no significant main effect of group on RL (SH vs HC), condition (Social, SH or Monetary) or group x condition interaction (p > 0.05). There was a significant main effect of condition on RA (p < 0.05) but not group or group x condition interaction (p > 0.05). Past-week SH frequency and RA were significantly and positively correlated in social, social neutral and monetary conditions (p < 0.05).ConclusionOverall, there was a non-significant effect of NA on reward processing. However, as greater past-week SH frequency was significantly associated with greater RA, understanding how reward processing and NA interact in SH can provide greater insight into its triggers. Given this study's limited sample size and cross-sectional nature, future studies should investigate how NA and reward processing interact longitudinally and in larger samples to understand how SH can be reduced.

0658 Slow-Wave Sleep Disruption Decreases Ability to Recognize Certain Negative Emotions

Abstract Introduction Research has demonstrated that sleep deprivation may alter emotion recognition. Given that emotion recognition is critical for effective human communication, it is essential to understand how sleep is involved in this process. Slow-wave sleep (SWS) has been suggested to be important for the consolidation and processing of emotional memories and neuroplasticity. This study aimed to examine the impact of experimental disruption of SWS on emotion recognition to further understand the contribution of SWS. Methods 31 participants (20 individuals diagnosed with Major Depressive Disorder (MDD), 11 healthy controls (HC)) completed two overnight sleep studies spaced one week apart. One night served as baseline (BL) and on the other night participants underwent slow-wave disruption (SWD), where SWS was disrupted using auditory stimulation. In the morning following each overnight visit, participants completed an emotion recognition task. Accuracy scores were computed as the percentage correct in each of 10 categories of emotions (anger, contempt, disgust, embarrassment, fear, joy, neutral, pride, sadness, and surprise). Repeated measures ANOVA was used to assess the impact of SWD on emotion recognition with group (HC, MDD) as the between subjects factor and condition (BL, SWD) as the within subjects factor. Results Results revealed a significant main effect of condition for disgust (F=13.72, p< .001), embarrassment (F=6.23, p=.019), and surprise (F=8.06, p=.008), with follow-up t-tests demonstrating that accuracy for the recognition of disgust and embarrassment decreased following SWD and accuracy for surprise increasing following SWD. No significant interactions were found for group*condition (ps>.105). Conclusion These results suggest that while SWD decreases the ability to recognize certain negative emotions, it also increases the ability to recognize surprise, which is in line with previous research examining acute total sleep deprivation. Interestingly, there appears to be no difference in the ability to recognize emotions between individuals with and without depression. Slow-wave sleep deficits, common in disorders such as depression and schizophrenia, may therefore contribute to poor communication abilities through decreased ability to recognize emotions, increasing the risk of interpersonal distress and mental health problems. Support (If Any) Goldschmied: K23MH118580 (NIMH)

Ischemia during rest intervals between sets prevents decreases in fatigue during the explosive squat exercise: a randomized, crossover study

The study aimed to evaluate the impact of ischemia, used only before particular sets of a lower limb resistance exercise on power output. Ten healthy resistance-trained males (age = 26 ± 6 years; body mass = 90 ± 9 kg; training experience = 9 ± 7 years) performed two experimental sessions (with ischemia; control without ischemia) following a randomized crossover design. During the ischemic condition, the cuffs were inflated to 60% of arterial occlusion pressure. The cuffs were applied before each set for 4.5 min and released 30 s before the start of the set as the reperfusion (4.5 min ischemia + 0.5 min reperfusion). In the control condition, ischemia was not applied. During the experimental sessions, the subjects performed the Keiser machine squat exercise protocol which consisted of 5 sets of two repetitions, at a load of 60% of one-repetition maximum (1RM), with 5 min rest intervals between sets. The repetitions were performed with maximal velocity. The two-way repeated-measures ANOVA showed a statistically significant interaction effect for power output (p < 0.01; η2 = 0.26). There was also a statistically significant main effect of condition for power output (p = 0.02; η2 = 0.40). The post hoc analysis for interaction did not show significant differences between conditions in particular sets. The post hoc analysis for the main effect of the condition revealed that power output was significantly lower in the control group compared to the group where ischemic was used (p = 0.02). The t-test comparisons for particular sets showed a significant lower power output in set 3 (p = 0.03); set 4 (p < 0.01) and set 5 (p < 0.01) for the control condition when compared to the ischemic condition. The results indicate that ischemia applied before each set and released 30 s prior to the start of the squat exercise did not increase power output performance. However, we observed a significantly lower decline in power for the ischemic condition (4.5 min ischemia + 0.5 min reperfusion) in sets 3–5 compared to the control condition. Thus repeated ischemia with reperfusion used between sets can be an effective form of performance enhancement by preventing or at least diminishing fatigue during resistance exercise.

Effect of exhaustion on dynamic balance of professional padel players

Padel is an intermittent multidirectional racket sport that uses tennis’ rules and its scoring system. The popularity of padel has seen exponential growth; becoming one of the most practiced sports in the world. Balance constitutes a central component of racquet sports competitive demands. The aim of this study was exploring the effect of an exhaustive exercise on dynamic balance in elite padel players. 34 first division padel players with national rankings (age: 31.6 ± 7.9 years, height: 181.1 cm ± 5.26 cm; body mass: 81.1 kg ± 9.95 kg) volunteered for this study. Subjects were first tested for dynamic balance using the Y balance test. Then, they performed a volitional exhaustion test, followed by a dynamic balance retest. A significant main effect of condition for all balance variables was detected (all p < 0.03) except for the postero-lateral distance. A significant main effect of time was only found for the anterior distance (p < 0.001). Significant condition*time interaction was found for all variables (p < 0.02) except for the posterolateral distance. Posthoc analysis of the condition × time interaction indicated that compared to the control condition, exhaustive exercise deteriorated balance as showed by the significant decrease in the composite score (p = 0.05) and in the anterior direction (p < 0.001). This makes us focus on elaborating novel training systems in padel to improve the anterior direction distance after fatigue, being the reason of the decrease of dynamic balance capacity. This will boost the possibilities of scoring during a competitive situation.

Effects of Individualized Versus Traditional Power Training on Strength, Power, Jump Performances, and Body Composition in Young Male Nordic Athletes.

This study aimed to examine the effects of individualized-load power training (IPT) versus traditional moderate-load power training (TPT) on strength, power, jump performance, and body composition in elite young Nordic athletes. In a randomized crossover design, 10 young male athletes (ski jumpers, Nordic combined athletes) age 17.5 (0.6) years (biological maturity status: +3.5y postpeak height velocity) who competed on a national or international level performed 5weeks of IPT (4 × 5 repetitions at 49%-72% 1-repetiton maximum [RM]) and TPT (5 × 5 repetitions at 50%-60% 1-RM) in addition to their regular training. Testing before, between, and after both training blocks comprised the assessment of muscle strength (loaded back squat 3-RM), power (maximal loaded back squat power), jump performance (eg,drop-jump height, reactive strength index), and body composition (eg,skeletal muscle mass). Significant, large-size main effects for time were found for muscle strength (P < .01; g = 2.7), reactive strength index (P = .03; g = 1.6), and drop-jump height (P = .02; g = 1.9) irrespective of the training condition (IPT, TPT). No significant time-by-condition interactions were observed. For measures of body composition, no significant main effects of condition and time or time-by-condition interactions were found. Our findings demonstrate that short-term IPT and TPT at moderate loads in addition to regular training were equally effective in improving measures of muscle strength (loaded back squat 3-RM) and vertical-jump performance (reactive strength index, drop jump, and height) in young Nordic athletes.

Virtual reality-based distraction on pain, performance, and anxiety during and after moderate-vigorous intensity cycling

Purpose: To determine whether increased visual perceptual load (PL) within an immersive virtual environment may help explain previously shown pain-relieving effects of virtual reality (VR) during high intensity cycling.Methods: Using a within-subjects design, participants cycled at a perceptually “hard” intensity for 10 min on three separate occasions. The first session did not use VR (i.e., no perceptual load - NPL). Subsequent sessions employed VR during cycling with either a low or high perceptual load (LPL or HPL). Quadriceps pain intensity (PI) was reported by participants throughout cycling.Results: Data were analyzed for 43 healthy participants (20 females, mean age 21 [SD 1.4]). For PI, ANOVA showed there were significant main effects of condition (F = 13.458, df =1.579, 66.334, p<0.001) and time (F = 113.045, df =1.618, 227.683, p<0.001). At every time point, t-tests revealed mean PI was significantly lower in the NPL than in the LPL condition (t(42)=4.737, p<0.001, d = 0.472) and HPL condition (t(42)=3.380, p = 0.002, d = 0.391). Dependent t-tests showed that more work (kilojoules) was performed during the LPL condition than the NPL (t(42)=2.992, p = 0.005) and HPL (t(42)=5.810, p<0.001) conditions.Conclusions: Compared to a traditional 10-minute bout of cycle ergometry (NPL), individuals who cycled in the LPL condition chose to exercise at a higher intensity despite greater PI. Those who cycled in the HPL condition did not change their exercise intensity, but did report higher PI, possibly, because of the greater mental effort/energy requirement.

Acute mood and cardiovascular responses to moderate intensity vinyasa yoga, static yin yoga and aerobic exercise in people with depression and/or anxiety disorders: A 5-arm randomised controlled trial

IntroductionDue to the multi-composite, mind-body features of yoga, it is of interest to determine what effect exercise plays as a component of modern yoga in providing psychological and physiological health benefits, and whether benefits are enhanced with a combination of components. Furthermore, although the effects of regular, long-term yoga practice are well documented, the acute effects have received less empirical investigation. MethodA within-subjects, repeated measures randomised controlled crossover trial with five conditions was conducted (trial registration: ACTRN12620000983909). Participants (N = 41, mean age = 32 years) with Depressive and/or Anxiety Disorders completed 1) yin yoga, 2) aerobic exercise, 3) vinyasa yoga, 4) stretching (sham) control and 5) no-intervention control. Acute changes in mood and cardiovascular tone were assessed. ResultsA significant main effect of condition on mood was observed (N = 38; F4,127.193 = 7.507, p = <.001). Participants receiving yin, vinyasa, aerobic exercise and stretching achieved comparable improvements in mood symptoms compared to no-intervention control. Cardiovascular changes were observed for aerobic exercise and vinyasa yoga. No adverse events were reported. ConclusionsThe acute mood benefits of a single initial session of yoga are not significantly greater than those derived from other forms of movement. Moderate-intensity styles of yoga can provide a sufficient and equivalent acute cardiovascular exercise effect to that of traditional exercise options (i.e., cycling).

Effects of short sleep duration on hemodynamic and psychological responses under long working hours in healthy middle-aged men: an experimental study.

This study examined the effects of short sleep duration (SSD) on hemodynamic and psychological responses under long working hours (LWH) in a laboratory experiment. Sixteen subjects participated in a crossover design experiment consisting of two conditions: normal (7-hours) sleep and short (5-hours) sleep. In each condition, participants engaged in simulated LWH (13 hours a day), comprising 12 task sessions. Hemodynamic and psychological responses were measured in each session. Results showed that there were significant main effects of condition and session but no interaction for hemodynamic and psychological responses. Systolic blood pressure and fatigue were higher in the later sessions than the first one. Stroke volume, sleepiness, fatigue, and stress were higher in the 5-hour than the 7-hour sleep condition (all p<0.05). These results suggest that although the combined effect of LWH and SSD was not significant, both LWH and SSD caused a hemodynamic and psychological burden.

Enhancement of Countermovement Jump Performance Using a Heavy Load with Velocity-Loss Repetition Control in Female Volleyball Players.

Although velocity control in resistance training is widely studied, its utilization in eliciting post-activation performance enhancement (PAPE) responses receives little attention. Therefore, this study aimed to evaluate the effectiveness of heavy-loaded barbell squats (BS) with velocity loss control conditioning activity (CA) on PAPE in subsequent countermovement jump (CMJ) performance. Sixteen resistance-trained female volleyball players participated in this study (age: 24 ± 5 yrs.; body mass: 63.5 ± 5.2 kg; height: 170 ± 6 cm; relative BS one-repetition maximum (1RM): 1.45 ± 0.19 kg/body mass). Each participant performed two different conditions: a set of the BS at 80% 1 RM with repetitions performed until a mean velocity loss of 10% as the CA or a control condition without CA (CNTRL). To assess changes in jump height (JH) and relative mean power output (MP), the CMJ was performed 5 min before and throughout the 10 min after the CA. The two-way analysis of variance with repeated measures showed a significant main effect of condition (p = 0.008; η2 = 0.387) and time (p < 0.0001; η2 = 0.257) for JH. The post hoc test showed a significant decrease in the 10th min in comparison to the value from baseline (p < 0.006) for the CNTRL condition. For the MP, a significant interaction (p = 0.045; η2 = 0.138) was found. The post hoc test showed a significant decrease in the 10th min in comparison to the values from baseline (p < 0.006) for the CNTRL condition. No significant differences were found between all of the time points and the baseline value for the CA condition. The CA used in the current study fails to enhance subsequent countermovement jump performance in female volleyball players. However, the individual analysis showed that 9 out of the 16 participants (56%) responded positively to the applied CA, suggesting that the PAPE effect may be individually dependent and should be carefully verified before implementation in a training program.

Tongue position variability in sustained vowels produced by healthy children and young adults with and without a semi-occluded vocal tract: A pilot study

Speech development is a process by which talkers learn, among other things, to coordinate neuromuscular activations of motor units spread across several muscles that effect articulator positioning and movement. This paper presents results from an analysis of tongue position variability during sustained vowel production. Data from two children (7 years 11 months, and 9years 7 months) and two young adults (both 20 years 7 months) are presented. Articulatory data were recorded with a 3D/4D ultrasound system, in two conditions: without a semi-occluded vocal tract (“without straw”) and with a semi-occluded vocal tract (“with straw”). Statistical analyses of tongue position variability revealed a main effect of age, with children showing greater variability than adults. There was no statistically significant main effect of condition, but the main effect of age was driven primarily by the “with straw” condition. We speculate that tongue position variability during sustained vowels may be an index of speech motor control maturity, and that the interaction between age and condition suggests children are less able than adults to rely on learned feed-forward motor programs under conditions of somatosensory perturbation, such as the presence of a straw between the lips.

Walking indoors, outdoors, and on a treadmill: Gait differences in healthy young and older adults.

Although human gait is typically studied in a laboratory environment, the findings of laboratory-based gait assessments are often applied to daily life scenarios. Assessing gait in varied conditions may offer a better understanding of the influence of environment on gait performance. How do spatiotemporal gait measures differ between indoor overground walking, outdoor walking, and treadmill walking in healthy adults? Do different walking environments exaggerate age-related alterations in gait performance in older compared to young adults? 30 young (18-30yrs) and 28 older adults (60-80yrs) completed four randomized conditions at their typical, comfortable walking pace: 1) 8 m of indoor walking, 2) continuous indoor walking, 3) treadmill walking, and 4) outdoor walking on a sidewalk. Wearable inertial sensors recorded gait data and the magnitudes and variability (in standard deviations) of the following gait measures were computed: cadence, percent double support, stride length (with sample entropy), and gait velocity. Despite the lack of significant univariate interactions between group and walking condition, significant main effects for condition and group were observed in both the magnitude and variability analyses. Treadmill walking resulted in a slower gait with shorter, less variable strides (p < .001), while walking outdoors resulted in faster gait with longer strides (p < .001) compared to other walking conditions. Stride length regularity was reduced when walking outdoors compared to treadmill walking (p = .019). The results showed that the effects of walking condition on gait measures were more dramatic than participant age, and gait performance differs between walking environments in both older and younger adults. Since daily life gait encompasses both tightly controlled and unconstrained, free-living walking, researchers and clinicians should use caution when generalizing gait performance across walking conditions. Measures of gait performance typically used in laboratory gait analyses may not adequately characterize daily life gait in indoor and outdoor environments.

Walking towards a visually distracting environment does not affect gait kinematics and spatiotemporal parameters of children with cerebral palsy diplegia

Although human gait is typically studied in a laboratory environment, the findings of laboratory-based gait assessments are often applied to daily life scenarios. Assessing gait in varied conditions may offer a better understanding of the influence of environment on gait performance.How do spatiotemporal gait measures differ between indoor overground walking, outdoor walking, and treadmill walking in healthy adults? Do different walking environments exaggerate age-related alterations in gait performance in older compared to young adults?30 young (18−30yrs) and 28 older adults (60−80yrs) completed four randomized conditions at their typical, comfortable walking pace: 1) 8 m of indoor walking, 2) continuous indoor walking, 3) treadmill walking, and 4) outdoor walking on a sidewalk. Wearable inertial sensors recorded gait data and the magnitudes and variability (in standard deviations) of the following gait measures were computed: cadence, percent double support, stride length (with sample entropy), and gait velocity.Despite the lack of significant univariate interactions between group and walking condition, significant main effects for condition and group were observed in both the magnitude and variability analyses. Treadmill walking resulted in a slower gait with shorter, less variable strides (p < .001), while walking outdoors resulted in faster gait with longer strides (p < .001) compared to other walking conditions. Stride length regularity was reduced when walking outdoors compared to treadmill walking (p = .019).The results showed that the effects of walking condition on gait measures were more dramatic than participant age, and gait performance differs between walking environments in both older and younger adults. Since daily life gait encompasses both tightly controlled and unconstrained, free-living walking, researchers and clinicians should use caution when generalizing gait performance across walking conditions. Measures of gait performance typically used in laboratory gait analyses may not adequately characterize daily life gait in indoor and outdoor environments.

Caffeine coingested with carbohydrate on performance recovery in national-level paddlers: a randomized, double-blind, crossover, placebo-controlled trial.

Caffeine enhances muscle glycogen resynthesis postexercise; however, the next-day effects on recovery are unknown. The present study aimed to examine the effects of carbohydrate (CHO) supplementation with or without caffeine (CAF) 24-h following exhaustive exercise on time trial performance in elite paddling athletes. Nine highly trained male paddlers (21±2 y) completed three experimental trials in a randomized, double-blind, crossover manner. Following an exhaustive exercise session (20-km timed paddle) participants ingested: 1) 0.6 g/kg of carbohydrate (CHO); 2) 0.6 g/kg of carbohydrate with 6 mg/kg of caffeine (CAF+CHO); or 3) placebo (PLA), at four time-points (immediately after, and 2, 6, and 12-h postexercise) in addition to their typical dietary intake. After 24 h, 5 attempts of on-water 500-m paddling time-trial was performed, and the average time was recorded. Blood samples were taken at rest and following both the 20-km and the 5×500 m exercise to determine changes in plasma cortisol, insulin, and glucose. There was a significant main effect of condition (P<0.001), with post-hoc analysis revealing that both CHO conditions (CHO: 98.7±2.8 s, P=0.0003; CAF+CHO: 97.9±2.3 s, P=0.0002) were significantly faster compared to PLA (101.0±3.1 s); however, CAF did not augment time trial performance compared to CHO (P=0.16). There was no significant condition by time interactions for glucose, cortisol, or insulin before and after the 20-km depleting exercise and 500-m time trial. In elite male paddlers, CHO, independent of caffeine, enhanced time trial performance 24 hours following exhaustive exercise.

The Effects of Ischemia During Rest Intervals on Bar Velocity in the Bench Press Exercise With Different External Loads.

The main aim of the present study was to evaluate the acute effects of ischemia used during rest periods on bar velocity changes during the bench press exercise at progressive loads, from 20 to 90% of 1RM. Ten healthy resistance trained men volunteered for the study (age = 26.3 ± 4.7 years; body mass = 89.8 ± 6.3 kg; bench press 1RM = 142.5 ± 16.9 kg; training experience = 7.8 ± 2.7 years). During the experimental sessions the subjects performed the bench press exercise under two different conditions, in a randomized and counterbalanced order: (a) ischemia condition, with ischemia applied before the first set and during every rest periods between sets, and (b) control condition where no ischemia was applied. During each experimental session eight sets of the bench press exercise were performed, against loads starting from 20 to 90% 1RM, increased progressively by 10% in each subsequent set. A 3-min rest interval between sets was used. For ischemia condition the cuffs was applied 3 min before the first set and during every rest period between sets. Ischemia was released during exercise. The cuff pressure was set to ∼80% of full arterial occlusion pressure. The two-way repeated measures ANOVA showed a statistically significant interaction effect for peak bar velocity (p = 0.04) and for mean bar velocity (p = 0.01). There was also a statistically significant main effect of condition for peak bar velocity (p < 0.01) but not for mean bar velocity (p = 0.25). The post hoc analysis for interaction showed significantly higher peak bar velocity for the ischemia condition compared to control at a load of 20% 1RM (p = 0.007) and at a load of 50% 1RM (p = 0.006). The results of the present study indicate that ischemia used before each set even for a brief duration of <3 min, has positive effects on peak bar velocity at light loads, but it is insufficient to induce such effect on higher loads.

Imaging Brain Glx Dynamics in Response to Pressure Pain Stimulation: A 1H-fMRS Study.

Glutamate signalling is increasingly implicated across a range of psychiatric, neurological and pain disorders. Reliable methodologies are needed to probe the glutamate system and understand glutamate dynamics in vivo. Functional magnetic resonance spectroscopy (1H-fMRS) is a technique that allows measurement of glutamatergic metabolites over time in response to task conditions including painful stimuli. In this study, 18 healthy volunteers underwent 1H-fMRS during a pressure-pain paradigm (8 blocks of REST and 8 blocks of PAIN) across two separate sessions. During each session, estimates of glutamate + glutamine (Glx), scaled to total creatine (tCr = creatine + phosphocreatine) were determined for averaged REST and PAIN conditions within two separate regions of interest: the anterior cingulate cortex (ACC) and dorsal ACC (dACC). A two-way repeated measures analysis of variance determined a significant main effect of CONDITION (p = 0.025), with higher Glx/tCr during PAIN compared to REST across combined sessions, in the dACC ROI only. However, increases in dACC Glx/tCr during PAIN compared to REST showed limited reliability and reproducibility across sessions. Future test-retest 1H-fMRS studies should examine modified or alternative paradigms to determine more reliable methodologies to challenge the glutamate system that may then be applied in patient groups and experimental medicine studies.

Does exposure to socially endorsed food images on social media influence food intake?

Social norms can influence the consumption of high and low energy-dense (HED/LED) snack foods. Such norms could be communicated via social media, however, there is little experimental research investigating this possibility. This laboratory study aimed to investigate the acute effect of socially endorsed social media posts on participants' eating behaviour. Healthy women students (n = 169; mean age = 20.9; mean BMI = 23.3) were assigned to either a HED, LED or control condition, where they viewed three types of images (HED foods, LED foods and interior design as control), but only one type was socially endorsed (e.g. in the control condition, only interior design images were socially endorsed). Participants completed questionnaires and were also provided a snack buffet of grapes and cookies. One-way ANOVA revealed a significant main effect of condition on participants’ relative consumption of grapes (percentage of grapes consumed out of total food intake), for both grams and calories consumed (both ps < .05). Follow-up t-tests revealed that participants consumed a larger proportion of grapes (grams and calories) in the LED condition vs HED condition (all ps < .05), and a larger proportion of calories from grapes in the LED compared to control condition (p < .05). These findings suggest that exposure to socially endorsed images of LED food on social media could nudge people to consume more of, and derive more calories from these foods in place of HED foods. Further research is required to examine the potential application of these findings.

Shoulder Joint Position Sense Can Be Reduced by Sensory Reference Frame Transformations.

Joint position sense (JPS) is commonly evaluated using an angle replication protocol with vision occluded. However, multiple sources of sensory information are integrated when moving limbs accurately, not just proprioception. The purpose of this study was to examine different availability of vision during an active JPS protocol at the shoulder. Specifically, the effects of four conditions of vision availability were examined for three target shoulder elevation angles (50°, 70° & 90°): vision occluded continuously (P-P); vision available continuously (VP-VP); vision occluded only during target memorization (P-VP); and vision occluded only during target position replication (VP-P). There were 18 participants (M age = 21, SD = 1 years). We used separate repeated ANOVAs to examine the effect of condition and target angle on participants' absolute error (AE, a measure of accuracy) and constant error (CE, a measure of directional bias). We found a significant main effect for condition and angle for both dependent variables (p < 0.01), and follow-up analysis indicated that participants were most accurate in the VP-VP condition and least accurate in the P-VP condition. Further follow-up analysis showed that accuracy improved with higher target elevation angles, consistent with previous research findings. Constant error results were similar, as there was a prominent tendency to overshoot the target. Unsurprisingly, participants performed best at the angle replication protocol with their eyes open. However, while accuracy was reduced when vision was occluded during target memorization, it was restored during target replication. This finding may have indicated an accuracy cost due to introduced noise when transforming sensory information from a proprioceptive reference frame into a visual reference frame.

Contrast Tempo of Movement and Its Effect on Power Output and Bar Velocity During Resistance Exercise.

In this study, we examined the impact of contrast movement tempo (fast vs. slow) on power output and bar velocity during the bench press exercise. Ten healthy men (age = 26.9 ± 4.1 years; body mass = 90.5 ± 10.3 kg; bench press 1RM = 136.8 ± 27.7 kg) with significant experience in resistance training (9.4 ± 5.6 years) performed the bench press exercise under three conditions: with an explosive tempo of movement in each of three repetitions (E/E/E = explosive, explosive, explosive); with a slow tempo of movement in the first repetition and an explosive tempo in the next two repetitions (S/E/E = slow, explosive, explosive); and with a slow tempo of movement in the first two repetitions and an explosive tempo in the last repetition (S/S/E = slow, slow, explosive). The slow repetitions were performed with a 5/0/5/0 (eccentric/isometric/concentric/isometric) movement tempo, while the explosive repetitions were performed with an X/0/X/0 (X- maximal speed of movement) movement tempo. During each experimental session, the participants performed one set of three repetitions at 60%1RM. The two-way repeated measures ANOVA showed a statistically significant interaction effect for peak power output (PP; p = 0.03; η2 = 0.26) and for peak bar velocity (PV; p = 0.04; η2 = 0.24). Futhermore there was a statistically significant main effect of condition for PP (p = 0.04; η2 = 0.30) and PV (p = 0.02; η2 = 0.35). The post hoc analysis for interaction revealed that PP was significantly higher in the 2nd and 3rd repetition for E/E/E compared with the S/S/E (p < 0.01 for both) and significantly higher in the 2nd repetition for the S/E/E compared with S/S/E (p < 0.01). The post hoc analysis for interaction revealed that PV was significantly higher in the 2nd and 3rd repetition for E/E/E compared with the S/S/E (p < 0.01 for both), and significantly higher in the 2nd repetition for the S/E/E compared with the S/S/E (p < 0.01). The post hoc analysis for main effect of condition revealed that PP and PV was significantly higher for the E/E/E compared to the S/S/E (p = 0.04; p = 0.02; respectively). The main finding of this study was that different distribution of movement tempo during a set has a significant impact on power output and bar velocity in the bench press exercise at 60%1RM. However, the use of one slow repetition at the beginning of a set does not decrease the level of power output in the third repetition of that set.